Current date: 2026-08-07
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Datestamp limit: 2026-08-07 (0 days ago)
Created/updated limit: 2026-07-31 (7 days ago)
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Scoring abstracts
Number of records retrieved: 673
Keyword score statistics
score 9 -- 3 abstracts
score 8 -- 1 abstracts
score 6 -- 2 abstracts
score 5 -- 4 abstracts
score 4 -- 2 abstracts
score 3 -- 3 abstracts
score 2 -- 18 abstracts
in total -- 33 abstracts
Articles that appeared on 2026-08-07
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[abstract 1 / 33] Wow! (score: 9)
- Title: Non-uniform particle injection into BLACK HOLE JETs by radiative MAGNETic RECONNECTionAuthors: Rin Oikawa, Kenji Toma, Shigeo S. Kimura,Comments: 25 pages, 15 figures. Accepted for publication in ApJSubjects: astro-ph.HE physics.plasm-phCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Active galactic nuclei often exhibit highly collimated RELATIVISTIC plasma outflows launched from the vicinity of their central BLACK HOLEs. One of the key theoretical challenges in understanding BLACK HOLE JET formation is the origin of the plasma that feeds the JET, which remains poorly understood, particularly in explaining the observed JET emission. In this study, we focus on electron positron pair production generated by high energy photons from non axisymmetric MAGNETic RECONNECTion near the BLACK HOLE, as suggested by recent three dimensional general RELATIVISTIC MAGNETohydrodynamics simulations. By employing general RELATIVISTIC ray tracing, we calculate the spatial distribution of the pair production rate in the JET, taking into account photon propagation and collision angles in curved spacetime. We find that our scenario can naturally supply a sufficient amount of plasma to explain the observed radio emission from the M87 JET, even when photon anisotropy is considered. Furthermore, we show that a spinning BLACK HOLE plays a crucial role in shaping the spartial dsitribution of the pairs, which in turn affects JET acceleration and very high energy emission from the JET base.
[abstract 2 / 33] Wow! (score: 9) - Title: Constraints on the VHE counterpart of two binary BLACK HOLE mergers observed by the MAGIC and CTAO LST-1 telescopesAuthors: K. Abe, S. Abe, J. Abhir, A. Abhishek, V. A. Acciari, F. Acero, A. Aguasca-Cabot, I. Agudo, I. Albanese, D. Ambrosino, F. Ambrosino, T. Aniello, S. Ansoldi, L. A. Antonelli, C. Aramo, C. Arauner, A. Arbet-Engels, C. Arcaro, T. T. H. Arnesen, P. Aubert, A. Babić, C. Bakshi, A. Baktash, M. Balbo, A. Bamba, A. Baquero-Larriva, U. Barres-de-Almeida, J. A. Barrio, L. Barrios-Jiménez, I. Batkovic, J. Baxter, J. Becerra-González, W. Bednarek, E. Bernardini, J. Bernete, A. Berti, J. Besenrieder, C. Bigongiari, A. Biland, E. Bissaldi, O. Blanch, Ž. Bošnjak, G. Bonnoli, P. Bordas, L. Breton-Zaourat, A. Briscioli, E. Bronzini, G. Brunelli, J. Buces, A. Bulgarelli, I. Burelli, L. Burmistrov, C. Campa, A. Campoy-Ordaz, M. Cardillo, S. Caroff, A. Carosi, R. Carosi, R. Carraro, M. Carretero-Castrillo, F. Cassol, A. J. Castro-Tirado, D. Cerasole, G. Ceribella, A. Cerviño-Cortínez, Y. Chai, A. Chiavassa, A. Chilingarian, G. Chon, L. Chytka, G. M. Cicciari, A. Cifuentes Santos, J. L. Contreras, J. Cortina, H. Costantini, S. Covino, M. Croisonnier, G. D'Amico, P. Da-Vela, M. Dalchenko, F. Dazzi, A. De-Angelis, M. de-Bony-de-Lavergne, B. De-Lotto, R. de-Menezes, G. De-Palma, V. de-Souza, R. Del-Burgo, L. Del-Peral, M. Delfino, C. Delgado Mendez, J. Delgado-Mengual, D. della-Volpe, L. Di-Bella, C. Di-Domenico, A. Di-Piano, F. Di-Pierro, R. Di-Tria, L. Di-Venere, C. Díaz, A. Dinesh, E. Do Souto Espineira, D. Dominis-Prester, A. Donini, D. Dorner, M. Doro, L. Eisenberger, D. Elsässer, G. Emery, J. Escudero, L. Farina, L. Feligioni, F. Ferrarotto, A. Fiasson, L. Foffano, L. Font, F. Frías-García-Lago, Y. Fukazawa, S. Gallozzi, J. Garcia-Garcia, R. J. García López, S. Garcia-Soto, D. Gasparrini, S. Gasparyan, M. Gaug, J. G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinovic, T. Gradetzke, R. Grau, J. Green, G. Grolleron, S. Gunji, P. Günther, D. Hadasch, A. Hahn, M. Hashizume, T. -Hassan, K. Hayashi, L. Heckmann, M. Heller, J. Herrera-Llorente, N. Hiroshima, D. Hoffmann, D. Horns, J. Houles, D. Hrupec, T. Inada, S. Inoue, K. Ioka, M. Iori, D. Israyelyan, A. Iuliano, J. Jahanvi, I. Jiménez-Martínez, J. Jiménez-Quiles, I. Jorge-Rodrigo, J. Jurysek, M. Kagaya, S. Kankkunen, V. Karas, H. Katagiri, T. Kayanoki, D. Kerszberg, M. Khachatryan, G. W. Kluge, Y. Kobayashi, K. Kohri, J. Konrad, P. Kornecki, P. M. Kouch, H. Kubo, J. Kushida, B. Lacave, M. Láinez, A. Lamastra, L. Lemoigne, E. Lindfors, M. Linhoff, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, A. Lorini, J. Lozano-Bahilo, F. Lucarelli, H. Luciani, L. Lulić, P. L. Luque-Escamilla, P. Majumdar, M. Makariev, M. Mallamaci, D. Mandat, G. Maneva, M. Manganaro, S. Mangano, D. K. Maniadakis, G. Manicò, K. Mannheim, F. Marini, M. Mariotti, G. Marsella, J. Martí, D. Martin, G. Martínez, M. Martínez, O. Martinez, P. Maru\v{s, evec, M. Massa, D. Mazin, S. Menchiari, J. Méndez-Gallego, S. Menon, E. Mestre-Guillen, D. Miceli, T. Miener, J. M. Miranda, J. M. Miranda, R. Mirzoyan, M. Mizuno, M. Molero-Gonzalez, E. Molina, H. A. Mondal, T. Montaruli, A. Moralejo, S. Morales-Sanchez-De-Lozada, K. Morita, A. -Morselli, V. Moya, K. Mrakovčić, A. L. Müller, H. Muraishi, T. Nagata, S. Nagataki, T. Nakamori, C. Nanci, A. Negro, A. Neronov, V. Neustroev, D. Nieto-Castaño, M. Nievas-Rosillo, C. Nigro, L. Nikolić, K. Nilsson, K. Noda, V. Novotny, S. Nozaki, M. Ohishi, A. Okumura, R. Orito, L. Orsini, J. Otero-Santos, P. Ottanelli, S. Paiano, M. Palatiello, G. Panebianco, D. Paneque, R. Paoletti, J. M. Paredes, M. Pech, M. Pecimotika, M. Peresano, F. Perrotta, M. Persic, F. Pfeifle, E. Pietropaolo, M. Pihet, G. Pirola, C. Plard, F. Podobnik, M. Polo, C. Pozo-Gonzaléz, P. G. Prada Moroni, E. Prandini, S. Rainò, R. Rando, W. Rhode, M. Ribó, J. Rico, V. Rizi, G. Rodriguez-Fernandez, A. Roy, E. Ruiz-Velasco, N. Sahakyan, T. Saito, S. Sakurai, D. A. Sanchez, H. Sano, E. Santos-Moura, T. Šarić, Y. Sato, F. G. Saturni, V. Savchenko, F. Schiavone, K. Schmitz, F. Schussler, T. Schweizer, M. Seglar-Arroyo, U. Sharma, T. Siegert, G. Silvestri, A. Simongini, J. Sitarek, V. Sliusar, D. Sobczynska, I. Sofia, A. Stamerra, J. Strišković, D. Strom, M. Strzys, Y. Suda, A. Sunny, H. Tajima, M. Takahashi, R. Takeishi, S. J. Tanaka, J. Tartera Barberà, T. Tavernier, P. Temnikov, Y. Terada, K. Terauchi, T. Terzic, M. Teshima, M. Tluczykont, T. Tomura, D. F. Torres, F. Tramonti, P. Travnicek, G. Tripodo, A. Tutone, S. Ubach, M. Vacula, M. Vázquez-Acosta, S. Ventura, G. Verna, I. Viale, A. Viana, A. Vigliano, C. F. Vigorito, E. Visentin, V. Vitale, M. Vorbrugg, G. Voutsinas, I. Vovk, T. Vuillaume, R. Walter, C. Walther, L. Wan, P. Witczak, F. Wersig, T. Yamamoto, R. Yamazaki, Y. Yao, P. K. H. Yeung, T. Yoshida, T. Yoshikoshi, W. Zhang,Comments: Published version. Corresponding authors: Andrea Simongini, Juan Jiménez Quiles, Mario Pecimotika, Monica Seglar-ArroyoSubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
We present very-high-energy gamma-ray observations of two binary BLACK HOLE merger candidates, GW240615_113620 and GW241125_010116, performed with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes and the first Large-Sized Telescope of the Cherenkov Telescope Array Observatory's (CTAO LST-1). GW240615_113620 was the best localized event of the fourth observing run of the LIGO-Virgo-KAGRA gravitational waves interferometers. GW241125_010116 was temporally and spatially coincident with a sub-threshold short-duration burst detected with the SWIFT-Burst Alert Telescope (BAT), the SWIFT-X-Ray Telescope (XRT) and the Einstein Probe Follow-up X-ray Telescope (FXT). We observed the two events in stereoscopic mode, taking advantage of the improved sensitivity of joint MAGIC+LST-1 observations. No detection was achieved in the GeV-TeV gamma-ray band for any of the two sources. The unfavourable observing conditions of both events posed a challenge for a standard analysis and therefore a non standard analysis was necessary for both objects. Owing to the small localization area and the association with a GRB-like burst respectively, these events represented an unprecedented opportunity to study in details the electroMAGNETic emission from binary BLACK HOLEs merger events and, in particular, we discussed two theoretical models that predict a detectable gamma-ray emission and the possible future applications.
[abstract 3 / 33] Wow! (score: 9) - Title: A broadband outburst of the compact steep-spectrum QUASAR 3C 138 in 2024-2026Authors: T. V. Mufakharov, Yu. V. Sotnikova, V. V. Vlasyuk, S. Yu. Sazonov, M. L. Khabibullina, A. G. Mikhailov, A. B. Pushkarev, T. An, Y. A. Kovalev, Y. Y. Kovalev, A. V. Popkov, M. A. Kharinov, G. S. Uskov, I. Yu. Lapshov, E. V. Filippova, A. Yu. Tkachenko, K. V. Iuzhanina, A. K. Erkenov, R. Yu. Udovitskiy, O. I. Spiridonova, I. A. Rakhimov, T. S. Andreeva, A. A. Ogloblin,Comments: 20 pages, 12 figures. Submitted to MNRASSubjects: astro-ph.HE astro-ph.GACreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
After several decades of relative quiescence, the compact steep-spectrum QUASAR 3C 138 entered an active phase in 2024-2026, exhibiting strong broadband flaring. We investigate its multiwavelength behaviour using dense multifrequency radio monitoring at 1-22 GHz with RATAN-600 and RT-32, optical R-band observations with Zeiss-1000 and AS-500/2, X-ray measurements with SWIFT/XRT and SRG/ART-XC, and the FERMI-LAT $γ$-ray light curve. The radio brightening accelerated after 2022 and was strongest at the highest frequencies. The radio spectra hardened markedly, with the 11-22 GHz spectral index evolving from steep to flat or inverted during the active phase. The X-ray flux increased by more than a factor of three during 2025-2026, while the photon index hardened from $Γ_{\rm X}\simeq 1.6$ to $Γ_{\rm X}\simeq 0.9$ and softened back after the peak. Flare decomposition revealed five $γ$-ray flares and a sequence of optical subflares during the later stages of the activity. The $γ$-ray, X-ray, and optical maxima occur within a $\simeq 13$-day interval, suggesting a common activity episode, whereas the radio brightens more gradually and in a frequency-dependent manner. Under the adopted compact-zone geometries, the sparse two-state spectral energy distributions (SEDs) can be represented by one-zone SYNCHROTRON self-Compton (SSC) solutions, while the relative contribution of external Compton (EC) remains geometry dependent. The flare shifts the modelled energy partition towards RELATIVISTIC electrons. These results favour a longer-lived, core-dominated activity phase, with later high-energy and optical flares superposed on the opacity-driven radio evolution of an emerging SYNCHROTRON component.
[abstract 4 / 33] Wow! (score: 8) - Title: Compression-Driven Kinetic Instabilities in Magnetically Arrested DisksAuthors: Vedant Dhruv, Lorenzo Sironi, Jordy Davelaar, Aaron Tran,Comments: 28 pages, 21 figures, accepted for publication in ApJSubjects: astro-ph.HE physics.plasm-phCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Event horizon-scale observations of low-luminosity BLACK HOLE accretion flows favor MAGNETically arrested disks, characterized by dynamically important MAGNETic fields ($β\lesssim1$, where $β$ is the ratio of plasma thermal pressure to MAGNETic pressure) and a two-temperature transRELATIVISTIC plasma. Motivated by plasma conditions in the SYNCHROTRON-emitting regions of these models, we perform 2D particle-in-cell simulations of electron-ion plasmas with a realistic mass ratio, subject to continuous compression perpendicular to the mean MAGNETic field $\boldsymbol{B}_0$. Conservation of particle MAGNETic moments drives pressure anisotropy $P_{\perp}>P_{\parallel}$, triggering anisotropy-driven instabilities. For ion plasma beta $β_{i0}=0.5$ and ion temperature $k_{\text{B}}T_{i0}/m_i c^2=0.05$, the ion pressure anisotropy is regulated by the ion cyclotron instability, while the mirror mode influences the late-time electron anisotropy. Both species develop nonthermal components at high energies, consistent with stochastic acceleration by cyclotron-scale fluctuations. We characterize how the onset and time evolution of the plasma instabilities, as well as the resulting ion and electron anisotropies and energy spectra, vary with $β_{i0}$, $k_{\text{B}}T_{i0}/m_i c^2$, electron-to-ion temperature ratio $T_{e0}/T_{i0}$, and the compression rate. Increasing the thermal energy toward RELATIVISTIC values raises the anisotropy thresholds for all instabilities observed in our simulations, allowing larger anisotropies to develop. For $T_{e0}/T_{i0}<1$, as expected in collisionless two-temperature accretion flows, the growth of mirror and whistler instabilities is delayed or suppressed, leading to increasingly adiabatic evolution of the electrons. Our findings can be used to inform global fluid models of BLACK HOLE accretion.
[abstract 5 / 33] Yes (score: 6) - Title: Suppressed diffusion and gamma-ray emission from the Cygnus bubbleAuthors: Ben Li, Pasquale Blasi, Elena Amato,Comments: 15 pages, 11 figures. Published in A&ASubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Recent gamma-ray observations indicate that star clusters can be efficient particle accelerators. In particular, LHAASO has detected diffuse gamma-ray emission from Cygnus OB2 extending to $\gtrsim$ PeV energies, indicating that particles are accelerated to at least $\gtrsim$1 PeV. In this work, we study the gamma-ray emission from the Cygnus region assuming particle acceleration either at the termination shock of the cluster wind (WTS) or in an unspecified source at the bubble center, taken to be either steady or bursting. We numerically solve the transport equation for non-thermal particles in all scenarios and derive their spatial and spectral distributions throughout the bubble. We then calculate the gamma-ray emission from pp interactions, including the contribution from particles interacting with the surrounding molecular cloud, which may help explain the extended emission observed by LHAASO. We also include the penetration of Galactic COSMIC RAYs (GCRs) and the resulting shock reacceleration. The predicted emission is compared with FERMI-LAT, HAWC and LHAASO observations. For three diffusion models, we find that a spatially dependent Bohm diffusion coefficient is required to reproduce both the spectrum and morphology in the cluster wind scenario. Penetrating GCRs can contribute significantly to the gamma-ray emission above $\sim$300 TeV. A suppressed diffusion coefficient with respect to the Galactic average in a region extending to at least 150 pc from the cluster center is needed to reproduce the LHAASO morphology. Our conclusion is that explaining both the spectrum and morphology of the $\sim$PeV emission with hadrons accelerated in a non-RELATIVISTIC steady source requires extreme assumptions. We also speculate on the possibility that some of the highest-energy gamma rays may originate from sources behind the Cygnus association.
[abstract 6 / 33] Yes (score: 6) - Title: GeV γ-ray emission in the star-forming region S140Authors: Li-Nuo Yang, Pak-Hin Thomas Tam,Comments: Accepted for publication in ApJSubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
We report the detection of a GeV γ-ray source in the S140 HII region using 17.75 years of FERMI-LAT data, with a source-detection significance of ~32.1σ in the 0.1-500 GeV energy band. The emission is significantly extended (AIC evidence ratio above 1 GeV is 2x10^9) and is therefore designated as 4FGL J2220.8+6319e. The γ-ray emission coincides spatially with a molecular cloud that hosts the massive young stellar object S140 IRS1. Its spectrum is best fitted by a log-parabolic spectrum (TS_cur(LP) = 104.1) and can be reproduced by both hadronic and leptonic models. The JET driven by S140 IRS1 offers a viable particle acceleration site, yielding injection timescales and maximum particle energies consistent with theoretical expectations, whereas stellar winds are energetically disfavored.
[abstract 7 / 33] Yes (score: 5) - Title: Magnetic RECONNECTion in five-dimensional Kerr BLACK HOLEAuthors: Ikhtiyor Eshtursunov, Sanjar Shaymatov, Chengxun Yuan,Comments: 10 pages, 7 captioned figures; minor changes made, results unchangedSubjects: gr-qcCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
In this paper, we employ the Comisso-Asenjo MAGNETic RECONNECTion (MR) mechanism to investigate energy extraction from a rapidly rotating five-dimensional Kerr BLACK HOLE (BH) with single- and two-rotation configurations. We analyze the efficiency, phase-space structure of accelerated and decelerated plasma energies, and the extracted power as functions of the spin parameter, RECONNECTion location, plasma MAGNETization, and MAGNETic field orientation. We show that MR significantly enhances energy extraction from a five-dimensional BH with a single rotation and that the extraction efficiency is higher in the single rotation configuration than in the two-rotation case. We also evaluate the extraction rate and compare it with the Blandford-Znajek (BZ) mechanism, showing that the extracted power can exceed that of the BZ process in the single-rotation configuration. Our analysis shows that MR can significantly improve energy extraction in five-dimensional Kerr BHs with a single rotation, making them promising candidates for powering high-energy astrophysical phenomena.
[abstract 8 / 33] Yes (score: 5) - Title: Reconnection Jets Detected during the Footpoint Drift of a CME Flux Rope: New Signatures of Ongoing 3D Arcade-Flux Rope ReconnectionAuthors: Renjie Liu, Hechao Chen, Chun Xia,Comments: 12 pages, 5 figures, 3 animations; accepted for publication in The Astrophysical Journal LettersSubjects: astro-ph.SRCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Utilizing multi-wavelength data from the Solar Dynamics Observatory, we report the first imaging detection of RECONNECTion JETs driven by the footpoint drift of an erupting hot-channel flux rope (HFR) during an X1.6-class solar flare. Our results demonstrate that these JETs are inherent byproducts of the HFR eruption, exhibiting strong spatiotemporal coupling with the HFR footpoint drift and the morphological evolution of the associated flare ribbon hooks. Unlike standard coronal JETs, these ejections lack an inverted-Y morphology and show no association with underlying photospheric flux cancellation or emergence. They manifest as clusters of small-scale, collimated ejecta (180-200 km s$^{-1}$) featuring co-existing cool and hot emission components visible in both cool (304 and 171 Angstrom) and hot (94 Angstrom) EUV channels. The imaging observations reveal that these JETs are triggered by successive 3D arcade-flux rope (ar-rf) RECONNECTion as the expanding HFR interacts with the ambient coronal side arcades. The morphological and dynamic complexity of these observed JETs implies that the ongoing ar-rf RECONNECTion in solar eruptions is episodic and bursty in nature. Our estimates show that a decrease of approximately 9 G in localized MAGNETic field strength is required to power these individual JETs. As direct signatures of 3D MAGNETic RECONNECTion, these observed JETs pinpoint the exact site and characterize the nature of the process, providing new observational insight into 3D numerical simulation extensions of the standard flare model. Further observational case studies of these JETs are required to fully understand their prevalence across solar eruptions.
[abstract 9 / 33] Yes (score: 5) - Title: The plunging region of thin accretion discs across the BLACK HOLE spin rangeAuthors: Jake Rule, Andrew Mummery, Steven Balbus, James M. Stone, Lizhong Zhang,Comments: 16 pages, 10 figures, submitted to MNRAS, comments welcomeSubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
We compute and test analytic models for the plunging region dynamics, thermodynamics, and MAGNETic fields against dedicated 3D global general RELATIVISTIC MAGNETohydrodynamics (MHD) simulations of thin accretion discs around BLACK HOLEs across the spin range, using the code {\tt ATHENAK}. We find that the dynamics of the plunging fluid closely resembles that of a gravity-dominated geodesic plunge, with the best agreement at low spins. Additionally, we find good agreement between the thermodynamic framework and the simulated quantities across the spin range. Finally, we develop a new model for the MAGNETic fields in the plunging region that assumes a fixed geodesic inflow, into which the MAGNETic fields are frozen. Overall, our simulations are in good concordance with this model, albeit with some discrepancies that suggest a degree of non-ideal MHD dissipation. In addition, we investigate how the MHD stresses in the plunging region depend on the BLACK HOLE spin, interpreting our results through the lens of our flux-freezing model. We find that the magnitude of the stress increases as the BLACK HOLE spin is increased in the prograde direction. This question is of particular importance for observers who wish to determine the BLACK HOLE spin from X-ray measurements of the inner accretion disc, since a low-stress, high-spin solution is degenerate with a high-stress, low-spin solution. The spin-stress relationship that we report is approximately orthogonal to the contour of degenerate spin-stress pairings, indicating that the degeneracy is not fundamental. We show this explicitly for the case of M33 X-7.
[abstract 10 / 33] Yes (score: 5) - Title: A unified modeling of X-ray and gamma-ray spectro-polarimetric data: the case of Cygnus X-1Authors: Tristan Bouchet, Thomas Siegert, Victoria Grinberg, Jérôme Rodriguez, Floriane Cangemi, Philippe Laurent, Joern Wilms,Comments: 12 pages plus appendix. Submitted to A&ASubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Recent X-ray and soft gamma-ray spectro-polarimetric observations of BLACK HOLE X-ray binaries, such as Cygnus X-1, reveal discrepancies that challenge current models of accretion and high-energy emission. We present a general framework for broadband spectro-polarimetric modeling that simultaneously fits spectral and POLARIZATION data from independent instruments across different energy bands. The method robustly combines measurements with different energy binning and statistical significance while accounting for energy-dependent POLARIZATION mixing between model components. Applied to Cygnus X-1 over the 2 keV-2 MeV range, it provides an improved characterization of the soft gamma-ray hard-tail and constrains the optically thin SYNCHROTRON cutoff energy to $(3.9^{+0.6}_{-0.5}) \times 10^{2}$ keV. We discuss the implications for non-thermal electron acceleration in the context of Bohm diffusion and SYNCHROTRON cooling, and propose a new explanation for the observed POLARIZATION misalignment based on MAGNETic field helicity and Doppler boosting. The framework is broadly applicable to multi-instrument spectro-polarimetric analyses.
[abstract 11 / 33] Yes (score: 4) - Title: The impact of nuclear equations of state on the dynamics and multi-messenger emission of MAGNETorotational stellar explosionsAuthors: Andrea Celati, Matteo Bugli, Luca Del Zanna, Marco Cusinato, Martin Obergaulinger,Comments: Accepted for publication in Astronomy & Astrophysics. 21 pages, 17 figuresSubjects: astro-ph.HE astro-ph.SR nucl-thCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
The gravitational collapse of massive stars at the end of their life leads to powerful SUPERNOVA explosions that produce compact objects, regulate the dynamics of host galaxies, and contribute to cosmic chemical evolution. In the presence of fast rotation and strong MAGNETic fields, such explosions can reach extreme energies, explaining sources such as hypernovae and long GAMMA-RAY BURSTs. We investigate the impact of variations in the nuclear equation of state (EoS) on MAGNETorotational explosions and their multimessenger emission, including neutrinos and gravitational waves. Differences in stiffness, composition, and finite-temperature behavior of the EoS affect the collapse, bounce, and JET-launching phases. Using the Aenus-Alcar code, which includes RELATIVISTIC MAGNETohydrodynamics, two-moment neutrino transport, neutrino-matter interactions, and general-RELATIVISTIC corrections, we perform axisymmetric simulations with different EoSs. All models start from the same pre-SUPERNOVA progenitor with solar metallicity, a zero-age main sequence mass of 20 solar masses, a dipolar MAGNETic field, and a shellular rotation profile. The different EoSs produce significant variations in explosion dynamics, proto-neutron star properties, ejecta mass, and multimessenger signals. Our results show that MAGNETorotational core-collapse SUPERNOVA signatures depend not only on the cold stiffness of the EoS, but also on its thermal and compositional properties, highlighting the importance of combining gravitational-wave and neutrino observations to constrain dense matter physics and the explosion mechanism.
[abstract 12 / 33] Yes (score: 4) - Title: An "inside-out" approach to modeling supermassive BLACK HOLE binary inspiralAuthors: Laura Blecha,Comments: 29 pages, 12 figures, submitted to ApJ. Comments welcomeSubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
The inspiral and merger of two supermassive BLACK HOLEs (SMBHs) releases immense energy in low-frequency gravitational waves (GWs). Recent pulsar timing array (PTA) observations of the stochastic nHz GW background (GWB) are consistent with a SMBH binary origin. GW data from PTAs and from the upcoming Laser Interferometer Space Antenna (LISA) can probe late-stage binary evolution where electroMAGNETic constraints are scarce. However, the complexity of the relevant astrophysics necessitates a well optimized approach. I argue that a key physical quantity to constrain with PTAs is the orbital semi-major axis at which binary inspiral transitions from the astrophysical to the GW-dominated regime ($a_{\rm GW}$). This quantity should be treated as a free parameter in analysis of the GWB. Using this premise, I present a simple analytic framework for modeling SMBH binary inspiral in an "inside-out" fashion. At orbital separations slightly larger than $a_{\rm GW}$, a power-law scaling for the astrophysical inspiral timescale is assumed, while the outermost phase (prior to the PTA regime) is simply modeled via a delay time. I show that the GWB spectral shape and amplitude are most sensitive to $a_{\rm GW}$ (normalized to $10^9 M_{\odot}$, equal-mass binaries and expressed in gravitational units), with weaker dependence on the inner power-law index and the outer delay time. The GWB is largely insensitive to the mass and mass-ratio scaling of $a_{\rm GW}$ and to the boundary between the inner and outer astrophysical inspiral regimes. I compare with models for gas- and stellar-driven binary inspiral and discuss implications for LISA and for GW source parameter inference.
[abstract 13 / 33] (score: 3) - Title: No evidence for a supermassive BLACK HOLE binary in GSN 069Authors: Yuhe Zeng, Zhen Pan, Bin Liu, Cong Zhou,Comments: 11 pages, 5 figuresSubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Quasi-periodic eruptions (QPEs) are recurrent soft X-ray flares from galactic nuclei and provide a new time-domain probe of stellar-mass objects (SMOs) orbiting supermassive BLACK HOLEs (SMBHs). In an extreme-mass-ratio inspiral (EMRI) system interacting with an accretion disk, QPEs are produced when the SMO repeatedly crosses an accretion disk, so that the eruption times trace the orbital motion of the EMRI. We investigate whether such timing information can be used to probe a more distant SMBH companion. We develop two complementary diagnostics: (1) the motion of the EMRI host SMBH around the SMBH-binary (SMBHB) center of mass induces a light-travel-time modulation in the observed QPE arrival times, specifically an \emph{in-phase} modulation in arrival times of even and odd eruptions; (2) if the QPE source contains a surviving stellar orbiter, the external SMBH must not drive the SMO into tidal disruption through eccentricity excitation by the von Zeipel--Lidov--Kozai (ZLK) mechanism. Using GSN 069 as an example, we find \emph{no} in-phase modulation in the QPE timing (i.e., no evidence for a SMBHB) and constrain the excluded parameter space of the companion SMBH. These results demonstrate that QPE timing and stellar survival offer complementary routes for constraining otherwise hidden SMBH companions in nearby galactic nuclei.
[abstract 14 / 33] (score: 3) - Title: BORAY-3D: A ray tracing code for three-dimensional MAGNETized plasma configurationsAuthors: Yuxuan Wang, Huasheng Xie,Comments: 12 pages, 7 figuresSubjects: physics.plasm-phCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Ray tracing codes are useful tools for studying electroMAGNETic wave propagation and absorption using the geometrical-optics approximation. Existing codes commonly provide either broad radio-frequency coverage in axisymmetric equilibria or three-dimensional capability specialized for electron-cyclotron (EC) applications. BORAY-3D integrates three desirable features in a single version. First, it has a broad frequency range of validity regime from ion-cyclotron, helicon and lower-hybrid waves to EC waves and emission. Second, it provides a unified treatment of arbitrary two- and three-dimensional MAGNETic-plasma configurations, including both closed and open field-line regions. Third, it incorporates fully RELATIVISTIC Maxwellian EC absorption. The code extends the axisymmetric BORAY formulation by solving the ray equations in cylindrical coordinates $(r,ϕ,z)$ while allowing the toroidal mode number $n_ϕ$ to vary. Magnetic-field, density and temperature data are directly described in $(r,ϕ,z)$ coordinates without the restriction of flux functions, so that numerical equilibria and analytic field models can be handled in the same form. The non-RELATIVISTIC hot-plasma model inherited from BORAY is used for lower-hybrid, ion-cyclotron and helicon absorption, whereas the RELATIVISTIC model is coupled to reciprocal radiative transfer for electron cyclotron emission (ECE). Practical applications include 13.56 MHz helicon and 50 MHz fast waves, a 3.7 GHz lower-hybrid wave, and 115--220 GHz EC emission. BORAY-3D has been systematically benchmarked against GENRAY for tokamak toroidal-field ripple, Raytrax and TRAVIS for W7-X, as well as public HSX heating and W7-X ECE results.
[abstract 15 / 33] (score: 3) - Title: Thermal Non-equilibrium Cycles in a Non-eruptive Pseudo-StreamerAuthors: Clara Froment, Sophie Masson,Comments: 32 pages, 11 figures, published in Solar Physics. Truncated abstract to match arXiv requirementsSubjects: astro-ph.SRCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Thermal non-equilibrium (TNE) is a well-known thermodynamic mechanism, generally studied in coronal loops. These evaporation and condensation cycles are induced by a quasi-steady and stratified heating. Long-period EUV pulsations and coronal rain are two manifestations of TNE. The quasi-periodicity of the cycles is a strong characteristic of TNE as the system dynamically evolves around an equilibrium position that is not reachable. There are recent reports of coronal rain at open-closed boundaries such as fan-spine topologies and pseudo-streamers. However, no definite conclusions were drawn on the physical mechanisms driving these coronal rain events. We report the detection of long-period EUV pulsations and co-spatial recurring coronal rain showers in a pseudo-streamer observed with AIA on board SDO. The MAGNETic topology and evolution of the pseudo-streamer are studied in detail using a combination of PFSS modeling and EUV dynamics. The 2.5-day event exhibits all the characteristic features of previous TNE events reported in coronal loops: periodic EUV pulses appearing sequentially in the different channels, following the ordering of the peaks in their temperature response, and coronal rain showers appearing toward the end of these cycles. We further show that the TNE cycles in the pseudo-streamer occur not only in the closed field but also in the open field. Our observations support the findings of recent numerical studies showing that TNE can also occur in open field regions and at open-closed boundaries. In parallel, interchange RECONNECTion occurs continuously and non-impulsively all along the open-closed boundary as seen in EUV. The interplay between TNE and interchange RECONNECTion should be studied in detail in future works. This observation opens further perspectives for the understanding of TNE in the solar atmosphere and its potential implications for the solar wind.
[abstract 16 / 33] (score: 2) - Title: Large Gravitational Wave Phase Shifts from Strong 3-body Interactions in Dense Stellar ClustersAuthors: Kai Hendriks, Dany Atallah, Miguel Martinez, Michael Zevin, Lorenz Zwick, Alessandro A. Trani, Pankaj Saini, János Takátsy, Johan Samsing,Comments: Accepted for publication in Physical Review DSubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
The phase evolution of gravitational waves (GWs) can be modulated by the astrophysical environment surrounding the source, which provides a probe for the origin of individual binary BLACK HOLEs (BBHs) using GWs alone. We here study the evolving phase of the GW waveform derived from a large set of simulations of BBH mergers forming in dense stellar clusters through binary-single interactions. We uncover that a well-defined fraction of the assembled eccentric GW sources will have a notable GW phase shift induced by the remaining third object. The magnitude of the GW phase shift often exceeds conservative analytical estimates due to strong 3-body interactions, which occasionally results in GW sources with clearly shifted and perturbed GW waveforms. This opens up promising opportunities for current and future GW detectors, as observing such a phase shift can identify the formation environment of a BBH, as well as help to characterise the local properties of its surrounding environment.
[abstract 17 / 33] (score: 2) - Title: Geodesic extended modes in low MAGNETic shear tokamaks and stellaratorsAuthors: Richard Nies, Felix Parra,Comments: Revised version, accepted for publication in Journal of Plasma PhysicsSubjects: physics.plasm-phCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Theories of ion-scale microinstabilities in tokamaks and stellarators typically assume that the passing electrons respond adiabatically due to their fast propagation speed. However, when the MAGNETic shear becomes sufficiently small, ion-scale modes can extend far along the MAGNETic field and the non-adiabatic response of passing electrons becomes important. We derive a theory of extended modes at low MAGNETic shear through a multiscale expansion of the gyrokinetic equation. The theory elucidates the physics of the geodesic extended mode, a new type of microinstability. The new mode couples the non-adiabatic physics of both electrons and ions, unlike extended modes at MAGNETic shear of order unity. The theory is validated against gyrokinetic simulations and the parameter dependences of the new mode are studied.
[abstract 18 / 33] (score: 2) - Title: TDCOSMO XXVI: Uniform lens modeling of eight doubly imaged QUASARsAuthors: Ryan Brady, Xiang-Yu Huang, Simon Birrer, Anowar J. Shajib, Nafis Sadik Nihal, Cameron Lemon, Martin Millon, Veronica Motta, Dominique Sluse, Frederic Courbin,Comments: Published in the Open Journal of AstrophysicsSubjects: astro-ph.CO astro-ph.GACreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
We present the first uniform gravitational lens modeling analysis of eight doubly imaged QUASARs from multi-band observations with the Hubble Space Telescope. Previous time-delay cosmography analyses by the TDCOSMO Collaboration have primarily relied on quadruply imaged QUASARs, while doubly imaged systems, despite being more abundant, remain underutilized due to their fewer geometric constraints. Using an open-source $\texttt{Lenstronomy}$ framework, we reconstruct the lensing systems with a pipeline tailored for doubles. Comparing our results to the literature, the modeled Einstein radii agree at an average of 1.5$σ$, which is expected given data and modeling heterogeneity, while modeled image separations differ from Gaia DR2 measurements with an r.m.s of only 3.6 mas. We find a strong correlation between Fermat potential precision and the surface brightness of the spatially extended host arcs, establishing that arc surface brightness is the primary driver of mass model precision in doubly imaged systems. To further quantify the information contributed by the lensed arcs, we performed a conjugate point analysis that uses only the QUASAR image positions to constrain the lens mass profiles. The resulting posteriors are substantially broader than those from full image modeling, and a strong anti-correlation between mass parameter hypervolume and arc magnitude additionally confirms that arc brightness determines the degree to which the lens mass profile can be constrained in doubles. A hierarchical cosmographic analysis incorporating time-delay measurements and stellar kinematics to infer $\text{H}_0$ will be presented in a subsequent publication. The uniform pipeline and arc surface brightness trends established here will significantly accelerate the construction of time-delay cosmography samples from the large lens populations expected from LSST, Roman, and Euclid.
[abstract 19 / 33] (score: 2) - Title: Primordial BLACK HOLE contribution to the stochastic background of gravitational wavesAuthors: D. Martín-González,Comments: 6 pages, 7 figures, accepted in Astronomy & Astrophysics on 28 July 2026Subjects: astro-ph.CO astro-ph.HE gr-qcCreated: 2026-08-05; Updated: 2026-08-07; Datestamp: 2026-08-07
The amplitude of the detected stochastic gravitational-wave background (SGWB) measured by pulsar timing arrays (PTAs) and the discovery of early and over-massive central BLACK HOLEs at high redshift by the James Webb Space Telescope (JWST) challenge current models of supermassive BLACK HOLE (SMBH) formation. We aim to study if halos containing a significant population of primordial BLACK HOLEs (PBHs) would increase the amplitude of the PTA signal. PBHs add an iso-curvature component to the matter power spectrum, accelerating the formation and merger of dark-matter halos at all redshifts. We propose that BLACK HOLEs in the halo sink to the center via dynamical friction. The central BLACK HOLE grows through hierarchical merging in addition to the gas-accretion channel. We computed the resulting GW amplitude and performed a Bayesian inference analysis using the NANOGrav 15-year dataset. We show that the predicted amplitude of the gravitational-wave background agrees with the observations. Our model only requires $0.09\%-0.12\%$ of the total mass of the halo to fall to the center; this is compatible with a fraction of $f_{\rm pbh}\sim 0.1$ PBHs being DARK MATTER if the in-falling PBHs in the stellar mass range represent about $1\%$ of the total population, as was found in our previous estimation of the formation of SMBHs at $z\sim 6-10$. The PBH model that explains the JWST new found populations of SMBHs also explain the amplitude of the stochastic background of gravitational waves.
[abstract 20 / 33] (score: 2) - Title: Prediction for IMAP: Revealing the Role of the Solar Magnetic Field in the HeliotailAuthors: M. Kornbleuth, M. Opher,Comments: Submitted to ApJLSubjects: astro-ph.SRCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
The classic paradigm of the heliosphere considered the solar MAGNETic field as having a passive role in the heliosheath, yet Opher et al. (2015) and Drake et al. (2015) suggested that the solar MAGNETic field plays an active role by collimating the solar wind plasma. Previous work has suggested that high-latitude lobes observed by IBEX-Hi energetic neutral atom (ENA) maps are solely due to the fast/slow solar wind profile, yet other works have found that the solar MAGNETic field may play a role in organizing the lobes as well. Here, using an MHD solution with and without the solar MAGNETic field, we find that the fast/slow wind profile largely dictates the ENA profile up to $\sim$10-18 keV. Beyond this energy, the collimation effects are more prominent and the fast/slow solar wind profile no longer organizes the maps. The collimation creates two high latitude lobes. By 80 keV, the heliosphere with collimation yields an enhancement of ENAs of the high-latitude tail lobes compared to the low-latitude region by a factor of $\gtrsim$ 1.3, whereas the uncollimated heliosphere yields a ratio $<$ 1. Therefore, IMAP should be able to identify whether the solar MAGNETic field collimates the solar wind in the deep heliotail.
[abstract 21 / 33] (score: 2) - Title: Microwave Resonant Discharges for Spatiotemporally Selective Plasma Breakdown Near SurfacesAuthors: Arnav Mohapatra, Joshua K. Goodrich, Usman Humayun, Thomas C. Underwood,Comments:Subjects: physics.plasm-phCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Generating non-equilibrium plasmas close to surfaces remains a significant challenge for conventional plasma sources. Existing plasma generation schemes create volumetric discharges with limited spatial selectivity that lead to inefficient energy deposition and poor coupling between reactive intermediates and nearby surfaces. This work establishes tailored resonant field enhancement as a mechanism for prescribing where plasma forms near dielectric surfaces through microwave excitation. In this approach, the geometry, refractive index, and packing configuration of dielectric materials define resonant field structures that interfere constructively and amplify electric fields locally. Plasma forms only within these resonant volumes where the amplified fields exceed the local breakdown threshold, while the surrounding gas remains below breakdown. Microwave pulse shaping then provides dynamic control over these modes and can be used to excite different families of resonances, determine where breakdown occurs, and reconfigure what locations microplasmas occupy from one pulse to the next. We validate this framework through theory, electroMAGNETic simulations, and experiments using a pair of high-permittivity dielectric resonators. These studies identify multiple resonant mode families, demonstrate dynamic repositioning of microplasmas between prescribed breakdown sites, quantify the ignition characteristics of each mode, and confirm that multiple resonant microplasmas remain confined to localized field-enhancement regions during a microwave pulse. Together, these results establish a framework for designing resonant dielectric materials that localize, reconfigure, and control atmospheric-pressure plasmas near surfaces.
[abstract 22 / 33] (score: 2) - Title: The Constant Evolution of the Neil Gehrels SWIFT Observatory: Two Decades of Operational Innovation for Time-Domain and Multi-Messenger AstrophysicsAuthors: Jamie A. Kennea,Comments: 12 pages, 6 figures, submitted to SPIESubjects: astro-ph.IMCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
The Neil Gehrels SWIFT Observatory has, for more than twenty years, served as NASA's premier rapid-response, multi-wavelength facility for the study of GAMMA-RAY BURSTs (GRBs) and the transient sky. While SWIFT's hardware has remained essentially unchanged since its 2004 launch, its operational capabilities have evolved continuously, driven by a philosophy of ``always be developing.'' Hosted entirely at The Pennsylvania State University, with co-located flight and science operations, SWIFT has repeatedly reinvented how a NASA mission can be commanded, transforming itself from a GRB-chasing autonomous robotic telescope into a flexible, automated platform for time-domain and multi-messenger astrophysics (TDAMM). We review the key operational innovations that have enabled this evolution: the development of automated target-of-opportunity (TOO) uploads in response to the early loss of active X-ray Telescope cooling; onboard tiling of large error regions; the ManyPoint flight-software capability for executing hundreds of pointings; the Gamma-ray Urgent Archiver for Novel Opportunities (GUANO); and the ``Urgency 0'' continuous-commanding mode that has reduced TOO response latencies from hours to seconds. We illustrate the scientific impact of these capabilities through SWIFT's gravitational-wave and neutrino follow-up campaigns, including GW170817/AT2017gfo and IceCube-170922A, and through real-time ``early-warning'' slewing toward predicted compact-binary mergers. Finally, we discuss the heritage SWIFT is creating for future TDAMM missions, and the ongoing efforts to extend SWIFT's life, both through attitude-based scheduling that minimizes the spacecraft's atmospheric drag cross-section and through a commercial orbit-boost mission.
[abstract 23 / 33] (score: 2) - Title: Where did all the Little Red Dots go? The abundance of LRD analogues among objects with broad lines at $z < 0.35$Authors: Lasse Seyberlich, Sarah E. I. Bosman,Comments: 15 pages, 6 figures. Submitted to A&ASubjects: astro-ph.GACreated: 2026-08-05; Updated: 2026-08-07; Datestamp: 2026-08-07
One of the most puzzling discoveries since the launch of the James Webb Space Telescope is a numerous population of sources at high redshift nicknamed ``Little Red Dots'' (LRDs). Characterized by broad Balmer emission lines, compact morphologies and v-shaped spectral energy distributions (SEDs) in the rest-frame optical, the nature of LRDs remains elusive. A major challenge is the high redshift nature of LRDs, which makes observations very expensive and difficult. Finding local LRD analogues is a crucial step in unravelling the physical processes giving rise to LRDs, as cheaper observations with many facilities would become available. In this paper, we conduct a search for local LRD analogues by starting from an unbiased parent catalogue of all SDSS objects with broad H$α$ or H$β$ emission lines (both galaxies and QUASARs) at $0 < z < 0.35$, complemented by archival photometry and spectroscopy. We find that among broad-line objects, $19\%$ show a v-shaped SED. We then select objects whose SED is well described by a modified black body (MBB), and identify nine local LRD analogues, corresponding to $0.08\%$ of all objects with broad lines. Among only objects which match the typical continuum and emission line luminosities of LRDs, $5\%$ display a v-shape and $0.37\%$ display a MBB-like SED. We recover one previously-identified local LRD analogue (the so-called ``Egg''), validating our methodology. Among the other eight analogues, one (J0302$-$0101) shows all the hallmarks of an LRD despite being visibly embedded in the core of a galaxy; another object is ambiguous, and the remaining six may have alternative explanations for their peculiar SEDs. Our study highlights that LRDs are extremely rare at $z < 0.35$; we find very few objects with broad lines which have LRD-like SEDs, even without attempting to match the compactness of LRDs.
[abstract 24 / 33] (score: 2) - Title: The glow of eternal BLACK HOLEsAuthors: Vladimir Strokov,Comments: 30 pages, 6 figures; for associated code, see https://github.com/CosmoVlad/white-hole-shadowSubjects: gr-qc astro-ph.HECreated: 2026-08-05; Updated: 2026-08-07; Datestamp: 2026-08-07
We compute the optical appearance of a maximally extended (eternal) Schwarzschild BLACK HOLE surrounded by a geometrically thin accretion disk. Unlike astrophysical BLACK HOLEs formed by gravitational collapse, the eternal solution contains a white hole (WH) region connected to a past singularity. Following Markov's hypothesis of a limiting density of matter, we replace the past singularity with a spacelike "surface of last scattering" at $r=r_{\rm m}$ and assume that it emits black-body radiation with temperature $T$. Past-directed rays that cross the past horizon terminate on this surface, resulting in a bright spot at the center of the shadow of an eternal BLACK HOLE. The radial profile of the spot is set by the gravitational frequency shift, with a blueshifted center when the spacelike surface is sufficiently close to the singularity. We use ray tracing to generate an image of the disk and the spot, and we derive a closed-form interferometric signature of the spot. Its visibility is a pure exponential in the baseline length, in contrast to the power-law envelopes of the disk and the photon ring. We constrain the product $r_{\rm m} T$ from the observed 230 GHz fluxes of M87* and Sgr A*. We also consider a Planck-star scenario in which the value of $r_{\rm m}$ is determined on dimensional grounds, and show that it is out of reach of any current or planned facilities. Nevertheless, the darkness of the observed shadows remains a test of whether these BLACK HOLEs are eternal.
[abstract 25 / 33] (score: 2) - Title: Confinement-induced evolution and breakup of viscoelastic filaments in microfluidic coflowsAuthors: U. K. Kar, T. Sujith, D. Ghosh, A. K. Sen,Comments:Subjects: physics.flu-dynCreated: 2026-08-05; Updated: 2026-08-07; Datestamp: 2026-08-07
Viscoelastic filament thinning is classically described by elastocapillary dynamics in extensional flows, yet in confined microchannels the combined effects of wall-induced shear, elasticity, and capillarity remain poorly understood. Here, we experimentally investigate the breakup of a shear-thinning viscoelastic liquid coflowing with an immiscible Newtonian fluid in a rectangular microchannel, focusing on the formation, stretching, instability, and breakup of the thin filament connecting the primary droplet to the upstream liquid. Four regimes: stable coflow, squeezing, dripping, and JETting are identified and mapped using the capillary numbers of the dispersed and continuous phases and an elastocapillary parameter. Although elasticity weakly affects the onset of primary droplet formation, it strongly alters later filament dynamics by delaying capillary breakup and stabilising long-lived filaments. Scaling analyses based on capillary, viscous, and elastic force balances predict the primary droplet size, critical filament thickness at instability onset, maximum filament length, and critical JET length. Particle tracking shows that confinement creates a non-uniform wall-induced shear field along the inclined filament, producing spatial variations in interfacial velocity and initiating the first bead-on-a-string instability at the location of maximum shear. A Rayleigh-Plateau analysis incorporating an effective viscosity derived from the Oldroyd-B model predicts the instability wavelength and growth rate to the correct order of magnitude. These results show that confined viscoelastic breakup is governed not solely by classical elastocapillary thinning, but by a coupled wall-shear-elasticity mechanism controlling filament stretching, instability, and secondary droplet formation, thereby providing a predictive framework for filament-mediated breakup in confined viscoelastic multiphase flows.
[abstract 26 / 33] (score: 2) - Title: A Symplectic Map Approach to Magnetic Field-Line Dynamics in TokamaksAuthors: Diego F. M. Oliveira, Edson D. Leonel,Comments:Subjects: nlin.CD physics.plasm-phCreated: 2026-08-05; Updated: 2026-08-07; Datestamp: 2026-08-07
Magnetic field-line transport in tokamaks is governed by the interplay between chaotic dynamics and invariant phase-space structures that act as partial transport barriers. We investigate the conservative Tokamap, an exact symplectic mapping for MAGNETic field-line dynamics, using a unified geometrical, dynamical, and statistical framework. Phase-space portraits and Lyapunov exponents characterize the mixed Hamiltonian dynamics, while ensemble-averaged transport exhibits universal dynamic scaling with growth, crossover, and saturation regimes connected through a homogeneous scaling theory. Poincaré recurrence statistics reveal that decreasing the MAGNETic-shear parameter systematically slows transport, with the characteristic transport time following the algebraic scaling $τ_c\propto x_q^{-0.213}$. This behavior reflects increasingly dominant stickiness associated with KAM islands, resonance chains, and cantori. Our results establish a direct connection between the geometrical organization of Hamiltonian phase space and macroscopic transport properties, providing a comprehensive framework for understanding long-time MAGNETic field-line transport in tokamaks and other Hamiltonian systems with mixed phase space.
[abstract 27 / 33] (score: 2) - Title: SafeDivertor: Faithful Divertor Heat Flux Reconstruction from Macroscopic Plasma State Signals via Time-Frequency Prior ExploitationAuthors: Hao Si, Zehua Chen, Qingquan Yang, Xiao Wang, Dengdi Sun, Wanli Lyu, Gaoting Chen, Guosheng Xu, Hang Su, Jin Tang, Jun Zhu,Comments:Subjects: physics.plasm-ph cs.AI cs.CVCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Divertor heat-flux analysis is essential for understanding plasma-wall interactions and protecting plasma-facing components in MAGNETic-confinement fusion devices, while conventional infrared-based inversion is usually performed after discharge and requires heat-conduction modeling with device-specific material properties, divertor geometry, and boundary conditions. Rather than accelerating this conventional infrared-based inversion paradigm, we introduce a new online-oriented signal-based reconstruction paradigm that directly reconstructs time-resolved radial heat-flux profiles from multi-source macroscopic plasma-state signals available during discharge. To enable systematic study of this task, we construct \textbf{DivMPS2HF}, a multi-source discharge dataset that provides the data foundation and benchmark for signal-based divertor heat-flux reconstruction. We further propose \textbf{SafeDivertor}, a task-driven framework designed to address the key challenges of signal-based heat-flux reconstruction. It employs physical prior-aware initialization to provide radial-distribution guidance for target channels, input perturbation to reduce over-reliance on specific heterogeneous signals, spectral-aware reconstruction optimization to exploit time-frequency priors and preserve transient dynamics, and progressive training to stabilize the optimization of these complementary objectives. Experiments on DivMPS2HF demonstrate that SafeDivertor achieves the best overall performance among the evaluated time-series baselines across all five metrics, establishing a new performance benchmark for signal-based divertor heat-flux reconstruction. The source code will be released on https://github.com/Event-AHU/OpenFusion
[abstract 28 / 33] (score: 2) - Title: Cosmological Distance Measurements of High Redshift Blazars: OJ 248 (z=0.939) and 4C +38.41 (z=1.814)Authors: Young-Bin Shin, Sang-Sung Lee, Sincheol Kang, Whee Yeon Cheong, Chanwoo Song, Jeffrey A. Hodgson,Comments: 10 pages, 1 figures, published in JKASSubjects: astro-ph.GA astro-ph.COCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
In this study, we estimated the angular diameter distances to two high-redshift ACTIVE GALACTIC NUCLEi (AGNs), OJ 248 (z = 0.939) and 4C +38.41 (z = 1.814), using 43 GHz radio light curves. The aim of this work is to extend AGN variability-based distance measurement methods to the high-redshift regime. The distance estimates were analyzed under two assumptions for the maximum intrinsic brightness temperature TB,int: (1) the equipartition temperature, and (2) the sample-averaged TB,int. As a representative result, when adopting the equipartition temperature, the angular diameter distances to OJ 248 and 4C +38.41 are estimated to be 7592.7 +/- 396.7 Mpc and 11069.8 +/- 1216.9 Mpc, respectively. In addition, Doppler factors were calculated using the inverse-Compton method, and additional distance estimates were obtained based on these values. Our error budget analysis shows that the most significant systematic uncertainty arises from epoch selection. These results indicate that systematic effects have a substantial impact on the derived distance estimates and limit their reliability, particularly in the high-redshift regime. Reducing these uncertainties will require improved observational cadence and reduced post-fit noise. AGN variability provides an alternative approach to distance estimation. However, our results reveal significant limitations in the current methodology and indicate that further methodological and observational improvements are required before its cosmological applicability can be reliably assessed.
[abstract 29 / 33] (score: 2) - Title: Phase-resolved QPO Analysis of GX 339-4: Improved Technique and Consistent Behaviors between QPOs and Broadband NoiseAuthors: Jin Qin, Hua Feng, Liang Zhang, Lian Tao, Qing-Cang Shui, Qing-Chang Zhao, Shu Zhang, Shuang-Nan Zhang,Comments: Accepted for publication in ApJ. The figure sets associated with Figures 2 and 3 can be found in the TeX sourceSubjects: astro-ph.HECreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
The nature of low-frequency quasi-periodic oscillations (QPOs) in BLACK HOLE X-ray binaries remains unclear, and their relationship with the accompanying broadband noise (BBN) is still under debate. Here, we propose an improved variational mode decomposition (VMD) technique. Compared with the original algorithm that requires iterative, case-by-case parameter tuning, the new algorithm automatically and consistently determines the relevant VMD parameters based on the QPO central frequency and width measured from the power spectral density (PSD). This enables a more robust phase determination for QPOs and can also be applied to the study of BBN. We found that, for low-frequency type-C QPOs without significant harmonics in the BLACK HOLE X-ray binary GX 339-4, the spectral properties of the QPOs and BBN are statistically consistent with each other: (1) the photon index is positively correlated with count rate as a function of phase, and (2) the PSD ratio spectra across different energy bands show no statistically significant QPO-like structures near the QPO frequencies, indicating that both components share the same energy dependence. These suggest that QPOs and BBN may be driven by the same physical processes. The QPO models based on geometric modulation struggle to account for the results, while those invoking corona oscillations are favored.
[abstract 30 / 33] (score: 2) - Title: Optical Counterparts of MeerKLASS L-band and UHF-band surveysAuthors: M. Klein, S. Mangla, J. Mohr, S. Chatterjee, K. Grainge, S. Paul, M. G. Santos, O. M. Smirnov, C. Tasse, L. Wolz,Comments: 17 pages, 19 figures, submitted to A&ASubjects: astro-ph.GA astro-ph.CO astro-ph.IMCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
Context: Wide-area radio continuum surveys require reliable optical and infrared counterpart identification, but high optical source densities and extended or multi-component radio morphologies make this challenging. Aims: We present optical and infrared counterpart catalogs for MeerKLASS L-band and UHF-band on-the-fly continuum sources using KiDS DR5 and DESI Legacy Imaging Surveys DR10 (LS DR10), including counterpart probabilities, redshifts, and host-galaxy properties. Methods: We developed the Stellar-mass Enhanced Density Association (SEDA) method, an empirical framework that compares candidate densities around radio positions with those in a position-displaced control catalog. For galaxies we use positional offset, stellar mass, and redshift; QUASAR candidates are treated separately using offset and mid-infrared selection. A second-pass search associates multi-component radio sources with common hosts. Results: In the L-band survey, we identify 20,400 KiDS-based counterparts with $P_{\rm true}>0.5$, corresponding to 66% of L-band sources within the KiDS footprint. In the UHF-band survey, we identify 61,633 LS DR10 counterparts, corresponding to 81% of the radio sources. Spectroscopic redshifts are available for 22% and 44% of the L-band and UHF-band counterparts, respectively. The redshift distributions show low-redshift star-forming galaxies, intermediate-redshift RADIO GALAXies, and a high-redshift tail dominated by QUASARs. SEDA also recovers rare radio-loud QUASARs, including QSO J2318-3113 at $z=6.44$ and UHF_DR1 J+111111.8+053626.6 at $z=5.24$. Conclusions: SEDA provides a data-driven route to counterpart identification for wide-area radio surveys with complex source morphologies. The catalogs enable future MeerKLASS studies of radio source populations, host-galaxy demographics, and rare high-redshift radio QUASARs.
[abstract 31 / 33] (score: 2) - Title: Prandtl--Batchelor and flux-expulsion selection for steady MHD flows in a diskAuthors: Chen Gao, Zhiwu Lin, Jianfeng Zhao,Comments: 76 pagesSubjects: math.AP physics.flu-dynCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
We study the simultaneous vanishing-viscosity and vanishing-resistivity limit of steady incompressible MHD flows in a disk. The boundary velocity is a small nonaxisymmetric perturbation of a rigid rotation with mean angular speed \(α\), while the prescribed tangential MAGNETic trace has mean \(β\). Assuming \(α\neq0\) and the non-Alfvénic condition \(|α|\neq|β|\), we construct solutions converging on compact interior subdisks to a rigidly rotating ideal MHD core with constant vorticity and out-of-plane current density. A new MHD--Wood law determines the two core rotations from the boundary data: the velocity core is selected by a coupled kinetic--MAGNETic balance, whereas the MAGNETic core is fixed by the imposed mean circulation. Consequently, zero circulation gives complete interior MAGNETic expulsion, while nonzero circulation leaves a uniform MAGNETic rotation after the nonaxisymmetric modes are confined to a thin boundary layer. This provides a fully coupled realization of Prandtl--Batchelor selection and flux expulsion; unlike classical kinematic models, the MAGNETic field actively changes the flow and need not be weak. The proof combines a non-Alfvénic coercive theory for a periodic MHD boundary layer, global matching of the two fields, and a coupled stability estimate adapted to the MAGNETic boundary condition. A separate conditional rigidity argument, using exact viscous identities and local convergence but no interior asymptotic expansion, explains the same core structure for a broader single-eddy family.
[abstract 32 / 33] (score: 2) - Title: Luminosity function of QUASARs at $1.0[abstract 33 / 33] (score: 2)Authors: Gaocheng Yin, Linhua Jiang, Zhiwei Pan, Paul Martini, Wei-Jian Guo, Siwei Zou, Shengxiu Sun, Swayamtrupta Panda, Abhijeet Anand, Benjamin Alan Weaver, Aaron Meisner, Andrei Cuceu, Arjun Dey, Axel de la Macorra, Christophe Magneville, David Brooks, David Kirkby, David Schlegel, David Sprayberry, Davide Bianchi, Dick Joyce, Enrique Gaztañaga, Eusebio Sanchez, Francisco Javier Castander, Francisco Prada, Gaston Gutierrez, Graziano Rossi, Gregory Tarlé, Hiram K. Herrera-Alcantar, Hu Zou, Ignasi Pérez-Ràfols, Jaime E. Forero-Romero, Jessica Nicole Aguilar, John Moustakas, Joseph Harry Silber, Klaus Honscheid, Laurent Le Guillou, Marc Manera, Martin Landriau, Michael Schubnell, Mustapha Ishak, Nathalie Palanque-Delabrouille, Peter Doel, Ramon Miquel, Robert Kehoe, Satya Gontcho A Gontcho, Seshadri Nadathur, Simone Ferraro, Stephanie Juneau, Steven Ahlen, Theodore Kisner, Todd Claybaugh, Will Percival, Anthony Kremin, Claire Lamman, Claire Poppett, Rongpu Zhou,Comments: 16 pages, 6 figures. Accepted for publication in The Astrophysical JournalSubjects: astro-ph.GACreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07
We present a study of the evolution of type 1 QUASARs at $1.0
arXiv:2608.06316 [pdf, ps, other]Title: Strong Zeeman effects in the Fe I 5434.5 Å line observed in a sunspot on August 17, 2024Authors: Ivan I. Yakovkin, Vsevolod G. Lozitsky,Comments:Subjects: astro-ph.SRCreated: 2026-08-06; Updated: 2026-08-07; Datestamp: 2026-08-07The Fe I 5434.5 Å line is widely used as a non-MAGNETic reference due to its small effective Landé factor of $-0.014$. Nevertheless, this line can show significant non-zero Stokes $V$ POLARIZATION in active regions on the Sun. In this work, we study the distribution of MAGNETic fields in the sunspot observed on August 17, 2024 using the high-fidelity Stokes $I+V$ and $I-V$ spectra of three photospheric spectral lines of different MAGNETic sensitivity: Fe I 5434.5 Å, Ni I 5435.9 Å and Mn I 5432.5 Å. The observed splitting of the Stokes $I\pm V$ bisectors in the Fe I 5434.5 Å line follows the variation of the corresponding splitting in the two other spectral lines, indicating the presence of a spatial component with an extraordinarily strong MAGNETic field reaching 22 kG.
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