Current date: 2026-07-13

Setting default datestamp limit: 0

Datestamp limit: 2026-07-13 (0 days ago)

Created/updated limit: 2026-07-06 (7 days ago)

Suggested sets: physics, physics:astro-ph, physics:gr-qc, physics:physics

Setting default set: physics

OAI-PMH request: http://export.arxiv.org/oai2?verb=ListRecords&from=2026-07-13&until=2026-07-13&set=physics&metadataPrefix=arXiv

Scoring abstracts

Number of records retrieved: 622

Keyword score statistics

score 15 -- 1 abstracts

score 8 -- 1 abstracts

score 6 -- 2 abstracts

score 5 -- 1 abstracts

score 4 -- 6 abstracts

score 3 -- 5 abstracts

score 2 -- 13 abstracts

in total -- 29 abstracts

Articles that appeared on 2026-07-13

[abstract 1 / 29] Wow! (score: 15)
arXiv:2606.21966 [pdf, ps, other]

Title: Fast Optical Variability of the TeV Blazar PKS 1725+123 Observed by SVOM-VT and Insights from Multi-wavelength Follow-up Observations

Authors: Shuo-Yu Liu, Yu-Wei Yu, Ji-Shun Lian, Xin-Ke Hu, Alexis Coleiro, Zhu-Heng Yao, Li-Ping Xin, Jing Wang, Hua-Li Li, Zi-Qi Wang, Jin Zhang, Floriane Cangemi, Bertrand Cordier, Antoine Foisseau, Olivier Godet, Andrea Goldwurm, Diego Gotz, Sebastien Guillot, Xu-Hui Han, Ning Jiang, Cyril Lachaud, Sebastien Le Stum, En-Wei Liang, Pierre Maggi, Yu-Lei Qiu, Jerome Rodriguez, Lian Tao, Jian-Yan Wei, Chao Wu, Liang Zhang, Shuang-Nan Zhang, Shi-Jie Zheng,

Comments: 23 pages, 8 figures, accepted for publication in ApJL

Subjects: astro-ph.HE

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

PKS 1725+123 is a flat-spectrum radio QUASAR (FSRQ) with a redshift of $z=0.586$. The detection of this object in the TeV band was reported by the MAGIC telescopes and H.E.S.S. in August 2025. Subsequently, we promptly initiated Target-of-Opportunity observations using the Space-based multi-band astronomical Variable Objects Monitor (SVOM) satellite. By analyzing the observational optical data from SVOM-VT and comprehensively examining the FERMI-LAT and SWIFT-XRT observational data, it was found that the source is in a high-flux state across the optical, X-ray, and GeV $γ$-ray bands around the time of the TeV detections. Its optical flux reaches a historically unprecedented high level and shows significant variability on timescale as short as minutes. The variability is accompanied by changes in the color index, exhibiting a bluer when brighter behavior during the high-flux state. Based on the simultaneous multi-wavelength data, we construct the broadband spectral energy distribution (SED) of the source in the high-flux state. PKS 1725+123 demonstrates a remarkably high SYNCHROTRON peak frequency, which is distinctly different from that of other FSRQs. We propose a two-zone spine-sheath JET model to reproduce this SED. The optical--X-ray emission is generated by the SYNCHROTRON process of the RELATIVISTIC electrons within a compact zone. The inverse Compton (IC) scattering processes of the same electron population contribute to the low-energy end of the FERMI-LAT spectrum, while the high-energy end of the FERMI-LAT spectrum is ascribed to the IC scattering of the SYNCHROTRON photons within the compact zone by the higher-energy electrons in an extended region.

[abstract 2 / 29] Wow! (score: 8)
arXiv:2607.09569 [pdf, ps, other]

Title: Hamiltonian variational reconstruction of the 3D MAGNETic geometry of RELATIVISTIC JETs: accuracy across GRMHD models and the fundamental sign degeneracy

Authors: Buffoli Fabio,

Comments: 14 pages, 13 figures, 4 tables

Subjects: astro-ph.HE

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

Every resolved image of a RELATIVISTIC JET encodes its MAGNETic field, yet no image records which way the field points along the axis. Synchrotron intensity and linear POLARIZATION are blind to this: both probe the field only through even combinations of its components. We introduce H-MOG, a variational method that reconstructs the 3D field on a lattice from two projected observables, the JET width W(z) and the linear POLARIZATION p(z), regularized by a Hamiltonian prior and optimized with automatic differentiation. We apply H-MOG to ten GRMHD simulations spanning MAD and SANE states and five black-hole spins (a* = -0.94, -0.5, 0, +0.5, +0.94), and test three routes to break the intrinsic sign degeneracy of the reconstruction: a Faraday rotation-measure term, full 3D sampling, and a Blandford-Znajek spin prior. The unsigned field orientation is recovered at <|cos|> ~ 0.95-0.98, far above the random expectation of 0.5. The sense of the poloidal field, however, is not recovered, and we prove it cannot be: W and p are invariant under B -> -B. All three routes to break this degeneracy fail for distinct physical reasons; the spin-sense relation in these turbulent JETs is not monotonic, differing sharply between MAD and SANE. Recovering the sense requires a parity-odd observable: Faraday tomography or circular POLARIZATION.

[abstract 3 / 29] Yes (score: 6)
arXiv:2602.10208 [pdf, ps, other]

Title: Evidence for neutrino emission from X-ray Bright Seyfert Galaxies in the Southern Hemisphere using Enhanced Starting Track Events with IceCube

Authors: R. Abbasi, M. Ackermann, J. Adams, S. K. Agarwalla, J. A. Aguilar, M. Ahlers, J. M. Alameddine, S. Ali, N. M. Amin, K. Andeen, C. Argüelles, Y. Ashida, S. Athanasiadou, S. N. Axani, R. Babu, X. Bai, J. Baines-Holmes, A. Balagopal V., S. W. Barwick, S. Bash, 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, I. Bodo, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. Böser, O. Botner, J. Böttcher, J. Braun, B. Brinson, Z. Brisson-Tsavoussis, R. T. Burley, D. Butterfield, M. A. Campana, K. Carloni, J. Carpio, S. Chattopadhyay, N. Chau, Z. Chen, D. Chirkin, S. Choi, B. A. Clark, P. Coleman, G. H. Collin, 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. Díaz-Vélez, 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. Elsässer, R. Engel, H. Erpenbeck, W. Esmail, S. Eulig, J. Evans, P. A. Evenson, K. L. Fan, K. Fang, K. Farrag, A. R. Fazely, A. Fedynitch, N. Feigl, C. Finley, L. Fischer, D. Fox, A. Franckowiak, S. Fukami, P. Fürst, J. Gallagher, E. Ganster, A. Garcia, M. Garcia, G. Garg, E. Genton, L. Gerhardt, A. Ghadimi, C. Glaser, T. Glüsenkamp, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, S. Griffin, S. Griswold, K. M. Groth, D. Guevel, C. Günther, P. Gutjahr, C. Ha, C. Haack, A. Hallgren, L. Halve, F. Halzen, L. Hamacher, M. Ha Minh, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. Häußler, 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, 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, M. Karl, A. Karle, A. Katil, M. Kauer, J. L. Kelley, M. Khanal, A. Khatee Zathul, A. Kheirandish, H. Kimku, J. Kiryluk, C. Klein, S. R. Klein, Y. Kobayashi, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. Köpke, C. Kopper, D. J. Koskinen, P. Koundal, M. Kowalski, T. Kozynets, A. Kravka, N. Krieger, J. Krishnamoorthi, T. Krishnan, K. Kruiswijk, E. Krupczak, A. Kumar, E. Kun, N. Kurahashi, N. Lad, C. Lagunas Gualda, L. Lallement Arnaud, M. J. Larson, F. Lauber, J. P. Lazar, K. Leonard DeHolton, A. Leszczyńska, 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, J. Madsen, E. Magnus, Y. Makino, E. Manao, S. Mancina, A. Mand, I. C. Mariş, S. Marka, Z. Marka, L. Marten, I. Martinez-Soler, R. Maruyama, J. Mauro, F. Mayhew, F. McNally, K. Meagher, S. Mechbal, A. Medina, M. Meier, Y. Merckx, L. Merten, J. Mitchell, L. Molchany, S. Mondal, T. Montaruli, R. W. Moore, Y. Morii, A. Mosbrugger, M. Moulai, D. Mousadi, E. Moyaux, T. Mukherjee, R. Naab, M. Nakos, U. Naumann, J. Necker, 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, V. Palusova, H. Pandya, A. Parenti, N. Park, V. Parrish, E. N. Paudel, L. Paul, C. Pérez de los Heros, T. Pernice, T. C. Petersen, J. Peterson, M. Plum, A. Pontén, V. Poojyam, Y. Popovych, M. Prado Rodriguez, 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, S. Reusch, 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, P. Schaile, M. Schaufel, H. Schieler, S. Schindler, L. Schlickmann, B. Schlüter, F. Schlüter, N. Schmeisser, T. Schmidt, F. G. Schröder, L. Schumacher, S. Schwirn, S. Sclafani, D. Seckel, L. Seen, M. Seikh, S. Seunarine, P. A. Sevle Myhr, R. Shah, S. Shah, S. Shefali, N. Shimizu, B. Skrzypek, R. Snihur, J. Soedingrekso, D. Soldin, P. Soldin, G. Sommani, C. Spannfellner, G. M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, T. Stezelberger, T. Stürwald, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, A. Thakuri, M. Thiesmeyer, W. G. Thompson, J. Thwaites, S. Tilav, K. Tollefson, S. Toscano, D. Tosi, A. Trettin, A. K. Upadhyay, 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. 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, M. Wolf, G. Wrede, X. W. Xu, J. P. Yanez, Y. Yao, E. Yildizci, S. Yoshida, R. Young, F. Yu, S. Yu, T. Yuan, S. Yun-Cárcamo, A. Zander Jurowitzki, A. Zegarelli, S. Zhang, Z. Zhang, P. Zhelnin, P. Zilberman,

Comments: 4 figures and 4 tables, submitted to APJ-Letters. Published as is without modification

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

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

IceCube recently reported the observation of TeV neutrinos from the nearby Seyfert galaxy NGC~1068, and the corresponding neutrino flux is significantly higher than the upper limit implied by observations of GeV-TeV gamma rays. This suggests that neutrinos are produced near the supermassive BLACK HOLE, where the radiation density is high enough to obscure gamma rays. We use a set of muon neutrinos with interaction vertices inside the detector, which have good sensitivity to sources in the Southern sky, from IceCube data recorded between 2011 and 2021. We then search for individual and collective neutrino signals from 14 Seyfert galaxies in the Southern Sky selected from the SWIFT Burst Alert Telescope (BAT) AGN Spectroscopic Survey. Using the correlations between keV X-rays and TeV neutrinos predicted by disk-corona models, and assuming production characteristics similar to NGC~1068, a collective neutrino signal search reveals an excess of $6.7_{-3.2}^{+4.0}$ events, which is inconsistent with background expectations at the 3$σ$ level of significance. In this paper, we present new independent evidence that Seyfert galaxies contribute to the extragalactic flux of high-energy neutrinos.

[abstract 4 / 29] Yes (score: 6)
arXiv:2607.09036 [pdf, ps, other]

Title: In the Eye of the Storm: The Third Giant X-ray Outburst of the Extreme Changing-look AGN IC 3599

Authors: D. Grupe, S. Komossa, W. Zheng, A. V. Filippenko, T. G. Brink, N. Schartel, J. Wang, V. Oknyansky, A. V. Dodin, S. Wolsing, E. Elien, C. Tapper, P. Lynam,

Comments: Accepted for publication in the Astrophysical Journal Letter, 7 figures, 1 Table

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

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

We report the discovery and multiwavelength follow-up observations of a giant (factor >100) X-ray outburst of the exceptional changing-look ACTIVE GALACTIC NUCLEus (AGN) IC 3599. This is the third such outburst after two previous ones serendipitously discovered in 1990 and 2010. Based on our dedicated long-term monitoring of IC 3599 with {\it SWIFT}, the third outburst was detected while it was happening, and we triggered multiple follow-up observations within days to weeks for the first time. The SWIFT outburst spectra are supersoft and almost no photons are detected beyond 2.5 keV. The XMM-Newton short-term light curve shows a remarkable apparent oscillatory pattern that is reminiscent of quasiperiodic oscillations (QPOs). The optical high-state spectra reveal a multitude of bright coronal emission lines that have dramatically brightened and were absent or much fainter in low-state spectra. The new results eliminate outburst scenarios that require a constant time interval of repetitions (like certain variants of repeat tidal stripping, or of an orbiting supermassive BLACK HOLE impacting the inner accretion disk), but remain in excellent agreement with an accretion disk radiation-pressure instability when assuming that local conditions in the disk of this long-lived AGN affect the onset time of each new instability. The combination of recurrent, giant, supersoft outbursts on decadal timescales, the exceptional emission-line response, and the rapid, candidate quasiperiodic, short-term variability on an hours timescale makes IC 3599 unique among AGN, and establishes it as a key system for studying accretion physics under extreme conditions and at the Eddington limit.

[abstract 5 / 29] Yes (score: 5)
arXiv:2607.08994 [pdf, ps, other]

Title: A cooler look at the environment of Cygnus X-1: Searching for dynamical interactions within cold molecular gas

Authors: Pau Bosch-Cabot, Alexandra J. Tetarenko, Valentí Bosch-Ramon, James C. A. Miller-Jones, David M. Russell, Sara E. Motta, Pikky Atri, María Díaz-Trigo, Isabella Mariani, Steve Prabu,

Comments: 18 pages, 7 figures

Subjects: astro-ph.HE

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

We present IRAM--30m observations aimed at identifying potential outflow-interstellar medium interaction sites in the vicinity of the BLACK HOLE X-ray binary Cygnus X--1, which displays persistent RELATIVISTIC JETs and a prominent stellar wind. Using this dataset, we construct molecular line emission maps, identifying a never before seen molecular structure potentially linked to X-ray binary-driven feedback. This structure, surrounding the source, exhibits properties consistent with an interaction powered primarily by the stellar wind of the massive stellar companion and further sculpted by the RELATIVISTIC JETs. Our results indicate that multiple outflow mechanisms (stellar winds and RELATIVISTIC JETs) may simultaneously be shaping the interstellar medium around Cygnus X--1, and that molecular line imaging can help to disentangle complex feedback processes in environments where multiple outflows take place.

[abstract 6 / 29] Yes (score: 4)
arXiv:2607.07100 [pdf, ps, other]

Title: MicroQUASAR Cygnus X-3 as the PeVatron powering the Cygnus Bubble

Authors: Zhaodong Shi, Guangwei Wang, Ruizhi Yang, Felix Aharonian,

Comments: Accepted for publication in ApJL. 15 pages, 4 figures, and 2 tables

Subjects: astro-ph.HE

Created: 2026-07-08; Updated: 2026-07-13; Datestamp: 2026-07-13

The recent discovery by the LHAASO collaboration of a variable ultra-high-energy (UHE; $E_γ\ge$ 100 TeV) $γ$-ray source associated with the microQUASAR Cygnus X-3, with a spectrum extending to several PeV, provides compelling evidence for a hadronic super-PeVatron operating within the binary system. Inside the binary, the accelerated protons lose only a small fraction of their energy; upon escaping into the interstellar medium, they propagate diffusively to form a vast gamma-ray ``halo" structure extended to hundreds of parsecs. We argue that this halo has already been detected and corresponds to the Cygnus Bubble, an extended UHE $γ$-ray source reported by the LHAASO collaboration -- which possesses an angular extension of $\approx 6^{\circ}$ and an energy spectrum reaching 1 PeV. While the Cygnus Bubble is generally attributed to the star-forming region Cygnus X (specifically the Cygnus OB2 association at 1.4 kpc), we demonstrate that an association with Cygnus X-3 is physically more natural at energies above 400 TeV. This is supported by the cosmic-ray radial distribution, derived from the $γ$-ray and gas distributions, which points to continuous injection from a point-like source. The energetic requirements of the central accelerator are reasonably affordable and feasible. This reassignment identifies the Cygnus Bubble as a member of the recently discovered population of microQUASAR UHE $γ$-ray halos.

[abstract 7 / 29] Yes (score: 4)
arXiv:2607.08596 [pdf, ps, other]

Title: FAST Discovery of $μ$Jy Radio Pulsations from PSR J2238+5903, Providing a DM Distance Anchor for the Candidate TeV Halo 1LHAASO J2238+5900

Authors: Jianli Zhang, Hui Zhu, Guanhong Lin, Dejia Zhou, Yuting Chu, Songzhan Chen, Min Zha, WenJun Huang, ZiWei Ou, P. H. Thomas Tam, Sha Wu, Qiang Yuan, Yi Zhang,

Comments: 8 pages, 2 figures, comments welcome

Subjects: astro-ph.HE

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

We report the first detection of radio pulsations from PSR J2238+5903, a gamma-ray pulsar spatially coincident with the extended TeV source 1LHAASO J2238+5900. Our 3000 s FAST L-band observation reveals a weak periodic signal at the known FERMI-LAT spin period, with $P=162.76568$ ms and $\mathrm{DM}=247.5\pm3.0~\mathrm{pc~cm^{-3}}$. The signal is independently confirmed by both FFT-based and Fast Folding Algorithm searches. The radiometer equation gives a flux density of $S_{1250}\simeq3\,μ$Jy, placing PSR J2238+5903 among the faintest radio-detected FERMI pulsars. Interpreting the DM with Galactic electron-density models gives $d_{\rm DM}=7.4\pm3.9$ kpc. At this distance, the LHAASO WCDA 39\% containment radius corresponds to a characteristic diameter of $\sim132$ pc, and the $>1$ TeV luminosity is $L_{\rm TeV}\simeq7.1\times10^{34}$ erg s$^{-1}$, about 8\% of the pulsar's spin-down power. The radio DM thus provides the first pulsar-specific distance constraint for assessing whether 1LHAASO J2238+5900 is a young relic-PWN / TeV-halo transition system.

[abstract 8 / 29] Yes (score: 4)
arXiv:2607.08832 [pdf, ps, other]

Title: Massive Perturbers and Transient Pickup Discs in Disc-Crossing Encounters in OJ 287-like Supermassive Black Hole Binaries

Authors: Debojyoti Garain, Jonathan Zrake, Zoltan Haiman,

Comments: 17 pages, 5 figures

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

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

We study the hydrodynamical response of a massive BLACK HOLE accretion disc punctured by a lower mass BLACK HOLE on an inclined, eccentric orbit, as motivated by the quasi-periodic outbursts seen in the BLAZAR OJ 287. Using three-dimensional smoothed particle hydrodynamics simulations, we explore how the secondary BLACK HOLE's mass and orbital eccentricity, and the disc thickness and viscosity, affect the time variation of mass accretion onto both BLACK HOLEs. We find that disc-crossing events only lead to significant spikes in the primary BLACK HOLE's accretion rate when the perturber is quite massive ($q \gtrsim 0.1$) and that such spikes are delayed by roughly a free-fall time ($\sim$ months for OJ 287) after the first disc-crossing. The orbital eccentricity, disc thickness, and viscosity can influence the amplitude and temporal structure of the response; in particular, higher eccentricity causes larger and less delayed delivery of gas to the primary, however the condition $q \gtrsim 0.1$ seems to be robust. We also show that when the secondary is this massive, it generally acquires a "pickup" disc which could produce its own luminous signature. For systems like OJ 287, the secondary pickup disc can contain $10^{2-3} M_\odot$, which if accreted over a timescale comparable to the orbital period can power near-Eddington secondary luminosities with thermal emission peaking in the UV/EUV.

[abstract 9 / 29] Yes (score: 4)
arXiv:2607.08835 [pdf, ps, other]

Title: Hybrid Simulations of Proton Acceleration at Oblique High-$β$ Shocks

Authors: Yevhen Kylivnyk, Damiano Caprioli, Luca Orusa,

Comments: 9 pages, 4 figures. Submitted to ApJ

Subjects: astro-ph.HE

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

Collisionless shocks in the intracluster and intergalactic medium (ICM/IGM) are expected to energize both electrons and ions. While electron acceleration is revealed by prominent radio emission, $γ$-ray emission from hadronic interactions remains undetected, suggesting that high-$β$ (ratio of thermal to MAGNETic pressure), low-Mach-number shocks cannot accelerate protons efficiently. We present three-dimensional hybrid simulations, in which ions are treated kinetically and electrons as a fluid, of quasi-perpendicular (MAGNETic obliquity $\vartheta = 80^\circ$) shocks with sonic Mach numbers $M_s \sim 3{-}15$ and plasma $β\gtrsim 15$, representative of cluster environments. We find that weak shocks ($M_s \lesssim 5$) fail to develop significant nonthermal populations, with COSMIC RAY (CR) acceleration efficiencies $\varepsilon_{\rm CR} \lesssim 0.1\%$. In contrast, stronger shocks ($M_s \gtrsim 10$) develop clear power-law tails with slopes $q \sim 4.0 $ and reach $\varepsilon_{\rm CR} \sim 3\%$. These results suggest that weak, oblique ICM shocks are generally unlikely to accelerate protons efficiently. However, reducing $\vartheta$ to $\sim 45^\circ$ leads to substantially higher acceleration efficiencies, indicating that MAGNETic obliquity plays a critical role in determining proton acceleration. Our findings provide a microphysical framework for interpreting radio relic observations, whose POLARIZATION suggests that electrons are accelerated at oblique shocks, and the absence of cluster $γ$-ray detections.

[abstract 10 / 29] Yes (score: 4)
arXiv:2607.09119 [pdf, ps, other]

Title: Effects of DARK MATTER and MAGNETic field on neutron star properties in RELATIVISTIC mean-field theory: A single-fluid approach

Authors: Neeshu Rani, M. Mishra, Deepak Kumar, Arpan Das,

Comments: 15 pages, 12 figures article

Subjects: astro-ph.HE gr-qc

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

Neutron stars, due to their extremely high matter density and strong MAGNETic field, provide the best environment for exploring new physics beyond the Standard Model of particle physics. In this work, we study the effect of pre-existing DARK MATTER component and an internal MAGNETic field on the structural properties of neutron stars. We employed RELATIVISTIC mean field theory based equations of state and used a single fluid approach for solving the Tolman-Oppenheimer-Volkoff (TOV) equation to compute properties like mass-radius, tidal deformability, compactness, and non-radial oscillation frequencies. We consider the following two scenarios for equation of state (EoS): (1) density-independent couplings along with non-linear interactions of mesons, and (2) density-dependent couplings, with only considering linear interactions for mesons. These mesons mediate the interactions between nucleonic constituents of a neutron star. In the DARK MATTER sector we consider a massive fermionic DARK MATTER which interacts with the nucleons through a Higgs portal interaction. We explore parameter regions for FERMI momentum of DARK MATTER in the range $k_F = 0.01$ GeV - $0.06$ GeV, and two different values of the mass of fermionic DARK MATTER, $M_χ= 200$ GeV and $300$ GeV. We consider two values of the central MAGNETic field, $B_c = 7\times10^{17}$ Gauss, $9 \times 10^{17}$ Gauss, for a MAGNETized neutron star. Finally, we compare the theoretical predictions with the observed mass-radius and tidal deformability data of pulsars obtained from gravitational wave observations.

[abstract 11 / 29] Yes (score: 4)
arXiv:2607.09509 [pdf, ps, other]

Title: 3D Plasma plume characterization of an electrodeless thruster cluster in MAGNETic arch configuration

Authors: Sacha A. Huot, Marco Riccardo Inchingolo, Jaume Navarro-Cavallé, Mario Merino,

Comments: 14 pages, 8 figures, preprint

Subjects: physics.plasm-ph

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

Clustering electrodeless plasma thrusters in pairs with opposing MAGNETic polarities offers an easy means to scale-up the propulsion system of future missions, and also, to mutually cancel their respective MAGNETic dipoles. Their MAGNETic nozzles merges to form a new topology, the `MAGNETic arch', which can yield a lower plasma plume divergence than two separate MAGNETic nozzles. This work characterizes the plasma expansion in the fully-closed MAGNETic arch of a cluster of two electron-cyclotron resonance thrusters with electrostatic probes (Langmuir probes, Faraday cups, and a Retarding Potential Analyzer). Electrostatic potential, plasma density, electron temperature, ion current and energy are measured in the two orthogonal planes of symmetry of the setup for various operating conditions. Results show that a plasma JET can be extracted even from this MAGNETic configuration, albeit with a reduced ion energy. A slight potential hill and hotter electrons exist in the central part of the arch. Ion current profiles are doubly-peaked in the horizontal plane, likely corresponding to the beamlet of each thruster. Trends with xenon mass flow rate and input power are consistent with the expectations of electrodeless plasma thrusters. The plume experiences an upward or downward deflection depending on the direction of the applied MAGNETic field, which could be attributed to the effect of the lateral electron drifts in the MAGNETic arch.

[abstract 12 / 29] (score: 3)
arXiv:2512.24936 [pdf, ps, other]

Title: Searching for Periodicity in FRB 20240114A

Authors: J. I. Katz,

Comments: 5 pp., 2 figs

Subjects: astro-ph.HE

Created: 2026-07-08; Updated: 2026-07-13; Datestamp: 2026-07-13

FRB 20240114A is extraordinarily active, and therefore presents an opportunity to search for the periodicity predicted by MAGNETar models of Fast Radio Bursts (FRB). Zhang, et al. (2025) observed 11,553 bursts, including 3196 on MJD 60381 (March 12, 2024). We find no significant peak in the periodogram of those bursts, which occur within 15628 s. This interval is short enough that even with a characteristic slowing age of 1 year a periodicity $\ge 0.1\,$s it would not significantly dephase within the observation. Introducing modulation artificially shows that an amplitude of 0.15 would have been detected robustly.

[abstract 13 / 29] (score: 3)
arXiv:2603.19037 [pdf, ps, other]

Title: Non-Markovian Cosmic-Ray Pitch-Angle Transport from Mirror Interactions

Authors: Kai Yan, Huirong Yan, Parth Pavaskar, Chuanpeng Hou, Ruo-Yu Liu,

Comments: 11 pages, 7 figures

Subjects: astro-ph.HE

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

Cosmic-ray pitch-angle transport in MAGNETohydrodynamic (MHD) turbulence is governed by the interplay between MAGNETic mirroring and gyroresonant scattering. We develop a guiding-center (GC) Langevin model with explicit mirror drift and gyroresonant diffusion to describe the pitch angle evolution. This model accurately captures our test-particle simulation results in three-dimensional MHD turbulence, driven both solenoidally and compressively. We find that MAGNETic mirroring can drive anomalous pitch-angle diffusion at large pitch angles (including $90^\circ$) with non-Markovian memory effects, which arises from trapping of particles in MAGNETic wells. Gyroresonant scattering controls the escape rate from these wells. Across $M_{\rm A}$, large-pitch-angle particles are jointly regulated by mirror trapping and gyroresonant escape, exhibiting a transition from anomalous to normal diffusive pitch-angle transport as scattering strengthens, whereas small-pitch-angle particles remain gyroresonance-dominated and diffusive throughout. The pitch angle transport is found to be dominated by the compressible perturbations with marginal influence from Alfvén modes. In compressible turbulence with realistic damping accounted for, transit time damping (TTD) treatment fully recovers mirror interactions.

[abstract 14 / 29] (score: 3)
arXiv:2607.08823 [pdf, ps, other]

Title: Star-Disk Collisions II: Debris Stream Dynamics and Implications for QPEs and Other Transients Near SMBHs

Authors: Philippe Z. Yao, Eliot Quataert, Yan-Fei Jiang, Itai Linial,

Comments: 15 pages, 8 figures, 2 tables; submitted to ApJ

Subjects: astro-ph.HE

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

Quasi-periodic eruptions (QPEs) are repeating soft X-ray nuclear transients with recurrence times of hours-days and flare duty cycles of $\sim$10-20%. Many aspects of QPEs can be modeled as a stellar-mass orbiter that intersects an accretion disk producing a shocked debris cloud and a flare of radiation. We present three-dimensional Athena++ hydrodynamic simulations of star-disk interactions around a $10^{6}\,M_\odot$ supermassive BLACK HOLE, including the BLACK HOLE's tidal potential, the disk's Keplerian rotation, and orbital periods similar to those observed. After each disk encounter, freshly stripped stellar debris exits the Hill sphere to form an extended, asymmetric, roughly triaxial stream. Subsequent stream-disk collisions shock both stellar debris and disk gas to high specific energies and drive a wind-like outflow. At larger orbital periods the shocked stellar debris dominates the high specific energy debris, while at shorter orbital periods the shocked disk energy can be similar. From the shocked stellar mass measured in the simulations over time, we infer flare durations set by the time it takes the stellar debris stream to collide with the disk, consistent with the observed constant duty cycle of $\sim$10-20%, independent of orbital period. The total shocked debris energy is consistent with QPE flare energetics. Our results favor one observable flare per stellar orbit except perhaps at the shortest orbital periods where the shocked star and disk energetics can be similar. Variations in the stream's center of mass relative to the star, the stream density, and other properties can produce diverse changes in the time of the flare's peak relative to the time of the star-disk collision. We discuss the implications of our results for QPE timing and for other transients in galactic nuclei.

[abstract 15 / 29] (score: 3)
arXiv:2607.08876 [pdf, ps, other]

Title: Studying the Variable Continuum and Emission Line Spectrum of 4U 1700-377 using NUSTAR's Stray Light

Authors: Colin J Bourque, McKinley C Brumback, Brian W Grefenstette, Douglas J K Buisson, Renee M Ludlam, Guglielmo Mastroserio, Steven Rossland,

Comments:

Subjects: astro-ph.HE

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

The high-mass X-ray binary 4U 1700-377 shows strong variation in brightness on timescales of hundreds of seconds due to accretion from a highly clumped stellar wind from the companion. Using two focused observations and five stray light observations from NUSTAR, we are able to expand the baseline of observations of the source and track spectral parameters throughout the source's variability. The focused NUSTAR observations confidently detect excess emission lines at energies above Fe K$α$, but are unable to universally constrain the nature of these lines independently of model choice. Strong Fe K$α$ fluorescence is ubiquitous in the stray light data, but these observations lack sufficient signal-to-noise to further measure additional emission lines. We discuss the statistics of a claimed cyclotron resonant scattering feature as seen in the stray light spectra, but find no conclusive evidence for its existence. Finally, we investigate two instances of sustained low-flux states of up to 60 ks. When this occurs, luminosity can fall by almost an order of magnitude and the high-energy continuum softens significantly without corresponding to increased absorption. We discuss the manner in which the changing shape of the continuum during these intervals may show accretion during an extended rarefied interval of stellar wind, or a possible change of the dominant accretion regime.

[abstract 16 / 29] (score: 3)
arXiv:2607.09644 [pdf, ps, other]

Title: Periodic line-of-sight velocity-driven modulations to gravitational waves emitted by compact binaries in Keplerian outer orbits

Authors: Avinash Tiwari, Shasvath J. Kapadia, Aditya Vijaykumar, Sourav Chatterjee,

Comments:

Subjects: gr-qc astro-ph.HE

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

The centre of mass (CoM) of compact binary coalescences (CBCs) occurring in the vicinity of a supermassive BLACK HOLE, through interaction with an arbitrary third body (e.g., of stellar mass), or in a dense stellar environment, will undergo a time-varying line-of-sight (LOS) velocity. This in turn leads to a time-varying Doppler shift and corresponding modulations in the shape of the gravitational waves (GWs). The phase and amplitude corrections arising from constant LOS acceleration and its higher-order time derivatives are already known. Specifically, these effects lead to corrections to the GW waveform at $-4n$ post-Newtonian (PN) order, where $n$ is the $n^{th}$ time derivative of the LOS velocity. In the context of a circular or eccentric outer orbit of the CoM of the CBC, these effects can be thought of as approximations to the LOS velocity in the limit: observation duration $\ll$ period of the outer orbit. However, this condition is not necessarily always satisfied. In this {\it paper}, we present phase and amplitude corrections to the GW waveforms arising from a periodic non-RELATIVISTIC LOS velocity for circular and eccentric outer orbits of the CBC's CoM. Specifically, these lead to phase and amplitude modulations at 4 PN order, and reduce to the known corrections for constant kinematic parameters under appropriate limits mentioned above. We also perform a Fisher matrix analysis to forecast constraints on the environment that is sourcing the time-varying LOS velocity, for various future ground and space-based detectors. We further show that constraints acquired using GW waveforms derived in this work improve significantly in comparison to those acquired from approximate methods valid for constant kinematic parameters.

[abstract 17 / 29] (score: 2)
arXiv:2601.18926 [pdf, ps, other]

Title: Multiwavelength Analysis of Six Luminous Fast Blue Optical Transients

Authors: Cassie Sevilla, Anna Y. Q. Ho, Nayana A. J., Steve Schulze, Daniel A. Perley, Michael Bremer, Igor Andreoni, Ivan Altunin, Thomas G. Brink, Michael Camilo, Poonam Chandra, Ping Chen, Ashley A. Chrimes, Michael W. Coughlin, Kaustav K. Das, Andrew Drake, Alexei V. Filippenko, Christoffer Fremling, James Freeburn, Avishay Gal Yam, Mary Gerhart, Matthew J. Graham, George Helou, K-Ryan Hinds, Natalya Johnson, Mansi M. Kasliwal, Harsh Kumar, Russ R. Laher, Natalie LeBaron, Maggie L. Li, Chang Liu, Ben Margalit, Gokul P Srinivasaragavan, Yu-Jing Qin, Nabeel Rehemtulla, Sophia Risin, Sam Rose, Rupak Roy, Ben Rusholme, Genevieve Schroeder, Jesper Sollerman, Kailai Wang, Jacob L. Wise, Yi Yang, Yuhan Yao, WeiKang Zheng,

Comments: 42 pages, 12 figures

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

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

We present multiwavelength observations and analysis of six luminous fast blue optical transients (LFBOTs) discovered in Zwicky Transient Facility (ZTF) survey data. We identified these LFBOTs from their fast light-curve evolution ($t_{1/2}\leq 12 $d), blue colors at peak brightness ($g-r\leq-0.5 $mag), a visible host galaxy, high optical luminosity ($M_g<-20$), and an X-ray or radio detection. With the exception of AT2024aehp (ZTF24abygbss), these transients exhibit peaks in their $10\,$GHz radio light curves at $t_{\text{rest}} \approx 50-100$ d, with peak radio luminosities ranging from $10^{38}-10^{40}$ erg s$^{-1}$. Modeling the radio emission as SYNCHROTRON radiation indicates a fast ($v=0.1-0.3c$) shock in a dense ($n_e\approx10^{3}-10^{4}$ cm$^{-3}$) medium. The X-ray emission varies by $\approx2$ orders of magnitude in luminosity ($10^{42}-10^{44}$ erg s$^{-1}$) at $t_{\text{rest}}\sim20 $d. Analysis of the host-galaxy photometry and spectroscopy for each transient shows that they are predominantly nonnuclear (a few kpc offset) with star-forming host galaxies of stellar masses $10^{9}-10^{11} ,M_\odot$. Unlike all other LFBOTs to date, AT2024aehp exhibited a luminous ($M<-19 $mag) plateau in the optical light curve; spectra during this plateau phase showed a featureless blue continuum. The $6-15$ GHz radio emission of AT2024aehp brightened by over an order of magnitude from $t_{\text{rest}} \approx70 $d to $t_{\mathrm{rest}} \approx130 $d. The mostly consistent radio behavior between optically selected LFBOTs implies a similar circumburst medium, leading us to prefer a progenitor scenario in which mass is lost in a consistent way shortly prior to the terminal event, such as a massive star merging with a compact object.

[abstract 18 / 29] (score: 2)
arXiv:2602.17756 [pdf, ps, other]

Title: Pushing spectral siren cosmology into the third-generation era: a blinded mock data challenge

Authors: Matteo Tagliazucchi, Michele Moresco, Alessandro Agapito, Michele Mancarella, Sarah Ferraiuolo, Simone Mastrogiovanni, Nicola Borghi, Francesco Pannarale, Daniele Bonacorsi,

Comments: 13 pages, 8 figures

Subjects: astro-ph.CO gr-qc

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

Gravitational wave (GW) spectral sirens offer a promising method for measuring cosmological parameters using GW data only - without relying on external redshift information such as electroMAGNETic counterparts or galaxy catalogs - by exploiting distributional features in the population of GW sources. The advent of third-generation detectors like the Einstein Telescope (ET) will provide catalogs three orders of magnitudes larger than current ones, raising questions about the scalability and robustness of existing inference pipelines. We present a blinded mock data challenge that tests three public pipelines with distinct numerical implementations, namely, $\texttt{ICAROGW}$, $\texttt{CHIMERA}$, and $\texttt{pymcpop-gw}$, on simulated ET observations containing the best $\mathcal{O}(10^4)$ binary BLACK HOLE mergers that can be observed in 1 year. We assess their computational performance, validate their agreement in a blinded setting, and forecast cosmological constraints. We find that, thanks to GPU acceleration, these pipelines can process the events expected from ET within a manageable timeframe. All pipelines recover consistent cosmological and population parameters. Assuming a flat $Λ$CDM model, we measure $H(z)$ at $z\sim1.5$ with 2.4% precision, and achieve a mean precision on $H(z)$ of 2.8% across $0.7

[abstract 19 / 29] (score: 2)
arXiv:2606.19285 [pdf, ps, other]

Title: Direct Tests of Black Hole Accretion Rate Prescriptions: I. Bondi Accretion at Different Scales

Authors: James Agostino, Ming-Yi Lin, Natasha Jones, Anne M. Medling, Loreto Barcos-Muñoz, Daniel Anglés-Alcázar, Claudio Ricci, George C. Privon, Vivian U, Paul Torrey, Philip F. Hopkins, Claire Max,

Comments: 21 pages, 4 figures

Subjects: astro-ph.GA

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

We present spatially resolved parsec-scale measurements of nuclear conditions (gas density and kinetic temperature) relevant for BLACK HOLE accretion rate predictions in the Seyfert 2 galaxy, NGC 1068. We inject these parameters into the prescription for a Bondi-like accretion model, then compare the resulting accretion rate prediction to the empirical accretion rate derived from hard X-ray observations. Cosmological simulations have spatial resolution ranging from $\sim$10 pc to $\sim$kpc scales, and so for reasonable comparison we test these accretion rate predictions in pixel-sized radial steps out to 500 pc. Compared to warm H$_2$ gas, CO gas is the dominant mass carrier close to the SMBH. We find that the Bondi accretion rate ($\dot{\mathrm{M}}_{\mathrm{Bondi}}$) of cold molecular gas alone (measured using CO) overestimates the true accretion rate by up to 14 dex in a small aperture (r$\lesssim$5 pc) around the BLACK HOLE, and by at least 8 dex inside large apertures (r$\lesssim$500 pc). These results are the first in a series of direct tests of accretion rate prescriptions, and they suggest that using a Bondi accretion formalism to model supermassive BLACK HOLE accretion in Seyfert 2 galaxies may lead to overestimated accretion rates in simulations.

[abstract 20 / 29] (score: 2)
arXiv:2607.08812 [pdf, ps, other]

Title: Magnetogenesis by galactic processes: impact on circumgalactic and intergalactic fields

Authors: Rahul Ramesh, Enrico Garaldi, Chris Byrohl,

Comments: Submitted to PASA. 20 pages, 14 figures (including appnd.)

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

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

We investigate the origin and evolution of cosmic MAGNETic fields using a suite of large-volume cosmological MAGNETohydrodynamic simulations (L$_\mathrm{box}=25$ Mpc/h) run with the moving-mesh code AREPO. Atop the IllustrisTNG galaxy formation model, we implement additional recipes for MAGNETogenesis in which MAGNETic energy is injected during SUPERNOVAe (SNe) and supermassive BLACK HOLE (SMBH) feedback events, and compare these to simulations initialized with uniform primordial seed fields. Halo MAGNETic field strengths at $z=0$ are largely similar across seeding models and are primarily amplified and sustained by small-scale and halo-scale dynamo action. Nevertheless, we find differences in MAGNETic field topology, with SMBH-driven models exhibiting systematically smaller coherence lengths than primordial-only and SNe-only runs. We find that feedback-driven injection accelerates the onset of dynamo growth, leading to more rapid convergence of MAGNETic field strengths with numerical resolution, particularly in low-mass halos. In the intergalactic medium (IGM), SNe-only injection underproduces MAGNETic fields relative to inferred lower limits from $γ$-ray cascade constraints at both $z=0$ and $z \sim 3$, whereas our specific SMBH-based injection prescription satisfies present-day constraints but remains in mild tension at high redshifts. Reconciling these specific high-$z$ constraints therefore likely requires either modified feedback prescriptions or an additional primordial seeding component.

[abstract 21 / 29] (score: 2)
arXiv:2607.08854 [pdf, ps, other]

Title: The SPOTLIGHT Pulsar Search Pipeline: A GPU-Accelerated FFT Approach

Authors: Jyotirmoy Das, Jayanta Roy, Nishant Pradeep Deo, Karel Adámek, Wes Armour, Kshitij Bane, Jayaram Chengalur, Kenil Ajudiya, Chahat Dudeja, Sridhar Gajendran, Zhaocheng Gong, Param Joshi, Sanjay Kudale, Arpan Pal, Ujjwal Panda, Adityan S, Raghav Wani, Junhao Zhang, Deepak Bhong, Shelton Gnanaraj, Santaji N. Katore, Mekhala Muley, Harshavardhan Reddy,

Comments: 15 pages and 8 figures; Submitted to Astrophysical Journal (ApJ)

Subjects: astro-ph.HE

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

We present the pulsar search component of SPOTLIGHT (Survey for sPoradic radiO bursTs via a commensaL multI-beam Gpu-powered Hpc at the gmrT), a GPU-accelerated commensal backend operating at the upgraded Giant Metrewave Radio Telescope (uGMRT). While SPOTLIGHT is primarily designed for real-time detection and localisation of fast radio bursts (FRBs), it simultaneously records a subset of beamformed data products for periodicity searches without requiring dedicated telescope time. To process the large data volumes generated by the survey, we have developed a scalable FFT-based pulsar search pipeline that combines radio-frequency interference mitigation, GPU-accelerated dedispersion and periodicity searches, multi-beam candidate sifting, efficient folding and machine-learning classification. Using population synthesis and archival uGMRT observations, we estimate that a fully operational SPOTLIGHT survey with 160 PC and one IA beam could discover $\sim$ 450 new pulsars, probing both high-sky coverage and faint pulsars over three and a half years of commensal observations. The pipeline has been validated on GMRT Cycle 48 and 49 observations (i.e. April 2025 to Mar 2026), successfully re-detecting numerous known pulsars with a wide range of Period, DM and flux densities, and is currently operational for SPOTLIGHT commensal data processing. We describe the SPOTLIGHT observing system, pulsar survey design, search parameter space, candidate-selection strategy, current status, and future developments. SPOTLIGHT demonstrates the scientific potential of commensal pulsar surveys and serves as a pathfinder for real-time, large-scale pulsar and transient searches in the SKA era.

[abstract 22 / 29] (score: 2)
arXiv:2607.08884 [pdf, ps, other]

Title: Probing Rotating Einstein-Power-Yang-Mills Black Holes through Shadows and Quasinormal Modes: Prospects for Event Horizon Telescope Constraints

Authors: I. Ezzaki, A. El Boukili, H. Lekbich, A. Benami,

Comments:

Subjects: gr-qc

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

Within Einstein power-Yang-Mills gravity (EPYM), we build a rotating BLACK HOLE via the Newman-Janis procedure applied to the spherically symmetric static seed, obtaining a Kerr-like metric controlled by the spin \(a\), the MAGNETic Yang-Mills charge \(Q\), and the power parameter \(q\). We analyse the horizon structure and the photon region, and we compute the shadow as it appears to a remote observer for different values of these parameters. Using the published Event Horizon Telescope measurements of M87\(^*\) and Sgr A\(^*\), we constrain the Yang-Mills charge and the power parameter from the angular size and the Schwarzschild deviation \(δ\) of the observed images. At the Maxwell point \(q = 1\) the spin marginalized likelihood combining both sources bounds the charge to \(Q \lesssim 0.26\,M\) at \(1σ\), while the fixed-spin band intersection at \(a = 0.7\,M\) gives the weaker \(Q \lesssim 0.52\,M\) from the M87\(^*\) angular size alone. The bound weakens as \(q \to 3/2\), where the shadow diameter becomes nearly insensitive to the charge. The shadow radius also fixes the limiting absorption cross section at high frequencies and hence the energy emission rate, which is suppressed by the charge, enhanced by the power parameter, and suppressed at near-extremal spin. We then compute the quasinormal modes of a massless scalar on the rotating background from the leading-order Wentzel-Kramers-Brillouin (WKB) conditions on the Teukolsky type radial potential, finding that the oscillation frequency rises and the damping rate falls as the charge or spin increases. The power parameter leaves an imprint on the shadow size and its charge sensitivity and in the quasinormal spectrum the shift is in principle present but lies below the resolution of current detectors.

[abstract 23 / 29] (score: 2)
arXiv:2607.08972 [pdf, ps, other]

Title: Self-similar Worthington JETs

Authors: José M. Gordillo, Javier Rodríguez-Rodríguez, Vatsal Sanjay,

Comments:

Subjects: physics.flu-dyn

Created: 2026-07-09; Updated: 2026-07-13; Datestamp: 2026-07-13

When a micron-sized bubble bursts, capillary waves deform the cavity into a cone that ejects a Worthington JET. The JET is born by inertial focusing, and the local collapse follows self-similar Euler solutions set by the semiangle $β$. Writing $r_j$ and $v_j$ for the dimensionless JET-base radius and velocity, the local Weber number $We_j=r_j v^2_j$ measures inertia relative to capillarity. The theory, supported by accurate numerical simulations gives $r_j\proptoτ^{α(β)}$ with $α\simeq0.63$ and, hence $We_j\gg1$, with $We_j\to\infty$ as $r_j\to0$, so inertia increasingly overwhelms capillarity. In simulations, the interface collapses onto a universal shape for more than two decades in dimensionless time when lengths are scaled using our prediction for $r_j$. For water, this gives incipient radii of $\mathcal{O}(1)$ nm, predicting nanometric sea-spray aerosols.

[abstract 24 / 29] (score: 2)
arXiv:2607.09046 [pdf, ps, other]

Title: Implicit discretization schemes for full-kinetic ion and drift-kinetic electron simulations

Authors: Zilong Li, Yang Chen, Haotian Chen, Lei Ye, Zhe Gao, Wei Chen,

Comments:

Subjects: physics.plasm-ph

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

We present a new electroMAGNETic plasma simulation model with full-kinetic ions and drift-kinetic electrons. This model (termed as FIDES) solves the electric field using the implicit perpendicular Ohm's law and a novel implicit parallel Ampere's law, where the latter requires an implicit scheme for the parallel electric field in advancing the electron weights. To suppress unphysical high-frequency instabilities, ion weights are advanced using an implicit scheme for perpendicular electric fields. Simulations of perpendicular and parallel waves validate the model's capability in handling high-frequency physics. Low-frequency wave simulations demonstrate that the implicit parallel Ampere's law can mitigate the cancellation problem more effectively than the conventional schemes using the parallel Ohm's law. To reduce the numerical damping from implicit time-stepping, we develop a second-order scheme for particle pushing. Meanwhile, an integrated strategy combining the first- and second-order schemes is employed to suppress odd-even decoupling while maintaining the accuracy of the second-order formulation.

[abstract 25 / 29] (score: 2)
arXiv:2607.09112 [pdf, ps, other]

Title: Physics and Astrophysics of Black Holes with eXTP

Authors: Cosimo Bambi,

Comments: 12 pages, 3 figures. Talk given at the workshop "Frontier Research in Astrophysics - V" (Palermo, Italy, 15-20 June 2026)

Subjects: astro-ph.HE gr-qc

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

The enhanced X-ray Timing and Polarimetry (eXTP) mission will combine spectral, timing, and polarimetric techniques to study accreting BLACK HOLEs, measure their masses and spins, and test Einstein's theory of General Relativity in the strong-field regime. In this contribution, I review the capabilities of eXTP to advance our current understanding of BLACK HOLE physics and astrophysics.

[abstract 26 / 29] (score: 2)
arXiv:2607.09154 [pdf, ps, other]

Title: Enhancing the sensitivity to FCNC top decays $t\to cH $ and $t\to cS $ in the boosted regime at CLIC

Authors: Shuo Yang, Peng-Bo Zhao, Ji-Chong Yang,

Comments: 19 pages, 11 figures

Subjects: hep-ph

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

The top QUARK, having the largest Yukawa coupling to the Higgs sector, provides a unique window into electroweak symmetry breaking and possible new physics beyond the Standard Model. Searches for rare top-QUARK processes are thus powerful probes of new physics. In this work, we investigate the flavor-changing neutral-current (FCNC) top-QUARK decays $t\to cH$ and $t\to cS$, where $S$ denotes a light scalar, at the Compact Linear Collider (CLIC) with a center-of-mass energy of $\sqrt{s}=1.5~\mathrm{TeV}$. Our analysis focuses on a kinematic regime distinct from most previous studies, in which the top QUARKs are typically highly boosted. To enhance signal discrimination in the boosted regime, we construct multi-channel JET images and employ a convolutional neural network (CNN) classifier to capture JET-substructure patterns relevant to the FCNC signals. Assuming an integrated luminosity of $4~\mathrm{ab}^{-1}$, we obtain the expected $95\%$ C.L. upper limit $\mathrm{BR}(t\to cH)\times \mathrm{BR}(H\to b\bar b)<5.27\times10^{-5}$. For the exotic scalar singlet, expected $95\%$ C.L. upper limits between $3.25\times10^{-5}$ and $5.26\times10^{-5}$ are obtained for $\mathrm{BR}(t\to cS)\times \mathrm{BR}(S\to b\bar b)$, for scalar masses between $30$ and $80~\mathrm{GeV}$.

[abstract 27 / 29] (score: 2)
arXiv:2607.09286 [pdf, ps, other]

Title: Enhancing the Cherenkov Telescope Array Observatory high-level performance through an event-type-based analysis

Authors: Juan Bernete, Silvia García-Soto, Tarek Hassan, Orel Gueta, Maximilian Linhoff, Atreyee Sinha, Gernot Maier,

Comments: 37 pages, 12 figures

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

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

The analysis traditionally employed by Imaging Atmospheric Cherenkov Telescopes involves optimizing quality cuts to select a sub-sample of high-quality events. These events are used for the scientific interpretation of the data, employing a single set of Instrument Response Functions (IRFs). All selected events are treated equally and assumed to be well represented by these IRFs, while the rest are discarded. An alternative approach, successfully applied in experiments such as FERMI-LAT, is an event-type-based analysis. This method divides datasets into subsamples, each containing events of a given expected reconstruction quality. IRFs are computed for each subsample independently, improving the accuracy with which IRFs represent the reconstruction quality of each event. The high-level analysis of these subsamples is performed treating them as independent observations, each with their own set of IRFs, and analyzed jointly. In this work we present a proof-of-concept implementation of an event-type-based analysis for the future CTAO using simulated data. A neural network (specifically a multi-layer perceptron) is trained to predict the direction reconstruction error of each event, and the simulated dataset is divided into event types based on this predicted variable. We compute IRFs for each event type and compare them with those from the standard analysis (without event types). Finally, we simulate observations using these event-type-wise IRFs and analyze them with high-level analysis tools to test the performance of both approaches. This implementation demonstrates notable improvements: 25% to 50% boost in spatial resolving power and ~25% in sensitivity. This boost in performance will have strong implications in the scientific exploitation of the CTAO data, especially in crowded regions such as the Galactic Plane or searching for spectral signatures like Dark Matter annihilation lines.

[abstract 28 / 29] (score: 2)
arXiv:2607.09369 [pdf, ps, other]

Title: Bayesian inference of the dense matter equation of state built upon extended Skyrme interactions: A generalization

Authors: Mikhail V. Beznogov, Adriana R. Raduta,

Comments: 15 pages, 8 figures, 3 tables. Submitted to PRC

Subjects: nucl-th astro-ph.HE

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

The nonRELATIVISTIC theory of nuclear matter (NM) based on Brussels-Skyrme interactions is employed to develop models for dense and neutron-rich matter within a Bayesian framework. We employ the following set of constraints: the four best-known nuclear empirical parameters, density dependence of the energy per particle in pure neutron matter (PNM), density dependence of the Landau effective mass ($m_\mathrm{eff}$) of neutrons in PNM and symmetric NM, and a lower limit on the maximum gravitational mass that neutron stars (NSs) can sustain. In addition, a number of ``sanity checks'' are added: the values of the speed of sound, neutron and proton Landau effective masses and FERMI velocities are constrained up to the central density of the most massive NS configuration and for isospin asymmetries $δ=(n_n-n_p)/(n_n+n_p)$ ranging from 0 to 1. Our ensemble of models \emph{fully} explores the capacity of non-RELATIVISTIC Brussels-Skyrme effective interactions to describe NM at densities exceeding several times the nuclear saturation density. This is a necessary step toward a better understanding of the properties of dense matter and possible correlations between the parameters of NSs and the parameters of NM. Due to pronounced U-shaped density-dependencies of $m_\mathrm{eff}$, all our models exhibit a non-monotonic ``rise-and-fall'' behavior of the thermal pressure ($p_\mathrm{th}$) as a function of density, which in extreme cases leads to $p_\mathrm{th} < 0$. This work is a generalization of [Beznogov and Raduta, Phys. Rev. C 110, 035805 (2024)].

[abstract 29 / 29] (score: 2)
arXiv:2607.09658 [pdf, ps, other]

Title: Identifying and characterizing extragalactic circum-CBC exoplanets with future gravitational-wave detectors

Authors: Avinash Tiwari, Aditya Vijaykumar, Shasvath J. Kapadia, Sourav Chatterjee,

Comments:

Subjects: astro-ph.HE gr-qc

Created: 2026-07-10; Updated: 2026-07-13; Datestamp: 2026-07-13

Exoplanets are high-value targets for a variety of ground and space-based telescopes. All known exoplanets are Galactic, and a fraction of them orbit compact objects. In this work, we investigate the possibility of detecting extragalactic exoplanets orbiting stellar-mass compact binary coalescences (CBCs), such as binary neutron stars, neutron star-BLACK HOLEs, and binary BLACK HOLEs, using future gravitational wave (GW) detectors, including A+ (LIGO in O5), Einstein Telescope, and DECIGO. We use the technique of reconstructing an external potential's profile by extracting information about the centre-of-mass (CoM) kinematics of a CBC encoded in the GWs it emits. In this work, the external potential is provided by the circum-CBC exoplanet, and the resulting signature on the GW waveform comes from the ``wobble'' of the CBC's CoM around the CBC-exoplanet barycentre. As a proof of principle, we consider a few example CBCs detectable with future detectors and a range of circum-CBC exoplanet parameters in circular and eccentric orbits. We find that for a significant fraction of the range of parameters considered, we can identify the presence of a circum-CBC exoplanet by extracting its mass (up to an unknown orbital inclination angle) within a factor $\mathcal{O}(1)$ of its true value, at $68\%$ confidence.