Current date: 2026-08-31
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Scoring abstracts
Number of records retrieved: 690
Keyword score statistics
score 13 -- 1 abstracts
score 8 -- 1 abstracts
score 7 -- 2 abstracts
score 5 -- 2 abstracts
score 4 -- 8 abstracts
score 3 -- 9 abstracts
score 2 -- 19 abstracts
in total -- 42 abstracts
Articles that appeared on 2026-08-31
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[abstract 1 / 42] Wow! (score: 13)
- Title: Rapid Variability and Broadband Spectral Modeling in the Flaring Activity of BL LacertaeAuthors: Xin Chang, Dingrong Xiong, Chenxu Liu, Rui Xue, Tingfeng Yi, Jia Zhang, Yu Pan, Xingzhu Zou, Xinlei Chen, YeHao Cheng, Yuanpei Yang, Jinghua Zhang, Xiangkun Liu, Yuan Fang, Guowang Du, Tao Wang, Xufeng Zhu, Zhongxiang Wang, Sarira Sahu, Xiaowei Liu,Comments:Subjects: astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
We report a multi-wavelength study of two flaring episodes of the BLAZAR BL Lacertae during MJD 60500-60800 (9 July 2024 - 5 May 2025). The source reached a daily-averaged $γ$-ray flux of $(1.03 \pm 0.05) \times 10^{-5} \, \mathrm{ph \, cm^{-2} \, s^{-1}}$ ($E > 100$ MeV) on MJD 60588 (5 October 2024). Using orbit-binned data from the Large Area Telescope (LAT) onboard the \textit{FERMI Gamma-ray Space Telescope}, we identify a minimum flux halving timescale of $τ= 1.33 \pm 0.29$ hr. This constrains the upper limit on the $γ$-ray emitting region size to $R \le 2.0 \times 10^{15}$ cm, as well as its distance from the central supermassive BLACK HOLE to $R_\mathrm{H} \le 5.9 \times 10^{16}$ cm, assuming a Doppler factor of $δ= 14.8$ derived from the spectral energy distribution (SED) modeling. We find tentative evidence for sub-minute $γ$-ray variability with a minimum doubling time of $0.7 \pm 0.2$ min ($p$-value = 0.03). This may originate from an extremely compact region with a size of $R \le 1.8 \times 10^{13}$ cm, suggesting that the emission arises from MAGNETohydrodynamic substructures, such as plasmoids within a MAGNETic RECONNECTion zone. Spectral analysis reveals a significant ``softer-when-brighter'' trend ($r = 0.96, p = 4.5 \times 10^{-4}$) during the minute-scale flare peaks, indicating a complex interplay between particle acceleration and radiative cooling. The SED is reproduced using a one-zone leptonic model, in which SYNCHROTRON self-Compton (SSC) and external Compton (EC) scattering effectively account for the high-energy emissions. The reduced MAGNETic field strengths and hard electron injection spectral indices observed during the flaring states suggest enhanced particle acceleration efficiency, possibly associated with RELATIVISTIC MAGNETic RECONNECTion.
[abstract 2 / 42] Wow! (score: 8) - Title: The Geometry of Ultra-Fast Outflows Probed by Soft X-ray Variability in PDS 456Authors: Riki Sato, Kouichi Hagino, Toshiya Iwata, Ehud Behar, Valentina Braito, Chris Done, Misaki Mizumoto, James N. Reeves, Rozenn Boissay-Malaquin, Pierpaolo Condó, Luigi C. Gallo, Adam G. Gonzalez, Alfredo Luminari, Aiko Miyamoto, Ryuki Mizukawa, Hirokazu Odaka, Atsushi Tanimoto, Makoto Tashiro, Francesco Tombesi, Yerong Xu, Satoshi Yamada, Tahir Yaqoob, Aya Bamba,Comments: 13 pages, 16 figures, 2 tables, accepted for publication in PASJSubjects: astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Constraining the location and geometry of ultra-fast outflows (UFOs) is essential for identifying where they are launched and how they are accelerated. We investigate the soft X-ray variability of the luminous QUASAR PDS 456 using simultaneous March 2024 observations with XRISM/Xtend and NUSTAR. A model-independent comparison between the flare and quiescent phases reveals spectral variability around 1 keV in the rest frame, while the hard X-ray spectral shape remains nearly unchanged. Broadband spectral fitting shows that the soft X-ray structure is well described by a partial-covering low-ionization UFO with $\log (ξ/(\mathrm{erg~cm~s^{-1}})) \simeq 3.1$ and $v_{\mathrm{out}} \simeq 0.30c$. Time-sliced spectral analysis further reveals significant variability in the covering fraction of this absorber. Interpreting this variability as transverse motion across the X-ray source, we constrain the crossing velocity to be $v_{\mathrm{cross}} \lesssim 5 \times 10^{-3}c$ and derive a lower limit on the absorber distance of $r \gtrsim 4 \times 10^3 R_{\mathrm{g}}$. This location is substantially farther out than the high-ionization UFO previously inferred at ~200-600 $R_{\mathrm{g}}$, while the two phases have comparable outflow velocities. The resulting velocity-distance structure disfavors a self-similar MAGNETocentrifugal wind and instead suggests either radiation-pressure acceleration following a Castor-Abbott-Klein-like velocity law or compact MAGNETic acceleration through MAGNETic RECONNECTion. These results demonstrate that soft X-ray partial-covering variability can provide a geometrical probe of UFOs and directly connect spectral variability to wind acceleration.
[abstract 3 / 42] Wow! (score: 7) - Title: A first-principles binary neutron star merger model of GW170817, GRB170817A, and AT2017gfoAuthors: Kenta Kiuchi, Sho Fujibayashi, Kota Hayashi, Kyohei Kawaguchi, Quentin Pognan, Alexis Reboul-Salze, Yuichiro Sekiguchi, Masaru Shibata, Shinya Wanajo,Comments: 9 pages for the main text and 3 figures. 40 pages for the Supplementary MaterialSubjects: astro-ph.HE gr-qcCreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
The multimessenger observation of the binary neutron star merger event GW170817, associated with its electroMAGNETic counterparts GRB170817A and AT2017gfo, marked a milestone in astrophysics, yet its unified physical explanation remains elusive. We conduct an end-to-end simulation based on a first-principles general-RELATIVISTIC MAGNETohydrodynamics neutrino-radiation transfer merger simulation, followed by nucleosynthesis calculations and photon radiative transfer to generate kilonova light curves. We show that the large-scale dynamo simultaneously produces a RELATIVISTIC JET with an isotropic-equivalent luminosity of $\sim 10^{51}~{\rm erg~s^{-1}}$ and $\approx 0.08M_\odot$ of neutron-rich ejecta, reproducing the GRB170817A afterglow and the AT2017gfo kilonova light curves. Our results establish a unified first-principles framework for interpreting binary neutron star mergers across gravitational wave, GAMMA-RAY BURST, and kilonova observations.
[abstract 4 / 42] Wow! (score: 7) - Title: Reassessing the contribution of long-GRB high-energy afterglows to the isotropic gamma-ray background after GRB 221009AAuthors: S. V. Troitsky,Comments: 11 pages, 5 figuresSubjects: astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Very-high-energy photons from GAMMA-RAY BURSTs (GRBs) are absorbed by the extragalactic background light and partly reprocessed into the GeV band. We update previous estimates of the long-GRB contribution to the FERMI-LAT isotropic gamma-ray background (IGRB), using a time-integrated high-energy afterglow template of GRB 221009A, anchored by GeV-TeV data, together with an explicitly specified scaling with prompt energy and beaming. Despite the observed multi-TeV afterglow, the cascade component reaches only 1.6e-4 of the IGRB. Including direct GeV emission raises the maximum fraction to 1.1e-3, but makes the result more dependent on the population-averaged broadband template. Variations of the extragalactic background light, propagation implementation, intrinsic spectral cutoff, and population prescription do not change the conclusion: the multi-TeV detection of GRB 221009A does not make long GRBs a significant source of the IGRB.
[abstract 5 / 42] Yes (score: 5) - Title: Distinct Jet Properties in the X-Ray-Obscured State of GRS 1915+105Authors: Xi Yan, Lang Cui, Sergei Trushkin, Shuangjing Xu, Wu Jiang, Zhen Yan, Sándor Frey, Timur Mufakharov, Ruchika Dhaka,Comments: ApJ in pressSubjects: astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
GRS 1915+105 has remained in an X-ray-obscured state since its transition from a long-lasting unobscured state in 2019. We report on 6.7-GHz East Asia VLBI Network observations of GRS 1915+105 obtained during strong radio flares detected at 2.3--11.2 GHz with the RATAN-600 radio telescope in 2025. Our images reveal two contrasting JET morphologies. The first epoch, associated with a flare evolving from an optically thick to an optically thin spectrum, shows a bright radio core accompanied by an extended JET structure. By contrast, the second epoch, observed near the peak of another flare displaying optically thin emission at lower frequencies, is dominated by two bright, symmetric, well-separated JET blobs and shows no detectable radio core. If these JETs exhibited the apparent superluminal motions commonly observed prior to 2019, measurable angular shifts would be expected over the five-hour observations. However, no significant JET motion is detected. Combined with our derived JET speed of $βΓ\lesssim 0.40$, these results suggest that the JETs launched during the current obscured state are slower than the RELATIVISTIC JETs ($βΓ\gtrsim 1$) observed earlier during the unobscured state. Together with the recently reported large variations in JET orientation, our findings in GRS 1915+105 provide robust support for the emerging paradigm that X-ray binary JETs launched in obscured and unobscured states likely exhibit distinct propagation properties.
[abstract 6 / 42] Yes (score: 5) - Title: Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanismsAuthors: Joheen Chakraborty, Erin Kara, Wenbin Lu, Brian D. Metzger, Peter Kosec, Riccardo Arcodia, Itai Linial, Olivia Aspegren, Ehud Behar, Sudip Bhattacharyya, Margherita Giustini, Lorena Hernandez-Garcia, Daniel Kasen, Giovanni Miniutti, Frits Paerels, Erwan Quintin, Claudio Ricci, Daniele Rogantini, Paula Sanchez-Saez, Fatima Zaidouni,Comments: Submitted, comments welcome!Subjects: astro-ph.HE astro-ph.GACreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Quasi-periodic eruptions (QPEs) are recurring bursts of X-ray radiation originating from supermassive BLACK HOLEs (SMBHs). They are an unprecedented type of structured, high-amplitude SMBH variability, but the physical origins of their regularity, timescales, energetics, and emission are uncertain. We present new XMM-Newton observations of the QPEs in ZTF19acnskyy/``Ansky'', constituting the deepest observations of individual bursts in any source thus far. The X-ray spectra reveal time-evolving P Cygni profiles comprising blueshifted absorption and redshifted emission from L-shell transitions of Fe XIX-XXIV, with column densities $N_H\sim 10^{22-23}$ cm$^{-2}$ and bulk velocities of $|v_w/c|\sim 0.2$, indicating RELATIVISTIC mass ejections during each eruption. We construct a time-dependent analytical model of a wind turning on to self-consistently compute its evolving luminosity and ionization properties, and find that the light curve and spectral lines can be simultaneously produced by a wide-angle outflow with $\dot{M}\sim 10^{-9}-10^{-8}\,M_\odot$ s$^{-1}$ kinetically powering the X-rays with an efficiency of $L_X/\dot{E}_K\sim 0.1$. Each eruption ejects $\sim 10^{-3}\,M_\odot$ and $\gtrsim 10^{49}$ erg of kinetic energy, setting an upper bound on the QPE lifetime of $\lesssim30$ years if the underlying mass reservoir is $\sim1 M_\odot$, and implying that the bursts may result in detectable multiwavelength signatures of reverberation and feedback. These measurements provide new quantitative constraints on QPE energetics, emission mechanisms, and the mass/energy they recycle into their circumnuclear environments, as well as an observational probe for direct comparison with physical models and hydrodynamical simulations of QPEs.
[abstract 7 / 42] Yes (score: 4) - Title: Photon Acceleration in Magnetized Plasma: A Mechanism for Fast Radio BurstsAuthors: Sergei V. Bulanov, Gabriele Maria Grittani, Marcel Lamac, Petr Valenta, Stepan S. Bulanov, Timur Zh. Esirkepov, Gianluca Gregori, Brandon K. Russell, Alexander G. R. Thomas, Arno Vanthieghem,Comments: 26 pages, 6 figuresSubjects: physics.space-ph astro-ph.HE physics.plasm-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
We propose a mechanism for fast radio bursts based on photon acceleration by RELATIVISTIC shocks propagating through highly MAGNETized electron--positron plasmas, as expected in MAGNETar MAGNETospheres. Density modulations at the shock front create RELATIVISTICally moving refractive-index perturbations that transform low-frequency electroMAGNETic precursors into amplified high-frequency radiation. We show that the predicted frequencies, durations, and energetics of the resulting fast radio bursts are consistent with the MAGNETic-field strengths, shock Lorentz factors, and characteristic spatial scales expected in MAGNETar MAGNETospheres.
[abstract 8 / 42] Yes (score: 4) - Title: On the astrophysical origin of COSMIC RAYs: Constraining the Ultra-High-Energy Cosmic Ray Horizon through Nearby Galaxy DistributionsAuthors: F. Dávila-Kurbán, F. Duplancic, D. Garcia Lambas,Comments: 18 pages, 10 figuresSubjects: astro-ph.HE astro-ph.CO astro-ph.GACreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
The origin of ultra-high-energy COSMIC RAYs (UHECR) remains a central open problem in astroparticle physics. The observed large-scale anisotropy of UHECR arrival directions above several EeV, together with the spectral suppression at the highest energies, suggests extragalactic sources confined to a limited volume of the nearby Universe, though the effective spatial scale of this contribution remains poorly constrained. We aim to constrain the effective propagation horizon of UHECR with energies E >= 8 EeV by studying how well the observed large-scale anisotropy is reproduced by the distribution of nearby galaxies at different distances, accounting for Galactic MAGNETic-field deflections. We construct volume-limited galaxy samples from the GLADE+ catalogue extending to 10000 km/s (~150 Mpc) and use both dipole comparisons and angular cross-correlation analyses with the Pierre Auger Observatory UHECR flux map (E >= 8 EeV) to characterize the distance dependence of the anisotropy signal, further weighting the galaxy-UHECR correlations using deflection maps derived from a Galactic MAGNETic field model. We find that the angular separation between the galaxy and UHECR dipoles is minimized for galaxies within cz < 4000 km/s (< 60 Mpc), where the galaxy dipole amplitude is also maximal. The galaxy-UHECR cross-correlation signal is dominated by this nearby population and weakens rapidly at larger distances. Accounting for Galactic MAGNETic field deflections enhances the correlation amplitude by more than a factor of two, indicating that MAGNETic effects significantly shape the observed anisotropy. Our results indicate that the observed anisotropy of UHECR of 8 EeV and above is primarily driven by sources within ~50-60 Mpc, consistent with expectations from energy losses and MAGNETic deflections, retaining a measurable imprint of the nearby extragalactic matter distribution.
[abstract 9 / 42] Yes (score: 4) - Title: Constraints on the MAGNETic field in the hadronic scenario for the origin of the radio halo in the A1795 galaxy clusterAuthors: P. Marchegiani, V. Vacca, F. Loi, F. Govoni, M. Murgia,Comments: 5 pages, 1 appendix, 4 figures, 1 table; accepted for publication in A&ASubjects: astro-ph.HE astro-ph.COCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
The radio halo in the cool-core galaxy cluster, A1795, has recently been proposed to be of hadronic origin, because it extends on megaparsec scales, where no turbulence is expected to be injected into a relaxed cluster. In this paper we aim to constrain the properties of nonthermal protons and the cluster MAGNETic field strength under the hypothesis of a hadronic origin for the radio halo in the light of the available gamma-ray upper limits for this cluster. We assumed a radial profile and several central MAGNETic field intensity values, then derived the corresponding properties of the nonthermal protons necessary to reproduce the flux density and surface brightness profile of the radio halo. For the obtained results, we calculated the corresponding gamma-ray emission and compared it with the FERMI-LAT upper limit. We find that, for a MAGNETic field energy radial profile following that of the thermal gas, central MAGNETic field intensities $B_0<5\,μ$G imply a gamma-ray emission at or above the FERMI-LAT upper limit. Therefore, larger values of the MAGNETic field are necessary in the hadronic scenario. For these values the radial profile of nonthermal protons must slightly decrease with radius, though more slowly than that of the thermal gas. For smaller values of the MAGNETic field, different mechanisms for producing or accelerating the nonthermal electrons are necessary.
[abstract 10 / 42] Yes (score: 4) - Title: Exploring the capabilities of combined modelling strategies for SUPERNOVA with RELATIVISTIC JETs using RedbackAuthors: L. Cotter, N. Sarin, A. Martin-Carrillo,Comments:Subjects: astro-ph.HECreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
Events in which a SUPERNOVA (SN) is associated with a RELATIVISTIC JET present multi-component light curves. In the past, the analysis of such complex light curves was carried out largely by investigating each component individually due to limitations in modelling and inference. Such decoupled analyses are susceptible to biased parameter estimation due to cross-contamination between the emission of the RELATIVISTIC JET and the SN. Additionally, differences in adopted methodologies make it difficult to compare physical parameters across populations. In this work, we investigate three common modelling strategies adopted for events where a Gamma-ray Burst (GRB) is associated with an SN and compare them with a joint model and inference approach. We assess the ability of each approach to fit and reproduce the true injection parameters of 1000 simulated GRB-SN datasets using Redback. We split these datasets into three common GRB-SN light curve morphologies: one where the SN is dominant, one where the GRB is dominant, and one where the SN and GRB have relatively equal contributions to the light curve. We also investigate the behaviour of each modelling technique when the JET break of the GRB afterglow occurs at early times and at late times. We find that treating each component independently with an individual model leads to significant bias in the estimated parameters even though the resulting best fit to the data may appear acceptable. We further demonstrate that afterglow subtraction is unreliable for GRB-SN modelling as uncertainties in the afterglow fit are not fully propagated into the resulting afterglow-subtracted light curve. Instead, our results show that jointly modelling the RELATIVISTIC JET and SN components provides the most reliable modelling approach, particularly when multi-band X-ray and radio observations are available.
[abstract 11 / 42] Yes (score: 4) - Title: The Limited Lifetime of Self-Gravitating Accretion Disks In Galactic CentersAuthors: Isaac Shlosman,Comments: Accepted by Galaxies/MDPI 2026, Volume 14, Issue 5, 82Subjects: astro-ph.GA astro-ph.COCreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
Globally self-gravitating accretion disks in ACTIVE GALACTIC NUCLEi (AGN) have been frequently discussed in the literature, but never observed. Few dozen mega-masering accretion disks in AGN have been detected, which display a clear Keplerian rotation on scales of 0.1-1 pc, allowing to estimate their masses within the sphere of influence (SoI) of the central supermassive BLACK HOLEs (SMBHs) to be smaller by more than a factor of 10, compared with the parent SMBH masses. Furthermore, the stellar components, deep inside the SoI, are dwarfed by the SMBH masses of M_BH ~ few X 10^6 - few X 10^7 Mo. Theoretically, no limit exists on sizes and masses of gaseous disks in AGN, which in principle, can exceed masses of their central compact objects. We analyze instabilities which can operate in gaseous disks, i.e., fragmentation for a locally dominant self-gravity and spontaneous breaking of axial symmetry for the globally self-gravitating disks. We invoke the gas response to the latter instability which leads to gravitational collapse, leaving a negligible mass behind and dynamically stable remnants. Consequently, the characteristic timescale for globally self-gravitating disks to exist in AGN should not exceed few rotations, t_phi ~ 10^{3-4} yrs for M_BH ~ 10^{6-8} Mo. Disk rebuilding is expected to be > 10^7 yrs, meaning that probability of finding is < 10^{-3}, which explains their lack of detection. We conclude that observed sub-parsec disks in AGN, at least the Keplerian masering ones, can be remnants of globally self-gravitating accretion disks, and the instability timescale can be related to the duty cycle of AGN, t_duty ~ 10t_phi ~ 10^{4-5} yr.
[abstract 12 / 42] Yes (score: 4) - Title: Formation of BLACK HOLE stars via star--BLACK HOLE collisionsAuthors: Yanlong Shi, Qingru Hu, Zhenghao Xu, Douglas N. C. Lin, Norman Murray,Comments: 13 pages, 7 figuresSubjects: astro-ph.HE astro-ph.GA astro-ph.SRCreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
In dense stellar environments such as globular clusters and ACTIVE GALACTIC NUCLEus (AGN) disks, stellar-mass BLACK HOLEs (sBHs) may frequently collide with massive stars. We investigate this process using semi-analytic models, three-dimensional hydrodynamical simulations, and one-dimensional stellar evolution calculations, focusing on collisions between sBHs and a $100\,M_\odot$ main-sequence star. We find that gas drag retains the BH within the stellar envelope unless the impact velocity exceeds $\sim2\sqrt{G(M_\star+M_\bullet)/R_\star}$. The post-collision outcome depends primarily on the BH-to-star mass ratio. For $M_\bullet\gtrsim30\,M_\odot$, the retained envelope is either quasi-spherical or disc-like, but remains dynamically unstable because of shock heating. In contrast, for $M_\bullet\lesssim10\,M_\odot$, the collision forms a ``BLACK HOLE star'' (BH*): a quasi-hydrostatic, extended stellar envelope surrounding the embedded BH. These results agree with our analytic prediction that BH* formation necessarily requires $M_\bullet\lesssim0.2\,M_\star$. Follow-up \texttt{MESA} calculations further show that, for these low-mass BHs, the shock-heated remnant thermally relaxes without triggering runaway expansion. We discuss several astrophysical implications of BH*s, including their evolution, the possibility of gravitational-wave events from BH binaries assembled within a stellar envelope, and repeated star--sBH collisions as a pathway for rapid BH growth in dense stellar systems. This mechanism may contribute to the formation of massive BHs in high-redshift nuclear star clusters and may be relevant to the origin of the ``little red dots'' discovered by JWST.
[abstract 13 / 42] Yes (score: 4) - Title: Near-Infrared Spectroscopy of Low-Redshift Palomar-Green Quasars and Composite SpectraAuthors: Amy Cavanaugh, Michael Brotherton, Jacob McLane, Richard Green,Comments:Subjects: astro-ph.GACreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
The Palomar-Green (PG) Quasars have been used extensively to establish the spectral properties of luminous ACTIVE GALACTIC NUCLEi (AGNs) at low redshifts in many wavebands, but not the near-infrared (NIR). We present NIR spectra of all 87 PG QUASARs with z < 0.5 observed with the Apache Point Observatory 3.5-m telescope and the TripleSpec spectrograph in standard cross-dispersed mode. Here we employ our data set to construct a NIR composite QUASAR spectrum spanning rest-frame wavelengths from approximately 8800-22000 angstroms reaching a signal-to-noise ratio of several hundred in the H-band for 4 angstrom pixels. We characterize the continuum and emission-line properties of this composite. Additionally, we construct composite spectra as a function of luminosity and Eddington ratio, finding some differences, not entirely unexpected. In particular, more luminous composite NIR spectra grow increasingly red at long wavelengths, consistent with relatively stronger dust emission at higher temperatures.
[abstract 14 / 42] Yes (score: 4) - Title: From Inspiral to Expansion: The Wake-Driven Torque on Binary Black Holes in Gaseous MediumAuthors: Jixuan Yang, Lile Wang, Xinyu Li, Rixin Li,Comments:Subjects: astro-ph.HE astro-ph.GACreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Binary BLACK HOLEs (BBHs) in gaseous medium, such as ACTIVE GALACTIC NUCLEus (AGN) disks, are important gravitational-wave sources, yet the gas-driven torque that governs their orbital evolution remains to be fully understood. Most existing studies of BBHs in gas often approximate the net torque as the sum of independent dynamical friction (DF) forces exerted on each BLACK HOLE by its own wake, neglecting the mutual gravitational coupling between the two wakes. We perform three-dimensional hydrodynamic simulations of circular BBHs in a uniform flow and find the torque is determined by the wake-wake interactions. The net torque is controlled by a single parameter $η\equiv v_g/v_o$, the ratio of the gas flow velocity to the binary orbital velocity. At small $η$, the wakes merge into a single overdense envelope and the time-averaged torque is negative; as $η$ increases, the wakes separate and the torque becomes positive. In AGN disks, capture-channel binaries in a disk model naturally produce $η$ in the positive-torque regime; the expansion timescale is comparable to or shorter than the disk lifetime, suggesting that gas-driven expansion can compete with gravitational-wave inspiral and suppress the capture-channel merger rate.
[abstract 15 / 42] (score: 3) - Title: Revealing the Nonlinear Amplification of Radiation Reaction Effects via Vortex RadiationAuthors: Yi-Ju Kang, Yu-Meng Gao, Jia-Qi Wang, Mamutjan Ababekri, Qian Zhao, Jian-Xing Li,Comments:Subjects: physics.plasm-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Radiation reaction (RR), the back-action of emitted radiation on an accelerated charge, dominates the dynamics of ultraRELATIVISTIC electrons in an intense electroMAGNETic field. By solving the Landau-Lifshitz (LL) equation for an electron in an intense circularly polarized plane wave, we find that once the cumulative RR effect on the oscillation radius becomes non-negligible over hundreds of LASER cycles, the LASER intensity nonlinearly amplifies RR through the modified longitudinal drift velocity, reshaping the vortex $γ$-ray emission in nonlinear inverse Thomson scattering. The energy spectrum acquires MeV-scale central-frequency red shifts, spectral broadening, and harmonic overlap, while the ellipticity of higher-order harmonics becomes non-smooth and overlapping in frequency--angle space, so that the superposed total ellipticity deviates progressively from the RR-free case. These harmonic-resolved spectral and POLARIZATION fingerprints constitute a self-referenced multidimensional diagnostic of RR effects that complements energy-spectrum measurements, with direct implications for bright high-energy $γ$-ray sources and the modeling of extreme astrophysical environments such as neutron-star MAGNETospheres.
[abstract 16 / 42] (score: 3) - Title: Supernova 1987A was a "failed SUPERNOVA" twenty thousand years before its JET-driven explosionAuthors: Noam Soker,Comments: Updated, including references, following comments by readersSubjects: astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
I show that the progenitor of SUPERNOVA (SN) 1987A faded substantially and became red for hundreds of years to observers in and near the plane of the equatorial ring, because the equatorial ring, which was formed by a binary interaction between the SN 1987A progenitor and a main-sequence companion that ejected material about 20,000 years before the explosion, obscured the progenitor. For a few hundred years, the luminosity for such hypothetical observers was mainly light scattered by the two outer rings, which amounted to ~5% of the progenitor luminosity. In present terms, this event would have been classified as a "failed SUPERNOVA" by these observers, although there was no core collapse, no BLACK HOLE formation, and nothing failed. Rather, this event was a type II ILOT (intermediate-luminosity optical transient), in which equatorial ejecta temporarily obscured the central source. After a few hundred years, the outer rings became transparent, the inner ring became more transparent, and the SN 1987A progenitor brightened over a few thousand years to its normal luminosity for equatorial observers. This finding strengthens the claim that "failed SUPERNOVA" candidates are likely to be type II ILOTs. Although the binary interaction also spun up the core, the bipolar morphology of SN 1987A (its Keyhole) is misaligned with the triple-ring system. I use the jittering JETs explosion mechanism (JJEM) to speculate on a scenario that might explain this misalignment. This study adds small but unique support to the claim that the JJEM is the primary explosion mechanism of CCSNe.
[abstract 17 / 42] (score: 3) - Title: Dynamical formation of high-eccentricity compact binaries through BH--BH*/TZO collisionsAuthors: Qingru Hu, Yanlong Shi, Douglas N. C. Lin, Norman Murray,Comments: 13 pages, 9 figuresSubjects: astro-ph.HE astro-ph.GA astro-ph.SRCreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
The rapidly accumulating discoveries of binary stellar-mass black-hole (sBH) coalescences, detected by LIGO, have opened a new window into the formation and evolution of compact binaries. In particular, residual orbital eccentricity may provide a distinctive signature of their formation channels. Here, we investigate a scenario in which high-eccentricity compact binaries form through the sequential capture of multiple sBHs by massive main-sequence stars, using a combination of hydrodynamical and semianalytic few-body simulations. We find that sBHs with $M_\bullet\lesssim 0.2\,M_{\star}$ can be captured by massive stars and settle into a quasi-hydrostatic black-hole star (BH*) through gas dynamical friction. A subsequent encounter with a second sBH can then produce a compact binary embedded within the stellar envelope. Our hydrodynamical simulations show that through captures with small impact parameter, some binaries are born with high eccentricity ($e\gtrsim 0.5$), with its orbital frequency already entering the LISA band. Our semianalytic models further demonstrate that gas dynamical friction can pump the eccentricity to $e_{\rm 10\,Hz}>0.9$ before gravitational-wave emission eventually circularizes the binary during the final stage of coalescence. Once formed, the binary can merge quickly in $\sim 10$ hours. This channel may operate in dense stellar environments, such as star clusters and ACTIVE GALACTIC NUCLEus (AGN) disks. The same mechanism can also be applied to Thorne-Żytkow objects. A high-eccentricity binary in the LIGO band could therefore provide a distinctive signature of this formation scenario.
[abstract 18 / 42] (score: 3) - Title: Magnetospheric birefringence breaks the rotating-vector model and depolarises X-ray pulsarsAuthors: Alexander A. Mushtukov, Sergey S. Tsygankov, Silvia Zane, Nabil Brice, Ruth M. E. Kelly, Roberto Taverna, Roberto Turolla,Comments: submitted to MNRAS, 17 pages, 10 figuresSubjects: astro-ph.HE astro-ph.SR physics.space-phCreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
Accreting X-ray pulsars have long been expected to show large linear polarisation below the cyclotron resonance. In the standard picture, this follows from two facts: radiative opacities in the strongly MAGNETised neutron star environment depend strongly on polarisation mode, and the emission comes from compact polar regions. The emerging radiation should therefore be locally polarised and add almost coherently, with a polarisation angle tracing the projected MAGNETic field as in the rotating-vector model. Recent X-ray polarimetric observations, instead, show modest polarisation fractions and position angle swings that often depart from this simple picture. Here we show that propagation through the MAGNETosphere of an accreting neutron star can naturally produce both effects. Using general-RELATIVISTIC ray tracing and Stokes-parameter transport, we find that photons emitted from compact polar regions acquire ray-dependent polarisation angle offsets in two ways. First, nearly field-aligned trajectories can cross local non-adiabatic pockets inside the QED birefringent region. Second, photons that intersect the plasma-loaded accretion flow accumulate additional phase shifts between plasma normal modes. Both effects broaden the distribution of polarisation angles across the ray bundle and reduce the hotspot-integrated linear polarisation, while also producing systematic deviations from rotating-vector-model expectations. Magnetospheric propagation should therefore be treated as part of the polarimetric transfer problem in accreting X-ray pulsars, and may help explain the observed low polarisation fractions and anomalous angle swings.
[abstract 19 / 42] (score: 3) - Title: Overmassive supermassive BLACK HOLEs in SDSS close galaxy pairsAuthors: Maggie C. Huber, Julia M. Comerford, Joseph Simon,Comments: ApJ Accepted version. 28 pages, 8 figures, 5 tables. Tables 1 and 2 are available as machine-readable tables in the published versionSubjects: astro-ph.GACreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
Supermassive BLACK HOLEs (SMBHs) and their host-galaxies coevolve through channels such as hierarchical merging and AGN feedback, establishing tight scaling relations between SMBH masses and properties of the host-galaxy. These scaling relations, particularly those with host-galaxy bulge mass (M${_\text{b}}$) and stellar velocity dispersion ($σ$), are widely used to estimate SMBH masses. Galaxy mergers drive gas into the centers of galaxies, enhancing SMBH growth and stellar bulge growth but not necessarily in tandem, so it is necessary to determine if galaxies undergoing a merger still follow SMBH-host-galaxy scaling relations. In this study, we explore scaling relations in galaxy mergers by taking advantage of the well-established value-added catalogs in the Sloan Digital Sky Survey. These catalogs provide close galaxy pairs, AGN broad lines for SMBH mass measurements, and bulge-disk decomposed stellar masses. We compare SMBH mass estimates from M$_\bullet-$M${_\text{b}}$ to SMBH mass estimates from AGN broad lines and find that SMBH mass growth outpaces the bulge for AGN residing in the secondary (less massive) bulge and for smaller physical separations between galaxies in a pair. Using our full sample of close galaxy pairs, we find that M$_\bullet-$M${_\text{b}}$ and M$_\bullet- σ$ predict significantly different fractions of major and minor BLACK HOLE mergers with M$_\bullet-$M${_\text{b}}$ predicting BLACK HOLE mass ratios closer to 1:1 and $6-20\%$ more major mergers overall. These results have major implications, including for predictions of astrophysical gravitational-waves and high-redshift overmassive SMBHs.
[abstract 20 / 42] (score: 3) - Title: PolPy: A universal tool for X-ray/gamma-ray polarimetry using common data format standardsAuthors: Sujay Mate, Hancheng Li, Utkarsh Pathak, Yashowardhan Rai, Nicolas De Angelis, Varun Bhalerao, Merlin Kole,Comments: 12 pages, 8 figures, submitted to ApJ/AJSubjects: astro-ph.IM astro-ph.HECreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
X-ray/gamma-ray polarimetry has been a rapidly developing field in recent years. However, the lack of standardized analysis frameworks has hindered cross-instrument comparisons and joint multi-mission studies. To address this, we present PolPy, a universal tool designed for polarimetry of high-energy astrophysical transients. Built as a plugin for the Multi-Mission Maximum Likelihood (3ML) framework, PolPy introduces standardized data and response formats, common reference frames based on IAU conventions for defining POLARIZATION angles, and a robust likelihood-based template-matching algorithm. The article briefly describes these standards and presents tests and results performed to validate the software using simulated GAMMA-RAY BURST (GRB) injections across two different mission mass models: POLAR and Daksha. Our verification tests demonstrate that PolPy accurately recovers the injected POLARIZATION angles and fractions without systematic bias. Furthermore, we show that performing simultaneous joint fits across multiple detectors and instruments can significantly improve parameter constraints compared to single-instrument analyses. By unifying data formats and methodology, PolPy enables reliable joint polarimetric analysis for current and future high-energy polarimeters.
[abstract 21 / 42] (score: 3) - Title: Spherical Accretion onto Konoplya Zhidenko Black Holes: Sonic Point Analysis and Fluid DynamicsAuthors: M H Waheed, M Z A Moughal,Comments:Subjects: astro-ph.HE gr-qcCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
We investigate the spherical accretion onto a static Konoplya Zhidenko BLACK HOLE and examine how the deformation of the spacetime affects the dynamics of the accreting matter. By applying the conservation laws of particle number and energy-momentum, we formulate the accretion problem and derive the corresponding Hamiltonian describing the fluid motion. The critical points and sonic transitions are then analyzed for ultra stiff, ultra RELATIVISTIC, radiation, and sub RELATIVISTIC fluids. We study the dependence of the critical point structure and flow trajectories on the KZ deformation and compare the results with those obtained for asymptotically safe, Schwarzschild MOG, and Reissner Nordström BLACK HOLEs. The comparison shows that the location and behavior of the critical points vary significantly with the underlying BH geometry and the equation of state of the fluid. In particular, the KZ deformation produces noticeable changes in the radial structure of the accretion flow, with different effects observed for the considered fluid models. These results provide a comparative picture of spherical accretion in different BLACK HOLE spacetimes and help clarify how modifications of the background geometry influence matter dynamics in the strong field region.
[abstract 22 / 42] (score: 3) - Title: ElectroMAGNETic pressure-gradient-driven instabilities with moderate high mode numbers in tokamak plasmasAuthors: Yann Narbutt, Ksenia Aleynikova, Matthias Borchardt, Thomas Hayward-Schneider, Ralf Kleiber, Axel Könies, Alexey Mishchenko, Carolin Nührenberg, Edilberto Sánchez,Comments:Subjects: physics.plasm-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Pressure gradient-driven instabilities are investigated in tokamak plasmas using the global gyrokinetic code EUTERPE emphasizing the role of moderate high mode numbers. As the normalized plasma pressure $β$ is increased, there is a well-known, sudden transition from ion-temperature-gradient (ITG) instabilities to kinetic ballooning modes (KBM), if the MAGNETohydrodynamic (MHD) geometry is held fixed. However, if the equilibrium field is recomputed for each value of $β$, so that the equilibrium is consistent with the stability calculation, the transition can disappear. In a number of cases, we are only able to find an ITG-KBM transition if inconsistent equilibria are used. In the MHD unstable regime, gyrokinetic simulations and MHD stability calculations show good agreement for moderate ratios of ion temperature gradient to density gradient and small values of the ion gyro-radius. Otherwise, non-MHD contributions are important, such as the diaMAGNETic stabilization and ion wave--particle resonant effects.
[abstract 23 / 42] (score: 3) - Title: A high-frequency type II radio burst associated with an X2.3 class flareAuthors: Divya Paliwal, Anshu Kumari, Vishwa Vijay Singh, Dinesh Mishra, Pritam Das, Nadiya K,Comments: Accepted for publication in The Astrophysical Journal, 18 Pages, 8 Figures, 1 TableSubjects: astro-ph.SR astro-ph.HE physics.plasm-ph physics.space-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Radio observations provide a powerful diagnostic of the solar corona, enabling investigations of dynamic phenomena associated with solar flares, coronal mass ejections (CMEs), and shock waves. We present a multiwavelength analysis of a rare high-frequency type II radio burst (starting frequency of $\sim$750 MHz and frequency drift rate of $\sim$0.5 MHz s$^{-1}$) associated with the X2.3-class solar flare that occurred on 6 November 2024. A propagating EUV disturbance was observed shortly after the flare onset in the SDO/AIA field of view, while radio spectrographs recorded the type II burst between 13:46 and 13:56 UT over a frequency range of $\sim$750 to 45 MHz. Radio imaging observations from the Nançay Radioheliograph (NRH) show that the radio sources propagate southward during the event. X-ray spectroscopy from HEL1OS onboard Aditya-L1 and imaging observations from STIX onboard Solar Orbiter reveal signatures of efficient non-thermal electron acceleration associated with the flare. An NLFFF extrapolation identifies a pre-eruptive MAGNETic flux rope in the source region, while white-light coronagraph observations obtained during the event show no detectable large-scale CME. The speed of the erupting flux rope, derived from stereoscopic EUV observations, is consistent, within measurement uncertainties, with the shock speed inferred from the radio dynamic spectrum. Together, these observations suggest that compact flux rope eruptions, even in the absence of a detectable white-light CME, can generate low-coronal shocks capable of producing high-frequency type II radio emission.
[abstract 24 / 42] (score: 2) - Title: Polarization measurement of $Λ^+_c$ and $\overlineΛ{}^-_c$ baryons in $p$Ne collisions at $\sqrt{s_{NN}} = 68.6$ GeVAuthors: 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, 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, 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, S. Dadabaev, 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. Didenko, S. Ding, Y. Ding, L. Dittmann, V. Dobishuk, 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, S. Gromov, 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. H. 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. Iniukhin, A. Iohner, A. Ishteev, K. Ivshin, 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, A. Kharisova, 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, S. Legotin, 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, G. Panshin, 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, G. 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, L. Shekhtman, J. Shen, Z. Shen, S. Sheng, V. Shevchenko, B. Shi, J. Shi, Q. Shi, W. S. Shi, Y. Shimizu, 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, Z. Xu, Z. Xu, Z. Xu, S. Yadav, K. Yang, X. Yang, Y. Yang, Y. 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, 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://lhcb-glance.cern.ch/alcm/public/analysis/full-details/5290Subjects: hep-exCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
The first measurement of the POLARIZATION of charm baryons by the LHCb experiment recorded in fixed-target mode is presented. The POLARIZATION of $Λ_c$ baryons is studied in collisions of protons, at an energy of 2.51 TeV, incident on a gaseous target of neon, at a nucleon-nucleon center-of-mass energy of $68.6$ GeV. The world's first measurement of separate-charge POLARIZATIONs for $Λ^+_c$ and $\overlineΛ{}^-_c$ baryons is performed, determining $$ P_{Λ^+_c} = ( 24 \pm 9 \pm 2 \, )\% , $$ $$ P_{\overlineΛ{}^-_c} = (-8 \pm 12 \pm 3 \, ) \% , $$ where the first uncertainty is statistical and the second systematic. The POLARIZATION is also measured in intervals of baryon transverse momentum and the Feynman-$x$ variable.
[abstract 25 / 42] (score: 2) - Title: Fast modelling of ionization balance in the intergalactic medium: I- implications for the IGM metallicityAuthors: Bhaskar Arya, Kartick C. Sarkar, Shiv K. Sethi,Comments: 17 pages, 13 figures, accepted for publication in MNRAS. Corrected an error in the calculation of PIE ion fractions and revised its discussions. The main conclusions are unchangedSubjects: astro-ph.COCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Ionization balance in the intergalactic medium (IGM) is central to the interpretation of QUASAR absorption spectra, linking observed ionic columns to the underlying gas density, temperature, metallicity, and ionizing radiation field. Because ionization, recombination, and cooling timescales can be comparable to the timescales over which the ultraviolet background (UVB) and gas thermodynamic state evolve, ion populations may retain a strong memory of their past history. To this end, we present a fast, metals-inclusive, zero-dimensional framework for modeling the redshift evolution of the IGM. The model follows the coupled thermal and ionization evolution of a Lagrangian gas parcel in a redshift-dependent UVB, solving stiff, time-dependent rate equations for H, He, and 107 metal ions while self-consistently evolving the temperature through photoheating and standard cooling processes. We validate the framework against full three-dimensional hydrodynamical non-equilibrium calculations and find that it reproduces the thermal and ionization histories of the IGM with good accuracy over a wide redshift range, including the heating associated with $\rm He_{\,\rm II}$ reionization. As an application, we predict the cosmic $\rm C_{\,\rm IV}$ density parameter, $Ω_{\rm CIV}$, and use it to infer the origin of metal ions in the IGM and the corresponding metallicities from observational measurements, obtaining values broadly consistent with literature constraints. The framework is well suited for rapid parameter studies of how reionization timing, UVB spectral hardness, self-shielding, and UVB inhomogeneity shape the thermal and ionization history of the IGM and the resulting metal-line observables.
[abstract 26 / 42] (score: 2) - Title: Remarks on electrical Penrose process for MAGNETized Reissner-Nordström BLACK HOLEAuthors: A. Baez, Nora Breton, I. Cabrera-Munguia,Comments: 19 pages, 16 figures, published version in PRDSubjects: gr-qcCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
The energy extraction from a MAGNETized Reissner-Nordström BLACK HOLE is analyzed within the framework of the electric Penrose mechanism. The presence of an external MAGNETic field induces an axisymmetric configuration and an ergosphere (the region where energy extraction is possible) arises, allowing for negative energy states even in an otherwise static spacetime. By analyzing the decay of particles at turning points of the radial motion, we derive the general expression for the efficiency of the process in terms of the metric coefficients and the electroMAGNETic potential. The resulting efficiencies are interpreted as Killing energy efficiencies associated with the local splitting process, while the escape of the positive energy fragment is treated as an additional effective-potential requirement. This formulation provides a direct criterion for identifying the ergoregions and we show that the MAGNETic field acts as a control parameter that governs both the configuration of the ergosphere and the efficiency of the process. In particular, analytical expressions for the critical MAGNETic fields that determine the onset and suppression of energy extraction are determined. Our results extend previous analysis of the electric Penrose process for MAGNETized configurations and clarify the role of the external field in enhancing or inhibiting energy extraction from charged BLACK HOLEs.
[abstract 27 / 42] (score: 2) - Title: A Reduced-Order Particle-in-Cell Method with Azimuthal Fourier-Decomposed Fields for Nominally Axisymmetric PlasmasAuthors: Shaun Andrews,Comments: 26 pages, 11 figures; Accepted manuscript for publication in Physics of Plasmas. Revisions after peer reviewSubjects: physics.plasm-ph physics.comp-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
A reduced-order Particle-in-Cell method is introduced for kinetic simulation of otherwise axisymmetric cylindrical plasmas that exhibit azimuthal instabilities. The method spatially decomposes all field quantities into a small number of azimuthal Fourier modes $m=0,...,N_m,\quad N_m \ll N_θ$, reducing the costly three-dimensional field solve $\mathcal{O}(N_zN_rN_θ)$ to a family of decoupled independent two-dimensional problems $\mathcal{O}((N_m+1)N_zN_r)$ on the meridional plane - one per mode - while particles continue to move in full three-dimensional space. Fields are reconstructed at particle positions by coherent superposition of these modal contributions, preserving complete azimuthal variation at a fraction of the cost of a conventional three-dimensional simulation. For initial validation, the method is tested against two benchmark problems with restricted axial dimension: The diocotron instability of a hollow electron annulus across three geometrically distinct configurations, recovering linear growth rates and eigenpotential structures within 7% of closed-form analytic predictions, and reproducing the non-linear vortex dynamics characteristic of the instability saturation; and a further benchmark against the community-standard Landmark Penning discharge problem recovers the rotating-spoke frequency, radial plasma profiles, and modal energy hierarchy in quantitative agreement with long-time reference simulations, at approximately 640 CPU-hours - a factor of 46 speed-up compared to the median benchmark cost. The approach represents a step toward addressing the important gap between computationally prohibitive full three-dimensional kinetic simulation and the physically limited reduced-dimensionality models on which predictive modelling of anomalous transport in MAGNETised plasma devices currently relies.
[abstract 28 / 42] (score: 2) - Title: GATOS XV: A JWST/MIRI survey of extended circumnuclear dust emission in nearby Seyfert galaxiesAuthors: David J. Rosario, Houda Haidar, Steph Campbell, John Schneider, Chris Packham, Nancy A. Levenson, Almudena Alonso-Herrero, Richard I. Davies, Dan Delaney, Santiago García-Burillo, Erin K. S. Hicks, Sebastian F. Hönig, Mason Leist, Enrique Lopez-Rodriguez, Miguel Pereira-Santaella, Anelise Audibert, Enrica Bellocchi, Françoise Combes, Ismael García-Bernete, Peter Boorman, Andrew J. Bunker, Luis Colina, Tanio Diaz Santos, Fergus R. Donnan, Poshak Gandhi, Omaira González-Martín, Laura Hermosa Muñoz, Alvaro Labiano, Cristina Ramos Almeida, Claudio Ricci, Rogemar A. Riffel, Dimitra Rigopoulou, Daniel Rouan, Marko Stalevski, Lulu Zhang,Comments: 31 pages, 18 figures, MNRAS in pressSubjects: astro-ph.GA astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
The subarcsecond angular resolution and stable background of JWST has given us the first high-fidelity images of the arcsecond-scale environment around Active Galactic Nuclei (AGNs) in the nearby Universe. With mid-infrared (MIR) surface brightness sensitivities that are much deeper than the best ground-based instruments, the Mid-InfraRed Instrument imager (MIRIM) now allows us to understand the structure and thermal properties of dust using information over wavelengths of $5$-$25$ $μ$m, almost all of the MIR range. We present a Cycle 1 JWST MIRIM survey of Seyfert galaxies with the express aim of characterising AGN-heated dust in the central few 100 pcs, and searching for signatures of dust-laden nuclear outflows. This paper outlines the motivation behind the programme, the data reduction and analysis techniques used to isolate the nuclear and extended emission, and a comparison of the observed MIR structures with those seen in other phases (stars, ionised and molecular gas, absorbing dust). In concert with earlier studies that used these data, we conclude that resolved AGN-heated dust is widespread in the Seyfert population, extending out to a few hundred pcs from the nucleus and often displaying a higher surface-brightness compared to the more widespread star-forming dusty circumnuclear disk. Even after accounting for contamination from emission lines in the MIRI filters, we find strong spatial correlations between MIR dust emission and the AGN-ionised gas in the narrow-line region (NLR).
[abstract 29 / 42] (score: 2) - Title: Resolved Dust in $z\approx1$ Galaxies with JWST/MIRI MRS: Survey Description and First View on PAHs, Mid-IR Atomic Emission, and Warm H$_2$Authors: Wuji Wang, Andreas L. Faisst, Thomas S. -Y. Lai, Kyle Finner, Jed McKinney, Andrew J. Battisti, Irene Shivaei, Leindert A. Boogaard, Daizhong Liu, Yu-Heng Lin, Lun-Jun Liu, Georgios Magdis, Vincenzo Mainieri, Alexander Rodriguez, John D. Silverman, Zhaoxuan Liu, Minju M. Lee, Ghassem Gozaliasl, Maximilien Franco,Comments: Accepted for publication in ApJ; main text 20 pages, 12 figures, 2 TablesSubjects: astro-ph.GACreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
Dust is a key component of galaxies that regulates their thermal balance and, consequently, STAR FORMATION and the build-up of stellar mass. Polycyclic aromatic hydrocarbons (PAHs) are responsible for reprocessing radiative energy of the galaxies thus tracing dust evolution. Using JWST/MIRI MRS, we present the first resolved view of the PAHs and mid-infrared emission lines in a sample of eight $z\approx1$ galaxies. A key novelty is our ability to directly map PAH emission near the end of cosmic noon at JWST's limits. The sample is selected to be on the star-forming main-sequence with stellar masses $M_{\star}=10^{10.6-11.2}\,M_{\odot}$ and infrared luminosities $L_{\rm IR}=10^{11.5-11.9}\,L_{\odot}$. Two of them contain ACTIVE GALACTIC NUCLEi (AGN), and two are interacting systems. We detect and quantify primary PAH emissions from 3.3$\,\rm μm$ to 11.3$\,\rmμm$ throughout the galaxies, alongside atomic fine structure lines (Ar, Ne, and Fe), Br$α$, and H$_{2}$ rotational transitions. Through PAH ratio diagnostics and comparison to theoretical models, we qualitatively probe the physical properties of PAH molecules, i.e., size and charge. The AGN and mergers in our sample exhibit a higher fraction of neutral PAHs, possibly related to high radiation intensity and/or shocks, as suggested by increased atomic and H$_{2}$ line ratios. Leveraging the IFU data, we find that the grain sizes of the centrally located PAHs tend to be larger and less ionized than those in the outskirts of the galaxies. Finally, we compare our results to observations of PAHs in local and similar-redshift galaxies, revealing a potential evolutionary trend when controlling $L_{\rm IR}$.
[abstract 30 / 42] (score: 2) - Title: TDCOSMO. XXVII. JWST-based Lens Models and H$_0$ Measurement of WFI2033, HE0435, and PG1115Authors: D. M. Williams, T. Treu, D. P. Johnson, P. Mozumdar, S. Knabel, S. Birrer, C. D. Fassnacht, A. Galan, A. J. Shajib, K. C. Wong, M. Cappellari, F. Courbin, T. Morishita, V. Motta, D. Sluse, M. Stiavelli,Comments: 27 pages, 19 figures, submitted to Physical Review DSubjects: astro-ph.CO astro-ph.GACreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
Time-delay cosmography offers a one-step, distance-ladder-independent route to the Hubble-Lemaitre constant, H_0. We present new cosmography-grade lens models of three quadruply imaged QUASARs based on JWST-NIRCam/F115W imaging (WFI2033-4723, HE0435-1223, PG1115+080). We use the STARRED modeling technique, introduced in our previous analysis of WFI2033-4723, to reconstruct the complex JWST-NIRCam Point Spread Function at high fidelity. We combine NIRCam-based lens models with improved external convergence estimates, published time delays, and aperture-integrated stellar velocity dispersions from JWST NIRSpec to infer H_0. The analysis was carried out blindly for HE0435-1223 and PG1115+080, while it was not blind for WFI2033-4723, as we build upon the previous published model. For comparison with previous HST-based work, we limit our analysis to the case of no internal mass-sheet degeneracy ($λ_{\rm int}=1$). We quantify the impact of improved imaging, single-aperture kinematics, and environment measurements on central values and uncertainties. Within flat $Λ$CDM, assuming a uniform prior on $Ω_{\rm m}$, we find H_0 = 71.8$_{-7.0}^{+9.2}$ $λ_{\rm int}$ km s$^{-1}$ Mpc$^{-1}$ for PG1115+080, 74.2$_{-4.2}^{+4.2}$ $λ_{\rm int}$ km s$^{-1}$ Mpc$^{-1}$ for HE0435-1223, and 73.4$_{-4.4}^{+3.4}$ $λ_{\rm int}$ km s$^{-1}$ Mpc$^{-1}$ for WFI2033-4723. Combining the three lenses yields H_0 = 73.5$_{-2.8}^{+2.7}$ $λ_{\rm int}$ km s$^{-1}$ Mpc$^{-1}$, consistent with HST-based results (73.6$_{-2.6}^{+2.6}$ $λ_{\rm int}$ km s$^{-1}$ Mpc$^{-1}$), but with reduced scatter between the three systems. These models will be incorporated in the TDCOSMO-2026 milestone paper with free $λ_{\rm int}$ in a hierarchical fashion. We close by outlining how 16 forthcoming JWST NIRCam targets will further tighten uncertainties toward percent-level precision on H_0.
[abstract 31 / 42] (score: 2) - Title: Toward a realistic test of black-hole movie correlations as a probe of extreme lensingAuthors: Barbora Bezděková, Shahar Hadar,Comments: 27 pages, 19 figuresSubjects: astro-ph.IM gr-qcCreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
In an optically thin setting, gravitational lensing around a BLACK HOLE creates multiple delayed images of any localized source, appearing at different positions on the observer's screen. Even if particular sources cannot be singled out, this effect may be revealed in a black-hole movie (time-dependent image) by examining the two-point spatiotemporal correlation function of intensity fluctuations in the movie. Recently, the correlation function derived from a movie obtained by ray tracing of a general-RELATIVISTIC MAGNETohydrodynamic simulation demonstrated the plausibility of this idea, even when the movie was blurred to angular resolutions corresponding to next-generation terrestrial very-long-baseline interferometric arrays. In this work, we further develop this method and study how some possible corruptions of the movie, motivated by real observational limitations, affect the ability to identify the extreme-lensing signatures by correlations. The effects are compared for both the original and blurred movies. We discuss the implications of our analysis for upcoming observations of M87* and Sgr A*, the two main targets of the Event Horizon Telescope and its future extensions. Our case study suggests that the types of data corruption we have explored, in themselves, do not preclude an identification of extreme-lensing effects in correlation measurements. We use our results to roughly estimate that, most importantly, for a successful correlation measurement, M87* may need to be continuously monitored for $\gtrsim 2$ years, while Sgr A* may need to be measured at a cadence $\gtrsim 1$ frame per minute. Finally, we outline a new analysis method that reduces the data in the complete correlation function---a large dataset defined on a five-dimensional configuration space---to a two-dimensional histogram that could be useful for black-hole parameter inference.
[abstract 32 / 42] (score: 2) - Title: Spin-disc misalignment drives periodic accretion and pulse profile asymmetry in X-ray pulsarsAuthors: A. A. Mushtukov, V. Ganesh, S. S. Tsygankov, S. Portegies Zwart, A. Palyam,Comments: accepted for publication in MNRAS, 14 pages, 7 figuresSubjects: astro-ph.HE astro-ph.SRCreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
We investigate MAGNETospheric accretion in disc-fed X-ray pulsars assuming that the neutron star spin axis is not perpendicular to the disc plane. We focus on X-ray pulsars, where a geometrically thin disc is truncated far from the stellar surface the channelled part of the accretion flow is expected to be guided by the large-scale dipolar MAGNETic field after coupling to it near the disc-MAGNETosphere boundary. Using numerical simulations of plasma motion from the inner disc edge to the neutron star surface, we show that a finite inclination between the disc normal and the stellar spin axis leads to periodic modulation of the mass accretion rate onto the MAGNETic poles even for a steady mass supply through the disc. This purely geometrical effect arises because stellar rotation changes the orientation of the MAGNETosphere relative to the disc, producing phase-dependent mass loading of MAGNETic field lines. The amplitude and shape of the modulation are determined by the system geometry and by the ratio of the stellar spin period to the flow time through the MAGNETosphere. The resulting variability affects the structure and luminosity of emitting regions near the neutron star surface and leads to asymmetric X-ray pulse profiles. Even without intrinsic asymmetries of the emission regions, this mechanism breaks the time-reversal symmetry expected for stationary accretion and naturally contributes to the observed asymmetry of pulse profiles and phase-resolved spectral features. The effect may also be relevant for ULX pulsars, where intrinsic accretion rate modulation can help preserve strong pulsations in the presence of geometric beaming.
[abstract 33 / 42] (score: 2) - Title: The Impact of Errors in the Shape Function of Rotating Neutron Stars in the Oblate Schwarzschild ApproximationAuthors: John Ming Ngo, Charlee Amason, Sharon M. Morsink,Comments:Subjects: astro-ph.HECreated: 2026-08-27; Updated: 2026-08-31; Datestamp: 2026-08-31
Measurements of thermal X-ray flux emitted by neutron stars can constrain their radii and the equation of state of cold dense matter. Accurate flux modeling of rapidly rotating neutron stars requires an approximation for their oblate surface shape, usually given by a shape function. We examine the accuracy of five shape functions by comparing them against numerical RELATIVISTIC stellar surfaces for seven representative equations of state over a broad range of compactness and spin. We characterize their errors in the surface radius and their derivative with respect to colatitude, test the extent of quasi-universality, and propagate these errors into the differential solid angle dΩ, a geometric factor underlying the observed flux, under the oblate Schwarzschild approximation. We find that the shape functions produce distinct error patterns associated with their forms and parameter ranges. These errors remain structured in compactness, spin, and colatitude. Simple polynomial corrections substantially reduce the radius errors of several shape functions, with most corrected errors within approximately 0.5%. We show that errors in dΩ may be understood as coming from an area contribution, which scales with twice the relative radius error, and a projection contribution controlled primarily by the error in the surface derivative. The projection contribution grows towards the limb, where small surface errors can produce much larger local errors in dΩ. We provide a set of guidelines for the construction of improved quasi-universal shape functions that can be used in future radius estimation efforts. Our recommendations include that both the shape and its derivative be modeled accurately, that more accurate predictions of the polar radius be developed, and that the shape function be calibrated over the same compactness-spin range that is to be tested.
[abstract 34 / 42] (score: 2) - Title: Quiescent and Interacting Compact Remnant Binary Populations in the Space Telescope EraAuthors: Erin Eastep, Jan J. Eldridge, J. C. Bray,Comments: Submitted to PASA on 28/08/2026. Posted to arXiv so that predictions for Roman's Galactic Bulge survey are available pre-launch. Synthetic populations will be made available on the BPASS website upon paper acceptance, until then request directly from the authors. The authors also welcome commentsSubjects: astro-ph.SR astro-ph.GA astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Since the discovery of Gaia BH1, interest in quiescent binary systems has grown. Two additional black-hole binaries have since been discovered alongside several candidate neutron-star binaries, yet the formation pathways of these systems remain poorly understood. Theoretical studies of these systems, together with the populations into which they evolve, such as X-ray binaries (XRBs), can help constrain their formation channels. We present predictions for the Galactic population of quiescent binary systems and their later evolutionary phases, including XRBs and post-interaction quiescent binaries. We combine stellar models from the Binary Population and Spectral Synthesis code (BPASS) with a synthetic Milky Way generated using Feedback In Realistic Environments (FIRE) simulations. We compare our results with existing observations to assess how well the synthetic population reproduces the observations. We find generally good agreement, with observed donor masses, compact-object masses, and orbital periods largely reproduced, except for the Gaia BH systems. Our results also suggest that some accreting compact remnants with low-mass donors and wide orbital periods may not be X-ray bright. Remaining discrepancies indicate that the BPASS initial parameter space should be expanded, the common-envelope evolution prescription revised, and MAGNETic braking included in low-mass donor models. We also predict the number of systems detectable in future Gaia data releases and by the Nancy Grace Roman Space Telescope (hereafter referred to as Roman). In particular, the Galactic Bulge Time Domain Survey is expected to yield a significant population of quiescent black-hole binaries. We predict that ~200-600 candidate quiescent binary systems will be detected in the Galactic Bulge Time Domain Survey, while ~2500-4000 candidate systems will be identified in Gaia DR5.
[abstract 35 / 42] (score: 2) - Title: Reinforcement-learning control of turbulence transition in the modified Hasegawa-Wakatani systemAuthors: Luning Sun, Ben Zhu, Xin-Yang Liu, Deepak Akhare, Jian-Xun Wang,Comments: 28 pages, 12 figuresSubjects: physics.plasm-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Control of plasma turbulence remains a long-standing challenge in MAGNETically confined fusion research. Here, we explore a reinforcement-learning (RL) approach for bidirectional control of the turbulence-zonal-flow transition in the modified Hasegawa-Wakatani system, a minimal model of electrostatic drift-wave turbulence. Within our model, a weak zonal drag damps the otherwise long-lived zonal structures, giving them a finite lifetime and restoring the drive-damping balance required for repeatable transitions within finite control episodes; meanwhile, actuation is applied through a spatially distributed Gaussian source field under a time-weighted budget constraint on actuation costs. The plasma model is then coupled to CNN-based soft actor-critic and twin-delayed deterministic policy-gradient agents through a GPU-native JAX solver that is highly optimized for fast online training. In the turbulence-suppression task, the learned budget-aware schedule achieves the lowest time-integrated turbulent flux for a given consumed budget, outperforming both constant and linearly decreasing baselines across all tested unseen initial conditions. In the inverse zonal-break task, the agent discovers an up-down antisymmetric actuation pattern that induces radial $E\times B$ convection, disrupts the zonal structure, and sustains the turbulent state. A physics-informed warm-buffer initialization facilitates this discovery, as random exploration alone struggles to locate the narrow optimal manifold within the vast action space. These results demonstrate reinforcement learning as a practical trajectory optimizer for nonlinear plasma dynamics, such as turbulence control, and highlight the importance of physics guidance in such applications.
[abstract 36 / 42] (score: 2) - Title: Counter-rotating density and current structures in a partially MAGNETized $\mathbf{E}\times\mathbf{B}$ plasmaAuthors: Pengze Xiao, Ya Zhang, Hongyu Wang, Wei Jiang, Jean-Pierre Boeuf,Comments:Subjects: physics.plasm-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
The first 3D kinetic simulation of a MAGNETron discharge reproduces the measured rotating spoke and reveals that density and current rotate in opposite directions: the $m=1$ spoke turns in the $\mathbf{E}\times\mathbf{B}$ direction at 90~kHz while $m\simeq16$ electron-cyclotron-drift-type filaments turn at 1.0~MHz, with no net propagation along $\mathbf{B}$. Magnetic drifts exchange far more energy than they deposit, yet their spoke-front heating sustains the ionization. Following helical paths, the anode-directed current is relayed by de-trapping turbulence at the sheath edge (50\%) and by the spoke channel in the bulk (97\%).
[abstract 37 / 42] (score: 2) - Title: Higher-Order Topological Phase in the Two-Dimensional Type-IV Magnet MgCr$_2$O$_4$Authors: Xiaorong Zou, Hyeon Suk Shin, Yanmei Zang, Ying Dai, Chengwang Niu, Chang-Jong Kang, Chang Woo Myung,Comments: 4 figuresSubjects: physics.comp-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Type-IV two-dimensional (2D) MAGNETism-a newly classified collinear MAGNETic phase featuring nonRELATIVISTIC spin degeneracy and spin-orbit-coupling-induced momentum-dependent spin splitting-extends the symmetry classification of collinear MAGNETs, opening new opportunities for unconventional topological quantum states. Here, we reveal that the recently proposed two-dimensional type-IV 2D MAGNET MgCr$_2$O$_4$ hosts an intrinsic higher-order topological insulating phase, featuring $\mathcal{C}_{3z}$-protected corner states and a nontrivial rotational topological invariant of $χ^{(3)}$ = $\{-2,4\}$ with a quantized fractional corner charge of $4e/3$. Spin-orbit coupling breaks the spin-degeneracy-enforcing symmetry $[C_{2}||M_z]$ while preserving the crystalline $\mathcal{C}_{3z}$ rotational symmetry that protects the higher-order topological phase, thereby enabling spin splitting to coexist with the nontrivial topology. Furthermore, the higher-order topological phase remains intact throughout a wide range of biaxial strains without band-gap closing and topological phase transition, demonstrating the robustness of the symmetry-protected topological state against external perturbations. Our work establishes a direct connection between type-IV MAGNETic system and higher-order topology, providing a new route for symmetry-engineered MAGNETic topological quantum states.
[abstract 38 / 42] (score: 2) - Title: Devoured by a Hairy Gargantua: Probing Massive Scalar Charges with Non-minimal Curvature Coupling with Extreme-Mass-Ratio InspiralsAuthors: Leif Lui, Adrian Ka-Wai Chung, Alejandro Torres-Orjuela,Comments: 6 pages (+9 pages supplementary material), 6 figures, 2 tablesSubjects: gr-qc astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Ultralight scalar fields nonminimally coupled to curvature can endow rotating BLACK HOLEs with stationary hair and alter nearby orbits. Using recently constructed hairy black-hole spacetimes, we model the transition to plunge of an extreme-mass-ratio inspiral. For scalar masses $μM=0.01$ and $0.1$ and dimensionless curvature coupling $ζ=10^{-3},10^{-4}$, we find $\mathcal{O}(10)$ rad of gravitational-wave dephasing relative to general relativity over $\mathcal{O}(10^3)$ orbits. A multimode Fisher forecast at $μM=0.2$, where neighbouring hair solutions permit a numerical $μ$-derivative, suggests that $ζ$ and $μ$ could be measured to precisions of $\simeq0.2\%$ and $0.6$--$1.1\%$, respectively, for a source with signal-to-noise ratio of about 80 in LISA.
[abstract 39 / 42] (score: 2) - Title: LES of iron-powder combustion in a JET-in-hot-coflow burner - Insights on flame structure and ignition characteristicsAuthors: Shyam Hemamalini, XiaoCheng Mi,Comments: Preprint accepted for publication in Proceedings of the Combustion Institute. Supplementary material available upon request or at final publicationSubjects: physics.flu-dynCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Micron-sized iron powders are a rapidly advancing novel energy storage technology. In order to improve the design of real-world iron-powder combustors, adequate understanding of the ignition behavior in such settings is necessary. In this work, a JET-in-hot-coflow (JHC) burner designed by Hameete et al. (2024) to test ignition of iron particles in lab-scale turbulent flames is modeled numerically using LES and Lagrangian point-particles. The JHC burner is simulated in two different modes--an open flame and an enclosed flame--similar to the experimental reference. Two iron-oxidation-rate models--the first-order model and oxide-layer model--are used to examine the effect on capturing the ignition behavior. For the radiative heat transfer between the two phases, a simplified Stefan-Boltzmann approximation model and the P1 model are considered, similar to Ramaekers et al. (2025). Analysis of flame structure indicates ignition in the circumference of the JET, aided by the break-up of the coflow. At higher $T_\mathrm{coflow}$, ignition onset and oxidation completion is earlier prior to JET break-up. Minimum coflow temperature for particle ignition with the oxide layer model is $1125\mathrm{K}$ with complete oxidation at $1250\mathrm{K}$, and for the first-order model at $800\mathrm{K}$ and $900\mathrm{K}$, respectively. Both of these results do not match the experimental results of Hameete. Oxidation degree is predictably higher for enclosed flames. For the chosen particle distribution, the P1 model exhibits higher radiative heat loss and results in a slightly lower oxidation degree. Analysis on particle ensembles with partial oxidation shows that the overall oxidation degree at a sufficient height above the nozzle reflects particle ignition probability. Further analysis in regards to particle size shows ignition failure is more prevalent in larger particles.
[abstract 40 / 42] (score: 2) - Title: Wakefield-Dressed Relativistic Vortex Electrons in Plasma AcceleratorsAuthors: Zhigang Bu, Lingang Zhang, Liangliang Ji,Comments: This version was submitted to Physical Review Journals on August 19th, 2026Subjects: physics.acc-ph physics.plasm-phCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Plasma wakefield acceleration is usually regarded as a classical mechanism for producing high- energy charged-particle beams. Here we show that an axisymmetric plasma wakefield can also act as a moving quantum structure that supports RELATIVISTIC vortex electron states. Starting from the Dirac equation, we derive the electron spinor eigenstates with definite total angular momentum in an ideal bubble-regime wakefield. The transverse focusing field confines and quantizes the electron transverse motion into Laguerre-Gaussian vortex modes, while the longitudinal electric field acceler- ates the electron without destroying the symmetry-protected angular momenta. We further analyze the localized and off-axis vortex electron wave-packets, and non-ideal wakefield perturbations, and identify the conditions for preserving electron-vortex-state purity. These results suggest plasma wakefield as a route toward high-energy vortex electrons and extend plasma-based acceleration from classical beam dynamics to quantum-state control of RELATIVISTIC particles.
[abstract 41 / 42] (score: 2) - Title: Real-Time Monitoring of MHD Liquid Metal Flows with Shallow Recurrent DecodersAuthors: Claudio Scardino, Stefano Riva, Carolina Introini, Matteo Lo Verso, Eric Cervi, Antonio Cammi, Laura Savoldi,Comments:Subjects: physics.comp-ph cs.LG physics.flu-dynCreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
State estimation in MAGNETohydrodynamic flows is critical for real-time monitoring of liquid metal blankets in tokamak fusion reactors. Due to the multiphysics nature of these phenomena, high-fidelity simulations are computationally prohibitive for real-time applications. This work investigates a data- driven Reduced Order Model framework: the Shallow Recurrent Decoder (SHRED) coupled with Principal Component Analysis, to map sparse temperature measurements to the full thermo-hydraulic system's state. The major contribution of this work lies in the two-parameter analysis of a fully three-dimensional domain representative of the DEMO breeding blanket configuration. Here, the flow is subjected to an external MAGNETic field varying in direction and intensity and is hindered by two cylinders acting as a water-cooling system, which impose a temperature boundary condition on their surfaces. This double-parametric MAGNETic variation induces nonlinear transitions in the flow dynamics, ranging from chaotic behavior at low MAGNETic field intensities to laminarized regimes at high intensities, characterized by the formation of asymmetric side layers at an inclination angle of 30 degrees. SHRED reconstruction maintains a mean relative error of approximately 5% for the temperature, pressure, and velocity fields. This accuracy is maintained across both weak and strong MAGNETic fields, ranging from 0.075 T to 0.300 T, and for inclination angles from 5 to 30 degrees, reflecting its dominant toroidal component. These errors are only slightly larger than the lower error bound dictated by low-rank truncation. The results establish SHRED as a reliable state estimator for complex and realistic engineering applications involving completely unseen parametric scenarios and validate it as an accurate real-time state estimation technique suitable for online monitoring and control of real facilities.
[abstract 42 / 42] (score: 2) - Title: Astrophysical Sensitivity Projections for the IceCube UpgradeAuthors: R. Abbasi, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, J. M. Alameddine, S. Ali, N. M. Amin, K. Andeen, C. Arg{ü}elles, S. Athanasiadou, S. N. Axani, R. Babu, X. Bai, A. Balagopal V., S. W. Barwick, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, P. Behrens, J. Beise, C. Bellenghi, S. Benkel, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. B{ö}ser, O. Botner, J. B{ö}ttcher, J. Braun, B. Brinson, Z. Brisson-Tsavoussis, L. Brusa, R. T. Burley, D. Butterfield, K. Carloni, J. Carpio, N. Chau, Y. C. Chen, Z. Chen, D. Chirkin, S. Choi, A. Chubarov, B. A. Clark, D. A. Coloma Borja, A. Connolly, J. M. Conrad, D. F. Cowen, C. De Clercq, J. J. DeLaunay, D. Delgado, T. Delmeulle, S. Deng, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, J. C. D{\'ı}az-V{é}lez, S. DiKerby, T. Ding, M. Dittmer, A. Domi, L. Draper, L. Dueser, D. Durnford, K. Dutta, M. A. DuVernois, T. Ehrhardt, L. Eidenschink, A. Eimer, C. Eldridge, P. Eller, E. Ellinger, D. Els{ä}sser, R. Engel, H. Erpenbeck, W. Esmail, S. Eulig, J. Evans, P. A. Evenson, K. L. Fan, K. Fang, K. Farrag, A. Fattorini, A. R. Fazely, A. Fedynitch, N. Feigl, C. Finley, D. Fox, A. Franckowiak, S. Fukami, P. F{ü}rst, J. Gallagher, E. Ganster, A. Garcia, M. Garcia, E. Genton, L. Gerhardt, A. Ghadimi, C. Glaser, T. Gl{ü}senkamp, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, S. Griffin, S. Griswold, K. M. Groth, D. Guevel, C. G{ü}nther, P. Gutjahr, C. Ha, A. Hallgren, L. Halve, F. Halzen, L. Hamacher, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. H{ä}ußler, K. Helbing, J. Hellrung, B. Henke, L. Hennig, F. Henningsen, L. Heuermann, R. Hewett, N. Heyer, S. Hickford, A. Hidvegi, C. Hill, G. C. Hill, R. Hmaid, K. D. Hoffman, A. Hollnagel, D. Hooper, S. Hori, K. Hoshina, M. Hostert, W. Hou, M. Hrywniak, T. Huber, K. Hultqvist, K. Hymon, A. Ishihara, W. Iwakiri, M. Jacquart, S. Jain, O. Janik, M. Jansson, M. Jin, N. Kamp, D. Kang, W. Kang, A. Kappes, L. Kardum, T. Karg, A. Karle, A. Katil, M. Kauer, J. L. Kelley, M. Khanal, A. Khatee Zathul, A. Kheirandish, T. Kim, H. Kimku, F. Kirchner, J. Kiryluk, C. Klein, S. R. Klein, Y. Kobayashi, S. Koch, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. K{ö}pke, C. Kopper, D. J. Koskinen, P. Koundal, M. Kowalski, T. Kozynets, A. Kravka, N. Krieger, T. Krishnan, K. Kruiswijk, E. Krupczak, E. Kun, N. Kurahashi, C. Lagunas Gualda, L. Lallement Arnaud, M. J. Larson, F. Lauber, J. P. Lazar, K. Leonard DeHolton, A. Leszczy{ń}ska, C. Li, J. Liao, C. Lin, Q. R. Liu, Y. T. Liu, M. Liubarska, C. Love, L. Lu, F. Lucarelli, W. Luszczak, Y. Lyu, M. Macdonald, E. Magnus, Y. Makino, E. Manao, S. Mancina, A. Mand, I. C. Mari{ş}, S. Marka, Z. Marka, L. Marten, I. Martinez-Soler, R. Maruyama, J. Mauro, F. Mayhew, F. McNally, K. Meagher, A. Medina, M. Meier, Y. Merckx, L. Merten, J. Mitchell, L. Molchany, S. Mondal, T. Montaruli, R. W. Moore, Y. Morii, A. Mosbrugger, D. Mousadi, E. Moyaux, T. Mukherjee, M. Nakos, U. Naumann, R. Neshat, L. Neste, M. Neumann, H. Niederhausen, M. U. Nisa, K. Noda, A. Noell, A. Novikov, A. Obertacke, V. O'Dell, A. Olivas, R. Orsoe, J. Osborn, E. O'Sullivan, B. Owens, V. Palusova, H. Pandya, A. Parenti, C. Parisel, N. Park, V. Parrish, E. N. Paudel, L. Paul, T. Pernice, T. C. Petersen, J. Peterson, S. Pick, M. Plum, A. Pont{é}n, V. Poojyam, B. Pries, R. Procter-Murphy, G. T. Przybylski, L. Pyras, C. Raab, J. Rack-Helleis, N. Rad, M. Ravn, K. Rawlins, Z. Rechav, A. Rehman, I. Reistroffer, E. Resconi, C. D. Rho, W. Rhode, L. Ricca, B. Riedel, A. Rifaie, E. J. Roberts, S. Rodan, M. Rongen, A. Rosted, C. Rott, T. Ruhe, L. Ruohan, D. Ryckbosch, J. Saffer, D. Salazar-Gallegos, P. Sampathkumar, A. Sandrock, G. Sanger-Johnson, M. Santander, S. Sarkar, M. Scarnera, M. Schaufel, H. Schieler, S. Schindler, L. Schlickmann, B. Schl{ü}ter, F. Schl{ü}ter, N. Schmeisser, T. Schmidt, F. Schmitt, A. Scholz, F. G. Schr{ö}der, S. Schwirn, S. Sclafani, D. Seckel, L. Seen, M. Seikh, S. Seunarine, P. A. Sevle Myhr, R. Shah, S. Shah, S. Shefali, N. Shimizu, M. Shin, B. Skrzypek, R. Snihur, J. Soedingrekso, D. Soldin, P. Soldin, G. Sommani, D. Song, C. Spannfellner, G. M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, T. Stezelberger, T. St{ü}rwald, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, A. Thakuri, M. Thiesmeyer, W. G. Thompson, J. Thwaites, W. Tian, S. Tilav, K. Tollefson, J. A. Torres, S. Toscano, D. Tosi, K. Upshaw, A. Vaidyanathan, N. Valtonen-Mattila, J. Valverde, J. Vandenbroucke, T. Van Eeden, N. van Eijndhoven, L. Van Rootselaar, J. van Santen, J. Vara, F. Varsi, M. Velazquez, M. Venugopal, M. Vereecken, S. Vergara Carrasco, S. Verpoest, D. Veske, A. Vijai, J. Villarreal, C. Walck, A. Wang, E. H. S. Warrick, C. Weaver, P. Weigel, A. Weindl, J. Weldert, A. Y. Wen, C. Wendt, J. Werthebach, M. Weyrauch, N. Whitehorn, C. H. Wiebusch, D. R. Williams, L. Witthaus, J. Woodward, G. Wrede, X. W. Xu, J. P. Yanez, Y. Yao, E. Yildizci, S. Yoshida, F. Yu, S. Yu, T. Yuan, S. Yun-C{á}rcamo, A. Zander Jurowitzki, A. Zegarelli, S. Zhang, Z. Zhang, P. Zhelnin, P. Zilberman, C. Zilleruelo Ca{ñ}as,Comments: 18 pages, 12 figuresSubjects: astro-ph.HECreated: 2026-08-28; Updated: 2026-08-31; Datestamp: 2026-08-31
Embedded in the South Pole's glacial ice, IceCube detects neutrino-induced Cherenkov light using an array of digital optical modules equipped with single photomultiplier tubes (PMTs). The new extension installed in 2025/2026, the IceCube Upgrade, introduces densely instrumented multi-PMT optical modules within the existing infill array known as IceCube DeepCore. It is expected to enhance sensitivity in the GeV regime, with commissioning of the detector expected to be complete by the end of 2026. We present the projected sensitivities of the IceCube Upgrade for three key analyses: neutrino transient searches, steady emission from point sources such as NGC 1068, and diffuse emission from the Milky Way. These case studies represent direct extensions of current IceCube analyses. Using new Monte Carlo datasets, we demonstrate that the IceCube Upgrade achieves order-of-magnitude improvement in sensitivity at low energies ($\lesssim 10$ GeV) for time-dependent sources across short timescales. Conversely, for time-independent searches, the relative impact of the IceCube Upgrade's low-energy data is diluted by the decade-long accumulation of high-energy archival data. Nevertheless, we project significant improvements for soft-spectrum sources especially across the southern sky, driven by the IceCube Upgrade's superior background rejection capabilities. The improved sensitivity at low energies for both transient and steady sources will open up an expanded discovery window for IceCube in the GeV band over the next decade.
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