Current date: 2026-06-16

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Datestamp limit: 2026-06-16 (0 days ago)

Created/updated limit: 2026-06-09 (7 days ago)

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OAI-PMH request: http://export.arxiv.org/oai2?verb=ListRecords&from=2026-06-16&until=2026-06-16&set=physics&metadataPrefix=arXiv

Scoring abstracts

Number of records retrieved: 1243

Keyword score statistics

score 10 -- 1 abstracts

score 9 -- 2 abstracts

score 8 -- 1 abstracts

score 7 -- 1 abstracts

score 6 -- 1 abstracts

score 5 -- 5 abstracts

score 4 -- 6 abstracts

score 3 -- 15 abstracts

score 2 -- 33 abstracts

in total -- 65 abstracts

Articles that appeared on 2026-06-16

[abstract 1 / 65] Wow! (score: 10)
arXiv:2606.15759 [pdf, ps, other]

Title: A Universal Physics Defining the Radiation Spectra of Blazars and Gamma-Ray Bursts

Authors: Z. Lucas Uhm, Sang-Sung Lee, Bing Zhang, Judith Racusin, Bindu Rani, Myungshin Im, Aeree Chung, Hyung Mok Lee,

Comments: ApJ published, 9 pages, 4 figures, 1 table

Subjects: astro-ph.HE

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

Blazars and GAMMA-RAY BURSTs (GRBs) are both cosmic beacons of extreme energy release powered by RELATIVISTIC JETs. However, they originate from tremendously different environments. Blazars are the sustained powerhouses driven by supermassive BLACK HOLEs at galactic centers, whereas GRBs are the transient death signals of massive stars or merging compact objects. Here we show that, despite the enormous differences, a universal physics defines the radiation spectra of BLAZARs and GRBs. The BLAZAR spectrum is well described by a "log-parabola" function. Employing a simple toy model with a single optically-thin region of a decreasing MAGNETic field, we produce the log-parabola spectrum very naturally for BLAZARs. We find that the BLAZAR spectrum is shaped by the "cooling physics" of RELATIVISTIC electrons in the fast-cooling regime, which we identify as the universal physics since we previously showed that the fast-cooling physics of electrons with a decreasing MAGNETic field also explains the mysterious low-energy spectral index of the gamma-ray spectrum for a majority of GRBs. This fast-cooling physics of electrons likely nails down the physical origin underlying the universal scaling of the JET energetics between BLAZARs and GRBs, which was observationally suggested more than a decade ago. We highlight that the spectrum shaper in both BLAZARs and GRBs is the cooling physics, not the acceleration mechanism. This finding is conventional-belief-defying and may open up new avenues in a wide range of astrophysics.

[abstract 2 / 65] Wow! (score: 9)
arXiv:2512.19259 [pdf, ps, other]

Title: Projected sensitivity of CTAO to axion-like particles from BLAZARs with a machine learning approach

Authors: Francesco Schiavone, Leonardo Di Venere, Francesco Giordano,

Comments: Accepted for publication in EPJC

Subjects: astro-ph.HE

Created: 2026-06-11; Updated: 2026-06-16; Datestamp: 2026-06-16

Blazars are a class of ACTIVE GALACTIC NUCLEi, supermassive BLACK HOLEs located at the centres of distant galaxies characterised by strong emission across the entire electroMAGNETic spectrum, from radio waves to gamma rays. Their RELATIVISTIC JETs, closely aligned to the line of sight from Earth, are a rich and complex environment, characterised by the presence of strong MAGNETic fields over parsec-scale lengths. Owing to their cosmological distance from Earth, these sources serve as ideal targets to probe non-standard gamma-ray propagation. In particular, axion-like particles (ALPs) could be detected through their coupling to photons, which enables ALP-photon conversions in external MAGNETic fields, leading to distinct signatures in the BLAZARs' gamma-ray spectra. In this work, we estimate the potential of the Cherenkov Telescope Array Observatory (CTAO) to constrain the ALP parameter space by simulating observations of two bright BLAZARs, Mrk 501 and PKS 2155$-$304. We obtain projected $2σ$ exclusion regions, demonstrating that CTAO will be able to consistently improve present limits thanks to its greater energy resolution and point-source sensitivity with respect to present ground-based gamma-ray telescopes. In addition to the standard statistical technique based on the likelihood ratio test, we further demonstrate the application of a new method based on machine learning classifiers, which may help in reducing the effect of systematic model-dependent uncertainties in future ALP searches.

[abstract 3 / 65] Wow! (score: 9)
arXiv:2606.15365 [pdf, ps, other]

Title: PEARLS: NUSTAR and XMM-Newton Extragalactic Survey of the JWST North Ecliptic Pole Time Domain Field VI: Multiwavelength SED Analysis

Authors: Rafael Ortiz, Francesca Civano, Rogier A. Windhorst, S. P. Willner, Gibson B. Bowling, Timothy Carleton, Seth H. Cohen, Samantha Creech, Vicente Estrada-Carpenter, Brenda L. Frye, Norman A. Grogin, Heidi B. Hammel, Timothy Heckman, Rachel Honor, Rolf A. Jansen, Satoshi Kikuta, Anton M. Koekemoer, Madeline A. Marshall, Sylvia Mesicek, Mar Mezcua, Stefanie N. Milam, Simon D. Mork, Rosalia O'Brien, Payaswini Saikia, Ross M. Silver, Brent M. Smith, Hyewon Suh, Christopher N. A. Willmer, Haojing Yan, Xiurui Zhao,

Comments: 27 pages, 15 figures, 3 tables

Subjects: astro-ph.GA astro-ph.HE

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

We model spectral energy distributions of 261 X-ray sources to $z \sim 5$ in the North Ecliptic Pole Time Domain Field, extending prior XMM-Newton and NUSTAR analyses. Using the star-forming main sequence (SFMS) and BLACK HOLE accretion rate (BHAR) frameworks, we find that SFRs generally lie below the SFMS while most BHARs exceed the population average, as expected for X-ray-selected samples. There is a strong correlation ($ρ=+0.73$) between SFR relative to the SFMS and specific AGN luminosity, $L_{AGN}/M_*$; galaxies with the highest $L_{AGN}/M_*$ exist at or above the SFMS. X-ray luminosity correlates with SFR ($ρ=+0.80$), revealing a star-forming and X-ray luminous "cold QUASAR" population consistent with dramatic, short-timescale accretion episodes. Low-mass galaxies show BHARs well above the population averaged value for their mass whereas high-mass galaxies' SMBHs accrete at the population averaged BHAR, suggesting "growth spurt" and "maintenance-mode" accretion, respectively. Traditional AGN classifications (obscured, unobscured, or radio-loud) do not reveal these distinctions, demonstrating the X-ray perspective's unique ability to identify rare AGN phases that are critical for the instantaneous link between galaxies and their SMBHs.

[abstract 4 / 65] Wow! (score: 8)
arXiv:2605.12931 [pdf, ps, other]

Title: Jets from Scratch: Dynamo-Generated Poloidal Magnetic Fields in 3D Collapsar Simulations

Authors: Ho-Sang Chan, Ore Gottlieb, Jonatan Jacquemin-Ide, Matteo Cantiello, Mathieu Renzo,

Comments: 24 pages, 10 figures, submitted to APJL

Subjects: astro-ph.HE gr-qc

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

The origin of the large-scale poloidal MAGNETic field required to power RELATIVISTIC JETs in collapsars remains uncertain. While such a field may be inherited during PNS collapse, the efficiency of this process is unclear, motivating an in situ mechanism to generate poloidal fields out of the predominantly toroidal fields produced by stellar differential rotation. We present the first 3D general-RELATIVISTIC MAGNETohydrodynamic collapsar simulations initialized with toroidal MAGNETic field profiles that closely follows those of pre-collapse stellar models. As the toroidal field in the disk becomes dynamically important, it seeds the dynamo, producing coherent poloidal MAGNETic loops that appear at $\sim \mathcal{O}(100)$ gravitational radii and are then advected inward along paths that may deviate from the disk midplane. The resulting poloidal fields thread the BLACK HOLE (BH) and launch highly variable, wobbling RELATIVISTIC JETs on timescales of order seconds, with the onset depending on the initial MAGNETic field and the plasma circularization radius. Although the JETs are highly variable and misaligned with the BH spin axis, they sustain $\gtrsim 10^{50}\,\mathrm{erg\,s^{-1}}$, comparable to that inferred for long GAMMA-RAY BURSTs (LGRB). We identify MAGNETic-flux inversions driven by the stochastic dynamo, leading to the formation of striped JETs that could be imprinted in LGRB light curves. These results demonstrate that accretion-disk dynamos provide a robust pathway for JET production in collapsars across a broad range of progenitors.

[abstract 5 / 65] Wow! (score: 7)
arXiv:2606.15676 [pdf, ps, other]

Title: Gamma-Ray Periodicity in Jetted AGN: Revisiting Periodicity Candidates with >17 years of FERMI-LAT Data

Authors: P. Peñil, A. Rico, A. Domínguez, M. Ajello, S. Buson, S. Adhikari,

Comments: 27 pages, 15 figures, and 10 tables

Subjects: astro-ph.HE

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

We reanalyze previously reported gamma-ray periodicity candidates in JETted ACTIVE GALACTIC NUCLEi using more than 17 years of FERMI-LAT observations. The updated data provide a robust test of whether earlier results correspond to persistent periodic behavior, to transient quasi-periodic oscillations (QPOs), or to fluctuations produced by stochastic variability. We apply complementary timing methods, including the Generalized Lomb-Scargle periodogram, Phase Dispersion Minimization, and Singular Spectrum Analysis, and estimate the test statistics using artificial light curves generated from different variability models, including simple and bending power-law power spectral densities, as well as ARIMA and ARFIMA autoregressive models. We find that most previously proposed candidates in literature are not confirmed when the longer baseline is considered, indicating that many reported periods were likely driven by limited temporal coverage and red-noise variability or transient QPO-like features rather than persistent periodic behavior. Only eight sources retain hints of periodic behavior at the >2sigma local test statistics. Among them, PG 1553+113 and S5 1044+71 remain the most significant cases, with local test statistics above 3sigma, and with a global significance consistent with ~0sigma (because of the large trial factor). In addition, we assess predictions from previous studies as an independent test of the proposed periods and find that some are consistent with the new observations.

[abstract 6 / 65] Yes (score: 6)
arXiv:2606.16228 [pdf, ps, other]

Title: Discovery of Unusual Jet Orientation Variations in the MicroQUASAR GRS 1915+105

Authors: Xi Yan, Lang Cui, Wu Jiang, Zhen Yan, Sándor Frey, Sergei Trushkin, Timur Mufakharov, Ruchika Dhaka, Shuangjing Xu,

Comments: ApJL in press

Subjects: astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We report large day-timescale variations in the orientation of the southeast--northwest JET in the prototype microQUASAR GRS 1915+105. These results are based on three-epoch East Asia VLBI Network (EAVN) observations at 6.7 GHz, obtained during giant radio flares in 2025 detected by the RATAN-600 monitoring program. Our observations reveal the smallest position angle (PA) of $118^\circ \pm 7^\circ$ ever measured for the JET in GRS 1915+105, which increases to $152^\circ \pm 2^\circ$ within 37 days. Based on the literature results, we further suggest that the JET orientation has exhibited significant variations over a PA range of $118^\circ$--$188^\circ$ since 2023. This unusual JET orientation behavior in GRS 1915+105 during its current X-ray-obscured state may arise from a warped, precessing inner accretion disk, as implied by recent X-ray spectroscopy. Notably, one image reveals a peculiar morphology in GRS 1915+105, which likely indicates lateral spreading of the approaching southeast JET. Future observations are essential to clarify the issues raised in this work.

[abstract 7 / 65] Yes (score: 5)
arXiv:2606.15388 [pdf, ps, other]

Title: Comparison of X-ray Emission Properties of TDEs and Soft Flares from AGNs

Authors: Samaresh Mondal, K. Decker French, Jason T. Hinkle,

Comments: 19 pages, 15 figures, accepted for publication in ApJ

Subjects: astro-ph.HE

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

X-ray flaring activity from ACTIVE GALACTIC NUCLEi (AGNs) may mimic the expected emission from tidal disruption events (TDEs), thus contaminating TDE searches. To compare X-ray emission properties between TDEs and AGNs, we cross-match publicly available XMM-Newton and SWIFT-XRT point source catalogs with the Million Quasars Catalog and optically selected TDEs. We find that AGNs tend to become softer with a similar hardness ratio (HR) value as TDEs during their flaring events. The soft HRs during flaring events in these AGNs are driven by the emergence of a blackbody-like component below $\sim$2 keV, likely associated with the soft X-ray excess, as well as the continuum emission becoming steeper with the increase of accretion rate. We find 2.5% in XMM-Newton (23 out of 920) and 4.4% in SWIFT-XRT (179 out of 4089) AGNs display flares with peak count rate $>$$2σ$ from the median count rate and peak HR$<$$-0.75$. The rate of such flares in XMM-Newton and SWIFT-XRT is (1.1-2.5)$\times10^{-3}\rm\ galaxy^{-1}\ yr^{-1}$ and (0.9-2.0)$\times10^{-3}\rm\ galaxy^{-1}\ yr^{-1}$, respectively. We also estimate the rate of flares with a maximum flux change (peak/min) of $>20\times$ over on a rest-frame time scale of two years or more with a HR$<$$-0.75$ at peak to be (4.7-11.0)$\times10^{-5}\rm\ galaxy^{-1}\ yr^{-1}$ and (3.1-7.1)$\times10^{-5}\rm\ galaxy^{-1}\ yr^{-1}$ in XMM-Newton and SWIFT-XRT, respectively. Finding an optical or infrared counterpart may help to identify these flaring AGNs. We confirm 61% and 79% of flaring sources from XMM-Newton and SWIFT-XRT, respectively, as AGNs through variability in ZTF light curves or a WISE $W1$$-$$W2$$>$0.8 mag color cut.

[abstract 8 / 65] Yes (score: 5)
arXiv:2606.16297 [pdf, ps, other]

Title: Tomography of the gamma-ray sky from cross-correlation with DESI DR2 and unWISE galaxies

Authors: Alex Krolewski, Neal Dalal, Will J. Percival, Elena Pinetti, J. Aguilar, S. Ahlen, S. BenZvi, D. Bianchi, D. Brooks, T. Claybaugh, A. Cuceu, A. de la Macorra, P. Doel, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, E. Gaztanaga, S. Gontcho A Gontcho, G. Gutierrez, J. Guy, D. Huterer, M. Ishak, R. Joyce, A. Kremin, O. Lahav, M. Landriau, L. Le Guillou, M. E. Levi, M. Manera, A. Meisner, R. Miquel, A. D. Myers, S. Nadathur, F. Prada, I. Perez-Rafols, G. Rossi, E. Sanchez, D. Schlegel, J. Silber, D. Sprayberry, G. Tarle, B. A. Weaver,

Comments: 26 pages, 11+9 figures

Subjects: astro-ph.CO astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We study the origin of extragalactic gamma-ray emission observed by FERMI-LAT, using the cross-correlation of the gamma-ray sky with maps of large-scale structure provided by the DESI and unWISE surveys. Tomographic cross-correlation reveals the bias-weighted redshift distributions of gamma-ray sources. We first illustrate this method by cross-correlating detected gamma-ray point sources with large-scale structure. We find a significant cross-correlation and infer a point source redshift distribution broadly consistent with the distribution of identified optical counterparts previously reported in the literature, as well as a similar linear bias ($b \approx 2$) to massive galaxies that host bright ACTIVE GALACTIC NUCLEi. We then study the clustering of the FERMI unresolved gamma-ray background (UGRB), both in auto-correlation and in cross-correlation with large-scale structure. We detect the cross-correlation of the UGRB and LSS at $\sim 10σ$ in total, with highly significant detections from both DESI and unWISE. Our measurements suggest that the redshift distribution of the UGRB is broadly consistent with the redshift distribution of detected point sources. Additionally, we find a relatively weak amplitude for the cross-correlation with large-scale structure at z < 2, suggesting a significant fraction of the UGRB does not come from z < 2 large-scale structure. A natural candidate is contamination of from residual Galactic emission, and our best estimate of the contamination level derived from the UGRB auto-spectrum suggests that the mean bias of UGRB sources is indeed quite similar to the bias of detected FERMI point sources. However, we cannot exclude additional emission from gamma-ray sources at high redshift, z > 2, and we suggest that cross-correlation with tracers at z > 2, including CMB lensing, would be the ideal way to determine the fraction of z > 2 emission.

[abstract 9 / 65] Yes (score: 5)
arXiv:2606.16363 [pdf, ps, other]

Title: The Effect of Anomalous Resistivity on Tearing Instability

Authors: D. Tsiklauri,

Comments: submitted for publication

Subjects: physics.plasm-ph astro-ph.SR physics.space-ph

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We study the modification of classical tearing instability due to anomalous resistivity by incorporating a variable, second-order resistivity model into the resistive MAGNETohydrodynamics (MHD) framework. We evaluate the resulting multi-order perturbation modifications and boundary-layer scaling laws. By extending the perturbation analysis to second-order accuracy, we resolve localized spatial singularities ($δ$ and $δ'$) at the threshold boundary. These singularities generate unexpected matching jump conditions, demonstrating an early-stage phase-slip layer that forces a hyperbolic, time-dependent growth rate divergence prior to macroscopic saturation. Physical estimates for fusion devices and solar flares prove that this multi-order approach triggers an abrupt transition into the explosive RECONNECTion regime, offering an exact analytical resolution to the long-standing solar and tokamak flare/disruption ``trigger problem,'' respectively. Finally, a comparative analysis using a truncated linear expansion of the threshold model regularizes the singular behavior, confirming that the explosive finite-time singularity is uniquely driven by the higher-order non-linear current feedback.

[abstract 10 / 65] Yes (score: 5)
arXiv:2606.16805 [pdf, ps, other]

Title: Detection and luminosity-dependent evolution of the high-energy hump in the Be/X-ray pulsar 1A 1118-61

Authors: Alexander Salganik, Sergey S. Tsygankov, Sergey V. Molkov, Hua Xiao, QingChang Zhao, Long Ji, Alexander A. Mushtukov, Igor Yu. Lapshov, Alexander A. Lutovinov, Alexey Yu. Tkachenko, Hua Feng, Shuang-Nan Zhang, Xiao-Bo Li, Shu Zhang, Juri Poutanen,

Comments: 9 pages, 6 figures, 2 tables. Submitted to A&A

Subjects: astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Context. Accreting X-ray pulsars exhibit strong luminosity-dependent changes in their broad-band spectra. At high luminosities, their spectra are usually described by a power-law continuum with a high-energy cutoff, whereas low-luminosity observations have revealed a two-hump spectral morphology. Aims. We aim to trace the luminosity-dependent spectral evolution of the Be/X-ray pulsar 1A 1118-61 and to constrain the luminosity range over which the high-energy hump becomes clearly distinguishable. Methods. We use dense SRG/ART-XC and Insight-HXMT monitoring, together with three broad-band NUSTAR observations of 1A 1118-61 obtained during its 2026 outburst, to trace the luminosity-dependent evolution of the spectral shape. The ART-XC data follow the decay from a peak luminosity of $\simeq7\times10^{37}$ erg s$^{-1}$ to a low-luminosity plateau at $\simeq(3$-$8)\times10^{35}$ erg s$^{-1}$ in the 4-35 keV band, while the NUSTAR observations provide broad-band spectra during the bright phase, the decline, and the plateau. We describe the continuum with a phenomenological two-component Comptonization model. Results. As the source faded, the broad-band continuum developed a distinct high-energy hump, giving rise to a two-hump morphology with broad maxima near $\sim$10 keV and $\sim$30-40 keV. The ART-XC monitoring constrains the transition to this morphology to $L_{4-35}\simeq(0.8$-$1.8)\times10^{36}$ erg s$^{-1}$. We also find a break in the luminosity dependence of the flux ratio between the two continuum humps around $L_{4-35}\sim10^{37}$ erg s$^{-1}$. A cyclotron line at $\simeq55$ keV is detected in the high-energy hump, with no significant luminosity dependence of its centroid energy. We discuss this behavior in the context of resonant interactions in the MAGNETized accretion flow.

[abstract 11 / 65] Yes (score: 5)
arXiv:2606.16818 [pdf, ps, other]

Title: From Morphology to Variability: Radiative Cooling Effects on Horizon-Scale Polarization in Two-Temperature GRMHD Simulations

Authors: Jane SiNan Long, Akhil Uniyal, Mingyuan Zhang, Yosuke Mizuno, Ziri Younsi, Christian M. Fromm, Kinwah Wu,

Comments: Accepted by MNRAS

Subjects: astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Polarization signatures provide a new window to investigate the effects of radiative cooling in the horizon-scale accretion flows. Morphology and variability of POLARIZATION offer quantifiable diagnostics of how cooling modifies the polarised emission from two-temperature GRMHD simulations. We find that cooling enhances the effective Faraday depth, leading to stronger large-scale Faraday scrambling, particularly at higher accretion rates. In contrast, dePOLARIZATION associated with higher-order photons is comparable between cooling and non-cooling models. Radiative cooling also increases the intrinsic asymmetry in both the ring structure and the POLARIZATION pattern. This effect is quantified by enhanced power in non-axisymmetric azimuthal modes ($β_m$, $m \neq 2$) relative to the dominant quadrupolar component $β_2$. The increased asymmetry is directly linked to stronger temporal variability of the POLARIZATION angle $\angleβ_2$, including frequent sign reversals that are absent in non-cooling models. The radial profile of $\angle β_2$ further localizes the physical origin of these effects, distinguishing regions dominated by Faraday rotation from those influenced by photon ring contributions, and providing a clear separation between cooling and non-cooling cases. Additional tests including a non-thermal electron population indicate that the POLARIZATION structure at 230 GHz is largely insensitive to the detailed form of the electron distribution functions. Our results demonstrate that horizon-scale POLARIZATION asymmetry, variability, and radial structure encode robust signatures of radiative cooling. These findings highlight the diagnostic power of time-resolved polarimetry and high-resolution imaging for constraining radiative processes in BLACK HOLE accretion flows with EHT-like observations.

[abstract 12 / 65] Yes (score: 4)
arXiv:2212.07094 [pdf, ps, other]

Title: Evidence of High-latitude Emission in the Prompt Phase of GRBs: How Far from the Central Engine are the GRBs Produced?

Authors: Z. Lucas Uhm, Donggeun Tak, Bing Zhang, Judith Racusin, Daniel Kocevski, Sylvain Guiriec, Bin-Bin Zhang, Julie McEnery,

Comments: ApJL published, 8 pages, 4 figures

Subjects: astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

One of the difficulties in nailing down the physical mechanism of GAMMA-RAY BURSTs (GRBs) comes from the fact that there has been no clear observational evidence on how far from the central engine the prompt gamma-rays of GRBs are emitted. Here we present a simple study addressing this question by making use of the "high-latitude emission" (HLE). We show that our detailed numerical modeling exhibits a clear signature of HLE in the decaying phase of "broad pulses" of GRBs. We show that the HLE can emerge as a prominent spectral break in $F_ν$ spectra and dominate the peak of $νF_ν$ spectra even while the "line-of-sight emission" (LoSE) is still ongoing. This finding provides a new view of HLE emergence since it has been believed so far that the HLE can show up and dominate the spectra only after the LoSE is turned off. We remark, however, that this "HLE break" can be hidden in some broad pulses, depending on the proximity between the peak energies of the LoSE and the HLE. Therefore, this new picture on HLE emergence explains both detection and non-detection of HLE signature in observations of broad pulses. Also, we present three examples of FERMI-GBM GRBs with broad pulses that exhibit the HLE signature. We show that their gamma-ray emitting region should be located at $\sim 10^{16}$ cm from the central engine, which places a constraint on the GRB models.

[abstract 13 / 65] Yes (score: 4)
arXiv:2604.02901 [pdf, ps, other]

Title: Tearing Driven Reconnection: Energy Conversion Involving Firehose Kinetic Instabilities (2D Hybrid Möbius Simulations)

Authors: Etienne Berriot, Petr Hellinger, Olga Alexandrova, Alexandra Alexandrova, Pascal Démoulin,

Comments: 23 pages, 13 figures

Subjects: astro-ph.SR physics.plasm-ph

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

This study focuses on energy conversion related to tearing-driven MAGNETic RECONNECTion in the context of weakly collisional astrophysical plasmas. We present results from a two-dimensional hybrid particle-in-cell simulation employing novel periodic conditions with a topology akin to the Möbius strip, which double the computation efficiency as compared to regular periodic conditions. Evaluation of the ion electric work rate ($\mathbf{j}_i \cdot \mathbf{E}$) and pressure strain interaction ($\mathbf{P}_i : \mathbf{\nabla u}_i)$ shows that most of the energy conversion occurs during the nonlinear phase of the instability, where MAGNETic energy is transferred towards ion kinetic energy (bulk outflows) and internal energy (heating). These energy conversion rates are of the same order but inhomogeneous. Heating predominantly occurs within the MAGNETic islands, while near the X-points, nearly the same amount of MAGNETic energy is transferred to bulk plasma flow and heating. The RECONNECTed plasma moreover exhibits an ion temperature higher parallel than perpendicular to the local MAGNETic field $\mathbf{B}$. This temperature anisotropy is sustained by the islands' contraction, but eventually gets regulated by kinetic firehose instabilities (parallel and oblique), and/or firehose-like processes, whose main effect is to redistribute the internal energy from the parallel to the perpendicular direction.

[abstract 14 / 65] Yes (score: 4)
arXiv:2604.11698 [pdf, ps, other]

Title: Interaction of Strong ElectroMAGNETic Waves with UnMAGNETized Pair Plasmas

Authors: Navin Sridhar, Emanuele Sobacchi, Lorenzo Sironi, Masanori Iwamoto, Daniel Grošelj, Brandon K. Russell,

Comments: Accepted for publication in Physical Review Letters; 8 pages, 4 figures

Subjects: physics.plasm-ph astro-ph.HE physics.class-ph physics.optics physics.space-ph

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

We investigate analytically and numerically the interaction of strong electroMAGNETic waves with unMAGNETized pair plasmas. We show that the interaction is governed by a single nonlinearity parameter, $\varepsilon_{\rm p}$, defined as the ratio of the wave strength parameter to the wave frequency in units of the plasma frequency (with both frequencies measured in the plasma rest frame prior to the interaction). When $\varepsilon_{\rm p}<1$, the number of wavelengths that propagate through the plasma without attenuation from induced Compton scattering is approximately $\varepsilon_{\rm p}^{-2/3}$. This attenuation can imprint sub-structures as narrow as a few wavelengths on the pulse profile. When $\varepsilon_{\rm p}>1$, the electroMAGNETic pulse acts as a RELATIVISTIC piston and drives a shock into the plasma. Our results establish a framework for the interaction of strong electroMAGNETic waves with pair plasmas, a process relevant for intense radio pulses from neutron stars and for next-generation pair plasma experiments at multi-petawatt LASER facilities.

[abstract 15 / 65] Yes (score: 4)
arXiv:2605.27510 [pdf, ps, other]

Title: The strength of Type-C quasi-periodic oscillations in BLACK HOLE X-ray binaries correlates with the JET inclination

Authors: F. M. Vincentelli, N. Bollemeijer, A. Veledina, D. Altamirano, Q. Bu, F. Carotenuto, P. Casella, Y. Cavecchi, R. Ma, G. Marcel, G. Mastroserio, S. Motta, L. Zhang,

Comments: Accepted for publication on MNRAS; 9 pages, 6 Figures. Online data repository: https://github.com/fvince90/QPO-rms-vs-Jet-Inclination/tree/main

Subjects: astro-ph.HE

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

X-ray quasi-periodic oscillations (QPOs) are a characteristic feature of low-mass X-ray binaries (LMXBs). These oscillations have been studied for decades and revealed a rich and complex phenomenology that is still not fully understood. RXTE archival studies have shown that the amplitude of these oscillations differs significantly between BLACK HOLEs (BH) with high or low inclination. Yet, the actual dependence on inclination has never been adequately estimated. Thanks to the improvement of inclination measurements through radio observations and the recent observations by the HXMT satellite, we quantified for the first time the dependence of Type-C QPO amplitudes on the JET inclination of individual BH LMXBs. Our analysis reveals the presence of a significant linear correlation up to 8 Hz, strengthening the case for a ''geometrical'' origin of the QPOs. In addition, for a given QPO frequency, we observe systematically lower amplitudes during the decay of outbursts compared to the rise. This data collection represents a key benchmark for any QPO model. Our comparison with the predictions from a precessing hot flow shows that the amplitude of the QPOs can be reproduced by this scenario if the spin-orbit misalignment is at least $\approx$10-15$^\circ$.

[abstract 16 / 65] Yes (score: 4)
arXiv:2606.15674 [pdf, ps, other]

Title: Mrk 382: A Narrow-line Seyfert 1 Galaxy with Recurrent X-ray State Transitions

Authors: Yanli Ai, Wenfeng Wen, Liming Dou, Jiahua Wu, Chen Hu, Tinggui Wang, Xiaohui Yang, Jing Wang, Xue-Bing Wu, Qiusheng Gu, Xinwen Shu, Pudu, Jian-Min Wang,

Comments: ApJ, submitted

Subjects: astro-ph.HE astro-ph.GA

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

We report recurrent X-ray state transitions in the nearby narrow-line Seyfert~1 galaxy Mrk~382 using multi-epoch observations from \textit{SWIFT}, \textit{Chandra}, \textit{XMM-Newton}, and eROSITA, together with archival ultraviolet, optical, and infrared data. The 0.3--2 keV flux varies by nearly an order of magnitude over the past $\sim15$ yr, with multiple transitions between bright and faint states. The source brightened by a factor of $\sim10$ between the 2010 \textit{Chandra} observation and the 2011 \textit{XMM-Newton} high state, then declined by $\sim6$--7 to a low state in 2019, followed by renewed brightening in recent \textit{SWIFT} monitoring. The X-ray spectrum shows strong state-dependent evolution, changing from a steep high-state continuum ($Γ=2.32\pm0.04$) to a much harder low-state spectrum ($Γ=1.39\pm0.06$). The low-state spectrum also exhibits a narrow Fe K$α$ line with an equivalent width of $\sim330$ eV. Reflection modeling indicates that the low-flux state is strongly reflection dominated, with the reflection fraction increasing from $R_{\rm refl}\sim4$ to $\sim34$, consistent with a compact corona subject to strong light-bending effects. The ultraviolet emission broadly follows the long-term X-ray variability but with smaller amplitude, while the optical and mid-infrared bands vary more mildly. Despite the dramatic X-ray variability, Mrk~382 does not enter an extreme X-ray-weak state, and we did not detect clear optical spectral-type changes based on the currently available observations. Mrk~382 is therefore a rare nearby Seyfert galaxy undergoing recurrent X-ray state transitions, providing a valuable laboratory for studying changing coronal geometry and multiwavelength AGN variability.

[abstract 17 / 65] Yes (score: 4)
arXiv:2606.16796 [pdf, ps, other]

Title: A HINSA view of cosmic-ray ionization in IC 348 and NGC 1333: evidence for a strong low-energy cosmic-ray disparity

Authors: Gan Luo, Marco Padovani, Daniele Galli, Thomas G. Bisbas, Brandt A. L. Gaches, Di Li, Marko Krčo, Ningyu Tang,

Comments: 12pages, 12 figures, A&A accepted

Subjects: astro-ph.GA astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

The cosmic-ray ionization rate (CRIR) is one of the fundamental parameters influencing the chemical and dynamical evolution of molecular clouds. Although observations in recent years have revealed high CRIR values in massive star-forming regions and in the vicinity of protostars, the sources and acceleration mechanisms of COSMIC RAYs remain uncertain. In this work, we present our new estimates of CRIR using the H\,{\sc i} narrow self-absorption (HINSA) technique towards two nearby low-mass star-forming clouds, IC~348 and NGC~1333. In both clouds, the CRIR decreases with increasing H$_2$ column density, but IC~348 exhibits values that are roughly an order of magnitude higher than those in NGC~1333. To interpret this contrast, we model the low-energy spectrum of CRs in a finite slab attenuation framework, using additional constraints from the high-energy CR spectrum inferred from FERMI $γ$-ray observations. The best-fit spectra reproduce the observed CRIR profiles and the contrast between IC~348 and NGC~1333 suggests an order of magnitude difference in low-energy CR populations, likely originating from local acceleration sources beyond protostars (e.g., stellar-wind termination shocks), and partly from the same sources responsible for the GeV $γ$-ray excess. Although uncertainties in cloud structure and gas density may affect the absolute CRIR values, they do not erase the pronounced disparity between the two regions.

[abstract 18 / 65] (score: 3)
arXiv:2409.06389 [pdf, ps, other]

Title: Contemporaneous Appearances of Auroral Spiral and Transpolar Arc: Polar UVI Observations and Global MHD Simulations

Authors: Motoharu Nowada, Yukinaga Miyashita, Aoi Nakamizo, Noora Partamies, Quan-Qi Shi,

Comments: Manuscript: 34 pages; Figures: 11 (the main part of the paper) + 11 (Appendix part of the paper)

Subjects: physics.space-ph astro-ph.SR physics.plasm-ph

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

A local vortex-structured aurora and a large-scale transpolar arc (TPA) were contemporaneously observed by the Polar ultraviolet imager (UVI) during the late recovery phase of a substorm, and the interplanetary MAGNETic field (IMF) BY and BZ were negative and negative-to-positive. The TPA grew along the dawnside auroral oval from the nightside to the dayside, and an auroral spiral and several spots were located azimuthally near the poleward edge of the nightside auroral oval. Both auroras had tailward elongated source regions with scales of ~30 RE (spiral) and more than ~45 RE (TPA). To examine their MAGNETospheric/ionospheric field-aligned current (FAC) profiles, we performed global MAGNETohydrodynamic (MHD) simulations, using two different types of code: Block-Adaptive-Tree Solar-wind Roe Upwind Scheme (BATS-R-US) and improved REProduce Plasma Universe (REPPU). Both MHD simulations reproduced the tailward elongated TPA-associated FAC structures. The spiral-associated FAC intensity was, however, approximately three orders of magnitude weaker than the TPA-associated FAC intensity. Only improved REPPU simulations replicated faint but continuous poleward extending streak-like structures without evident FACs, instead of the auroral spiral. GeoMAGNETic field measurements showed that the spiral had upward (from the ionosphere to the MAGNETosphere) FACs, and its appearance might be accompanied by ultra-low-frequency Pc5 waves. Our results suggest that 1) a local-scale spiral might be formed with much weaker MAGNETotail FACs than global-scale TPA-associated FACs, although the spiral source region is elongated tailward, and 2) a solar wind-MAGNETosphere-ionosphere coupling system with minimal or no significant substorm effects is required to form the spiral with the weak MAGNETotail FACs.

[abstract 19 / 65] (score: 3)
arXiv:2512.09641 [pdf, ps, other]

Title: Extreme-Lensing Signatures Revealed by Correlations of Simulated Black-Hole Movies

Authors: Barbora Bezděková, Shahar Hadar, George Wong, Maciek Wielgus,

Comments: 21 pages, 14 figures

Subjects: astro-ph.HE astro-ph.IM gr-qc

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

A BLACK HOLE's gravitational pull can deflect light rays to an arbitrary degree. As a result, any source fluctuation near the BLACK HOLE creates multiple lagged images on an observer's screen. For optically thin stochastic emission, these light echoes give rise to correlations of brightness fluctuations across time-dependent images (movies). The correlation pattern disentangles source-specific characteristics from universal features dictated by general relativity. This picture has motivated a proposal to use the two-point image correlation function as a probe of extreme gravitational lensing in upcoming black-hole imaging campaigns. In this work, we test the feasibility of this method by computing the two-point correlation function of brightness fluctuations in a black-hole movie of state-of-the-art realism. The movie is generated by ray tracing a general RELATIVISTIC MAGNETohydrodynamic simulation, which can then be blurred to any angular resolution. At an effective resolution expected to be achieved by next-generation terrestrial very-long-baseline interferometric arrays, these lensing signatures appear in neither time-averaged images nor light-curve autocorrelations. However, we demonstrate that they are clearly visible in the more fine-grained two-point image correlation function. Our positive findings motivate a more comprehensive investigation into the instrument specifications and inference techniques needed to resolve extreme lensing effects through correlations.

[abstract 20 / 65] (score: 3)
arXiv:2601.10573 [pdf, ps, other]

Title: Origins of the UV continuum and Balmer emission lines in Little Red Dots: observational validation of dense gas envelope models enshrouding the AGN

Authors: Yoshihisa Asada, Kohei Inayoshi, Qinyue Fei, Seiji Fujimoto, Chris Willott,

Comments: Accepted for publication in ApJL

Subjects: astro-ph.GA

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

We present a statistical study on the origins of the UV continuum and narrow/broad emission lines in little red dots (LRDs), presumably involving ACTIVE GALACTIC NUCLEi (AGNs). Leveraging all archived JWST/NIRSpec data, we build a sample of 27 spectroscopically-confirmed LRDs at $5AGNs without red optical continua (hereafter little blue dots; LBDs), and examine correlations between rest UV and the narrow/broad H$α$ luminosities in these populations. In LRDs, both narrow and broad H$α$ components are tightly correlated with the UV continuum, and the luminosity ratios are consistent with those in young starburst galaxies. In contrast, the UV to broad H$α$ ratios in LBDs closely match local unobscured AGNs and are statistically different from LRDs. The Ly$α$ occurrence rates and strengths do not differ between LRDs and LBDs and are comparable to normal star-forming galaxies. These results are consistent with a scenario where the central BH in LRDs is enshrouded by a dense opaque gas envelope -- in this model, the UV continuum as well as narrow and even broad H$α$ emissions are not powered by AGNs but predominantly by young massive stars surrounding the envelope, while the envelope radiates as a $\sim 5000$ K blackbody. As the envelope dissipates, direct AGN emission can emerge, potentially transforming LRDs into LBDs and marking the end of a short-lived phase of rapid BLACK HOLE growth.

[abstract 21 / 65] (score: 3)
arXiv:2605.27047 [pdf, ps, other]

Title: Canonical quantization of massive vector field in Schwarzschild BLACK HOLE background

Authors: Chandra Prakash, Rajesh Karmakar,

Comments: Few typos corrected, some citations added

Subjects: gr-qc

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We perform a first-principles canonical quantization of a massive vector field, often referred to as the Proca field, in a Schwarzschild spacetime background. While scalar, fermionic, and electroMAGNETic fields are well studied in this context, the Proca field requires a more nuanced treatment because of the physical nature of the longitudinal POLARIZATION mode and the constrained dynamics of the field variables. By implementing the Dirac bracket formalism to treat the constraints inherent in the Proca action, we derive a consistent framework for the commutator algebra of creation and annihilation operators. Following this construction, we define the usual Boulware, Unruh, and Hartle-Hawking vacua. Using the Unruh vacuum, we derive and analyze the Hawking spectrum of the Proca field. Furthermore, we numerically evaluate the Proca condensate constructed from the two-point correlation function $\langle A_μ(x) A_ν(x') \rangle$, defined on all three vacuum states. We find that the condensate becomes significant near the boundary of the future horizon. Our results highlight the interplay among the different POLARIZATION modes and the significance of the Proca mass in quantum observables.

[abstract 22 / 65] (score: 3)
arXiv:2606.11380 [pdf, ps, other]

Title: Quasinormal modes and tidal responses of BLACK HOLEs in generic anisotropic matter environments

Authors: Yu-Qian Zhao, Paolo Pani,

Comments: 14 pages, 3 figures

Subjects: gr-qc astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We develop a perturbative framework for a BLACK HOLE embedded in a generic, possibly anisotropic, matter environment under spherical symmetry. Our approach extends previous analyses restricted to vanishing radial pressure or to perturbative matter configurations. Within this framework, we derive an analytical generalization of the Einstein cluster that incorporates a polytropic radial pressure, and we investigate the properties of this solution. We show that both the geodesic structure and the axial quasinormal-mode spectrum remain predominantly governed by an overall gravitational redshift effect, while the radial pressure systematically enhances the environmental corrections. In contrast, the tidal Love numbers are substantially more sensitive, and can exhibit order-unity deviations, including vanishing and negative strictly static MAGNETic Love numbers for sufficiently large anisotropy. We present the full linearized equations, which can be applied to various extensions, including ringdown analysis and extreme-mass-ratio inspirals.

[abstract 23 / 65] (score: 3)
arXiv:2606.14807 [pdf, ps, other]

Title: Centaurus A Inner Lobes -- I. Hydrodynamic modeling of a Precessing Jet

Authors: Rita C. Anjos, Brian Reville,

Comments: Accepted for publication in MNRAS

Subjects: astro-ph.HE hep-ph

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

We present a numerical investigation into the precessing JETs of the inner lobes of Centaurus A, focusing on their dynamical evolution and interaction with the surrounding medium. Using three-dimensional RELATIVISTIC hydrodynamic simulations, we model the development of large-scale JET and lobe structures driven by precession. Our setup incorporates physically motivated parameters to reproduce observed morphological features. We compare the resulting structures from our simulations with observed radio images of Centaurus A, particularly focusing on the S-shaped morphology, the distribution of bright emission regions, and the observed asymmetry between the northern and southern lobes. Our findings indicate a precession period of 1.8 Myr, which reproduces observational characteristics. This study explores the role of JET precession in shaping the inner lobes of Centaurus A.

[abstract 24 / 65] (score: 3)
arXiv:2606.14852 [pdf, ps, other]

Title: Intermediate-mass BLACK HOLE seeding in galactic nuclei from star cluster migration

Authors: Stefano Torniamenti, Nils Hoyer, Nadine Neumayer, Peter J. Smith, Manuel Arca Sedda,

Comments: 18 pages, 12 figures. Comments welcome

Subjects: astro-ph.GA astro-ph.HE

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

Nuclear star clusters are one of the most favorable sites to host hierarchical BLACK HOLE (BH) mergers, potentially bridging the gap from stellar-mass to massive BHs. However, their assembly and the evolution of their BH populations remain poorly constrained. We investigate the process of intermediate-mass BH (IMBH) seeding in galactic nuclei from star cluster migration. We introduce inSpyral, a new semi-analytic model that draws star cluster populations from a galaxy formation model (L-Galaxies 2020),and integrates their evolution across a wide range of spatial scales, from BH core dynamics to the orbital motion in the host galaxy. We find that dynamical friction drives the inspiral of the most massive clusters in galaxies with $M_{\mathrm{\star, gal}} \lesssim 5 \times 10^{10} \,\mathrm{M_\odot}$, seeding their nuclei with IMBHs as early as $z \sim 6$. The BH mass distribution from BH mergers in migrating clusters extends to $\sim 300 \, \mathrm{M_\odot}$, a factor of five above the upper limit from in-situ formation. If clusters form with sub-parsec scale radii ($\lesssim 0.5 \, \mathrm{pc}$), hierarchical mergers significantly enhance BH mass growth before migration, and seed galactic nuclei with IMBHs above $10^4 \, \mathrm{M_\odot}$. The most massive and highly spinning gravitational-wave events are well reproduced by BH mergers involving second-generation remnants that experienced relatively small RELATIVISTIC kicks ($\lesssim 100 \, \mathrm{km \, s^{-1}}$). GW231123 is consistent with BH mergers between a third-generation primary and a second-generation secondary, which occur in star clusters with mass $> 2 \times 10^{6} \, \mathrm{M_\odot}$.

[abstract 25 / 65] (score: 3)
arXiv:2606.14959 [pdf, ps, other]

Title: Probing Direct Contributions of Galaxies and AGN to Cosmic Reionization in a Quasar Field J0226+0302 with JWST NIRCam and NIRSpec

Authors: Xiangyu Jin, Jinyi Yang, Feige Wang, Koki Kakiichi, Xiaohui Fan, Enrico Garaldi, Jaclyn B. Champagne, George D. Becker, Yongda Zhu, Yunjing Wu, Marianne Vestergaard, Huanqing Chen, Valentina D'Odorico, Anna-Christina Eilers, Jiamu Huang, Hyunsung D. Jun, Mingyu Li, Maria Pudoka, Wei Leong Tee, Minghao Yue, Huanian Zhang, Siwei Zou,

Comments: Submitted to AAS Journals; 21 pages, 13 figures, 1 table. Comments are welcomed

Subjects: astro-ph.GA astro-ph.CO

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

We present JWST Cycle 2 NIRCam and NIRSpec observations in a QUASAR field J0226+0302 at z=6.5412 to probe the direct connections between the intergalactic medium (IGM), galaxies, and AGN during reionization. This field was previously observed by the JWST ASPIRE program and eight [OIII]-emitting galaxies were detected at 5.3AGN through detection of broad H-alpha emission lines with an AGN fraction of (8+/-4)%. By measuring the IGM effective optical depth around the AGN and the IGM-AGN cross-correlation function, we find that the IGM transmission is higher within 5 cMpc/h of the AGN than around the majority of [OIII] emitters. We interpret the excess IGM transmission as resulting from the local radiation enhancement by the AGN, and estimate f_esc of 50%-100% of the AGN from the IGM-AGN cross-correlation function. Future JWST NIRSpec observations in QUASAR fields will yield a more constraining IGM-AGN cross-correlation function, providing further insights into the roles of galaxies and AGN in reionization.

[abstract 26 / 65] (score: 3)
arXiv:2606.15111 [pdf, ps, other]

Title: Comparative Analysis of Ellerman and Quiet Sun Ellerman Bombs in the Solar Atmosphere

Authors: Ravi Chaurasiya, Ankala Raja Bayanna, Jayant Joshi,

Comments: Accepted for Publication in ApJ

Subjects: astro-ph.SR

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

Ellerman Bombs (EBs) and Quiet-Sun Ellerman Bombs (QSEBs) are small-scale signatures of MAGNETic RECONNECTion in the lower solar atmosphere, observed in active regions and quiet-Sun areas, respectively. We investigate and compare some of their properties using coordinated multiwavelength observations from the Swedish 1-m Solar Telescope, the Interface Region Imaging Spectrograph, and the Solar Dynamics Observatory. We employ k-means clustering to identify EBs and QSEBs and perform a detailed analysis of a subset of these events. Our results show that EBs are frequently associated with opposite MAGNETic polarities, whereas QSEBs generally lack clear polarity signatures, likely due to limited spatial resolution. Spectral inversions using the STiC code reveal temperature enhancements of up to 1700 K in the lower chromosphere for EBs. In contrast, no clear temperature enhancement is detected for QSEBs, which may be attributed to the limited spatial resolution or insufficient wavelength sampling of the Ca II 8542 A. We further find that some EBs exhibit signatures extending to transition-region temperatures. An analysis of EBs temporal evolution reveals episodic heating, with a range of periodicities, most commonly around 6-7 minutes. In addition, we identify spatial associations between the footpoints of some spicules and EBs/QSEBs, suggesting that RECONNECTion in these events may contribute to spicule formation. These results demonstrate similarities and differences between EBs and QSEBs and support the interpretation that small-scale MAGNETic RECONNECTion contributes to heating and dynamics in EBs, while the underlying mechanism of QSEBs requires further investigation.

[abstract 27 / 65] (score: 3)
arXiv:2606.15519 [pdf, ps, other]

Title: Axisymmetric reduction of the adjoint operator in ideal MHD equilibrium

Authors: Fumiya Tanji, Akinobu Matsuyama, Akio Sanpei, Sadao Masamune, Yasuaki Kuroe, Yuji Nakamura,

Comments:

Subjects: physics.plasm-ph

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

Adjoint formulations of MAGNETohydrodynamic (MHD) equilibrium are presented for sensitivity analysis and optimization-based equilibrium calculations. We derive the adjoint of the three-dimensional equilibrium equations under fixed-boundary conditions and analyse its axisymmetric reduction. The reduced operator coincides with the perturbed Grad-Shafranov operator, thereby making explicit the connection between the threedimensional adjoint construction and the axisymmetric adjoint problem. The resulting framework provides a basis for relating adjoint structures in both axisymmetric and fully three-dimensional ideal MHD equilibrium.

[abstract 28 / 65] (score: 3)
arXiv:2606.16012 [pdf, ps, other]

Title: HYPERION. The cold ISM of rapidly growing $z>6$ QUASARs: diverse gas reservoirs, dust enrichment, and feedback signatures

Authors: Claudia Maria Pierro, Roberta Tripodi, Laura Pentericci, Francesco Salvestrini, Luca Zappacosta, Alessia Tortosa, Blessing Musiimenta, Enrico Piconcelli, Livia Vallini, Fabio Di Mascia, Federico Esposito, Chiara Feruglio, Fabio Vito, Maria Vittoria Zanchettin,

Comments: 23 pages; 18 figures, 6 tables. Claudia Maria Pierro, Roberta Tripodi: These authors equally contributed to this work

Subjects: astro-ph.GA

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

Luminous QSOs at $z>6$ host some of the most rapidly assembled SMBHs in the early Universe. Characterizing their cold ISM is essential to determine their evolution. We investigate the molecular gas, cold dust, STAR FORMATION, gas-to-dust ratio, and ionized ISM of ten HYPERION QSOs using new ALMA Band 3 observations targeting CO(6-5) and the underlying $\sim100$ GHz continuum, complemented by archival and literature ALMA/NOEMA data. We detect $\sim100$ GHz continuum emission in eight targets and CO(6-5) emission in four QSO hosts, J025-33, J083+11, J231-20, and J0252-0503, as well as in the companion of J231-20. The inferred molecular gas masses are of order $10^{10}~M_\odot$, while the non-detections imply upper limits of a few $10^9~M_\odot$, indicating a broad range of molecular reservoirs within the HYPERION population. For J025-33 and J083+11, the FIR SEDs are well sampled and yield low dust temperatures, $T_{\rm dust}=36^{+13}_{-7}$ K and $32^{+4}_{-3}$ K, respectively, well below the average value for $z>6$ QSOs. Combining gas and dust masses, we find a gas-to-dust ratio for J083+11, ${\rm GDR}=16^{+5}_{-4}$, among the lowest measured in a high-redshift QSO host. We also detect [NII]$λ205\,μ$m emission in J025-33 and tentatively in J083+11, suggesting dense or highly structured ionized gas. Finally, we identify a tentative connection among $T_{\rm dust}$, the X-ray photon index $Γ$, and the C IV velocity shift. These trends may indicate that more powerful winds redistribute dust away from the central AGN heating source, lowering its temperature and weakening the connection between the large-scale dust reservoir and the X-ray corona. Overall, HYPERION QSOs emerge as a heterogeneous population in which SMBH growth, STAR FORMATION, gas consumption, enrichment, and feedback are not necessarily synchronized.

[abstract 29 / 65] (score: 3)
arXiv:2606.16105 [pdf, ps, other]

Title: Direct Observations of Magnetic Reconnection in the Solar Wind Current Sheets near Mars

Authors: Chi Zhang, Chuanfei Dong, Xinmin Li, Han-Wen Shen, Jasper Halekas, Tai Phan, Christian Mazelle, Yuki Harada, Hongyang Zhou, Jiawei Gao, Liang Wang, Shannon Curry, David L. Mitchell,

Comments:

Subjects: physics.space-ph astro-ph.EP astro-ph.SR physics.plasm-ph

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Magnetic RECONNECTion is a fundamental and ubiquitous process in astrophysical plasmas that converts MAGNETic energy into plasma kinetic and thermal energy. Throughout the heliosphere, the solar wind is permeated with current sheets (CSs), providing a natural laboratory for investigating this process. Using measurements from NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, we report the first direct observations of MAGNETic RECONNECTion occurring within the solar wind CSs near Mars. Specifically, MAVEN observed the classic Petschek-type RECONNECTion exhaust regions, evidenced by bifurcated MAGNETic field signatures and Alfvenic ion outflows. Notably, the observed exhaust region appears to be large-scale, significantly exceeding the typical thickness of solar wind CSs near Mars. This suggests that MAGNETic RECONNECTion may significantly broaden the CS. Our results underscore the ubiquity of MAGNETic RECONNECTion across heliocentric distances and may provide new insights into the large-scale evolution of the solar wind and the development of turbulence within it.

[abstract 30 / 65] (score: 3)
arXiv:2606.16518 [pdf, ps, other]

Title: Beyond Mean Solar Wind Conditions: Turbulence-Aware Forecasting of the AE Index

Authors: Cara L. Waters, Christopher H. K. Chen, Mathew J. Owens,

Comments: 38 pages, 7 figures, submitted to Space Weather 30th March 2026, revisions submitted 15th June 2026

Subjects: physics.space-ph

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

The auroral electroJET (AE) index is a key indicator of high latitude geoMAGNETic activity and is widely used in operational space weather monitoring, yet forecasting AE from upstream solar wind conditions remains challenging due to nonlinear coupling, internal MAGNETospheric dynamics, and multiscale variability. We test whether incorporating solar wind turbulence improves short timescale AE forecasts beyond models based only on mean solar wind and interplanetary MAGNETic field parameters. Two gradient boosted decision tree (XGBoost) models are developed using near-Earth solar wind observations: a baseline model using standard mean parameters and a turbulence-aware model that additionally includes measures of fluctuation amplitude, intermittency, and Alfvenic structure. Both models achieve peak performance at short lead times, with correlations exceeding 0.8 at 60 minutes. However, while the baseline model exhibits a clear skill peak at 75 minutes, the turbulence-aware model maintains comparable skill across 60-90 minute horizons, indicating reduced degradation with lead time. The turbulence-aware model also provides consistent improvements over both the baseline and persistence and, critically, improves forecast robustness for high-impact events. Cost-loss analysis shows that, for the baseline model, economic value decreases systematically with increasing AE threshold and the range of cost-loss ratios yielding positive value narrows. In contrast, the turbulence-aware model maintains an approximately constant zero-value cost-loss threshold across all event levels, indicating stable economic usefulness even for extreme AE conditions. This demonstrates that turbulence provides complementary, scale-dependent information beyond mean solar wind parameters, improving both forecast performance and decision-relevant value for operational space weather applications.

[abstract 31 / 65] (score: 3)
arXiv:2606.16967 [pdf, ps, other]

Title: Mapping a Quasar Outflow from Parsec to Kiloparsec Scales: A Combined HST Absorption and VLT Emission Investigation

Authors: Mayank Sharma, Travis C. Fischer, Manuela Bischetti, Nahum Arav, Fabrizio Fiore, Chiara Feruglio, Manoj Ghosh,

Comments: Accepted for publication in ApJ

Subjects: astro-ph.GA

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Linking nuclear winds to galactic-scale outflows remains a major observational challenge in understanding the multiscale physics of ACTIVE GALACTIC NUCLEi feedback. Here we present VLT/KMOS integral-field spectroscopy and SDSS observations of the $z = 0.9655$ QUASAR PKS J0352$-$0711. Our analysis reveals complex, multi-ionization emission, including a fast, unresolved nuclear wind and a spatially resolved galactic-scale outflow. We integrate the [O III] emission properties with those deduced from the mini-broad-absorption-line outflows detected in HST/COS observations of this QUASAR. This unique combination of datasets allows us to trace, for the first time, the physical progression of a QUASAR outflow from $\sim$ 10 pc to 10 kpc. The multiscale kinematics support a unified evolutionary scenario where the inner, constant-velocity ($\sim-3800 \textrm{ km s}^{-1}$) expansion of the wind is traced jointly in absorption ($\sim 9$ pc) and emission ($\gtrsim 40$ pc). As the wind propagates to $\sim$ 500 pc, the intermediate absorption system reveals a deceleration to $\sim-2100 \textrm{ km s}^{-1}$, consistent with mass-loading from the interstellar medium. Finally, our spatially resolved observations capture the gas breaking out of the inner galaxy, in the form of a wide-angle blueshifted outflow expanding beyond 8 kpc, with a velocity of $\sim -1000 \textrm{ km s}^{-1}$. Despite the three orders of magnitude variation in spatial scale, and a factor-of-four deceleration, the momentum fluxes remain consistent within uncertainties across all scales. These results suggest that the distinct outflow components represent the integrated history of a sustained feedback cycle from nuclear to galactic scales.

[abstract 32 / 65] (score: 3)
arXiv:2606.17044 [pdf, ps, other]

Title: Galaxy-cluster-stacked FERMI-LAT, part IV: $\sim70$ GeV WIMP annihilation lines

Authors: Uri Keshet,

Comments: 21 pages, 5 figures, 5 tables

Subjects: astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

The strongest constraints on the velocity-dependent ($p$-wave) annihilation of weakly interacting massive particle (WIMP) DARK MATTER were derived from the deep potential wells of galaxy clusters. Even weaker signals can be extracted from sufficient aggregated clusters, by cross-correlating $γ$-rays with large-scale structure tracers or stacking over extensive cluster catalogs. Three independent such analyses show a similar triad of emission lines in FERMI-LAT data, around 70, 40, and 13 GeV, emerging from featureless spectra in wide-sky regions upon cross-correlation with eROSITA maps, and in stacked MCXC, eROSITA, and DESI catalog clusters once boosted to the cluster frame. These lines fit the anticipated $χχ\toγγ$, $γZ$, and $γh$ annihilation channels of a $\sim70$ GeV WIMP $χ$, detected by composite matched filters at trial-corrected global $Z$-scores reaching $5.6σ$ (cross-correlations) and $2.3σ$ (stacking), with intrinsic $\sim10^{[-20,-19]}$ cm$^3$ s$^{-1}$ channel cross-sections. High-resolution spectra establish six lines and a broad (three-line) feature in total, naturally aligned with the anticipated nine channels of two cross-annihilating WIMPs of masses $67.3_{-0.1}^{+0.1}$ and $71.4_{-0.1}^{+0.2}$ GeV (profile-likelihood bounds; $_{-5\%}^{+3\%}$ systematic; $5.3σ$). The Galactic-center GeV excess is broadly consistent with the corresponding $χχ\to b\bar{b}$ continuum.

[abstract 33 / 65] (score: 2)
arXiv:2102.00957 [pdf, ps, other]

Title: Gravitational effect of plasma particles on the shadow of Schwarzschild BLACK HOLEs

Authors: Qiang Li, Yanni Zhu, Towe Wang,

Comments: 12 pages, 4 figures, updated to match the published version

Subjects: gr-qc astro-ph.GA

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Considering a Schwarzschild BLACK HOLE surrounded by a fully ionized hydrogen plasma, we study the effect of the gravitational field of the plasma particles on the shadow. We take a formalism in which this effect is unified with the refractive effect of the plasma medium studied previously, but the two effects are characterized by two independent parameters. For semi-realistic values of parameters, we find their corrections to the shadow radius are both negligible, and the gravitational correction can overtake the refractive correction for ACTIVE GALACTIC NUCLEi of masses larger than $10^9M_{\odot}$. With unrealistically large values of parameters, we illustrate the two effects on the light trajectories and the intensity map.

[abstract 34 / 65] (score: 2)
arXiv:2312.16031 [pdf, ps, other]

Title: Transverse electric waves in Bandos-Lechner-Sorokin-Townsend nonlinear electrodynamics

Authors: Yang Shi, Qinyan Tan, Towe Wang,

Comments: 13 pages, 5 figures, updated to match the published version

Subjects: physics.class-ph

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

In the generalized Born-Infeld electrodynamics discovered by Bandos, Lechner, Sorokin and Townsend, we study transverse electric waves propagating perpendicular to a constant MAGNETic field background in a parallel-plate waveguide. The directions of propagation and POLARIZATION of the waves are perpendicular to each other, and both of them are parallel to the perfectly conducting plates. Two specific configurations are studied, in which the background MAGNETic field is either normal to the plates or along the POLARIZATION direction. The dispersion relation, the velocity and the cutoff frequency of the lowest-order lowest-frequency mode are calculated in both configurations. This paves the way for a potential test of the generalized Born-Infeld electrodynamics.

[abstract 35 / 65] (score: 2)
arXiv:2503.17442 [pdf, ps, other]

Title: Every Nearby Energetic Pulsar Is Surrounded by a Region of Inhibited Diffusion

Authors: Isabelle John, Tim Linden,

Comments: 7 pages, 4 figures, appendix adds 4 pages, 4 figures. Updated version matches version accepted by PRD

Subjects: astro-ph.HE hep-ph

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

The H.E.S.S. telescope has recently detected the total electron-plus-positron ($e^+e^-$) flux up to 40 TeV, finding it to be a featureless and steeply-falling power-law above 1 TeV. This result is in stark tension with standard one-zone models of pulsar $e^+e^-$ injection and diffusion, which predict a hard-spectrum signal above $\sim$10 TeV. We model the local pulsar population, and find 20 sources that would each $individually$ overproduce the H.E.S.S. $e^+e^-$ flux in a one-zone diffusion model. We conclude that $every$ energetic pulsar younger than $\sim$500 kyr must be surrounded by a region of inhibited diffusion ($e.g.$, a SUPERNOVA remnant, pulsar wind nebula, or TeV halo) that prevents the transport of these $e^+e^-$ to Earth. Because the high-electron density in these regions produces bright SYNCHROTRON and inverse-Compton emission, we conclude that all nearby pulsars are detectable as (potentially unassociated) radio, x-ray or $γ$-ray sources.

[abstract 36 / 65] (score: 2)
arXiv:2506.04703 [pdf, ps, other]

Title: Constraints on Shadow Radius and Instabilities Arising from Various Perturbations in Spherically Symmetric Black Holes in Einstein-power-Yang-Mills-Gauss-Bonnet Gravity

Authors: Zening Yan,

Comments: 72 pages, 22 figures, 4 tables

Subjects: gr-qc

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

The space-time geometry under investigation is chosen to be a high-dimensional, static, spherically symmetric solution in an asymptotically flat background within the Einstein-power-Yang-Mills-Gauss-Bonnet (EPYMGB) gravity. To address the limitations of previous shadow constraints, we construct a standardized framework based on the Schwarzschild-Tangherlini metric to constrain the characteristic parameters. Additionally, we provide a rigorous derivation of the shadow radius formula for a general high-dimensional spherically symmetric BLACK HOLE. Subsequently, we systematically and comprehensively present the effective potential equations governing spin-0, spin-1, $p$-form, and spin-2 perturbations in high-dimensional static spherically symmetric flat space-time. Our analysis reveals that the Yang-Mills MAGNETic charge $\mathcal{Q}$ and the power $q$ have a negligible impact on both the shadow radius and perturbations of the BLACK HOLE when compared to the Gauss-Bonnet coupling constant $α_2$ in various dimensions. Hence, the physical signatures of the parameters $\mathcal{Q}$ and $q$ in the BLACK HOLE environment remain undetectable through either perturbation analysis or shadow observations. Cross-validation of the allowable range of $α_2$ derived from the high-dimensional constraint on shadow radius and the dynamical stability analysis of gravitational perturbations demonstrates excellent agreement between these independent approaches. The conclusions derived from the cross-analysis further substantiate the validity of the high-dimensional shadow constraint formula proposed in this work and indicate that the duality between BLACK HOLE shadows and perturbations may persist in high-dimensional space-times.

[abstract 37 / 65] (score: 2)
arXiv:2507.08076 [pdf, ps, other]

Title: Dark, deep, deconfining: Phase transitions in neutron stars as powerful probes of hidden sectors

Authors: Aryaman Bhutani, Nirmal Raj, Zenia Zuraiq,

Comments: 5 pages revtex + references, 1 figure; v2 adds clarifying text and matches PRD

Subjects: hep-ph astro-ph.HE hep-ex

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

The interiors of neutron stars enjoy ideal conditions for the conversion of hadrons to a strange QUARK phase, theorized to be the stablest form of matter. Though numerous astrophysical means to prompt such a deconfinement phase transition have been suggested, they may be pre-empted by a large energy barrier for nucleation of QUARK matter droplets. We will show that interactions of hidden sectors of particles with nucleons may surmount the barrier if it exceeds deca-GeV energies, and spark a phase transition. The neutron star would then, depending on the equation of state of QCD matter, convert to a BLACK HOLE and/or set off a GAMMA-RAY BURST (GRB). Using the observed existence of ancient neutron stars and estimates of the GRB rate, we then set some of the strictest (albeit conditional) limits on DARK MATTER scatters, annihilations, and decays that are tens of orders stronger than those from terrestrial searches. For smaller energy barriers, lower limits on nucleon decay lifetimes of the order of $10^{64}$~yr may be obtained.

[abstract 38 / 65] (score: 2)
arXiv:2512.05193 [pdf, ps, other]

Title: Black-hole ringdown with templates capturing spin precession: A reanalysis of GW190521

Authors: Chiara Anselmo, Costantino Pacilio, Davide Gerosa,

Comments: 17 pages, 6 figures, 3 tables

Subjects: gr-qc astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

The ringdown stage of a binary black-hole merger provides a clean probe of strong-field gravity, as it can be modeled with minimal assumptions. The quasi-normal-mode frequencies encode the mass and spin of the Kerr BLACK HOLE remnant, while the mode excitation depends on the progenitor binary. In this paper, we implement a recently developed amplitude model that captures spin precession in a simulation-based inference pipeline that specifically targets ringdown signals. We present a reanalysis of GW190521-a short-duration, merger-dominated event with conflicting interpretations. Spin-aligned and precessing analyses at two ringdown start times show that precession induces modest but systematic shifts in inferred parameters and subdominant mode amplitudes, although such ringdown-only analyses provide no strong evidence for precession. Our results demonstrate the feasibility of physics-informed precessing ringdown modeling, paving the way for the identification of spin precession in gravitational-wave events using solely their ringdown stages, where waveform systematics are expected to be substantially less prominent.

[abstract 39 / 65] (score: 2)
arXiv:2601.21086 [pdf, ps, other]

Title: Rethinking Resonance Detectability during Binary Neutron Star Inspiral: Accurate Mismatch Computations for Low-lying Dynamical Tides

Authors: Alberto Revilla-Peña, Ruxandra Bondarescu, Andrew P. Lundgren, Jordi Miralda-Escudé,

Comments: 13 pages, 7 figures, Submitted to Physical Review D

Subjects: gr-qc astro-ph.HE astro-ph.SR

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

We compute deviations from observed gravitational wave signals, where the amplitude of the signal is unchanged. As an example, we consider the detectability of low lying dynamical tides in binary neutron star or neutron star BLACK HOLE mergers. Tidal forces can excite oscillatory modes of one or both of the stars in the binary when the orbital frequency of the binary system sweeps through the resonant mode frequency dissipating energy into the vibrational mode. The orbital energy loss to the vibrational mode extracts energy from the orbital motion, advancing the time to merger. The inspiral then continues with an excess phase and a time advance. Both will cause a mismatch when fitting to a system that has not gone through the resonance. To resolve this effect, we compute the mismatch for current and planned detectors using both a quasi-analytical approach that relies on the computation of moment integrals and an optimized version of the standard numerical match function. We conclude that detectability can occur for time advances of the order of 1 ms with advanced LVK detectors for an excess energy-flux that is a few percent of the gravitational wave emission. Our results contrast with previous work, which model this effect solely as a phase shift of the waveform or by using the difference in the number of cycles induced by the resonant behavior. We show that tidal resonance effects primarily cause a time advance of the merger, rather than a phase difference, and that the single-frequency approximation commonly used in the literature significantly overestimates the detectability of this effect.

[abstract 40 / 65] (score: 2)
arXiv:2603.23663 [pdf, ps, other]

Title: $B$-JET fragmentation with $B^{\pm} \to J/ψK^{\pm}$ decays in $\sqrt{s} = 13$ TeV $pp$ collisions at LHCb

Authors: LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, C. A. Aidala, Z. Ajaltouni, S. Akar, K. Akiba, P. Albicocco, J. Albrecht, R. Aleksiejunas, F. Alessio, P. Alvarez Cartelle, R. Amalric, S. Amato, J. L. Amey, Y. Amhis, L. An, L. Anderlini, M. Andersson, P. Andreola, M. Andreotti, S. Andres Estrada, A. Anelli, D. Ao, C. Arata, F. Archilli, Z. Areg, M. Argenton, S. Arguedas Cuendis, M. Arias, L. Arnone, A. Artamonov, M. Artuso, E. Aslanides, R. Ataíde Da Silva, M. Atzeni, B. Audurier, J. A. Authier, D. Bacher, I. Bachiller Perea, S. Bachmann, M. Bachmayer, J. J. Back, Z. B. Bai, P. Baladron Rodriguez, V. Balagura, A. Balboni, W. Baldini, Z. Baldwin, L. Balzani, H. Bao, J. Baptista de Souza Leite, C. Barbero Pretel, M. Barbetti, I. R. Barbosa, R. J. Barlow, M. Barnyakov, S. Barsuk, W. Barter, J. Bartz, S. Bashir, B. Batsukh, P. B. Battista, A. Bavarchee, A. Bay, A. Beck, M. Becker, F. Bedeschi, I. B. Bediaga, N. A. Behling, S. Belin, A. Bellavista, K. Belous, I. Belov, I. Belyaev, G. Benane, G. Bencivenni, E. Ben-Haim, A. Berezhnoy, R. Bernet, A. Bertolin, F. Betti, J. Bex, O. Bezshyyko, S. Bhattacharya, M. S. Bieker, N. V. Biesuz, A. Biolchini, M. Birch, F. C. R. Bishop, A. Bitadze, A. Bizzeti, T. Blake, F. Blanc, J. E. Blank, S. Blusk, V. Bocharnikov, J. A. Boelhauve, O. Boente Garcia, T. Boettcher, A. Bohare, A. Boldyrev, C. Bolognani, R. Bolzonella, R. B. Bonacci, N. Bondar, A. Bordelius, F. Borgato, S. Borghi, M. Borsato, J. T. Borsuk, E. Bottalico, S. A. Bouchiba, M. Bovill, T. J. V. Bowcock, A. Boyer, C. Bozzi, J. D. Brandenburg, A. Brea Rodriguez, N. Breer, J. Brodzicka, J. Brown, D. Brundu, E. Buchanan, M. Burgos Marcos, C. Burr, C. Buti, J. S. Butter, J. Buytaert, W. Byczynski, S. Cadeddu, H. Cai, Y. Cai, A. Caillet, R. Calabrese, L. Calefice, M. Calvi, M. Calvo Gomez, P. Camargo Magalhaes, J. I. Cambon Bouzas, P. Campana, A. C. Campos, A. F. Campoverde Quezada, Y. Cao, S. Capelli, M. Caporale, L. Capriotti, R. Caravaca-Mora, A. Carbone, L. Carcedo Salgado, R. Cardinale, A. Cardini, P. Carniti, L. Carus, A. Casais Vidal, R. Caspary, G. Casse, M. Cattaneo, G. Cavallero, V. Cavallini, S. Celani, I. Celestino, S. Cesare, A. J. Chadwick, I. Chahrour, H. Chang, M. Charles, Ph. Charpentier, E. Chatzianagnostou, R. Cheaib, M. Chefdeville, C. Chen, J. Chen, S. Chen, Z. Chen, A. Chen Hu, M. Cherif, A. Chernov, S. Chernyshenko, X. Chiotopoulos, G. Chizhik, V. Chobanova, M. Chrzaszcz, A. Chubykin, V. Chulikov, P. Ciambrone, X. Cid Vidal, G. Ciezarek, P. Cifra, P. E. L. Clarke, M. Clemencic, H. V. Cliff, J. Closier, C. Cocha Toapaxi, V. Coco, J. Cogan, E. Cogneras, L. Cojocariu, S. Collaviti, P. Collins, T. Colombo, M. Colonna, A. Comerma-Montells, L. Congedo, J. Connaughton, A. Contu, N. Cooke, G. Cordova, C. Coronel, I. Corredoira, A. Correia, G. Corti, J. Cottee Meldrum, B. Couturier, D. C. Craik, M. Cruz Torres, M. Cubero Campos, E. Curras Rivera, R. Currie, C. L. Da Silva, X. Dai, E. Dall'Occo, J. Dalseno, C. D'Ambrosio, J. Daniel, G. Darze, A. Davidson, J. E. Davies, O. De Aguiar Francisco, C. De Angelis, F. De Benedetti, J. de Boer, K. De Bruyn, S. De Capua, M. De Cian, U. De Freitas Carneiro Da Graca, E. De Lucia, J. M. De Miranda, L. De Paula, M. De Serio, P. De Simone, F. De Vellis, J. A. de Vries, F. Debernardis, D. Decamp, S. Dekkers, L. Del Buono, B. Delaney, J. Deng, V. Denysenko, O. Deschamps, F. Dettori, B. Dey, P. Di Nezza, I. Diachkov, S. Ding, Y. Ding, L. Dittmann, A. D. Docheva, A. Doheny, C. Dong, F. Dordei, A. C. dos Reis, A. D. Dowling, L. Dreyfus, W. Duan, P. Duda, L. Dufour, V. Duk, P. Durante, M. M. Duras, J. M. Durham, O. D. Durmus, A. Dziurda, A. Dzyuba, S. Easo, E. Eckstein, U. Egede, A. Egorychev, V. Egorychev, S. Eisenhardt, E. Ejopu, L. Eklund, M. Elashri, D. Elizondo Blanco, J. Ellbracht, S. Ely, A. Ene, J. Eschle, T. Evans, F. Fabiano, S. Faghih, L. N. Falcao, B. Fang, R. Fantechi, L. Fantini, M. Faria, K. Farmer, F. Fassin, D. Fazzini, L. Felkowski, C. Feng, M. Feng, A. Fernandez Casani, M. Fernandez Gomez, A. D. Fernez, F. Ferrari, F. Ferreira Rodrigues, M. Ferrillo, M. Ferro-Luzzi, S. Filippov, R. A. Fini, M. Fiorini, M. Firlej, K. L. Fischer, D. S. Fitzgerald, C. Fitzpatrick, T. Fiutowski, F. Fleuret, A. Fomin, M. Fontana, L. A. Foreman, R. Forty, D. Foulds-Holt, V. Franco Lima, M. Franco Sevilla, M. Frank, E. Franzoso, G. Frau, C. Frei, D. A. Friday, J. Fu, Q. Führing, T. Fulghesu, G. Galati, M. D. Galati, A. Gallas Torreira, D. Galli, S. Gambetta, M. Gandelman, P. Gandini, B. Ganie, H. Gao, R. Gao, T. Q. Gao, Y. Gao, Y. Gao, Y. Gao, L. M. Garcia Martin, P. Garcia Moreno, J. García Pardiñas, P. Gardner, L. Garrido, C. Gaspar, A. Gavrikov, L. L. Gerken, E. Gersabeck, M. Gersabeck, T. Gershon, S. Ghizzo, Z. Ghorbanimoghaddam, F. I. Giasemis, V. Gibson, H. K. Giemza, A. L. Gilman, M. Giovannetti, A. Gioventù, L. Girardey, M. A. Giza, F. C. Glaser, V. V. Gligorov, C. Göbel, L. Golinka-Bezshyyko, E. Golobardes, D. Golubkov, A. Golutvin, S. Gomez Fernandez, W. Gomulka, F. Goncalves Abrantes, I. Gonçales Vaz, M. Goncerz, G. Gong, J. A. Gooding, I. V. Gorelov, C. Gotti, E. Govorkova, J. P. Grabowski, L. A. Granado Cardoso, E. Graugés, E. Graverini, L. Grazette, G. Graziani, A. T. Grecu, N. A. Grieser, L. Grillo, C. Gu, M. Guarise, L. Guerry, A. -K. Guseinov, E. Gushchin, Y. Guz, T. Gys, K. Habermann, T. Hadavizadeh, C. Hadjivasiliou, G. Haefeli, C. Haen, S. Haken, G. Hallett, P. M. Hamilton, J. Hammerich, Q. Han, X. Han, S. Hansmann-Menzemer, L. Hao, N. Harnew, T. J. Harris, M. Hartmann, S. Hashmi, J. He, N. Heatley, A. Hedes, F. Hemmer, C. Henderson, R. Henderson, R. D. L. Henderson, A. M. Hennequin, K. Hennessy, J. Herd, P. Herrero Gascon, J. Heuel, A. Heyn, A. Hicheur, G. Hijano Mendizabal, J. Horswill, R. Hou, Y. Hou, D. C. Houston, N. Howarth, W. Hu, X. Hu, W. Hulsbergen, R. J. Hunter, M. Hushchyn, D. Hutchcroft, M. Idzik, D. Ilin, P. Ilten, A. Iohner, A. Ishteev, H. Jage, S. J. Jaimes Elles, S. Jakobsen, T. Jakoubek, E. Jans, B. K. Jashal, A. Jawahery, C. Jayaweera, A. Jelavic, V. Jevtic, Z. Jia, E. Jiang, X. Jiang, Y. Jiang, Y. J. Jiang, E. Jimenez Moya, N. Jindal, M. John, A. John Rubesh Rajan, D. Johnson, C. R. Jones, S. Joshi, B. Jost, J. Juan Castella, N. Jurik, I. Juszczak, K. Kalecinska, D. Kaminaris, S. Kandybei, M. Kane, Y. Kang, C. Kar, M. Karacson, A. Kauniskangas, J. W. Kautz, M. K. Kazanecki, F. Keizer, M. Kenzie, T. Ketel, B. Khanji, S. Kholodenko, G. Khreich, F. Kiraz, T. Kirn, V. S. Kirsebom, S. Klaver, N. Kleijne, A. Kleimenova, D. K. Klekots, K. Klimaszewski, M. R. Kmiec, T. Knospe, R. Kolb, S. Koliiev, L. Kolk, A. Konoplyannikov, P. Kopciewicz, P. Koppenburg, A. Korchin, I. Kostiuk, O. Kot, S. Kotriakhova, E. Kowalczyk, A. Kozachuk, P. Kravchenko, L. Kravchuk, O. Kravcov, M. Kreps, P. Krokovny, W. Krupa, W. Krzemien, O. Kshyvanskyi, S. Kubis, M. Kucharczyk, V. Kudryavtsev, E. Kulikova, A. Kupsc, V. Kushnir, B. Kutsenko, J. Kvapil, I. Kyryllin, D. Lacarrere, P. Laguarta Gonzalez, A. Lai, A. Lampis, D. Lancierini, C. Landesa Gomez, J. J. Lane, G. Lanfranchi, C. Langenbruch, J. Langer, T. Latham, F. Lazzari, C. Lazzeroni, R. Le Gac, H. Lee, R. Lefèvre, A. Leflat, M. Lehuraux, E. Lemos Cid, O. Leroy, T. Lesiak, E. D. Lesser, B. Leverington, A. Li, C. Li, C. Li, H. Li, J. Li, K. Li, L. Li, P. Li, P. -R. Li, Q. Li, T. Li, T. Li, Y. Li, Y. Li, Y. Li, Z. Lian, Q. Liang, X. Liang, Z. Liang, S. Libralon, A. Lightbody, C. Lin, T. Lin, R. Lindner, H. Linton, R. Litvinov, D. Liu, F. L. Liu, G. Liu, K. Liu, S. Liu, W. Liu, Y. Liu, Y. Liu, Y. L. Liu, G. Loachamin Ordonez, I. Lobo, A. Lobo Salvia, A. Loi, T. Long, F. C. L. Lopes, J. H. Lopes, A. Lopez Huertas, C. Lopez Iribarnegaray, S. López Soliño, Q. Lu, C. Lucarelli, D. Lucchesi, M. Lucio Martinez, Y. Luo, A. Lupato, E. Luppi, K. Lynch, S. Lyu, X. -R. Lyu, G. M. Ma, H. Ma, S. Maccolini, F. Machefert, F. Maciuc, B. Mack, I. Mackay, L. M. Mackey, L. R. Madhan Mohan, M. J. Madurai, D. Magdalinski, D. Maisuzenko, J. J. Malczewski, S. Malde, L. Malentacca, A. Malinin, T. Maltsev, G. Manca, G. Mancinelli, C. Mancuso, R. Manera Escalero, F. M. Manganella, D. Manuzzi, D. Marangotto, J. F. Marchand, R. Marchevski, U. Marconi, E. Mariani, S. Mariani, C. Marin Benito, J. Marks, A. M. Marshall, L. Martel, G. Martelli, G. Martellotti, L. Martinazzoli, M. Martinelli, D. Martinez Gomez, D. Martinez Santos, F. Martinez Vidal, A. Martorell i Granollers, A. Massafferri, R. Matev, A. Mathad, V. Matiunin, C. Matteuzzi, K. R. Mattioli, A. Mauri, E. Maurice, J. Mauricio, P. Mayencourt, J. Mazorra de Cos, M. Mazurek, D. Mazzanti Tarancon, M. McCann, N. T. McHugh, A. McNab, R. McNulty, B. Meadows, D. Melnychuk, D. Mendoza Granada, P. Menendez Valdes Perez, F. M. Meng, M. Merk, A. Merli, L. Meyer Garcia, D. Miao, H. Miao, M. Mikhasenko, D. A. Milanes, A. Minotti, E. Minucci, T. Miralles, B. Mitreska, D. S. Mitzel, R. Mocanu, A. Modak, L. Moeser, R. D. Moise, E. F. Molina Cardenas, T. Mombächer, M. Monk, T. Monnard, S. Monteil, A. Morcillo Gomez, G. Morello, M. J. Morello, M. P. Morgenthaler, A. Moro, J. Moron, W. Morren, A. B. Morris, A. G. Morris, R. Mountain, Z. Mu, E. Muhammad, F. Muheim, M. Mulder, K. Müller, F. Muñoz-Rojas, V. Mytrochenko, P. Naik, T. Nakada, R. Nandakumar, G. Napoletano, I. Nasteva, M. Needham, E. Nekrasova, N. Neri, S. Neubert, N. Neufeld, P. Neustroev, J. Nicolini, D. Nicotra, E. M. Niel, N. Nikitin, L. Nisi, Q. Niu, B. K. Njoki, P. Nogarolli, P. Nogga, C. Normand, J. Novoa Fernandez, G. Nowak, C. Nunez, H. N. Nur, A. Oblakowska-Mucha, V. Obraztsov, T. Oeser, A. Okhotnikov, O. Okhrimenko, R. Oldeman, F. Oliva, E. Olivart Pino, M. Olocco, R. H. O'Neil, J. S. Ordonez Soto, D. Osthues, J. M. Otalora Goicochea, P. Owen, A. Oyanguren, O. Ozcelik, F. Paciolla, A. Padee, K. O. Padeken, B. Pagare, T. Pajero, A. Palano, L. Palini, M. Palutan, C. Pan, X. Pan, S. Panebianco, S. Paniskaki, L. Paolucci, A. Papanestis, M. Pappagallo, L. L. Pappalardo, C. Pappenheimer, C. Parkes, D. Parmar, G. Passaleva, D. Passaro, A. Pastore, M. Patel, J. Patoc, C. Patrignani, A. Paul, C. J. Pawley, A. Pellegrino, J. Peng, X. Peng, M. Pepe Altarelli, S. Perazzini, D. Pereima, H. Pereira Da Costa, M. Pereira Martinez, A. Pereiro Castro, C. Perez, P. Perret, A. Perrevoort, A. Perro, M. J. Peters, K. Petridis, A. Petrolini, S. Pezzulo, J. P. Pfaller, H. Pham, L. Pica, M. Piccini, L. Piccolo, B. Pietrzyk, R. N. Pilato, D. Pinci, F. Pisani, M. Pizzichemi, V. M. Placinta, M. Plo Casasus, T. Poeschl, F. Polci, M. Poli Lener, A. Poluektov, N. Polukhina, I. Polyakov, E. Polycarpo, S. Ponce, D. Popov, K. Popp, S. Poslavskii, K. Prasanth, C. Prouve, D. Provenzano, V. Pugatch, A. Puicercus Gomez, G. Punzi, J. R. Pybus, Q. Qian, W. Qian, N. Qin, R. Quagliani, R. I. Rabadan Trejo, R. Racz, J. H. Rademacker, M. Rama, M. Ramírez García, V. Ramos De Oliveira, M. Ramos Pernas, M. S. Rangel, F. Ratnikov, G. Raven, M. Rebollo De Miguel, F. Redi, J. Reich, F. Reiss, Z. Ren, P. K. Resmi, M. Ribalda Galvez, R. Ribatti, G. Ricart, D. Riccardi, S. Ricciardi, K. Richardson, M. Richardson-Slipper, F. Riehn, K. Rinnert, P. Robbe, G. Robertson, E. Rodrigues, A. Rodriguez Alvarez, E. Rodriguez Fernandez, J. A. Rodriguez Lopez, E. Rodriguez Rodriguez, J. Roensch, A. Rogachev, A. Rogovskiy, D. L. Rolf, P. Roloff, V. Romanovskiy, A. Romero Vidal, G. Romolini, F. Ronchetti, T. Rong, M. Rotondo, M. S. Rudolph, M. Ruiz Diaz, R. A. Ruiz Fernandez, J. Ruiz Vidal, J. J. Saavedra-Arias, J. J. Saborido Silva, S. E. R. Sacha Emile R., N. Sagidova, D. Sahoo, N. Sahoo, B. Saitta, M. Salomoni, I. Sanderswood, R. Santacesaria, C. Santamarina Rios, M. Santimaria, L. Santoro, E. Santovetti, A. Saputi, D. Saranin, A. Sarnatskiy, G. Sarpis, M. Sarpis, C. Satriano, A. Satta, M. Saur, D. Savrina, H. Sazak, F. Sborzacchi, A. Scarabotto, S. Schael, S. Scherl, M. Schiller, H. Schindler, M. Schmelling, B. Schmidt, N. Schmidt, S. Schmitt, H. Schmitz, O. Schneider, A. Schopper, N. Schulte, M. H. Schune, G. Schwering, B. Sciascia, A. Sciuccati, G. Scriven, I. Segal, S. Sellam, A. Semennikov, T. Senger, M. Senghi Soares, A. Sergi, N. Serra, L. Sestini, B. Sevilla Sanjuan, Y. Shang, D. M. Shangase, M. Shapkin, R. S. Sharma, L. Shchutska, T. Shears, J. Shen, Z. Shen, S. Sheng, V. Shevchenko, B. Shi, J. Shi, Q. Shi, W. S. Shi, E. Shmanin, R. Shorkin, R. Silva Coutinho, G. Simi, S. Simone, M. Singha, I. Siral, N. Skidmore, T. Skwarnicki, M. W. Slater, E. Smith, M. Smith, L. Soares Lavra, M. D. Sokoloff, F. J. P. Soler, A. Solomin, A. Solovev, K. Solovieva, N. S. Sommerfeld, R. Song, Y. Song, Y. Song, Y. S. Song, F. L. Souza De Almeida, B. Souza De Paula, K. M. Sowa, E. Spadaro Norella, E. Spedicato, J. G. Speer, P. Spradlin, F. Stagni, M. Stahl, S. Stahl, S. Stanislaus, M. Stefaniak, O. Steinkamp, D. Strekalina, Y. Su, F. Suljik, J. Sun, J. Sun, L. Sun, D. Sundfeld, W. Sutcliffe, P. Svihra, V. Svintozelskyi, K. Swientek, F. Swystun, A. Szabelski, T. Szumlak, Y. Tan, Y. Tang, Y. T. Tang, M. D. Tat, J. A. Teijeiro Jimenez, A. Terentev, F. Terzuoli, F. Teubert, E. Thomas, D. J. D. Thompson, A. R. Thomson-Strong, H. Tilquin, V. Tisserand, S. T'Jampens, M. Tobin, T. T. Todorov, L. Tomassetti, G. Tonani, X. Tong, T. Tork, L. Toscano, D. Y. Tou, C. Trippl, G. Tuci, N. Tuning, L. H. Uecker, A. Ukleja, D. J. Unverzagt, A. Upadhyay, B. Urbach, A. Usachov, A. Ustyuzhanin, U. Uwer, V. Vagnoni, A. Vaitkevicius, V. Valcarce Cadenas, G. Valenti, N. Valls Canudas, J. van Eldik, H. Van Hecke, E. van Herwijnen, C. B. Van Hulse, R. Van Laak, M. van Veghel, G. Vasquez, R. Vazquez Gomez, P. Vazquez Regueiro, C. Vázquez Sierra, S. Vecchi, J. Velilla Serna, J. J. Velthuis, M. Veltri, A. Venkateswaran, M. Verdoglia, M. Vesterinen, W. Vetens, D. Vico Benet, P. Vidrier Villalba, M. Vieites Diaz, X. Vilasis-Cardona, E. Vilella Figueras, A. Villa, P. Vincent, B. Vivacqua, F. C. Volle, D. vom Bruch, N. Voropaev, K. Vos, C. Vrahas, J. Wagner, J. Walsh, E. J. Walton, G. Wan, A. Wang, B. Wang, C. Wang, G. Wang, H. Wang, J. Wang, J. Wang, J. Wang, J. Wang, M. Wang, N. W. Wang, R. Wang, X. Wang, X. Wang, X. W. Wang, Y. Wang, Y. Wang, Y. H. Wang, Z. Wang, Z. Wang, J. A. Ward, M. Waterlaat, N. K. Watson, D. Websdale, Y. Wei, Z. Weida, J. Wendel, B. D. C. Westhenry, C. White, M. Whitehead, E. Whiter, A. R. Wiederhold, D. Wiedner, M. A. Wiegertjes, C. Wild, G. Wilkinson, M. K. Wilkinson, M. Williams, M. J. Williams, M. R. J. Williams, R. Williams, S. Williams, Z. Williams, F. F. Wilson, M. Winn, W. Wislicki, M. Witek, L. Witola, T. Wolf, E. Wood, G. Wormser, S. A. Wotton, H. Wu, J. Wu, X. Wu, Y. Wu, Z. Wu, K. Wyllie, S. Xian, Z. Xiang, Y. Xie, T. X. Xing, A. Xu, L. Xu, M. Xu, R. Xu, Z. Xu, Z. Xu, Z. Xu, S. Yadav, K. Yang, X. Yang, Y. Yang, Y. Yang, Z. Yang, Z. Yang, H. Yeung, H. Yin, X. Yin, C. Y. Yu, J. Yu, X. Yuan, Y Yuan, J. A. Zamora Saa, M. Zavertyaev, M. Zdybal, F. Zenesini, C. Zeng, M. Zeng, S. H Zeng, C. Zhang, D. Zhang, J. Zhang, L. Zhang, R. Zhang, S. Zhang, S. L. Zhang, Y. Zhang, Y. Z. Zhang, Z. Zhang, Y. Zhao, A. Zhelezov, S. Z. Zheng, X. Z. Zheng, Y. Zheng, T. Zhou, X. Zhou, V. Zhovkovska, L. Z. Zhu, X. Zhu, X. Zhu, Y. Zhu, V. Zhukov, J. Zhuo, D. Zuliani, G. Zunica,

Comments: All figures and tables, along with any supplementary material and additional information, are available at https://lbfence.cern.ch/alcm/public/analysis/full-details/5692 (LHCb public pages)

Subjects: hep-ex

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

The collinear and transverse-momentum-dependent JET fragmentation function and the radial profile for $B^{\pm}$ mesons in JETs are measured. The $B^{\pm}$ mesons are reconstructed through the $J/ψ(\to μ^{+} μ^{-}) K^{\pm}$ decay channel using proton-proton collision data collected during 2016-2018 with the LHCb detector at a center-of-mass energy of $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of $5.4$ fb$^{-1}$. The results complement recent measurements of JET fragmentation functions for heavy-flavor hadrons and suggest a growing contribution of gluon fragmentation to $B^{\pm}$ mesons as the JET transverse momentum increases.

[abstract 41 / 65] (score: 2)
arXiv:2604.23479 [pdf, ps, other]

Title: FACET2-S2E: Start-to-end simulations of the FACET-II beamline

Authors: Nathan Majernik, Frederick Cropp, Claudio Emma, Thamine Dalichaouch,

Comments: Submitted to Journal of Open Source Software (JOSS) https://github.com/slaclab/FACET2-S2E

Subjects: physics.acc-ph

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

FACET2-S2E is a Python package for start-to-end simulations of the Facility for Advanced Accelerator Experimental Tests-II (FACET-II), a US Department of Energy National User Facility. A kilometer-long particle accelerator creates, manipulates, and accelerates electron beams to over 10 GeV before focusing and compressing them to the micron-scale. These beams create extreme electric and MAGNETic fields on the femtosecond timescale, uniquely enabling research into exotic states and advanced accelerator technology, including plasma wakefield acceleration. This software package enables present or prospective facility users to easily run the most common types of simulation pipelines to design experiments and interpret results.

[abstract 42 / 65] (score: 2)
arXiv:2605.21672 [pdf, ps, other]

Title: Numerical simulations of shock-driven, supersonic interstellar turbulence in colliding three-temperature laboratory plasmas

Authors: Stefano Merlini, James R. Beattie, Vicente Valenzuela-Villaseca,

Comments: Main: 24 pages, 17 figures. Appendix: 5 pages, 2 figures. Submitted to ApJ

Subjects: physics.plasm-ph astro-ph.GA astro-ph.HE physics.flu-dyn

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

Shock-driven turbulence is central to astrophysical plasmas in which explosions and compressive driving inject energy through shocks rather than steady stirring. We present three-dimensional, three-temperature (ion, electron, and radiation; 3T) radiation-hydrodynamic simulations of a laboratory platform in which two offset CH mesh targets are irradiated by a $30\,\rm ns$ X-ray pulse. Mesh ablation launches counter-streaming supersonic flows whose vorticity is seeded baroclinically at mesh-cell corners, advected into collimated channels over $\sim15\,\rm ns$, and injected into the outgoing streams before collision. The flows first collide at $t\simeq75\,\rm ns$, forming a shocked turbulent mixing layer that persists for at least $300\,\rm ns$, reaches $\ell_0\simeq4.5\,\rm mm$, and evolves toward an effectively isothermal equation of state with $γ_{\rm eff}\simeq1.1$. After stagnation, $u_0(t)\propto t^{-1.1}$ while $t_0/t_{c_s}\simeq0.2$ remains nearly fixed. Compression and stretching dominate the vorticity budget, and the velocity field relaxes toward a kinetic-energy partition of approximately $70\%$ solenoidal and $30\%$ compressive. The Reynolds stress is strongly anisotropic at the outer scale and remains measurably anisotropic over much of the resolved inertial interval, indicating directional memory of the collision axis and mesh geometry across many scales. The solenoidal strain spectrum implies $\ell_{ν,\rm s}\simeq92\,μ\rm m$, $\ell_0/\ell_{ν,\rm s}\simeq49$, and an effective Reynolds number $\mathrm{Re}\sim2\times10^2$. The density-gradient spectrum is directly tied to the compressive mode spectrum, which evolves independently from the incompressible cascade. Abridged.

[abstract 43 / 65] (score: 2)
arXiv:2605.23515 [pdf, ps, other]

Title: Ensemble asteroseismology: An ensemble approach to detecting signatures of solar-like oscillations in K-dwarfs

Authors: William J. Chaplin, Tiago L. Campante, Mikkel N. Lund, Martin B. Nielsen, Guy R. Davies, Emily Hatt, Rachel Howe, Amalie Stokholm,

Comments: 13 pages, 8 figures, accepted for publication in Astronomy & Astrophysics

Subjects: astro-ph.SR

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Solar-like oscillations have to date been observed in hundreds of main-sequence and sub-giant stars. However, only a handful of detections have been made in K-type dwarfs, using ground-based extreme precision radial velocity observations and space-based photometric observations made by the NASA \emph{Kepler} and TESS missions. Whilst the upcoming ESA PLATO Mission promises to add to these individual detections, it will do so only in a similar, modest number of stars. Here, we propose a new ensemble strategy to exploit the PLATO data, in which frequency power spectra on hundreds of K-dwarfs lying in constrained ranges of effective temperature are combined in a weighted manner to significantly improve the detectability of the oscillations. Whilst this approach means it is not possible to extract usable constraints on individual oscillation frequencies, it provides a way to detect and measure the characteristics of the composite envelope of oscillation power given by the ensemble, which in turn provides diagnostics of granulation and MAGNETo-convection and the impact of MAGNETic activity on the modes. We use data in the PLATO Input Catalogue (PIC) to make discrete numerical predictions of the detectability of the ensemble spectra. We also derive a simple analytical approximation of our method that obviates the need to perform numerical calculations over a discrete sample of targets, and which serves as a useful tool to make quick predictions for other future or planned missions. Our predictions indicate that PLATO has the potential to provide solid ensemble detections well into the K-dwarf regime. In summary, PLATO offers an ideal opportunity to exploit this new approach.

[abstract 44 / 65] (score: 2)
arXiv:2606.06595 [pdf, ps, other]

Title: VLA Observations Confirm AT 2023mfm as an Off-nuclear Tidal Disruption Event

Authors: Wenkai Li, Collin T. Christy, Kate D. Alexander, Itai Sfaradi, Xinya Huang, Ning Jiang, Tanmoy Laskar, Andrew Mummery, Noah Franz, Adelle J. Goodwin, Walter W. Golay, Raffaella Margutti, Ryan Chornock, Jiazheng Zhu, Sjoert van Velzen, Yvette Cendes, Wenbin Lu, Jimmy Lynch,

Comments: 4 pages, 1 figure, published in RNAAS

Subjects: astro-ph.HE astro-ph.GA

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

We report new radio observations of the tidal disruption event (TDE) AT 2023mfm, which we identified as a high-confidence candidate in a systematic search for off-nuclear TDEs. High-resolution NSF Karl G. Jansky Very Large Array C-band (6 GHz) imaging resolves two radio sources: one consistent with the host-galaxy nucleus and one offset by $0.651\pm0.036^{\prime\prime}$ ($1.06\pm0.06$ kpc), consistent with the Zwicky Transient Facility and Pan-STARRS1 positions of AT 2023mfm. These observations confirm the off-nuclear nature of AT 2023mfm, demonstrating the power of high-resolution radio imaging to validate off-nuclear TDE candidates and reveal hidden off-nuclear massive BLACK HOLEs.

[abstract 45 / 65] (score: 2)
arXiv:2606.12127 [pdf, ps, other]

Title: Ionization-Induced Electrostatic Hose Instability in Electron-Beam-Sustained Plasmas

Authors: Jia-Hong Chen, Yi Yu, Jian Chen, Zhi-Bin Wang,

Comments:

Subjects: physics.plasm-ph

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We report the discovery of a previously unrecognized electrostatic hose instability in electron-beam-sustained plasmas, driven by the coupling between the electron beam centroid and the plasma generated via the beam-impact ionization. Unlike the conventional hose instability of RELATIVISTIC beams propagating in underdense plasmas, this instability requires only ionization-capable electron beams readily produced by common emission processes and sheath acceleration, indicating broad relevance across various discharges. A linear theory is developed to predict the hosing frequency and growth rate, and particle-in-cell/Monte Carlo simulations confirm both the onset of instability and the theoretical predictions.

[abstract 46 / 65] (score: 2)
arXiv:2606.14472 [pdf, ps, other]

Title: Transitions in the Mass-ratio and Spin Properties of Binary Black Holes in GWTC-5

Authors: Elizabeth Flanagan, Fabio Antonini, Thomas Callister, Debatri Chattopadhyay, Fani Dosopoulou, Isobel Romero-Shaw, Jakob Stegmann,

Comments:

Subjects: astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We analyze the mass-ratio and effective-spin ($χ_{\rm eff}$) distributions of binary BLACK HOLE mergers in the latest gravitational-wave catalog, GWTC-5, as a function of primary mass. Using hierarchical Bayesian inference with flexible Gaussian-process population models, we identify four distinct mass regions separated by sharp transitions in both mass-ratio and spin properties. Below $\sim15~M_{\odot}$, the population strongly favors equal-mass binaries and exhibits a narrow $χ_{\rm eff}$ distribution peaked at positive values. In the range $18$-$30\,M_{\odot}$, the mass-ratio distribution becomes substantially flatter, while the $χ_{\rm eff}$ distribution broadens, shifts to a peak consistent with zero, and shows tentative--but not statistically required--evidence for positive skewness. The region associated with the feature near $\simeq35~M_{\odot}$ returns to a narrow $χ_{\rm eff}$ distribution consistent with symmetry at zero and strongly favors equal-mass binaries. Above $\simeq 45~M_{\odot}$, both the mass-ratio and $χ_{\rm eff}$ distributions broaden significantly. The inferred support of the spin distribution converges toward the range expected for binaries containing remnants of previous BLACK HOLE mergers, making the highest-mass region fully consistent with a star cluster population of hierarchical mergers. The close correspondence between transitions in mass ratio and effective spin suggests that different primary-mass ranges trace distinct formation channels, with isolated binary or triple evolution likely dominating the lower-mass population and dynamical assembly becoming increasingly important at higher masses.

[abstract 47 / 65] (score: 2)
arXiv:2606.14843 [pdf, ps, other]

Title: Red Giant Destruction by Stellar and Black Hole Collisions in Galactic Nuclei

Authors: Barak Rom, Eliot Quataert,

Comments: 15 Pages, 8 figures, Submitted to ApJ

Subjects: astro-ph.HE astro-ph.GA

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

We study the impact of collisions involving red giants (RGs) in the dense stellar environments of galactic nuclei. We analytically estimate when collisions with main-sequence stars or stellar-mass BLACK HOLEs can strip a RG's envelope via ram pressure or accretion-driven shocks, or eject its helium core through gravitational recoil. At high velocities, $v\gtrsim10^3~{\rm km/s}$, collisions with main-sequence stars efficiently deplete the RG population. At lower velocities, collisions with stellar-mass BHs typically dominate over stellar encounters, but the overall RG destruction rate is low and does not significantly affect the RG population. Nonetheless, these collisions produce low-mass helium white dwarfs, which are the stripped cores of the disrupted RGs, at a rate of $\sim 500~~{\rm Gyr}^{-1}$. Helium white dwarfs can produce an interesting class of white dwarf tidal disruption events around $\sim 10^{5-6} M_\odot$ massive BLACK HOLEs where Carbon-Oxygen white dwarfs cannot be tidally disrupted outside the horizon. Applied to our own Galactic Center, we quantify the impact of collisions on the observed population of RGs, as well as the effects of their intrinsic scarcity due to short RG lifetimes. We find that the RG projected density flattens within $\sim1$'', primarily due to collisions for fainter RGs and their short lifetimes for more luminous RGs.

[abstract 48 / 65] (score: 2)
arXiv:2606.14846 [pdf, ps, other]

Title: Black hole mergers from dense star clusters with realistic binary populations

Authors: Christopher E. O'Connor, Kyle Kremer, Saloni Agrawal, Elena González Prieto, Fulya Kıroğlu, Maia A. S. Martinez, Claire S. Ye, Frederic A. Rasio,

Comments: 6 figures, 3 tables; submitted to ApJ; BBH merger data available at https://doi.org/10.5281/zenodo.20651303

Subjects: astro-ph.GA astro-ph.HE

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

We present a suite of 24 full-lifetime simulations of dense star clusters with the Cluster Monte Carlo (CMC) code, featuring updated input physics and a realistic distribution of initial binary systems. The latter encompasses a mass-dependent binary fraction, period distribution, and eccentricity distribution based on observations of well-studied stellar populations in the Solar neighborhood and nearby star-forming regions. We predict the cosmic rate, masses, and spins of binary BLACK HOLE (BBH) mergers formed through dynamical assembly, primordial binary evolution, and hierarchical mergers within dense clusters. As with previous model grids with fewer binaries, dynamically assembled first-generation (1G) mergers dominate the rate of cluster-derived mergers, and the total merger rate is consistent with that inferred from LIGO-Virgo-KAGRA observations as of GWTC-5.0. Our models naturally reproduce key features of the inferred BBH population, including the broken-power-law behavior of the primary BH mass spectrum for $m_1 \gtrsim 20 M_\odot$, the shallower (steeper) slope of the secondary mass spectrum relative to the primary for $m_2 \lesssim 10 M_\odot$ ($m_2 \gtrsim 30 M_\odot$), and the shape of the mass-ratio distribution in the low- and high-mass domains. We predict broad distributions of the spin parameters $χ_{\mathrm{eff}}$ and $χ_{\mathrm{p}}$, consistent with previous studies of dynamical assembly in clusters. The merger rate from primordial binary systems within clusters is a small fraction of the total; however, their merger products are frequently involved in subsequent hierarchical mergers, with the result that the hierarchical merger rate evolves more steeply than the 1G dynamical merger rate with redshift.

[abstract 49 / 65] (score: 2)
arXiv:2606.15016 [pdf, ps, other]

Title: Seeing through the dust: Unraveling near-infrared variability in type 2 ACTIVE GALACTIC NUCLEi

Authors: J. Cerón-Meneses, P. Arévalo, P. Sánchez-Sáez, W. Yu, P. Lira, B. Milvang-Jensen,

Comments: Accepted for publication in Astronomy and Astrophysics. 17 pages, 18 figures and 3 tables

Subjects: astro-ph.GA

Created: 2026-06-12; Updated: 2026-06-16; Datestamp: 2026-06-16

Near-infrared (NIR) variability studies of ACTIVE GALACTIC NUCLEi (AGNs) are still limited, as long-term multiepoch monitoring in the NIR is observationally challenging. The depth, wavelength coverage, and 14-year temporal baseline of UltraVISTA make it one of the few surveys capable of providing a detailed characterization of AGN variability in this regime. We aim to quantify the NIR variability of known AGNs in the COSMOS field and to investigate the physical origin of variability in type 2 AGNs. In particular, we examine how NIR variability can help clarify the discrepancies between optical and X-ray classifications. Using the 14-year multiepoch UltraVISTA DR6 dataset in the YJHKs bands, we constructed calibrated NIR light curves and quantified their variability through a set of metrics. AGN-like stochastic variability was identified by modeling the light curves with a damped random walk (DRW) process. We find that about 7-17% of the 533 type 2 AGNs are variable in the NIR, with variability fractions increasing toward Ks, where the dusty torus dominates the emission. Based on the wavelength dependence of the DRW variability amplitude, we classify variable type 2 AGNs into disk-dominated, torus-dominated, and highly obscured groups. About one third of the X-ray unobscured (XR I) type 2 AGNs are variable in the NIR, consistent with misclassified weak type 1 or true type 2 AGNs. On the other hand, 21.4% (30/140) of the X-ray obscured (XR II) type 2 AGNs show detectable variability in the NIR, most of them only in H or Ks, consistent with obscuration of the bluer (accretion disk) bands. Type 2 AGNs without X-ray counterparts (165) show the smallest fraction (3.6%) of variable objects. NIR variability provides an effective and independent diagnostic for confirming optical classifications and for identifying weak or misclassified type 1 AGNs in deep extragalactic surveys.

[abstract 50 / 65] (score: 2)
arXiv:2606.15098 [pdf, ps, other]

Title: Short Spike, Long Story: Episode-Dependent Shifts of Long-Duration Type-I GRBs on $E_{\rm p,z}$--$E_{\rm iso}$ Plane

Authors: Ya-Hui Jiang, Run-Chao Chen, Zhen-Yu Yan, Kamil Nadaf, Xiao-Hong Zhao, Bin-Bin Zhang,

Comments: 14 pages, 5 figures, 2 tables

Subjects: astro-ph.HE

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

Observations of peculiar GRBs have challenged the traditional $T_{90}$-based classification, demonstrating that duration does not map uniquely onto progenitor type. A striking class is long-duration Type~I GRBs -- merger-origin events whose prompt emission lasts far longer than the canonical 2 s boundary, typically comprising an initial short hard spike followed by softer extended emission. Identifying the physical origin of such bursts requires diagnostics beyond duration alone, among which the Amati relation, linking rest-frame spectral peak energy $E_{\rm p,z}$ and isotropic-equivalent energy $E_{\rm iso}$, is widely used as a complementary classification tool. We analyze a sample of eight long-duration Type~I GRBs and merger candidates by separating the initial spike from the extended emission and examining their episode-dependent locations on the $E_{\rm p,z}$--$E_{\rm iso}$ plane. We find that the initial spike generally lies within, or close to, the empirical Type~I region, consistent with a compact-merger-like prompt-emission component. In contrast, the extended-emission episode systematically occupies a region closer to Type~II GRBs, and could be misidentified as collapsar-like if analyzed in isolation. This episode-dependent Type~I-to-Type~II transition is further supported by time-resolved spectral analysis, although its magnitude and trajectory vary among bursts, suggesting diversity in central-engine evolution or outflow properties between the two phases. Our results caution that the Amati relation alone can lead to misleading empirical classification when the initial hard spike is weak, outside the instrumental bandpass, or missed entirely, leaving only the extended emission to be analyzed. Broad temporal and spectral coverage, and independent multi-wavelength diagnostics, is therefore essential for identifying the physical origin of these events.

[abstract 51 / 65] (score: 2)
arXiv:2606.15143 [pdf, ps, other]

Title: Relativistic Accretion Flow in a Generic Class of Spherically Symmetric Static Spacetime

Authors: Pradeepkumar Yadav, Sayan Chakrabarti, Santabrata Das,

Comments: 14 pages, 8 figures

Subjects: astro-ph.HE gr-qc

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

We investigate the properties of low angular momentum, inviscid, advective accretion flows in a generic static and spherically symmetric spacetime that incorporates higher-order corrections up to the fourth order in $1/r$. Employing this metric, we self-consistently solve the RELATIVISTIC hydrodynamical equations and obtain the family of global transonic accretion solutions ($O$, $A$, $W$ and $I$-types) by means of the spacetime parameters ($δ$, $η$, $β$) and the flow parameters (specific energy $\mathscr{E}$ and angular momentum $λ$). Our analysis reveals that the accretion flow possesses either single or multiple critical points depending on these input parameters. We delineate the regions of the $δ-λ$ and $λ-\mathscr{E}$ parameter spaces that admits solutions with multiple critical points and demonstrate how these regions evolve with increasing spacetime parameter $δ$. Furthermore, while connecting the spacetime geometry with observable signatures, we compute the spectral energy distribution (SED) from thermal bremsstrahlung emission and observe that increasing $δ$ enhances the SED relative to the Schwarzschild case. Finally, we find that global transonic solutions harbouring inner critical points ($I$-types) yields more luminous power than those with only outer critical points ($O$ and $A$ types).

[abstract 52 / 65] (score: 2)
arXiv:2606.15150 [pdf, ps, other]

Title: Eccentricity in Disguise? Insights from GW231123 and Numerically Simulated Binary Black Hole Merger Signals

Authors: Koustav Chandra, Johann Fernandes, Akshita Mittal, Gregorio Carullo,

Comments: 13 pages, 9 figures

Subjects: gr-qc astro-ph.HE

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

GW231123 is a gravitational-wave signal originating from the merger of a BLACK HOLE binary with total mass $\sim 250 M_{\odot}$, the largest ever detected by the LIGO-Virgo-Kagra Collaboration. Remarkably, under standard priors, the system features among the fastest-spinning binary components confidently measured in binary mergers, $ χ_{1,2} \gtrsim 0.7$ at $90\%$ one-dimensional credibility, according to the most accurate model employed. As typical binary mergers result in remnants with $χ\sim 0.7$, such spin values are challenging to obtain even from previous (hierarchical) mergers. These inferred properties rely on waveform models lacking eccentric corrections in the merger-ringdown stage. Here, we show that binaries retaining significant eccentricity up to merger can be misinterpreted as near-extremally spinning when non-circular corrections are neglected. Binary-agnostic ringdown analysis instead provides unbiased estimates of the remnant properties, provided that a robust estimate of the signal peak can be obtained. We re-analyse GW231123 using available eccentric numerical-relativity catalogues, finding that although eccentric templates can provide a good fit to the data, quasi-spherical templates are still favoured. Ringdown analyses confirm a secondary likelihood peak correlated with large eccentricity values, but improved eccentric models will be required to assess the reliability of this interpretation. Finally, analysing GW231123 under population-informed parametric priors confirms the exceptional nature of this event within the current BLACK HOLE binary population.

[abstract 53 / 65] (score: 2)
arXiv:2606.15211 [pdf, ps, other]

Title: Effects of external MAGNETic field ripple on FRC equilibrium

Authors: Zitong Qu, Ping Zhu, Zhipeng Chen, Haolong Li,

Comments:

Subjects: physics.plasm-ph

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

The two-dimensional equilibrium of Field-Reversed Configuration (FRC) plasma in presence of an external ripple MAGNETic field is computed to show the emergence of multiple MAGNETic axes for hollow equilibrium current profiles. An increase in ripple amplitude reduces the hollowness threshold required for the development of multiple MAGNETic axes. For an intermediate range of the ripple axial period, the formation of multiple MAGNETic axes becomes the most likely. The ripple's radial extension and the curvature of the axial field are the critical factors underlying the non-monotonic effect of ripple's axial period. When the axial period increases from the lower range, the ripple's radial extension gradually grows and enhances the chance of forming multiple MAGNETic axes. Once the ripple's radial extension covers the entire radial domain, further increasing the ripple axial period decreases the ripple field curvature, which becomes the dominant factor for lowering the hollowness threshold for the formation of multiple MAGNETic axes.

[abstract 54 / 65] (score: 2)
arXiv:2606.15269 [pdf, ps, other]

Title: Line-of-sight MAGNETic-field propagation effects on axion-like particle constraints from GRB 221009A

Authors: Chengcheng Han, Zhanhong Lei, Jiajie Yang, Shutong Zhao,

Comments: 29 pages, 9 figures

Subjects: hep-ph astro-ph.HE

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

High-energy photons from GRB 221009A provide a powerful opportunity to probe axion-like particles (ALPs) through photon-ALP oscillations in cosmic MAGNETic fields. We revisit the ALP constraints implied by the LHAASO observation of this burst, with particular emphasis on the MAGNETic-field environments encountered along the line of sight. We include the host-galaxy, intergalactic, and Milky-Way MAGNETic fields and assess their respective impacts on the photon survival probability and on the exclusion limits in the ALP mass-coupling plane. We show that the constraints are only mildly affected by the choice of host-galaxy and Galactic MAGNETic-field models, but can change significantly once the intergalactic MAGNETic field is varied. Its field strength, coherence scale, and stochastic properties can all leave visible imprints on the derived exclusion contours, and in some cases generate pronounced oscillatory features. This demonstrates that the intergalactic MAGNETic field constitutes the dominant astrophysical uncertainty in extracting ALP limits from GRB 221009A. Our analysis highlights the importance of realistic propagation modeling in future gamma-ray searches for ALPs.

[abstract 55 / 65] (score: 2)
arXiv:2606.15406 [pdf, ps, other]

Title: Consistency between X-ray and UV-Optical reverberation measurements in NGC 5548

Authors: Amit Kumar Mandal, Bożena Czerny, Michal Dovčiak, Elias Kammoun, Iossif Papadakis,

Comments: 13 pages, 7 figures, 2 tables, accepted for publication in A\&A

Subjects: astro-ph.GA astro-ph.CO astro-ph.HE hep-ph

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

The hard X-ray$-$emitting hot corona is a key component of active galaxies. Constraints on the hot corona height can be derived from reverberation studies in both the X-ray and optical bands. X-ray reverberation (X-ray$-$RM) studies often imply a very low corona height, whereas UV/optical reverberation mapping (photometrcic continuum$-$RM) typically points to a much larger one. To reconcile this discrepancy, we examine the constraints provided by both methods for the same source. We adopt a uniform methodology using the {\tt KYNSED} and {\tt KYNXiltr} codes within a consistent modeling framework for reverberation mapping, applicable across both the X-ray and UV-optical spectral and time domains. We select the source NGC 5548, for which the necessary observational data are available in the literature. We carry out our analysis for NGC 5548, a source with extensive reverberation mapping data obtained independently in the X-ray and UV-optical bands across different epochs. Our results hint for a substantial discrepancy between the global parameters required to reproduce the X-ray and those needed to fit the UV-optical reverberation signals. In particular, the mismatch in the inferred BLACK HOLE mass and accretion rate presents a significant challenge for interpreting the observed time delays within a unified reflection-based framework. Our unified reflection-based modeling sheds light on X-ray and UV-optical variability of NGC 5548, but discrepancies in BLACK HOLE mass, accretion rate, and corona properties might imply fundamental challenges to a self-consistent model. However, future analyses leveraging extended X-ray dataset with improved treatment of absorption and variability coherence are crucial to obtaining more robust constraints.

[abstract 56 / 65] (score: 2)
arXiv:2606.15512 [pdf, ps, other]

Title: Towards Data-Efficient Cross-Device Generalization of Grad-Shafranov Equilibria via Transfer Learning Neural Operator

Authors: Jay Phil Yoo, William Howes, Yashika Ghai, Kazuma Kobayashi, Souvik Chakraborty, Syed Bahauddin Alam,

Comments:

Subjects: cs.LG physics.plasm-ph

Created: 2026-06-13; Updated: 2026-06-16; Datestamp: 2026-06-16

Real-time reconstruction of MAGNETohydrodynamic equilibria is essential for plasma shaping, stability assessment and feedback control in MAGNETic confinement fusion. However, Grad-Shafranov equilibrium calculations remain largely device-specific and iterative, limiting their use in latency-constrained control settings. Existing neural approaches can accelerate individual equilibrium predictions, but they do not generally provide reusable models across changing plasma boundaries or tokamak geometries. Here we show that equilibrium reconstruction can be recast as a cross-device operator learning problem. We develop a domain-specific neural operator framework that maps geometry and profile parameters directly to the poloidal flux field, replacing repeated solve-on-demand computation with amortized operator inference. Using the analytically tractable Solov'ev family as a controlled Grad-Shafranov testbed, we generate equilibria across eight geometrically distinct tokamak-like configurations and benchmark five neural operator architectures under four transfer-learning strategies. Single-geometry pretraining gives poor transfer to unseen devices, whereas multi-geometry pretraining enables data-efficient adaptation. The Wavelet Neural Operator gives the strongest cross-geometry performance, reaching mean relative L2 errors below 4% with 100 labelled target equilibria and below 2% with full fine-tuning. The predicted MAGNETic fields satisfy the divergence-free constraint to numerical precision, and four architectures achieve millisecond or sub-millisecond inference. These results identify neural operator pretraining as a route towards reusable, real-time equilibrium inference across fusion device configurations.

[abstract 57 / 65] (score: 2)
arXiv:2606.15773 [pdf, ps, other]

Title: CKM determination from $W$ decays with JET flavor tagging at CEPC

Authors: Zhao-Ling Zhang, Li-Bo Liao, Jia-Rong Li, Jia-Bao Gong, Wei-Min Song, Gang Li,

Comments:

Subjects: hep-ex

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

This study investigates the sensitivity of the CEPC to CKM matrix elements $|V_{ij}|$ in semileptonic $W$-pair decays using simulated $e^+e^- \to W^+W^- \to μν\bar{q}q^\prime$ samples corresponding to $21.6\,\mathrm{ab}^{-1}$ at $\sqrt{s}=240\,\mathrm{GeV}$, with $|V_{ub}|$ excluded because of its negligible contribution. The projected statistical precisions reach $0.59\,\%$ for $|V_{cb}|$ and $0.01\,\%$ for $|V_{cs}|$, indicating that the CEPC can provide direct, high-precision, and largely model-independent determinations of CKM matrix elements from hadronic $W$ decays. The main sources of systematic uncertainty are discussed, and further improvements are expected from both experimental and theoretical developments, including dedicated data-driven calibrations of detector response and JET flavor tagging performance, as well as more precise higher-order calculations of the relevant electroweak and QCD corrections. Such measurements would provide stringent consistency tests of the Standard Model charged-current flavor structure and offer sensitivity to possible new physics effects through deviations from the Standard Model expectations.

[abstract 58 / 65] (score: 2)
arXiv:2606.15785 [pdf, ps, other]

Title: Quasinormal modes and excitation factors of a regular BLACK HOLE with zero-point length

Authors: Milena Skvortsova,

Comments: 12 pages, 5 tables, 8 figures

Subjects: gr-qc

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

We study the ringdown of the regular Jusufi-Singleton BLACK HOLE, whose nonsingular core is controlled by a zero-point length arising from a non-local, T-duality-inspired gravitational model. Scalar, electroMAGNETic and Dirac perturbations are considered. The zero-point-length parameter raises the effective scattering barrier and produces a systematic increase of the oscillation frequencies, while also making the damping faster over most of the parameter range. High-order WKB results are checked against time-domain integration and show very good agreement for the dominant modes. We also compute excitation factors, which characterize the source-independent strength of the quasinormal-mode poles and show a smooth dependence on the new length scale.

[abstract 59 / 65] (score: 2)
arXiv:2606.15804 [pdf, ps, other]

Title: Polarization-controlled optical backflow in paraxial electroMAGNETic beams

Authors: Tomasz Radożycki,

Comments: 12 pages, 3 figures, ReVTeX

Subjects: physics.optics

Created: 2026-06-14; Updated: 2026-06-16; Datestamp: 2026-06-16

Optical backflow in paraxial Gaussian beams is investigated within the Maxwell framework. Scalar potential representations are employed to identify conditions under which the longitudinal Poynting component becomes negative, showing that backflow is enabled by local suppression of the leading-order transverse field and the dominance of higher-order vectorial contributions. The spatial topology of backflow regions is shown to be governed by POLARIZATION through the number of independent local constraints on the transverse field. When the local POLARIZATION phase is free, as in the generic case of circular POLARIZATION, the leading-order field vanishes only at isolated points, giving rise to point-like backflow regions (extended curves may arise if an additional global phase constraint is imposed). In contrast, when the POLARIZATION phase is locally fixed, as for linear, radial, or azimuthal POLARIZATION, the suppression condition reduces to a single real constraint, resulting in extended backflow curves. Analytical Gaussian-polynomial solutions explicitly illustrate these effects. These results clarify the role of vectorial interference, establish a POLARIZATION-controlled backflow geometry, and provide a foundation for further studies of optical backflow in structured and nonparaxial beam configurations, as well as potential applications in optical manipulation and structured light design.

[abstract 60 / 65] (score: 2)
arXiv:2606.16088 [pdf, ps, other]

Title: Vector Magnetic Field associated with an Active Region Filament Observed by SUNRISE III/SCIP in the Ca II 8542 Å Line

Authors: Takuma Matsumoto, Yukio Katsukawa, Masahito Kubo, Yusuke Kawabata, Takayoshi Oba, Ryohtaroh T. Ishikawa, Yoshihiro Naito, Hirohisa Hara, Toshifumi Shimizu, Fumihiro Uraguchi, Toshihiro Tsuduki, Kazuya Shinoda, Tomonori Tamura, Yoshinori Suematsu, Carlos Quintero Noda, Sami K. Solanki, Andreas Lagg, Achim Gandorfer, Jose Carlos Del Toro Iniesta, Pietro Bernasconi, Thomas Berkefeld, Alex Feller, Tino L. Riethmüller, Alberto Álvarez-Herrero, H. N. Smitha, David Orozco Suárez, Bianca Grauf, Michael Carpenter, Alexander Bell, Valentín Martínez Pillet, Francisco Javier Bailén, Julian Blanco Rodríguez, Juan Sebastián Castellanos Durán, Edvarda Harnes, Johannes Hölken, Francisco A. Iglesias, Azaymi L. Siu Tapia, Hanna Strecker, Dušan Vukadinović, Pablo Santamarina Guerrero, Nour E. Raouafi,

Comments: 9 pages, 5 figures, accepted for publication in ApJL

Subjects: astro-ph.SR

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We report high-spatial-resolution spectropolarimetric observations spatially associated with a solar filament, obtained with the SUNRISE Chromospheric Infrared spectro-Polarimeter (SCIP) onboard the SUNRISE III balloon-borne solar observatory on 15 July 2024. The observed filament was located near the solar disk center, adjacent to an active region, and remained quiescent for at least two hours during the observing period. SCIP recorded full Stokes profiles in the Ca II 8542 Å line, revealing clear signatures of linear POLARIZATION produced by the transverse Zeeman effect. The detected linear POLARIZATION signals within the filament region exceeded the 2$σ$ noise level and exhibited a characteristic Zeeman double-lobe spectral shape that distinguishes them from POLARIZATION due to scattering. The MAGNETic field strength derived using the weak field approximation is approximately -80 G along the line of sight and 300-500 G in the transverse direction. These values likely reflect the MAGNETic properties of the filament and its supporting chromospheric environment. The orientation of the MAGNETic field vector is nearly parallel to the filament axis in its northeastern portion, while the southeastern part of the filament extends outside the field of view. To our knowledge, this is the first unambiguous detection of linear POLARIZATION associated with a solar filament with the Ca II 8542 Å line. Our results open a new diagnostic window on the vector MAGNETic structure of solar filaments in the lower chromosphere, complementing existing He I based diagnostics that probe the upper chromosphere.

[abstract 61 / 65] (score: 2)
arXiv:2606.16280 [pdf, ps, other]

Title: Gravitational waveforms from periodic orbits around Gauss-Bonnet BLACK HOLEs

Authors: Yi-Han Huang, Sen Guo, Yu Liang, Lin Wen, Kai Lin,

Comments: 28 pages, 14 figures

Subjects: gr-qc

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Extreme mass-ratio inspirals (EMRIs) constitute one of the most promising probes of strong field gravity for future space borne gravitational-wave observatories. As a representative higher-curvature extension of General Relativity (GR), four-dimensional Einstein-Gauss-Bonnet (4D EGB) gravity is distinguished by its strictly linear geometric coupling. By this mathematical property, the pathological Fisher-matrix singularities that typically plague conventional modified BLACK HOLE models are effectively evaded, thereby providing an ideal framework to test topological deviations from classical spacetimes. Through the classification of equatorial periodic orbits via an integer taxonomy $(z,w,v)$, it is demonstrated that even modest Gauss-Bonnet couplings ($α\sim 0.1M^2$) imprint measurable geometric signatures onto the zoom-whirl architecture. Although the global conservative energy budget is shifted by a mere $\sim 0.2\%$, the short-range repulsive EGB core severely alters the strong field whirl dynamics, whereby a resolvable macroscopic dephasing of several radians per orbit is accumulated. Through semi-RELATIVISTIC waveform modeling, it is revealed that this temporal compression manifests as a rigid, high-frequency stretching of the gravitational-wave harmonic comb -- a clean, amplitude-independent spectral signature ideally suited for detection by LISA, Taiji, and TianQin. A rigorous Fisher information analysis confirms that for a typical four-year observation at a signal-to-noise ratio of $ρ=20$, the marginalized error on the EGB coupling can be tightly bounded to $σ_α\sim \mathcal{O}(10^{-6}) M^2$, with virtually negligible parameter degeneracy with the orbital eccentricity.

[abstract 62 / 65] (score: 2)
arXiv:2606.16343 [pdf, ps, other]

Title: Optical Variability as a Probe of Hidden Nuclear Activity in Type 2 AGNs

Authors: Maša Lakićević,

Comments: Published in A&A

Subjects: astro-ph.GA

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Optical variability in Type 2 ACTIVE GALACTIC NUCLEi (AGNs) is rarely explored because the direct accretion-disk continuum is obscured by circumnuclear dust. Nevertheless, detectable optical variations are present in multi-epoch surveys such as SDSS Stripe~82, indicating that some component of the nuclear emission is observed indirectly, for example through scattering or partial transmission. This study explores whether this variability is statistically connected to spectroscopic parameters of the narrow-line region (NLR), using the ALPAKA catalogue of spectral measurements. A subsample of 412 Type 2 AGNs was assembled by crossmatching SDSS Stripe 82 multi-epoch variability measurements in the $u,g,r,i,z$ bands with the ALPAKA spectroscopic catalogue. Correlations were then computed between the root-mean-square (RMS) variability amplitudes and the corresponding emission-line luminosities, kinematic widths and equivalent widths (EWs). Significant anti-correlations are found between the RMS amplitudes and [O III] 4949, [O III] 5007, [N II] 6548 and [NII] 6584 line luminosities. Velocity dispersions ($σ$) and EWs of forbidden-lines [O III] 5007 and [N II] 6584 also show moderate anti-correlations with RMS. The results demonstrate that even in obscured AGNs, optical variability carries information about the hidden nucleus. The anti-correlation between RMS and line luminosity suggests a connection between accretion stability and ionising output. Anti-correlations between RMS and the [O III] and [N II] velocity dispersions indicate a secondary correlation between optical RMS variability and the integrated kinematic state of the NLR. In addition, the anti-correlation between RMS and EW shows that the EW variations are primarily driven by changes in the continuum level, while the narrow-line flux itself remains effectively constant on the relevant timescales.

[abstract 63 / 65] (score: 2)
arXiv:2606.16390 [pdf, ps, other]

Title: Engine position effects on contrail evolution for a realistic aircraft configuration

Authors: Rémy Annunziata, Nicolas Bonne, François Garnier,

Comments:

Subjects: physics.flu-dyn

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

This study investigates the influence of representative engine positions on contrail evolution during the vortex and dissipation regimes, using three-dimensional simulations of a realistic aircraft geometry. Large Eddy Simulations are employed, coupled with an Eulerian microphysical bulk model, and initialized using fields obtained from prior Reynolds-Averaged Navier-Stokes simulations. This approach enables a consistent transition from near-field JET-vortex interactions to far-field wake dynamics. Three engine placements are examined under two atmospheric stratifications and two relative humidity conditions. The results reveal that engine position influences the onset and evolution of vortex instabilities, alters the descent of the vortex pair, and leads to slight changes in the distribution of particles within the wake. Despite these aerodynamic differences, the microphysical properties of the contrails tend to converge over time for the parameters and configurations covered in this study. From a broader perspective, engine placement strongly influences initial contrail formation and early vortex-regime dynamics. At later stages, these differences largely disappear, as vortex dynamics and atmospheric conditions dominate over the initial dilution changes induced by engine position.

[abstract 64 / 65] (score: 2)
arXiv:2606.16450 [pdf, ps, other]

Title: Minimising MAGNETic activity effects in PLATO observations: insights from the Sun-as-a-star

Authors: Jérôme Bétrisey, Anne-Marie Broomhall, Sylvain N. Breton, Eva Panetier, Rafael A. García, Henry Davenport, Oleg Kochukhov,

Comments:

Subjects: astro-ph.SR

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

Recent studies showed that MAGNETic activity effects in solar-type stars can substantially bias seismic inferences, particularly age estimates, regardless of modelling strategy or surface treatment. We quantified how MAGNETic activity effects in the Sun-as-a-star are smoothed by temporal averaging by analysing 182.5-, 365-, 730-, and 1460-day time series from the BiSON network and the GOLF instrument. We estimated the activity-induced systematic uncertainty using two metrics and compared results across baselines to evaluate how the observing window shapes activity-induced biases. Solar-cycle signatures persist even in 1460-day windows. The suppression of MAGNETic activity effects with increasing baseline is non-monotonic: one- and four-year windows reduce biases far more effectively than shorter baselines in most cases, whereas 730-day windows provide only limited improvement over 365-day ones. Improvements arise from enhanced frequency determination (dominant at 365 days) and from increasingly efficient temporal averaging of the activity cycle (dominant at 1460 days). In contrast, 730-day is an intermediate regime: frequency accuracy has already plateaued and the observing window remains too short to smooth out cycle-related variability. On average, we find that MAGNETic activity effects decrease by 24%, 12%, 30%, and 38% when transitioning from 182.5 to 365 days, 365 to 730 days, 730 to 1460 days, and 365 to 1460 days for frequency-based fits; the corresponding improvements for ratio-based fits are 13%, 14%, 20%, and 31%. These results indicate that a continuous single-field four-year PLATO observing programme would provide the most effective suppression of MAGNETic-activity biases for solar analogues, whereas a 2+2-year strategy (in two distinct fields) is significantly more sensitive to MAGNETic effects, with limited gains between 365- and 730-day windows.

[abstract 65 / 65] (score: 2)
arXiv:2606.17039 [pdf, ps, other]

Title: Curvature--Radiation Geometries Across the Second CHIME/FRB Fast Radio Burst Population

Authors: Thonimar V. Alencar, Jéferson A. S. Fortunato, Wiliam S. Hipólito-Ricaldi,

Comments: 14 pages and 4 figures

Subjects: astro-ph.HE

Created: 2026-06-15; Updated: 2026-06-16; Datestamp: 2026-06-16

We present a population-level spectral analysis of fast radio bursts from the second CHIME/FRB catalog using three curvature-radiation-motivated templates: point-source, one-dimensional bunch, and paired-bunch cavity models. Fits are evaluated with reduced chi-squared $χ^2_r$, AIC/BIC, and the Ljung-Box residual autocorrelation test. All three templates yield median $χ^2_r$ values close to unity for both repeating and non-repeating bursts. Repeaters show narrower $χ^2_r$ distributions than non-repeaters, with statistically significant but modest population-level differences. AIC favours the one-dimensional bunch model for the largest fraction of sources, whereas BIC increases the relative preference for the simpler point-source model. However, residual autocorrelation remains widespread across all models: only 15%-21% of sources simultaneously satisfy goodness-of-fit and residual-independence criteria, indicating persistent structured residuals beyond the tested templates. These results suggest that while curvature-radiation-motivated geometries capture the dominant spectral envelope of many FRBs, additional physical ingredients or spectral components are required to describe the fine-scale spectral structure of the data. The inferred coherence scales are $\sim$16-18 cm for the one-dimensional model and $\sim$25-28 cm for the cavity model.