Current date: 2026-06-08

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Datestamp limit: 2026-06-08 (0 days ago)

Created/updated limit: 2026-06-01 (7 days ago)

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OAI-PMH request: http://export.arxiv.org/oai2?verb=ListRecords&from=2026-06-08&until=2026-06-08&set=physics&metadataPrefix=arXiv

Scoring abstracts

Number of records retrieved: 563

Keyword score statistics

score 10 -- 1 abstracts

score 5 -- 2 abstracts

score 4 -- 6 abstracts

score 3 -- 5 abstracts

score 2 -- 18 abstracts

in total -- 32 abstracts

Articles that appeared on 2026-06-08

[abstract 1 / 32] Wow! (score: 10)
arXiv:2606.07452 [pdf, ps, other]

Title: The Western Jet of SS 433/W50: Hard X-ray Emission, Spectral Evolution, and Comparison to the Eastern Jet

Authors: Brydyn Mac Intyre, Samar Safi-Harb, Dmitry Khangulyan, Shuhan Zhang, Kaya Mori, Naomi Tsuji, Felix Aharonian, Laura Olivera-Nieto,

Comments: Accepted for publication in The Astrophysical Journal. 36 pages, 19 figures

Subjects: astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

The W50 nebula powered by the microQUASAR SS 433 is a unique laboratory for exploring several fundamental astrophysical phenomena. This study presents observations from NUSTAR and XMM-Newton, concentrating on the western lobe of W50. Detection of hard non-thermal X-ray emission is reported, extending up to approximately 30 keV. This emission originates from a compact, knotty area referred to as the "Head", located at approximately 17 arcmin (equivalent to 26.5 pc at an assumed distance of 5.5 kpc) to the west of SS 433, and characterized by a power-law spectrum with a hard photon index of 1.55 +/- 0.07 (0.5-30 keV). Moving westward from SS 433, the photon index gradually steepens, ultimately reaching a photon index of 2.10 +/- 0.05 in the "w2" region centered at approximately 35 arcmin or approximately 56 pc from SS 433. The distinct hard X-ray knots observed serve as clear markers for sites of particle acceleration within the western JET. The SYNCHROTRON radiation from the "Head" region implies equipartition MAGNETic field strength B of approximately 15 microG. Notably, these properties (western "Head" location, unusually hard spectral index, inferred MAGNETic field, and spectral evolution away from SS 433) are very similar to what has been observed in the eastern lobe, supporting a symmetric JET-driven origin. Finally, the broadband spectral energy distribution (SED) and X-ray morphology are modeled using semi-analytic JET models, exploring different JET velocity and MAGNETic field configurations. The results favor a scenario in which in-situ particle acceleration and SYNCHROTRON emission dominate, with implications for understanding particle transport, JET dynamics, and W50's role as a Galactic PeVatron.

[abstract 2 / 32] Yes (score: 5)
arXiv:2606.06620 [pdf, ps, other]

Title: JWST reveals how BLACK HOLEs are fed: kiloparsec-scale multiphase filaments feed sub-kiloparsec circumnuclear disks

Authors: Julie Hlavacek-Larrondo, Hyunseop Choi, Minghao Guo, Mathieu Marquis, Olivia Pereira, G. Mark Voit, Loïc Albert, Jorge Barrera-Ballesteros, Rebecca E. A. Canning, Francesco D'Eugenio, Megan Donahue, Andrew C. Fabian, Gary J. Ferland, John S. Gallagher, Marie-Lou Gendron-Marsolais, Pierre Guillard, Nina Hatch, Ralf Kottulla, Yuan Li, Roberto Maiolino, Allison Man, Michael A. McDonald, Brian R. McNamara, Valeria Olivares, Marine Prunier, Michael Reefe, Christopher S. Reynolds, Carter Rhea, Annabelle Richard-Larrière, Helen R. Russell, Philippe Salomé, Ming Sun, Prathamesh Tamhane, Gregory Taylor, Auriane Thilloy, Grant R. Tremblay, Benjamin Vigneron, Stephen A. Walker,

Comments: Submitted to ApJ Letters and revised in response to referee comments (14 pages, 4 figures)

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

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

The Centaurus cluster is one of the most important archetypes of radio-mode AGN feedback, with its central galaxy, NGC 4696, launching powerful JETs that inflate X-ray cavities and regulate cooling and STAR FORMATION. NGC 4696 lies within a spectacular multiphase nebula of filaments extending over tens of kiloparsecs and spanning six decades in temperature, from hot (10^8 K) X-ray-emitting plasma to cold molecular gas. Owing to its proximity, Hubble Space Telescope H_alpha imaging reveals a striking S-shaped ionized-gas swirl within the BLACK HOLE's sphere of influence - the first such structure identified in a cluster core. Here we present the first JWST observations of NGC 4696 with NIRSpec, probing the inner 618 pc * 618 pc at 10 pc resolution. These data reveal that the ionized swirl is a rotating, multiphase circumnuclear disk (CND) physically and kinematically connected to the larger-scale filamentary network. This provides the long-sought missing link between kiloparsec-scale cooling flows and BLACK HOLE accretion on <100 pc scales. Strikingly, the observed morphology and kinematics are reproduced by tailored MAGNETohydrodynamic simulations, in which filamentary gas condenses from the hot atmosphere, loses angular momentum, and feeds a rotating CND that mediates accretion onto the BLACK HOLE. A similar structure in NGC 1275, the Perseus cluster's central galaxy, together with our results on NGC 4696 - two prototypical radio-mode AGN feedback systems - points to a common mechanism: multiphase filaments transport gas from cluster scales down to the vicinity of the BLACK HOLE via a CND, closing the AGN feedback loop and establishing a physically grounded framework for self-regulated galaxy evolution.

[abstract 3 / 32] Yes (score: 5)
arXiv:2606.06884 [pdf, ps, other]

Title: Tidal Disruption of Blanets in Kerr Spacetime

Authors: Shreesham Pandey, Sunita Singh,

Comments: 9 pages; 10 figures

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Blanets are planetary-mass bodies ($20$--$3000\,\Me$) that may orbit supermassive BLACK HOLEs (SMBHs) in the circumnuclear disks of ACTIVE GALACTIC NUCLEi (AGN). We examine tidal disruption events produced by blanet--SMBH encounters, from the test-particle limit to massive planetary bodies in Kerr spacetime. Using the geodesic deviation equation and the Kerr tidal tensor, we derive disruption criteria, tidal radii, and Hills masses for planetary-mass objects, and show that blanet TDEs can remain observable for SMBHs up to $\sim10^{10}\,\Msun$, well above the stellar Hills mass of $\sim10^8\,\Msun$. The fallback rate retains the usual $t^{-5/3}$ form, but the peak timescales are shorter -- from hours to months -- with lower peak accretion rates and multi-wavelength signatures that differ from those of stellar TDEs. We also examine orbital stability, including Keplerian precession, Lense--Thirring nodal precession, migration in the circumnuclear disk, and the Kozai--Lidov resonance, and identify the region where blanets can survive before disruption. We derive RELATIVISTIC corrections to the tidal radius, spin-dependent disruption thresholds, and the effect of Kerr spin on the disruption geometry. We also discuss gravitational-wave emission from blanet debris EMRIs and the prospects for LISA detection, which may help in interpreting unusual TDE-like transients in AGN environments.

[abstract 4 / 32] Yes (score: 4)
arXiv:2501.18678 [pdf, ps, other]

Title: CRexit: how different COSMIC RAY transport modes affect thermal instability in the circumgalactic medium

Authors: Matthias Weber, Timon Thomas, Christoph Pfrommer, Ruediger Pakmor,

Comments: 20 pages and 17 figures in main text; submitted to A&A

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

The circumgalactic medium (CGM) plays a critical role in galaxy evolution, influencing gas flows, feedback processes, and galactic dynamics. Observations show a substantial cold gas reservoir in the CGM, but the mechanisms driving its formation and evolution remain unclear. Cosmic rays (CRs), as a source of non-thermal pressure, are increasingly recognized as key regulators of cold gas dynamics. This study explores how CRs affect cold clouds that condense from the hot CGM via thermal instability (TI). Using 3D CR-MAGNETohydrodynamic (CRMHD) simulations with AREPO, we assess the impact of various CR transport models on cold gas evolution. Under purely advective CR transport, CR pressure significantly suppresses the collapse of thermally unstable regions, altering the CGM's structure. In contrast, realistic CR transport models reveal that CRs escape collapsing regions via streaming and diffusion along MAGNETic fields, diminishing their influence on the thermal and dynamic structure of the cold CGM. The ratio of the CR escape time to the cloud collapse time emerges as a critical factor in determining the impact of CRs on TI. CRs remain confined within cold clouds when effective CR diffusion is slow which maximizes their pressure support and inhibits collapse. Fast effective CR diffusion, as realized in our 2-moment CRMHD model, facilitates rapid CR escape, reducing their stabilizing effect. This realistic CR transport model shows a wide dynamic range of the effective CR diffusion coefficient, ranging from $10^{29}$ to $10^{30}\,\mathrm{cm^{2}\,s^{-1}}$ for thermally- to CR-dominated atmospheres, respectively. In addition to these CR transport-related effects, we demonstrate that high numerical resolution is crucial to avoid spuriously large clouds formed in low-resolution simulations, which would result in overly long CR escape times and artificially amplified CR pressure support.

[abstract 5 / 32] Yes (score: 4)
arXiv:2508.01384 [pdf, ps, other]

Title: Dynamic disk-corona coupling during the state transition of SWIFT J1727.8-1613

Authors: Han He, Yi Long, Bei You, Fu-Guo Xie, Zhen Yan, Andrzej A. Zdziarski, Sai-En Xu,

Comments: submitted

Subjects: astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

State transitions during outbursts of BLACK HOLE X-ray binaries exhibit complex, rapidly evolving disk-corona coupling. Understanding this dynamic phase is essential for deciphering accretion physics and the mechanisms that drive outbursts, yet it remains poorly understood due to the scarcity of high-quality/-cadence observations. Here, we present an analysis of observations by the Hard X-ray Modulation Telescope (HXMT) during the 2023 outburst of the newly discovered low-mass BLACK HOLE X-ray binary SWIFT J1727.8-1613. Follow-up, high-cadence monitoring reveals pronounced variability in disk emission, attributable to fluctuations in the accretion rate. These disk fluctuations exhibit damped amplitudes and shortened flare periods. This evolving disk emission modulates the supply of soft seed photons to the corona, leading to a dynamically changing positive correlation between the photon index $Γ$ and the Comptonization luminosity $L_{\rm Comp}$. As the transition proceeds, the correlation shifts toward higher $Γ$ and a narrower range of $L_{\rm Comp}$. We further suggest that the damped disk variability arises from fluctuations generated at large disk radii and propagating inward, possibly linked to the thermal-viscous disk instability.

[abstract 6 / 32] Yes (score: 4)
arXiv:2512.10239 [pdf, ps, other]

Title: EP250827b/SN 2025wkm: An X-ray Flash-Supernova Powered by a Central Engine and Circumstellar Interaction

Authors: Gokul P. Srinivasaragavan, Dongyue Li, Xander J. Hall, Ore Gottlieb, Genevieve Schroeder, Heyang Liu, Brendan O'Connor, Chichuan Jin, Mansi Kasliwal, Tomás Ahumada, Qinyu Wu, Christopher L. Fryer, Annabelle E. Niblett, Dong Xu, Maria Edvige Ravasio, Grace Daja, Wenxiong Li, Shreya Anand, Anna Y. Q. Ho, Hui Sun, Daniel A. Perley, Lin Yan, Eric Burns, S. Bradley Cenko, Jesper Sollerman, Nikhil Sarin, Anthony L. Piro, Amar Aryan, M. Coleman Miller, Jie An, Tao An, Moira Andrews, Jule Augustin, Eric C. Bellm, Aleksandra Bochenek, Malte Busmann, Krittapas Chanchaiworawit, Huaqing Chen, Maria D. Caballero-García, Alberto J. Castro-Tirado, Ali Esamdin, Jennifer Faba-Moreno, Joseph Farah, Emilio Fernández-García, Shaoyu Fu, Johan P. U. Fynbo, Julius Gassert, Estefania Padilla Gonzalez, Ignacio Pérez-García, Matthew Graham, Maria Gritsevich, Daniel Gruen, Sergiy Guziy, D. Andrew Howell, Linbo He, Jingwei Hu, You-Dong Hu, Abdusamatjan Iskandar, Joahan Castaneda Jaims, Ji-An Jiang, Ning Jiang, Shuaijiao Jiang, Runduo Liang, Zhixing Ling, Jialian Liu, Xing Liu, Yuan Liu, Frank J. Masci, Curtis McCully, Megan Newsome, Kanthanakorn Noysena, Shashi B. Pandey, Kangrui Ni, Antonella Palmese, Han-Long Peng, Josiah Purdum, Yu-Jing Qin, Sam Rose, Ben Rusholme, Rubén Sánchez-Ramírez, Cassie Sevilla, Roger Smith, Yujia Song, Niharika Sravan, Robert Stein, Constantin Tabor, Giacomo Terreran, Samaporn Tinyanont, Pablo Vega, Letian Wang, Tinggu Wang, Xiaofeng Wang, Siyu Wu, Xuefeng Wu, Kathryn Wynn, Yunfei Xu, Shengyu Yan, Weimin Yuan, Binbin Zhang, Chen Zhang, Zipei Zhu, Xiaoxiong Zuo, Gursimran Bhullar,

Comments: 46 pages, 20 Figures, Accepted to ApJ Letters

Subjects: astro-ph.HE

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

We present the discovery of EP250827b/SN 2025wkm, an X-ray Flash (XRF) discovered by the Einstein Probe (EP), accompanied by a broad-line Type Ic SUPERNOVA (SN Ic-BL) at $z = 0.1194$. EP250827b possesses a prompt X-ray luminosity of $\sim 10^{45} \, \rm{erg \, s^{-1}}$, lasts over 1000 seconds, and has a peak energy $E_{\rm{p}} < 1.5$ keV at 90\% confidence. SN 2025wkm possesses a double-peaked optical light curve (LC), though its bolometric luminosity plateaus after its initial peak for $\sim 20$ days, consistent with a central engine injecting additional energy into the explosion. Its spectrum transitions from a blue to red continuum with clear blueshifted broad absorption features consistent with a SN Ic-BL classification. We do not detect any transient radio emission and rule out the existence of an on-axis, energetic JET $\gtrsim 10^{50}~$erg assuming a typical LGRB circumburst constant density ($n \approx 10^{-3}$--$10^{-1}~{\rm cm}^{-3}$) and microphysical parameters ($ε_{\rm e} = 0.1$ and $ε_{\rm B} = 0.01$). In the model we invoke, the collapse gives rise to a long-lived MAGNETar, potentially surrounded by an accretion disk. Magnetically--driven winds from the MAGNETar and the disk mix together and break out with a velocity $\sim 0.35c$ and interact with an extended circumstellar medium with radius $\sim 10^{13}$ cm, generating X-ray breakout emission through non-thermal free-free processes. The disk outflows and MAGNETar winds power blackbody photospheric emission as they cool adiabatically and thermalize, producing the first SN peak. The spin-down luminosity of the MAGNETar and radioactive decay of $^{56}$Ni powers the late-time emission. We end by discussing the landscape of XRF-SNe within the context of EP's recent discoveries.

[abstract 7 / 32] Yes (score: 4)
arXiv:2605.25586 [pdf, ps, other]

Title: Legacy analysis of Milky Way dwarf spheroidal satellite galaxies: an update

Authors: A. Circiello, M. Di Mauro, M. Ajello, C. Karwin, A. Drlica-Wagner, M. Á. Sánchez-Conde,

Comments:

Subjects: astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Studies of FERMI-Large Area Telescope (LAT) data coincident with dwarf spheroidal satellite galaxies (dSphs) of the Milky Way (MW) have put the most stringent constraints on models of annihilating DARK MATTER (DM) with candidate masses in the GeV-TeV range. Recent results found the presence of small, local significance excesses from these targets, at the 2-3 sigma level. However, these excesses disagree on the predicted properties of the DM candidate, and their significance vanishes when considering the correction factors for the number of trials. In this work, we apply key improvements to the analysis of the dSphs. We use stricter cuts on the data, implement a method to adaptively model the background, and assume an updated framework for DM annihilation. We find that our improved background modeling leads to a better agreement between the model and the data. This produces an increase in the local and global significance of the dSphs excess compared to previous studies. Finally, we find that the DM properties obtained in this work are less dependent on the sample of dSphs being considered compared to previous studies, while remaining in agreement with the predictions from the Galactic center excess observed by the FERMI-LAT and the antiproton excess observed by the Alpha Magnetic Spectrometer (AMS-02). Considering our improvements, a future significant increase in the number of dwarfs may lead to a definitive confirmation or exclusion of the DM interpretation of the Galactic center excess.

[abstract 8 / 32] Yes (score: 4)
arXiv:2606.06731 [pdf, ps, other]

Title: Direct simulations of very high energy COSMIC RAY acceleration in 3D MHD model of a compact star cluster

Authors: M. E. Kalyashova, A. M. Bykov, D. V. Badmaev,

Comments: 10 pages, 8 figures

Subjects: astro-ph.HE

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

Young compact clusters of massive stars contain dozens of O-, B- and WR-type stars with fast powerful winds in a small $\sim$ pc radius core. The particle acceleration by ensembles of shocks accompanied with long-wavelength compressions and rarefactions in the turbulent environment of young massive star clusters (YMSCs) is an alternative to the standard paradigm of Galactic COSMIC RAY acceleration on SUPERNOVA shocks. In recent years, the topic has been of great interest due to the fact that modern gamma- and X-ray observatories have detected the radiation from YMSCs, which indicates particle acceleration processes in these objects. We study particle propagation and acceleration in a YMSC with the help of 3D MAGNETohydrodynamic (MHD) modeling using an open source PLUTO code. The code allows modeling of the turbulent environment of YMSCs and obtaining crucial for particle acceleration values of velocity, density, and MAGNETic field inside the cluster core. The Particle module implemented in PLUTO allows solving the equations of motion for test charged particles together with MHD equations for the medium. We obtained that protons acceleration up to hundreds of TeV takes place in the cluster core near the termination shocks of O-stars, which are surrounded by shocks of their neighbour stars. We also modeled an interesting case of a young SUPERNOVA remnant expanding inside the cluster core. In this case a very fast acceleration takes place: particle energies $\gtrsim$ 100 TeV can be obtained in $\lesssim$ 100 years. The particle spectra and spatial distribution are discussed.

[abstract 9 / 32] Yes (score: 4)
arXiv:2606.06802 [pdf, ps, other]

Title: Radiation Pressure Instability in the "turn-on" Changing-Look AGN SDSS J1430+2303

Authors: Han He, Bei You, Marzena Śniegowska, Bożena Czerny,

Comments: submitted to apj. 16 pages, 10 figures, 3 tables

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

We present a multi-wavelength study of the changing-look AGN SDSS J1430+2303. The optical flux increased by an order of magnitude over four years, driving a spectral transition from Seyfert 1.9 to 1.2. During the brightened high state, optical, UV, and X-ray light curves exhibited rapid decaying periods with progressively decreasing amplitudes. X-ray spectral analysis reveals a remarkably weak soft excess which declines more steeply than the hard X-rays as the total luminosity decreases. X-ray timing analysis shows a constant break frequency and a hard lag at $\sim 10^{-4}$ Hz during the luminosity decline, indicating a stable disk-corona geometry. Further broad-band spectral energy distribution fitting constrains the BLACK HOLE mass to the range $M_{\rm BH}=4.7-19.5\times10^7\rm M_\odot$, corresponding to an Eddington ratio to $L/L_{\rm Edd}\sim0.024 - 0.046$, and favors a high spin ($a\gtrsim 0.86$). Consequently, we propose that the observed multi-wavelength decaying periods and damping amplitudes are associated with a shrinking unstable zone, driven by radiation pressure instabilities within the accretion disk.

[abstract 10 / 32] (score: 3)
arXiv:2604.02065 [pdf, ps, other]

Title: Triggering physical plasmoids in forming current sheets: conditions and diagnostics

Authors: Hubert Baty,

Comments:

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

We investigate the conditions for triggering the plasmoid instability in a dynamically forming current sheet in the resistive MAGNETohydrodynamic framework, using a pseudo-spectral code applied to the Orszag-Tang vortex at Lundquist number $S \sim 10^5$. Following García Morillo \& Alexakis (2025), we use the power spectrum of the current density $E_J(k)$, complemented by the vorticity spectrum $E_ω(k)$, to assess the convergence of our simulations, and show that this diagnostic remains valid even in the presence of physical plasmoids, allowing us to unambiguously distinguish them from spurious ones. We then show that physical plasmoids can be triggered in a well-resolved spectral simulation when three conditions are simultaneously met: a perturbation applied near the time of maximum current density, with amplitude above a critical threshold $\varepsilon_c \sim 10^{-5}$ for our numerical scheme, and with spectral content containing the unstable wavenumbers. These conditions are confirmed using continuous noise injection, which yields similar results at amplitudes one to two orders of magnitude lower. The resulting growth rates and plasmoid numbers are in good agreement with the theory of \citet{Comisso2017}. These results resolve the apparent paradox raised by García Morillo \& Alexakis (2025) and also clarify the role of numerical noise in the triggering of the plasmoid instability.

[abstract 11 / 32] (score: 3)
arXiv:2605.23484 [pdf, ps, other]

Title: Imaging spectroscopy reveals spike-like repeating radio burst pairs in the solar corona

Authors: Suli Ma, Eduard P. Kontar, Daniel L. Clarkson, Huadong Chen, Yihua Yan,

Comments: This manuscript has been accepted for publication in Nature Communications. (35 pages, 10 main figures, 3 supplement figures, 1 table, 1 movie)

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Solar radio bursts exhibit complex fine structures that reveal intricate coronal plasma dynamics. Here, we report detection of spike-like repeating burst pairs, characterized by two short-lived (0.1-2 s), narrowband components separated by about 4 s at frequencies 30-50 MHz. Using high-resolution dynamic spectra and spectroscopic imaging, we analyzed 613 burst pairs, measuring their durations, bandwidths, drift rates, flux densities, and spatial characteristics. Imaging links sources to an active region, with earlier components spatially concentrated above the region while delayed components are displaced and exhibit reduced drift rates. Radio-wave propagation simulations support the delayed bursts as turbulent echoes of harmonic emission in anisotropic coronal plasma. The location of the burst sources high in the corona suggests ongoing MAGNETic RECONNECTion and electron acceleration well above typical flare heights. Our findings offer new insights into coronal turbulence effects while advancing diagnostics of coronal plasma and the elusive nature of solar radio echoes from ground-based transmitters.

[abstract 12 / 32] (score: 3)
arXiv:2606.06575 [pdf, ps, other]

Title: The quasi-star model for Little Red Dots: potential and challenges

Authors: Fabrizio Gentile, Mauro Giavalisco, Emanuele Daddi, David Elbaz, Jean-Baptiste Billand, Maximilen Franco, Benjamin Magnelli, Guillermo Barro, Yingjie Cheng, Nikko J. Cleri, Kelcey Davis, Ivan Delvecchio, Mark Dickinson, Steven L. Finkelstein, Giovanni Gandolfi, Michaela Hirschmann, Weida Hu, Dale Kocevski, Anton M. Koekemoer, Ray Lucas, Sara Mascia, Lorenzo Napolitano, Casey Papovich, Borja Pérez-Díaz, Pablo Perez-Gonzalez, Jonathan R. Trump, Xin Wang, L. Y. Aaron Yung,

Comments: Submitted to A&A. The catalogue with the best-fit parameters will be available upon acceptance. 12 pages (+ 4 in the appendix), 7 (+3) figures, 2 (+1) tables. Comments welcome

Subjects: astro-ph.GA

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

(Abridged) Little Red Dots (LRDs) are a class of sources discovered by JWST observationally defined by a "V-shaped" rest-frame UV-Optical SED, a compact or unresolved morphology, and for having, frequently, broad hydrogen emission lines. Among various models, those involving a quasi-star interpret LRDs as an intermediate stage in the evolution of a super-massive BLACK HOLE (SMBH) seed into a classic AGN. In this paper, we employ the radiative-transfer code \texttt{Cloudy} to study whether this model is able to reproduce the spectral features commonly observed in LRDs. The model consists of an accreting SMBH ($M_{\rm BH}\sim10^{5-6} \ M_\odot$) surrounded by a convective layer where a black-body (BB) spectrum with $T\sim5000 \ {\rm K}$ and $L\sim10^{44.4} \ {\rm erg \ s}^{-1}$ is produced. This BB is then reprocessed by a concentric thick ($ΔR\sim1000 \ {\rm AU}$) shell of dense ($n_{\rm H}\sim10^{11} \ {\rm cm}^{-3}$) gas partially ionised by thermal collisions. The emerging radiation is further reprocessed by a diffuse clumpy medium surrounding the quasi-star. We fit this model to JWST/NIRSpec spectra of LRDs from the literature, deriving the main physical parameters and the SMBH masses. Once coupled with the UV emission from a host galaxy, this model is able to reproduce the shape of the UV-to-NIR continuum, including the presence of a Balmer break, as well as the luminosity of the hydrogen emission lines. However, this quasi-star model does not natively account for the presence of broad helium lines and for the possible presence of hot dust, needing additional components to match these observables. Our main result is to show how some LRDs can be modeled as quasi-stars, highlighting that a significant degeneracy exists among different LRD models. This has important consequences for our understanding of the mechanisms driving BLACK HOLE growth in the early Universe.

[abstract 13 / 32] (score: 3)
arXiv:2606.06577 [pdf, ps, other]

Title: Nonthermal line broadening at solar flare footpoints is primarily field-aligned

Authors: Andy S. H. To, Alexander J. B. Russell,

Comments: 22 pages, 5 figures, 3 tables, submitted for review

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

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

Magnetic RECONNECTion powers solar and stellar flares, but a full understanding of how the released energy is transported and converted within the solar atmosphere remains elusive. One clue lies at solar-flare footpoints, where spectral lines are far broader than the electron temperature alone can explain. Unresolved flows, waves, turbulence and ion heating have all been proposed, but observations have not yet conclusively distinguished between these mechanisms. Here we perform an unprecedented geometric test for flare footpoints, using 4,593 Hinode/EIS spectra from 407 C- to M-class flares. Line widths decrease systematically from disk centre to limb in all coronal emission lines, showing that the dominant broadening component is MAGNETic field aligned rather than isotropic or transverse. Cooler lines retain substantial broadening into the early decay phase, consistent with persistent unresolved field-aligned flows or line-of-sight velocity gradients. Hotter lines show an impulsive component that decays rapidly after the soft X-ray peak, consistent with preferential ion heating and ion temperature anisotropy. These findings resolve the long-standing question of the nature of line broadening at flare footpoints, place direct limits on flare energetics, and motivate a new direction in flare physics incorporating distinct field-aligned and perpendicular ion temperatures that exceed the electron temperature.

[abstract 14 / 32] (score: 3)
arXiv:2606.07072 [pdf, ps, other]

Title: Infrared Echoes of Precessing Tidal Disruption Events

Authors: Hong-Zhou Wu, Shao-Yu Fu, Wen-Long Xu, Chang Zhou, Wei-Hua Lei,

Comments: 15 pages,7 figures,submitted to ApJ

Subjects: astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

A tidal disruption event (TDE) occurs when a star is torn apart by a supermassive BLACK HOLE. The resulting UV/optical flare irradiates parsec-scale dust, producing delayed mid-infrared echoes that persist for years. These echoes provide unique calorimetric probes of the total radiated energy and dust geometry.Existing models usually assume static axisymmetric illumination patterns. However, the TDE accretion disk is likely misaligned and undergoes RELATIVISTIC precession.In this work, we present a theoretical framework for infrared dust echoes from a precessing TDE disk. The precession will lead to highly variable infrared light curves, which can be revealed by high-cadence observations. The overall profile of the infrared light curves shows double-peaked to single-peaked pattern transitions as a result of the changes in the viewing angle or precession angle.The results indicate that infrared echoes are dynamic tracers of the evolving lighting patterns of the central engine.

[abstract 15 / 32] (score: 2)
arXiv:2507.22260 [pdf, ps, other]

Title: Resonant interactions from dynamical perturbers on generic orbits around an extreme mass ratio inspiral

Authors: Makana Silva, Harrison G. Blake-Goszyk, Christopher M. Hirata,

Comments: 17 pages, 6 figures, v2: Updated to match published version

Subjects: gr-qc astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Extreme mass-ratio inspirals (EMRIs) are binary systems where a compact object slowly inspirals into its much larger compact partner. Since we anticipate such systems to exist within and be dynamically influenced by the galactic center environment, we expect them to be instrumental in studying these environments and testing our theories of gravity in the strong field regime. The gravitational waves associated with the EMRI motion fall within the mHz regime, making them target sources for future space-based detectors. However, because of the crowded nature of these galactic centers, these EMRIs could be perturbed by other nearby orbiting bodies. In this work, we analyze potential perturbations in EMRIs due to a third-body perturber near resonance. We use the formalism and code tools developed in the previous paper in this series [Silva \& Hirata, {\slshape Phys. Rev. D} {\bfseries 106}:084508 (2022)] and expand them to account for a general outer body orbit, allowing for multiple resonant interactions within an orbit and across a variety of SMBH spins. We find that, after investigating nearly 142,000 resonant interactions across a restricted set of 180 different simulated orbit systems, none cause changes to the EMRI dynamics beyond a perturbative correction, but could lead to potentially large changes in the phase of the waveform of order 0.1 radian. Detectable phase changes in the waveform induced by third-body perturbers could be a common occurrence and will require careful consideration for developing accurate EMRI waveform models. This analysis suggests that our formalism and pipeline are robust enough to handle a wide variety of resonances from various perturbing orbit configurations around the EMRI, which will aid in developing more accurate waveform models to better probe galactic center environments and test theories of gravity using gravitational wave observations of EMRIs.

[abstract 16 / 32] (score: 2)
arXiv:2510.06393 [pdf, ps, other]

Title: A comprehensive look into the accuracy of SpEC binary BLACK HOLE waveforms

Authors: Taylor Knapp, Katerina Chatziioannou, Keefe Mitman, Mark A. Scheel, Michael Boyle, Lawrence E. Kidder, Harald Pfeiffer,

Comments: 18 pages, 11 figures, accepted to PRD

Subjects: gr-qc astro-ph.HE

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

Numerical relativity simulations provide a full description of the dynamics of binary systems, including gravitational radiation. The waveforms produced by these simulations have a number of applications in gravitational-wave detection and inference. In this work, we revisit the accuracy of the waveforms produced by the Spectral Einstein Code. Motivated by the wide range of waveform applications, we propose and explore three accuracy metrics between simulation resolutions: (i) the generalized frequency-weighted mismatch, (ii) the relative amplitude difference, and (iii) the phase difference at different times. We confirm that numerical errors accumulate over the binary evolution, but the error is not intrinsically larger during the latest, more dynamical stages. Studying errors across the parameter space, we identify a positive correlation between both the mismatch and the phase difference with precessing spin, but little correlation with aligned spin or eccentricity. Lastly, amplitude and phases differences are symmetric upon exchanging resolutions across the catalog, suggesting that the dominant source of error is random, rather than something systematic that affects all waveforms similarly.

[abstract 17 / 32] (score: 2)
arXiv:2603.13813 [pdf, ps, other]

Title: Ultra-compact X-ray Binaries: A Review

Authors: Bo Wang, Dongdong Liu, Yunlang Guo, Hailiang Chen, Wencong Chen, Zhanwen Han,

Comments: 24 pages, 10 figures, accepted for publication in RAA, an invited review

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Ultra-compact X-ray binaries (UCXBs) are a subclass of low-mass X-ray binaries (LMXBs) characterized by ultra-short orbital periods, typically less than $60-80\,$min. They consist of a compact mass-accretor and a hydrogen-poor mass-donor, in which the mass-accretor could be a neuron star (NS) or even a BLACK HOLE (BH). UCXBs play an important role in multiple areas of astrophysics. In particular, they are considered strong, continuous gravitational wave (GW) sources in the low-frequency band, making them key targets for future space-based GW observatories such as LISA, TianQin and Taiji. As the most compact binaries, the formation and evolution of UCXBs remain highly uncertain. In this article, we review four classic formation channels: the white dwarf donor channel, the He star donor channel, the evolved main-sequence donor channel, and the accretion-induced collapse channel. We also discuss recent progress in these channels, covering evolutionary scenarios, the initial parameter space for UCXB formation, and associated objects. A comparison between observed UCXBs and theoretical expectations is provided, along with a discussion on the observed BH-UCXB candidates. The origin of UCXBs can be constrained by the chemical composition of mass-donors and their locations in diagrams of mass-transfer rate and X-ray luminosity versus orbital period. We also examine the implications of UCXBs for several astrophysical fields, including GW astronomy, multi-messenger astronomy, binary evolution, and NS physics under extreme conditions. Further progress will depend on multi-wavelength observations, the discovery of more UCXB samples, and more detailed theoretical simulations.

[abstract 18 / 32] (score: 2)
arXiv:2605.12356 [pdf, ps, other]

Title: Simulating the jittering-JETs explosion mechanism: Supernova remnant G11.2-0.3

Authors: Muhammad Akashi, Noam Soker,

Comments: Publications of the Astronomical Society of the Pacific

Subjects: astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

We hydrodynamically simulate a core-collapse SUPERNOVA (CCSN) explosion by launching three pairs of JETs in the framework of the jittering-JETs explosion mechanism (JJEM), and reproduce a morphology of two opposite circum-JET rings and a bar of dense gas perpendicular to the rings' axis, resembling these morphological features in the CCSN remnant SNR G11.2-0.3. The first pair of wide JETs is very energetic; it triggers the explosion and inflates two bubbles that compress the material in an expanding shell. The bubbles also compress material in a plane perpendicular to the JET axis. The second pair of wide JETs removes material from this plane, beside along a bar that is on an axis perpendicular to the two pairs' axes. The JETs of the third pair, now of narrow JETs, penetrate the expanding shell and compress material to their sides to form two opposite rings. These morphological features are qualitatively similar to those observed in the point-symmetric CCSN remnant G11.2-0.3. As competing theoretical CCSN explosion mechanisms cannot explain point-symmetric CCSN remnants, our study provides some support for the claim that the JJEM is the primary explosion mechanism of CCSNe.

[abstract 19 / 32] (score: 2)
arXiv:2605.26811 [pdf, ps, other]

Title: Interaction-Phase Dynamics and Spectral Organization in Damped Higher-Order Nonlinear Schrödinger Models

Authors: C. M. Schober,

Comments: 29 pages, 26 figures

Subjects: nlin.PS

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

We investigate the dynamical mechanisms underlying the contrasting Floquet spectral evolutions observed in viscously damped and in nonlinear mean-flow damped higher-order nonlinear Schrödinger models. Motivated by the persistent organized Floquet-band structure under nonlinear mean-flow damping and the repeated Floquet band RECONNECTion observed under viscous damping, we derive a reduced five-mode carrier-sideband truncation and reformulate the dynamics in amplitude-phase variables to isolate the dominant interaction phases associated with the principal four-wave interaction products. Within this framework, viscous damping acts primarily modewise and does not directly modify the leading interaction-phase dynamics. By contrast, nonlinear mean-flow damping contributes directly to the interaction-phase evolution through interaction-dependent dissipative corrections. In the carrier-sideband regime, these corrections generate terms of the form $-κ_j \sin(ψ_j)$, introducing dissipative feedback into the dominant carrier-sideband interaction dynamics. To interpret the resulting interaction-phase evolution, we examine recurrent finite-gap NLS benchmark solutions whose modulation dynamics are independently understood. These benchmarks show that substantial interaction-phase evolution and localized restructuring may occur even within organized quasiperiodic dynamics possessing invariant Floquet spectral structure. Numerical diagnostics show that the nonlinear mean-flow damped system exhibits persistent recurrent carrier-sideband focusing dynamics together with organized Floquet evolution despite substantial interaction-phase restructuring, whereas the viscous system exhibits progressively diffuse modulation dynamics together with repeated Floquet reconfiguration and weakening persistence of the recurrent carrier-sideband interaction structure.

[abstract 20 / 32] (score: 2)
arXiv:2606.06551 [pdf, ps, other]

Title: Baryon-to-Meson Ratios in Jets from Au+Au and $p$+$p$ Collisions at $\sqrt{s_{\mathrm{NN}}} = 200$ GeV

Authors: The STAR Collaboration,

Comments: Submitted to Physics Letters B, 7 pages, 4 figures

Subjects: nucl-ex

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

Jet probes have been used extensively to gain insights into QGP properties, with substantial modifications to JET yields and internal structures seen across multiple measurements, compared against $p$+$p$ results. Despite apparent medium-induced changes to JET fragmentation patterns and strong modifications of particle production at intermediate momenta ($2.0 < p_{\rm{T}} < 5.0$ GeV/$c$) in heavy ion collisions, RHIC hadron-hadron correlation results indicate that JET-related baryon-to-meson ratios remain similar to those of $p$+$p$ measurements and are significantly different from those of the QGP bulk. To look for possible medium effects on JET fragments at RHIC, we employ JET-track correlation and particle identification to perform the first measurement of in-JET proton-to-pion yield ratios for charged-hadrons with $2.0 < p_{\rm{T}} < 5.0$ GeV/$c$. We present the first in-cone (within a radial distance of $R$ from the determined JET axis direction) baryon-to-meson yield ratios associated with reconstructed charged-particle JETs from Au+Au and $p$+$p$ collisions at $\sqrt{s_{\mathrm{NN}}} = 200$ GeV using the STAR detector at RHIC. The measured in-JET ratios are found to be consistent within uncertainties between the two systems for the selected kinematic regime, despite significant differences between inclusive ratios for the same systems.

[abstract 21 / 32] (score: 2)
arXiv:2606.06557 [pdf, ps, other]

Title: Robustness of the RELATIVISTIC intermediate-axis instability around dark-matter-dressed rotating BLACK HOLEs

Authors: Mohsen Fathi,

Comments: 15 pages, 12 figures, 1 table

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

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

DARK-FLIP I introduced a semi-analytical and Python-based framework for studying a RELATIVISTIC version of the intermediate-axis instability (IAI) of a coherent non-axisymmetric matter element around rotating BLACK HOLEs dressed by DARK MATTER (DM). In this second paper I test the robustness of that idea. The main question is simple: if the local environment is changed by the DM profile, how does the flip frequency respond? To answer this, I use a controlled effective response model (ERM), not a full accretion or radiative-transfer simulation. The flip frequency is therefore treated as a diagnostic orientation-modulation timescale, not as a direct quasi-periodic oscillation (QPO) model. I vary the DM normalization, profile scale radius, intermediate principal moment of inertia, effective tidal coupling, initial perturbation, and initial orientation. Einasto and regularized cored Navarro--Frenk--White (cored-NFW) profiles are used as the main DM models, while Hernquist is kept as a control benchmark. The analysis includes one-dimensional scans, two-dimensional response maps, profile-contrast maps, time-domain flip simulations, a profile timing-response diagnostic, and a local projected-emissivity proxy. The results show a clear perturbative trend: increasing the enclosed DM normalization decreases the flip frequency relative to Kerr, while more extended profiles weaken the local response. DARK-FLIP II therefore strengthens the interpretation of the flip frequency as a controlled DM-sensitive orientation clock.

[abstract 22 / 32] (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, submitted to RNAAS

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

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

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 23 / 32] (score: 2)
arXiv:2606.06645 [pdf, ps, other]

Title: micrOMEGAs 7: Beyond standard cosmology

Authors: G. Belanger, A. Belyaev, N. Bernal, F. Boudjema, S. Chakraborti, A. Goudelis, A. Pukhov,

Comments: 24 pages, 7 figures

Subjects: hep-ph

Created: 2026-06-04; Updated: 2026-06-08; Datestamp: 2026-06-08

We present micrOMEGAs7, a major upgrade of the micrOMEGAs package for the computation of DARK MATTER observables in generic models. This release introduces a generalized treatment of the Boltzmann equations, allowing for user-defined modifications of the Hubble expansion rate, entropy evolution, and non-thermal DARK MATTER production from late-decaying cosmological components, thereby extending the framework beyond the standard radiation-dominated cosmology. The relic density can now be computed in scenarios such as low-temperature reheating, early matter domination, and kination. The new version also improves the treatment of sub-GeV DARK MATTER, in particular annihilation into light mesons through scalar mediators, and provides updated spectra for indirect detection. Several experimental and observational constraints have been implemented or revised, including CMB bounds from Planck on energy injection during recombination and FERMI-LAT limits from dwarf spheroidal galaxies. For direct detection, a recast of recent LZ results has been included, and the code now takes into account effective electroMAGNETic couplings of spin-$1/2$ and spin-1 DARK MATTER. Collider observables have also been extended through the implementation of CMS dilepton resonance constraints on $Z'$ mediators. Additional improvements include a more flexible treatment of effective RELATIVISTIC degrees of freedom and an updated LHAPDF interface.

[abstract 24 / 32] (score: 2)
arXiv:2606.06922 [pdf, ps, other]

Title: Pulsar searches of FERMI-LAT gamma-ray sources with the MWA

Authors: C. P. Lee, N. D. R. Bhat, B. W. Meyers, W. van Straten, D. A. Smith,

Comments: 21 pages, 9 figures, 5 tables, accepted for publication in PASA

Subjects: astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Searches of unassociated gamma-ray sources in the FERMI-LAT catalogues have led to the discoveries of around a fifth of all known millisecond pulsars (MSPs). These searches have almost exclusively been performed at radio frequencies above 300 MHz, where dispersion and scattering in the interstellar medium are less significant. We report on a shallow survey for pulsars targeting 308 unassociated FERMI-LAT sources in archival Murchison Widefield Array (MWA) observations from the Southern-sky MWA Rapid Two-metre (SMART) pulsar survey at 154 MHz. This is the largest radio survey of unassociated FERMI-LAT sources to date, and only the second to be conducted below 300 MHz after a survey with the Low Frequency Array (LOFAR) that discovered three MSPs. Each source was observed for 20 min by digitally beamforming the MWA tile voltages. Searches were then performed using a new pipeline that implements a semi-coherent dispersion removal scheme for MWA data, enabling greater sensitivities to MSPs than is possible with fully-incoherent dispersion removal (e.g. 2-3 times better sensitivity for dispersion measures between 20-40 pc/cm^3). No new pulsars were identified in the survey, which we attribute to insufficient sensitivity. We estimate flux density limits of approximately 30-220 mJy at 154 MHz (or 0.7-5.2 mJy at 1.4 GHz) for a spin period of 2 ms and a duty cycle of 28%. We discuss how the improved instantaneous sensitivity from the Phase III upgrade of the MWA will increase the number of detectable gamma-ray pulsars by ~30% for the same integration time. The semi-coherent search pipeline we have developed will also be useful for searches of SUPERNOVA remnants, globular clusters, and pulsar candidates identified in imaging surveys, all of which will help to inform the significance of future surveys with SKA-Low.

[abstract 25 / 32] (score: 2)
arXiv:2606.06963 [pdf, ps, other]

Title: From Cosmic Web to Supernova Remnants: Modeling FRB DM to Trace Baryons across Multiple Scales

Authors: Zhao Joseph Zhang,

Comments: PhD thesis, The University of Osaka, 2026

Subjects: astro-ph.CO

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Fast radio bursts (FRBs) provide a powerful probe of ionized baryons through their dispersion measures (DMs), but the observed signal contains contributions from the intergalactic medium (IGM), circumgalactic (CGM) gas, host galaxies, and source-local environments. In this thesis, I investigate FRB DMs from cosmic-web to source-local scales using cosmological simulations, zoom-in galaxy simulations, and SUPERNOVA-remnant (SNR) simulations. Using the CROCODILE simulation suite, I study the DM-$z$ relation, baryon distribution, halo contributions, and host-galaxy DMs. AGN feedback redistributes baryons from halo centers into the diffuse CGM/IGM gas, particularly affecting DM contributions from massive foreground halos. From the simulated DM-$z$ relation, I derive diffuse baryon fractions of $f_{\rm diff}=0.865^{+0.101}_{-0.165}$ and $0.856^{+0.101}_{-0.162}$ for the fiducial and NoBH models. Host-galaxy DM contributions range from below 100 pc cm$^{-3}$ in dwarf galaxies to above 1300 pc cm$^{-3}$ in cluster environments. I also model young MAGNETars embedded in SNRs using one-dimensional hydrodynamical simulations. The dominant time-variable DM component arises from unshocked ejecta, while the shocked region contributes only a minor fraction. Comparisons with FRB 20190520B and FRB 20121102 suggest source-local DM contributions of tens to hundreds of pc cm$^{-3}$. Most models become transparent to GHz radio emission within 70 yr. In contrast, the shocked region dominates the RM contribution and evolution, with the $11\,M_\odot$ single-star model best reproducing the RM evolution of FRB 20121102. These results demonstrate that FRB dispersion measures must be interpreted as multi-component signals spanning a wide range of physical scales, linking the cosmic web, gaseous halos, host galaxies, and compact-object environments

[abstract 26 / 32] (score: 2)
arXiv:2606.06973 [pdf, ps, other]

Title: Asymptotic behavior of the shear flow reactivity enhancement effect

Authors: Henry Fetsch, Nathaniel J. Fisch,

Comments: 15 pages, 7 figures

Subjects: physics.plasm-ph

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Fusion reactivity is enhanced in the vicinity of strongly sheared flow due to the tendency of fast ions near the Gamow peak to travel long distances between collisions, thereby sometimes crossing gradients in the background flow and attaining a velocity boost relative to the thermal background. This ``shear flow reactivity enhancement effect'' (SFRE) allows turbulent kinetic energy on fine spatial scales to contribute to fusion reactivity before thermalizing, which, remarkably, enables ignition of some inertial confinement fusion (ICF) hot spots under conditions where fully thermalized plasma would fail to ignite. The size of the SFRE is a consequence of the dramatic scale separations distinguishing thermal ions, which govern fluid quantities, and fast ions, which govern fusion reactivity. It is demonstrated in this work that, as the Gamow energy increases relative to the thermal energy, the SFRE in unMAGNETized plasma becomes asymptotically large compared to hydrodynamic effects such as viscous dissipation. An asymptotic formula is derived in this limit, quantifying the SFRE for reactants of disparate masses and charge states.

[abstract 27 / 32] (score: 2)
arXiv:2606.06974 [pdf, ps, other]

Title: LHAASO J1849$-$0002: A Hybrid Lepto-Hadronic Interpretation of PeV Gamma-Ray Emission

Authors: Yihan Shi, Yudong Cui, Lili Yang,

Comments: 6 pages, 4 figures, submitted to A&A

Subjects: astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Recently, LHAASO detected gamma-ray emission from the pulsar wind nebula (PWN) J1849-0001 extending up to approximately 2 PeV, providing strong evidence for PeV particle acceleration. To explain the origin of this ultra-high-energy emission, we investigate three physical scenarios: a pure leptonic model, a hadronic-dominated model, and a hybrid lepto-hadronic model. We show that while both pure leptonic and hadronic-dominated models can reproduce parts of the multiwavelength spectral energy distribution (SED), neither can simultaneously explain the entire dataset, particularly the PeV tail. The leptonic scenario requires an unrealistically high electron cutoff energy, while the hadronic model underpredicts the highest-energy emission. We therefore propose a hybrid model that combines inverse Compton emission from PWN electrons with hadronic interactions between escaped COSMIC RAYs and a nearby molecular cloud. In this framework, a suppressed diffusion coefficient ($\sim 1\%$ of the Galactic average) is required to confine PeV particles in the source vicinity. This model successfully reproduces the full SED, including the approximately 2 PeV emission. We further calculate the associated neutrino flux, and show the sensitivity of NEON to this source. Our results support the interpretation that evolved PWNe embedded in complex environments can act as Galactic PeVatrons.

[abstract 28 / 32] (score: 2)
arXiv:2606.07087 [pdf, ps, other]

Title: A series of unfortunate events: CHIME/FRB misclassification of a Galactic pulsar as a periodic fast radio burst

Authors: FRB Collaboration,

Comments:

Subjects: astro-ph.HE

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

In 2022, the CHIME/FRB Collaboration reported the detection of FRB 20191221A, an apparent fast radio burst exhibiting a significant periodicity of 217 ms. Recently, this event has been identified as a series of pulses originating from the known Galactic pulsar PSR J0248+6021. The initial misidentification was caused by an unusual calibration problem with the CHIME telescope, coupled with the atypical characteristics of the pulsar's emission. Here, we detail the issues with the calibration and how it led to a many-degree offset in the pointing of the calculated beams. We describe how we verified that this problem has not affected any other FRB localization, including those reported in the Second CHIME/FRB Catalog, and our newly implemented checks to ensure this mispointing problem does not affect future data.

[abstract 29 / 32] (score: 2)
arXiv:2606.07201 [pdf, ps, other]

Title: Impact of mechanical constraints on tokamak design and implications for high field power plants

Authors: Timothe Auclair, Baptiste Boudes, Jean-Luc Duchateau, Eric Nardon, Laura Pittaluga, Yanick Sarazin, Finn Sutcliffe, Alexandre Torre,

Comments: Submitted to Nuclear Fusion

Subjects: physics.plasm-ph

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Two analytical models for sizing the toroidal field coils and central solenoid of a tokamak are developed within the D0FUS system code: a pedagogical thin-cylinder model and a refined thick-cylinder and winding packs model. The refined model shows good agreement with six reference machines and the MADE MAGNET design code. When the high-field design space is explored for DEMO-class power plants (2 GW of fusion power, Q = 40, tplateau = 2 h), pushing the peak field at the Toroidal Field (TF) coil conductor up to Bmax = 20 T, the radial build emerges as the dominant constraint: in fact, in the baseline wedging/316L configuration, no viable design can be found beyond 20 T, making alternative strategies necessary. The primary levers identified are high-strength steels (e.g CHSN01), alternative mechanical architectures (bucking, plug), and reductions of the effective Central Solenoid (CS) flux demand (for example through auxiliary heating during ramp-up), each carrying an impact of the same order of magnitude on the minimum feasible major radius. Secondary optimisations (conductor shape, radial grading) are shown to provide additional but more modest gains. When all favourable levers are combined (CHSN01, bucking, etc.), compact machines (R0 < 4 m) appear feasible. This suggests that, provided one accepts the associated risks of combining new approaches (CHSN01, bucking, etc.), high-temperature superconductors could unlock the path to compact electricity generating tokamaks.

[abstract 30 / 32] (score: 2)
arXiv:2606.07209 [pdf, ps, other]

Title: Radial and angular evolution of MAGNETic cloud signatures in the turbulent solar wind: virtual spacecraft analysis

Authors: M. Sangalli, E. K. J. Kilpua, A. Verdini, S. W. Good, J. Pomoell, S. Landi,

Comments: 12 pages, 8 figures. Accepted by A&A

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Interplanetary coronal mass ejections (ICMEs) carry MAGNETic clouds (MCs), large-scale structures with average radial widths about a fifth of an astronomical unit at Earth's orbit. ICMEs display substructures in white light images and reveal rich dynamics across many spatial scales when directly measured by spacecraft. A spacecraft encounter with an ICME can result in smoothly rotating MC intervals or less organised MAGNETic obstacle (MO) ones. We investigate how the interplay of expansion, turbulence, and internal cloud dynamics affects MAGNETic cloud properties, which are reflected in the plasma signatures measured by spacecraft. We perform high-resolution 2.5D MHD simulations of a MAGNETic flux rope cross-section, which is embedded in the turbulent, expanding solar wind with the expanding box model. We probe the local plasma properties, and thus the flux rope signatures and angular coherence, with virtual spacecraft. Our simulations reproduce clear and stable MC signatures when the flux rope core is intercepted by virtual spacecraft. Disordered MO signatures appear at the edges of the flux rope, and are attributed to both expansion and turbulent transport. We vary some key physical parameters of the flux rope and the environment to understand their effect on the observed coherence and signatures. The pace of the expanding flow controls the angular extent of MC signatures, whereas the intensity of interplanetary turbulence controls how asymmetric and distorted the flux rope appears at 1 AU. The geometry of spacecraft encounters determines whether MC or MO signatures are observed. The presence of a MAGNETic structure which can result in MO signatures is strongly controlled by the flux rope's initial/early MAGNETic configuration: MO signatures can only be observed when the axial flux rope field is spatially not well confined by the rope's own MAGNETic tension, and disappear otherwise.

[abstract 31 / 32] (score: 2)
arXiv:2606.07330 [pdf, ps, other]

Title: Red noise and evolving signals: a complete frequentist approach to supermassive BLACK HOLE binary searches with pulsar timing array

Authors: Xuan Tao, Boris Goncharov, Yiqian Qian, Yan Wang, Soumya D. Mohanty,

Comments: 18 pages, 10 figures

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

Searches for gravitational waves (GWs) from isolated supermassive BLACK HOLE binaries (SMBHBs) in pulsar timing array (PTA) data require simultaneous estimation of signal and noise parameters, so the dimensionality of the fit scales with the number of observed pulsars. This computational difficulty is exacerbated when source evolution from GW emission is included, since retaining both Earth and pulsar terms introduces the unknown pulsar distances. Existing frequentist methods such as the $\mathcal{F}$-statistic, restricted so far to non-evolving sources, effectively, imply a circular analysis, which may lead to biased estimators. We present a Generalized Likelihood Ratio Test (GLRT) and the associated $\mathcal{T}$-statistic that overcomes the aforementioned limitations. The formulation of the GLRT extends earlier work in which the dimensionality of the fitting problem was drastically reduced by semi-analytical maximization of the likelihood over the pulsar phase parameters, followed by efficient global optimization over the remaining parameters using Particle Swarm Optimization. Our simulations demonstrate that for an evolving SMBHB signal with chirp mass $\mathcal{M}=10^{9.2}\,M_\odot$ and signal-to-noise ratio $20$, this detection statistic achieves a $100\%$ detection probability at a false-alarm probability of $0.06$ in a 30-pulsar timing array, which is characterized by a $100~\mathrm{ns}$ root-mean-square white noise residual and pulsar-specific red noise.

[abstract 32 / 32] (score: 2)
arXiv:2606.07446 [pdf, ps, other]

Title: Polarized and unpolarized SYNCHROTRON emission from DARK MATTER in extragalactic targets

Authors: Javier Reynoso-Cordova, Catherine Gibson, Stefano Profumo,

Comments: 32 pages, 6 figures

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

Created: 2026-06-05; Updated: 2026-06-08; Datestamp: 2026-06-08

We compute 95% confidence-level upper limits on the DARK MATTER annihilation cross section and decay rate from both total-intensity and polarized SYNCHROTRON emission in five extragalactic targets: M31, the Large Magellanic Cloud (LMC), the Draco and Sculptor dwarf spheroidal galaxies, and the Coma cluster. Using Planck maps at 30, 44, and 70 GHz, we solve the diffusion-loss equation for dark-matter-produced electrons and positrons numerically with DRAGON and integrate the resulting SYNCHROTRON emission along the line of sight with HERMES, computing both total-intensity and polarized-intensity maps for each target with target-specific MAGNETic-field, gas, and radiation-field environments. The 30 GHz channel yields the most stringent constraints in all cases, and limits on annihilation or decay into $e^+e^-$ are stronger than those for $b\bar{b}$ due to the harder injected spectrum. For most targets the total-intensity and polarized limits are broadly comparable; the LMC is an exception, where Faraday dePOLARIZATION in the turbulent disk suppresses the polarized signal relative to total intensity, making total intensity the primary estimator. Our results are robust against the choice of flux estimator and coordinate uncertainty. This work demonstrates that microwave polarimetry provides a complementary and largely independent probe of DARK MATTER SYNCHROTRON emission in extragalactic targets.