Current date: 2026-01-12
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Scoring abstracts
Number of records retrieved: 551
Keyword score statistics
score 10 -- 1 abstracts
score 9 -- 1 abstracts
score 6 -- 2 abstracts
score 5 -- 1 abstracts
score 4 -- 3 abstracts
score 3 -- 7 abstracts
score 2 -- 17 abstracts
in total -- 32 abstracts
Articles that appeared on 2026-01-12
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[abstract 1 / 32] Wow! (score: 10)
- Title: Investigating Active Galactic Nuclei variability with the Cherenkov Telescope Array ObservatoryAuthors: G. Grolleron, J. Biteau, M. Cerruti, R. Grau, L. Gréaux, T. Hovatta, J. -P. Lenain, E. Lindfors, W. Max-Moerbeck, D. Miceli, A. Moralejo, K. Nilsson, E. Prandini, E. Pueschel, S. Kankkunen, J. Becerra Gonzalez, J. Finke, M. Joshi, P. Morris, M. Petropoulou, A. Sarkar, P. Romano, S. Vercellone, M. Zacharias,Comments: Conference Gamma 2024Subjects: astro-ph.HECreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
Blazars, a type of ACTIVE GALACTIC NUCLEi (AGN) with RELATIVISTIC JETs pointed at the observer, exhibit flux variability across the electroMAGNETic spectrum due to particle acceleration in their JETs. Power spectral density (PSD) studies show breaks at specific frequencies, particularly in X-rays, linked to the accretion regime and BLACK HOLE mass. However, very-high-energy gamma-ray PSD breaks remain unexplored due to current instrument limitations. The Cherenkov Telescope Array Observatory (CTAO), with up to ten times greater sensitivity compared to current generation instruments, will allow precise PSD reconstruction and unprecedented study of BLAZAR flares. These flares reveal key insights into particle acceleration, photon production, and JET properties. The AGN monitoring and flare programs in CTAO's Key Science Project aim to deepen our understanding of BLAZAR emissions.
[abstract 2 / 32] Wow! (score: 9) - Title: Milliarcsecond-resolution Radio-imaging Survey of Blazar Candidates at 4 < z < 5.4Authors: Máté Krezinger, Alessandro Caccianiga, Daniele Dallacasa, Luca Ighina, Sándor Frey, Alberto Moretti, Sonia Anton, Silvia Belladitta, Claudia Cicone, Krisztina É. Gabányi, M. J. M. Marcha, Krisztina Perger,Comments: Published in The Astrophysical Journal Supplement SeriesSubjects: astro-ph.GACreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
We present a milliarcsecond-resolution radio survey of 17 high-redshift (4 < z < 5.4) BLAZAR candidates observed with the European Very Long Baseline Interferometry (VLBI) Network at 5 GHz. The primary objective of this study was to investigate the nature of these distant ACTIVE GALACTIC NUCLEi (AGN) and to confirm their BLAZAR nature. Utilizing the technique of VLBI, we obtained high-resolution radio images of compact core and core-JET structures. To confirm the classification of these sources, we collected multi-band archival data, including total radio flux densities from single-dish and low-resolution interferometric surveys, optical astrometric positions from Gaia, and X-ray data. These diagnostics collectively help distinguish between BLAZARs and misaligned JETted AGN. We were able to measure the core brightness temperatures and found that 11 objects show the Doppler-boosted emission expected from BLAZARs. For five additional sources, we do not see evidence of Doppler boosting even if X-ray data suggest that the source is a BLAZAR. These could be either borderline objects or variability may have affected the classifications, considering that VLBI and X-ray data are not simultaneous. Finally, for the two remaining objects the data suggest a non-BLAZAR classification. Our findings confirm that a significant fraction of these high-redshift radio-loud QUASARs are BLAZARs and mainly characterized by compact core structures. Overall, the VLBI classifcations are consistent with the X-ray classes. This study further increases the sample of VLBI-imaged radio QUASARs at z > 4 by ~10%, offering valuable on the population of AGN in the early Universe.
[abstract 3 / 32] Yes (score: 6) - Title: Convection-Driven Multi-Scale Magnetic Fields Determine the Observed Solar-Disk Gamma RaysAuthors: Jung-Tsung Li, Mahboubeh Asgari-Targhi, John F. Beacom, Annika H. G. Peter,Comments: 30 pages, 16 figures; Accepted for publication in The Astrophysical JournalSubjects: astro-ph.HE astro-ph.SR hep-phCreated: 2026-01-07; Updated: 2026-01-12; Datestamp: 2026-01-12
The solar disk is a continuous source of GeV--TeV gamma rays. The emission is thought to originate from hadronic Galactic COSMIC RAYs (GCRs) interacting with the gas in the photosphere and uppermost convection zone after being reflected by solar MAGNETic fields. Despite this general understanding, existing theoretical models have yet to match observational data. At the photosphere and the uppermost convection zone, granular convection drives a multi-scale MAGNETic field, forming a larger-scale filamentary structure while also generating turbulence-scale Alfvén wave turbulence. Here, we demonstrate that the larger-scale filamentary field shapes the overall gamma-ray emission spectrum, and the Alfvén wave turbulence is critical for further suppressing the gamma-ray emission spectrum below $\sim 100$~GeV. For a standard Alfvén wave turbulence level, our model's predicted spectrum slope from 1~GeV to 1~TeV is in excellent agreement with observations from FERMI-LAT and HAWC, an important achievement. The predicted absolute flux is a factor of 2--5 lower than the observed data; we outline future directions to resolve this discrepancy. The key contribution of our work is providing a new theoretical framework for using solar disk gamma-ray observations to probe hadronic GCR transport in the lower solar atmosphere.
[abstract 4 / 32] Yes (score: 6) - Title: First Results from the PanRadio Gamma-Ray Burst Collaboration: The 400-day Afterglow of GRB 230815AAuthors: James K. Leung, Gemma E. Anderson, Alexander J. van der Horst, Claire Morley, Benjamin Schneider, Fabio De Colle, Om Sharan Salafia, Giancarlo Ghirlanda, Sarah I. Chastain, Adelle J. Goodwin, Ashna Gulati, Lauren Rhodes, Stuart D. Ryder, Ashley A. Chrimes, Valerio D'Elia, Mathieu de Bony de Lavergne, Massimiliano De Pasquale, Antonio de Ugarte Postigo, Dieter H. Hartmann, Benjamin P. Gompertz, Andrew J. Levan, Tara Murphy, Gavin P. Rowell, Thomas D. Russell, Fabian Schüssler, Rhaana L. C. Starling, Nial R. Tanvir, Susanna D. Vergani, Ralph A. M. J. Wijers,Comments: 28 pages, 12 figures; accepted for publication in ApJLSubjects: astro-ph.HECreated: 2026-01-08; Updated: 2026-01-12; Datestamp: 2026-01-12
We introduce the PanRadio Gamma-ray Burst (GRB) program carried out on the Australia Telescope Compact Array: a systematic, multi-year, radio survey of all southern $\textit{SWIFT}$ GRB events, comprehensively following the multi-frequency evolution of their afterglows from within an hour to years post-burst. We present the results of the 400-day observing campaign following the afterglow of the long-duration (collapsar) GRB 230815A, the first one detected through this program. Typically, GRB 230815A would not otherwise receive traditional radio follow-up, given it has no known redshift and lacks comprehensive multi-wavelength follow-up due to its high line-of-sight extinction with $A_V=2.3$. We found its early X-ray JET break at ${\sim}0.1$ days post-burst to be at odds with the evolution of the multi-frequency radio light curves that were traced over an unusually long duration of $400$ days. The radio light curves approximately evolved (with minor deviations) according to the standard self-similar expansion for a RELATIVISTIC blast wave in a homogeneous environment prior to the JET break, showing no evidence for evolutions of the microphysical parameters describing the electron acceleration processes. We reconcile these features by proposing a two-component JET: the early X-ray break originates from a narrow component with a half-opening angle ${\sim}2.1^{\circ}$, while the evolution of the radio afterglow stems from a wider component with a half-opening angle of $\gtrapprox 35^{\circ}$. The PanRadio GRB program will establish a sample of comprehensively followed GRBs, where a rigorous inspection of their microphysical and dynamical parameters can be performed, thereby revealing the diversity of features in their outflows and environments.
[abstract 5 / 32] Yes (score: 5) - Title: Realistic assessment of a single gravitational wave source localization taking into account precise pulsar distances with pulsar timing arraysAuthors: Ryo Kato, Keitaro Takahashi,Comments: 19 pages, 6 figuresSubjects: gr-qc astro-ph.HECreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
Pulsar timing arrays (PTAs) are anticipated to detect continuous gravitational waves (GWs) from individual supermassive BLACK HOLE binaries (SMBHBs) in the near future. To identify the host galaxy of a GW source, PTAs require significantly improved angular resolution beyond the typical range of 100-1000 square degrees achieved by recent continuous GW searches. In this study, we investigate how precise pulsar distance measurements can enhance the localization of a single GW source. Accurate distance information, comparable to or better than the GW wavelength (typically 1~pc) can refine GW source localization. In the near future, with the advent of Square Kilometre Array (SKA), such high-precision distance measurements will be feasible for a few nearby pulsars. We focus on the relatively nearby pulsars J0437-4715 (156 pc) and J0030+0451 (331 pc), incorporating their actual distance uncertainties based on current VLBI measurements and the anticipated precision of the SKA-era. By simulating 87 pulsars with the GW signal and Gaussian white noise in the timing residuals, we assess the impact of the pulsar distance information on GW source localization. Our results show that without precise distance information, localization remains insufficient to identify host galaxies under 10 ns noise. However, incorporating SKA-era distance precision for nearby pulsars J0437-4715 and J0030+0451 can reduce localization uncertainties to the required level of $10^{-3}$ $\rm deg^{2}$. Localization accuracy strongly depends on the geometric configuration of pulsars with well-measured distances and improves notably near and between such pulsars. The improvement of the localization will greatly aid in identifying the host galaxy of a GW source and constructing an SMBHB catalog. It will further enable follow-up electroMAGNETic observations to investigate the SMBHB in greater detail.
[abstract 6 / 32] Yes (score: 4) - Title: A RELATIVISTIC treatment of accretion disk torques on extreme mass-ratio inspirals around non-spinning BLACK HOLEsAuthors: Abhishek Hegade K. R., Charles F. Gammie, Nicolás Yunes,Comments: 34 pages, 5 figures. Matches published version. Supplementary MATHEMATICA file available at https://github.com/AbhiHegade/Supplementary-Material-for-Disc-Torques-in-Schwarzschild-BackgroundSubjects: gr-qc astro-ph.HECreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
We develop a RELATIVISTICally accurate formalism to model the interaction between stellar mass compact objects embedded in thin accretion disks around a non-spinning supermassive BLACK HOLE, using tools from self-force theory and Hamiltonian perturbation theory. We then apply this formalism to analyze the evolution of a compact object on a nearly circular and equatorial orbit interacting with a thin equatorial disk. We provide analytic and RELATIVISTICally-accurate expressions for the rates of energy and angular momentum exchanged during interactions due to Lindblad and corotation resonances. Our results show that RELATIVISTIC corrections can enhance the magnitude of the torque by 1-2 orders of magnitude compared to purely Newtonian expressions when the orbit of the compact object is smaller than $10$ Schwarzschild radii of the supermassive BLACK HOLE. We also demonstrate that strong RELATIVISTIC shifts the inner Lindblad resonances closer to the compact object than the outer Lindblad resonances when the compact object is closer than 4 Schwarzschild radii to the supermassive BLACK HOLE, potentially leading to a reversal in the direction of the torque acting on the compact object. Finally, we provide a dephasing estimate and show that using the RELATIVISTIC torque formula is crucial to obtain reliable estimates for extreme mass ratio inspirals in orbits closer than 5 Schwarzschild radii to the supermassive BLACK HOLE. Our results highlight the importance of using RELATIVISTICally-accurate models of environmental interactions in extreme mass-ratio inspirals close to a supermassive BLACK HOLE.
[abstract 7 / 32] Yes (score: 4) - Title: Accretion disc winds in X-ray binariesAuthors: Teo Muñoz-Darias, María Díaz Trigo, Chris Done, Gabriele Ponti, Ryota Tomaru,Comments: Submitted to Space Science Reviews. 84 pages in total, including references (55 pages of main text)Subjects: astro-ph.HECreated: 2026-01-08; Updated: 2026-01-12; Datestamp: 2026-01-12
Despite early theoretical expectations that large-scale, massive outflows would be triggered by accretion onto BLACK HOLEs and neutron stars, their presence was not firmly established until the 2000s. Since then, they have been recognised as a common, perhaps ubiquitous, feature of accretion discs in X-ray binaries. Over the past two decades, our understanding of these outflows has expanded significantly, with their associated phenomenology now observed across the X-ray, ultraviolet, optical, and near-infrared regimes. In this review, we provide a comprehensive summary of the observational properties of both low- and high-ionisation winds, treating each separately as well as part of a broader phenomenon, and place these findings in the context of current theoretical modelling. We discuss their close connection with disc atmospheres, their impact on the accretion process, and their role within the broader framework that includes the radio JET and the different accretion flow configurations and states. We also address current challenges and outline some of the anticipated developments, particularly those linked to upcoming observational facilities.
[abstract 8 / 32] Yes (score: 4) - Title: Dust-obscured radio-emitting tidal disruption event coincident with a high-energy neutrino eventAuthors: Tianyao Zhou, Xinwen Shu, Guobin Mou, Lei Yang, Luming Sun, Fangkun Peng, Fabao Zhang, Hucheng Ding, Ning Jiang, Tinggui Wang, Yogesh Chandola, Daizhong Liu, Liming Dou, Yibo Wang, Jianguo Wang, Zhongzu Wu, Chenwei Yang,Comments: 15 pages, 6 figures; accepted for publication in PRDSubjects: astro-ph.HECreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
Despite the growing number of high-energy neutrinos (TeV-PeV) detected by IceCube, their astrophysical origins remain largely unidentified. Recent observations have linked a few tidal disruption events (TDEs) to the production of high-energy neutrino emission, all of which display dust-reprocessed infrared flares, indicating a dust- and gas-rich environment. By cross-matching the neutrino events and a sample of mid-infrared outbursts in nearby galaxies with transient radio flares, we uncover an optically obscured TDE candidate, SDSS J151345.75 $+$ 311125.2, which shows both spatial and temporal coincidence with the sub-PeV neutrino event IC170514B. Using a standard equipartition analysis of the SYNCHROTRON spectral evolution spanning 605 days post mid-infrared discovery, we find a little evolution in the radio-emitting region, with a kinetic energy up to $10^{51}$ erg, depending on the outflow geometry and shock acceleration efficiency assumed. High-resolution European VLBI Network imaging reveals a compact radio emission that is unresolved at a scale of $<$ 2.1 pc, with a brightness temperature of $T_b>5\times10^6$ K, suggesting that the observed late-time radio emission might originate from the interaction between a decelerating outflow and a dense circumnuclear medium. If the association is genuine, the neutrino production is possibly related to the acceleration of protons through pp collisions during the outflow expanding process, implying that the outflow-cloud interaction could provide a physical site with a high-density environment for producing the sub-PeV neutrinos. Such a scenario can be tested with future identifications of radio transients coincident with high-energy neutrinos.
[abstract 9 / 32] (score: 3) - Title: A RELATIVISTIC treatment of accretion disk torques on extreme mass ratio inspirals around spinning BLACK HOLEsAuthors: Abhishek Hegade K. R., Charles F. Gammie, Nicolás Yunes,Comments: Matches published version. 12 pages, 5 figures. Supplementary material available at https://github.com/AbhiHegade/Supplementary-Material-for-Disc-Torques-in-Schwarzschild-Background. Comments are welcome!Subjects: gr-qcCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
We model the motion of a small compact object on a nearly circular orbit around a spinning supermassive BLACK HOLE, which is also interacting with a thin equatorial accretion-disk surrounding the latter, through tools from self-force and Hamiltonian perturbation theory. We provide an analytical and RELATIVISTICally-accurate formalism to calculate the rate of energy and angular momentum exchanged at Lindblad resonances. We show that strong RELATIVISTIC effects can potentially cause a reversal in the direction of the torque on the small compact object if the surface density gradient is not too large. We analytically explore the dependence of the torque reversal location on the spin of the supermassive BLACK HOLE and demonstrate that the ratio of the reversal location to the innermost stable circular orbit is approximately insensitive to the spin of the supermassive BLACK HOLE. Our results show that RELATIVISTIC torques can be 1--2 order of magnitude larger than the Newtonian torque routinely used in the literature to model disk/small-compact-object interactions close to the supermassive BLACK HOLE. Our results highlight the importance of including RELATIVISTIC effects when modeling environmental effects in extreme mass-ratio inspirals.
[abstract 10 / 32] (score: 3) - Title: First detection of ultra-high energy emission from gamma-ray binary LS I +61 303Authors: Zhen Cao, F. Aharonian, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, W. Bian, J. Blunier, A. V. Bukevich, C. M. Cai, Y. Y. Cai, W. Y. Cao, Zhe Cao, J. Chang, J. F. Chang, E. S. Chen, G. H. Chen, H. K. Chen, L. F. Chen, Liang Chen, Long Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, X. B. Chen, X. J. Chen, X. P. Chen, Y. Chen, N. Cheng, Q. Y. Cheng, Y. D. Cheng, M. Y. Cui, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, Danzengluobu, Y. X. Diao, A. J. Dong, X. Q. Dong, K. K. Duan, J. H. Fan, Y. Z. Fan, J. Fang, J. H. Fang, K. Fang, C. F. Feng, H. Feng, L. Feng, S. H. Feng, X. T. Feng, Y. Feng, Y. L. Feng, S. Gabici, B. Gao, Q. Gao, W. Gao, W. K. Gao, M. M. Ge, T. T. Ge, L. S. Geng, G. Giacinti, G. H. Gong, Q. B. Gou, M. H. Gu, F. L. Guo, J. Guo, K. J. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, R. P. Han, O. A. Hannuksela, M. Hasan, H. H. He, H. N. He, J. Y. He, X. Y. He, Y. He, S. Hernández-Cadena, B. W. Hou, C. Hou, X. Hou, H. B. Hu, S. C. Hu, C. Huang, D. H. Huang, J. J. Huang, X. L. Huang, X. T. Huang, X. Y. Huang, Y. Huang, Y. Y. Huang, A. Inventar, X. L. Ji, H. Y. Jia, K. Jia, H. B. Jiang, K. Jiang, X. W. Jiang, Z. J. Jiang, M. Jin, S. Kaci, M. M. Kang, I. Karpikov, D. Khangulyan, D. Kuleshov, K. Kurinov, Cheng Li, Cong Li, D. Li, F. Li, H. B. Li, H. C. Li, Jian Li, Jie Li, K. Li, L. Li, R. L. Li, S. D. Li, T. Y. Li, W. L. Li, X. R. Li, Y. Li, Zhe Li, Zhuo Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, D. B. Liu, H. Liu, J. Liu, J. L. Liu, J. R. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, X. Liu, Y. Liu, Y. Liu, Y. N. Liu, Y. Q. Lou, Q. Luo, Y. Luo, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, I. O. Maliy, J. R. Mao, Z. Min, W. Mitthumsiri, Y. Mizuno, G. B. Mou, A. Neronov, K. C. Y. Ng, M. Y. Ni, L. Nie, L. J. Ou, Z. W. Ou, P. Pattarakijwanich, Z. Y. Pei, D. Y. Peng, J. C. Qi, M. Y. Qi, J. J. Qin, D. Qu, A. Raza, C. Y. Ren, D. Ruffolo, A. Sáiz, D. Savchenko, D. Semikoz, L. Shao, O. Shchegolev, Y. Z. Shen, X. D. Sheng, Z. D. Shi, F. W. Shu, H. C. Song, Yu. V. Stenkin, Y. Su, D. X. Sun, H. Sun, J. X. Sun, Q. N. Sun, X. N. Sun, Z. B. Sun, N. H. Tabasam, J. Takata, P. H. T. Tam, H. B. Tan, Q. W. Tang, R. Tang, Z. B. Tang, W. W. Tian, C. N. Tong, L. H. Wan, C. Wang, D. H. Wang, G. W. Wang, H. G. Wang, J. C. Wang, K. Wang, Kai Wang, Kai Wang, L. P. Wang, L. Y. Wang, L. Y. Wang, R. Wang, W. Wang, X. G. Wang, X. J. Wang, X. Y. Wang, Y. Wang, Y. D. Wang, Z. H. Wang, Z. X. Wang, Zheng Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, S. S. Weng, C. Y. Wu, H. R. Wu, Q. W. Wu, S. Wu, X. F. Wu, Y. S. Wu, S. Q. Xi, J. Xia, J. J. Xia, G. M. Xiang, D. X. Xiao, G. Xiao, Y. F. Xiao, Y. L. Xin, H. D. Xing, Y. Xing, D. R. Xiong, B. N. Xu, C. Y. Xu, D. L. Xu, R. F. Xu, R. X. Xu, S. S. Xu, W. L. Xu, L. Xue, D. H. Yan, T. Yan, C. W. Yang, C. Y. Yang, F. F. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, W. X. Yang, Z. H. Yang, Z. G. Yao, X. A. Ye, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Q. Yuan, H. Yue, H. D. Zeng, T. X. Zeng, W. Zeng, X. T. Zeng, M. Zha, B. B. Zhang, B. T. Zhang, C. Zhang, H. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, J. Y. Zhang, Li Zhang, P. F. Zhang, R. Zhang, S. R. Zhang, S. S. Zhang, S. Y. Zhang, W. Zhang, W. Y. Zhang, X. Zhang, X. P. Zhang, Yi Zhang, Yong Zhang, Z. P. Zhang, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, X. H. Zhao, Z. H. Zhao, F. Zheng, T. C. Zheng, B. Zhou, H. Zhou, J. N. Zhou, M. Zhou, P. Zhou, R. Zhou, X. X. Zhou, X. X. Zhou, B. Y. Zhu, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, Y. C. Zou, X. Zuo,Comments: 13 pages, 5 figuresSubjects: astro-ph.HECreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
We report the first detection of gamma-ray emission up to ultra-high-energy (UHE; $>$100 TeV) emission from the prototypical gamma-ray binary system LS I +61 303 using data from the Large High Altitude Air Shower Observatory (LHAASO). It is detected with significances of 9.2$σ$ in WCDA (1.4--30.5 TeV) and 6.2$σ$ in KM2A (25--267 TeV); in KM2A alone we identify 16 photon-like events above 100 TeV against an estimated 5.1 background events, corresponding to a 3.8$σ$ detection. These results provide compelling evidence of extreme particle acceleration in LS I +61 303. Furthermore, we observe orbital modulation at 4.0$σ$ confidence between 25 and 100 TeV, and a hint of energy-dependent orbital modulation. These features can be understood in a composite scenario in which leptonic and hadronic processes jointly contribute.
[abstract 11 / 32] (score: 3) - Title: Dual AGNs on 100 kpc Scales from the Million Quasar CatalogAuthors: Zhuojun Deng, Cheng Xiang, Qihang Chen, Liang Jing, Xingyu Zhu, Jianghua Wu,Comments: 22 pages, 14 figures, resubmittedSubjects: astro-ph.GACreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
Research on dual ACTIVE GALACTIC NUCLEi (AGNs) is crucial for understanding the coevolution of galaxies and supermassive BLACK HOLEs. However, the current number of dual AGNs remains scarce. In this work, we selected 173 new dual AGNs, 4 AGN triplets, and 1 AGN quadruplet from the Million Quasars Catalog, all with low redshift ($z < 0.5$), a projected distance ($r_p$) of no more than 100 kpc, and a line-of-sight velocity difference ($|Δv|$) of less than 600 km s$^{-1}$, thus supplementing existing low-redshift dual AGNs demographics. Visual inspection of the optical images from the Dark Energy Spectroscopic Instrument Legacy Survey was performed for each pair, revealing that $\sim$16\% of pairs exhibit tidal features. Statistical analyses show an increasing number of dual AGNs with decreasing redshift, with velocity difference primarily at $|Δv| < $ 300 km s$^{-1}$, which is likely an artifact of our selection strategy. The tidal sample peaks as having 13 pairs at 5-20$h^{-1}_{70}$ kpc, but drops to 1 pair $> 55\,h^{-1}_{70}$ kpc. Our study also explores thewide separation ($r_p>10$ kpc) dual AGNs, finding 165 such systems, with 25 displaying clear tidal features. Furthermore, some extra galaxies, AGNs, and/or their candidates were found in the same regions of the pairs or multiplets forming interacting systems with these pairs or multiplets.
[abstract 12 / 32] (score: 3) - Title: Dispersive Properties of MHD Waves in the Expanding Solar Wind for a Parker Spiral GeometryAuthors: Sebastián Saldivia, Felipe Asenjo, Pablo S. Moya,Comments: 16 pages, 6 figuresSubjects: astro-ph.SR physics.plasm-phCreated: 2026-01-08; Updated: 2026-01-12; Datestamp: 2026-01-12
In this work, we quantify the effects of solar wind expansion on the dispersive properties of the three normal modes of ideal MHD using the Expanding Box Model, under a background MAGNETic field that follows the Parker spiral geometry. From the linearized MHD-EBM equations, we construct the dispersion tensor and derive analytical expressions for the eigenfrequencies $ω(k,R)$, MAGNETic compressibility $C_B$, and the ratio of the parallel electric field to the perpendicular MAGNETic field $|δE_\parallel|/|δB_\perp|$ of the MAGNETosonic modes to quantify how radial solar wind expansion reshapes the character of compressive fluctuations in the solar wind. Magnetic compressibility increases with heliocentric distance, and this trend shows a better alignment with in-situ observations when expansion is included from the MHD-EBM framework. $C_B$ shows a well-defined minimum at small radii and then increases linearly with distance, which naturally reproduces the observed transition from Alfvénic to compressive fluctuations between $\sim$0.3-1 AU. The ratio $|δE_\parallel|/|δB_\perp|$ reveals opposite behaviors for the fast and slow modes: while the fast mode becomes more electrostatic with increasing distance, the slow mode evolves to a more MAGNETically dominated character. Expansion reduces the growth of their electroMAGNETic/compressive balance at large radii. Our results demonstrate that solar wind expansion actively redistributes energy between MAGNETically compressive modes and purely transverse fluctuations with respect to the background MAGNETic field, playing a major role in shaping the radial evolution of wave dynamics throughout the inner heliosphere.
[abstract 13 / 32] (score: 3) - Title: The Cosmic-ray Knee as a Local Signature of Nearby PeVatronsAuthors: Ke Fang, Francis Halzen,Comments: 11 pages, 6 figuresSubjects: astro-ph.HECreated: 2026-01-08; Updated: 2026-01-12; Datestamp: 2026-01-12
A "knee" in the cosmic-ray spectrum, characterized by a sudden steepening of the spectral shape at $\sim 4$ PeV, may be interpreted either as a global feature of Galactic COSMIC RAYs or as a local signature. In the former scenario, cosmic-ray spectra throughout the Galaxy would be similar to that observed in the solar neighborhood, and the knee would be a common feature of the cosmic-ray sea. In the latter scenario, the PeV cosmic-ray flux varies across the Galactic disk, and the knee is dominantly contributed by a small number of nearby sources. By simulating cosmic-ray propagation in the Galactic MAGNETic field and interstellar medium, we show that the two scenarios correspond to different regimes of the birth rate of PeV proton accelerators and depend on the presence of powerful nearby sources. By comparison with both cosmic-ray and gamma-ray observations, we find that a local knee would be best explained by sources located at distances of order $\sim1$ kpc and with ages in the range 0.1-1 Myr, with the Cygnus Cocoon being a particularly promising candidate.
[abstract 14 / 32] (score: 3) - Title: Kineclinic MAGNETogenesis in RELATIVISTIC collisionless plasmasAuthors: Modhuchandra Laishram, Suresh Basnet, Young Dae Yoon,Comments:Subjects: physics.plasm-phCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
The RELATIVISTIC momentum equation of a collisionless plasma is reformulated to describe the time evolution of canonical vorticity. Compared to the non-RELATIVISTIC counterpart, an additional source term for canonical vorticity is identified, which embodies the misalignment between the fluid momentum and fluid velocity gradients. This kineclinic term breaks the frozen-in condition of canonical vorticity, thereby enabling generation or dissipation of MAGNETic fields and vorticity. We verify the role of this effect through particle-in-cell simulations of a modified Beltrami flow. Kineclinicity should be finite for all RELATIVISTIC plasma systems due to the general lack of a functional relationship between fluid momentum and fluid velocity.
[abstract 15 / 32] (score: 3) - Title: Exploring Chaotic Motion of a Particle in the Centre of a Galaxy with a Prolate HaloAuthors: Uditi Nag, Yeasin Ali, Suparna Roychowdhury,Comments:Subjects: nlin.CDCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
The majority of galaxies are known to have supermassive BLACK HOLEs (SMBHs) at their core, which have a tremendous gravitational pull on the objects around them. When embedded within extended matter distributions such as prolate, shell-like halos, they give rise to complex gravitational fields that often drive nearby particles into chaotic orbits. The inherently nonlinear nature of such motion, shaped by general relativity, makes direct analysis highly challenging. To overcome this, pseudo-Newtonian potentials are used to approximate RELATIVISTIC effects within a Newtonian framework. In this study, we model the central SMBH using the Artemova-Bjornsson-Novikov (1996) potential to mimic the rotational effects of a Kerr-like BLACK HOLE. The surrounding prolate halo is treated as an axisymmetric, shell-like mass distribution, represented through a multipole expansion including dipole and quadrupole components. Poincare sections and the Maximum Lyapunov Exponent (MLE) reveal how the SMBH-halo system drives both order and chaos, with the SMBH spin modulating the dynamics by enhancing or suppressing chaos depending on its direction and magnitude.
[abstract 16 / 32] (score: 2) - Title: Graviton-Photon Mixing by a Kerr-Newman Black Hole with Worldline EFTAuthors: Qinyuan Zheng,Comments: Withdrawn by the author. The manuscript is incomplete and needs further scrutinySubjects: hep-th astro-ph.HE gr-qcCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
In BLACK HOLE perturbation theory, the difficulty in separating electroMAGNETic and gravitational sectors of the coupled Teukolsky equations has prevented a general treatment of scattering processes involving both electroMAGNETic waves and gravitational waves in presence of a Kerr-Newman BLACK HOLE. We present the first computation of the gauge-invariant, low-frequency scattering amplitude for graviton photoproduction by a Kerr-Newman BLACK HOLE at tree level up to $\mathcal{O}\big((ω/m)^2\big)$ or $\mathcal{O}(S^2)$ and linear in $κ$, using the worldline effective field theory. The relevant Wilson coefficients are determined by matching the graviton and photon one-point functions to the Kerr-Newman solution. We obtain the full angular dependence of the conversion cross section in the presence of spin and comment on the factorization relation between the graviton photoproduction amplitude and the photon Compton amplitude for a classical spinning source. The result provides a benchmark for future analyses of coupled gravitoelectroMAGNETic scattering in spinning charged compact object backgrounds.
[abstract 17 / 32] (score: 2) - Title: Interaction of the central JET with the surrounding gas in the protostellar outflow from IRAS 04166+2706Authors: M. Tafalla, D. Johnstone, J. Santiago-Garcia, Q. Zhang, H. Shang, C. -F. Lee,Comments: 16 pages, 14 figures, accepted for publication in A&ASubjects: astro-ph.GACreated: 2026-01-08; Updated: 2026-01-12; Datestamp: 2026-01-12
$Context.$ The outflow from the Class 0 protostar IRAS 04166+2706 (hereafter IRAS 04166) contains a remarkably symmetric JET-like component of extremely high-velocity (EHV) gas. $Aims.$ We studied the IRAS 04166 outflow and investigated the relation between its EHV component and the slower outflow gas. $Methods.$ We mosaicked the CO(2--1) emission from the IRAS 04166 outflow using the 12m and the Compact Arrays of ALMA. We also developed a ballistic toy model of the gas ejected laterally from a JET to interpret the data. $Results.$ In agreement with previous observations, the ALMA data show that the slow outflow component is distributed in two opposed conical lobes and has a shear-flow pattern with velocity increasing toward the axis. The EHV gas consists of a series of arc-like condensations that span the full width of the conical lobes and merge with their walls, suggesting that the fast and slow outflow components are physically connected. In addition, position--velocity diagrams along the outflow axis show finger-like extensions that connect the EHV emission with the origin of the diagram, as if part of the EHV gas had been decelerated by its interaction with the low-velocity outflow. A ballistic model can reproduce these finger-like extensions assuming that the EHV gas consists of JET material that has been ejected laterally over a short period of time and has transferred part of its momentum to the surrounding shear flow. $Conclusions.$ The EHV gas in the IRAS 04166 outflow seems to play a role in the acceleration of the slower gas component. The presence of similar finger-like extensions in the position-velocity diagrams of other outflows suggests that this process may be occurring in other systems, even if the EHV component is not seen because it has an atomic composition.
[abstract 18 / 32] (score: 2) - Title: Revised AGN Spectral Model Reveals a More Significant Role in Cosmic ReionizationAuthors: Tong Su, Qi Guo, Wenxiang Pei, Linhua Jiang,Comments: 12 pages, 7 figures. Accepted for publication in the Astrophysical Journal LetterSubjects: astro-ph.GACreated: 2026-01-08; Updated: 2026-01-12; Datestamp: 2026-01-12
Reionization marks one of the most important phase transitions in the history of the Universe, during which neutral baryonic matter was transformed into ionized plasma. While star-forming galaxies are widely regarded as the primary drivers of this process, the extent to which ACTIVE GALACTIC NUCLEi (AGNs) contribute remains a subject of ongoing investigation. In this study, we integrate a physically motivated AGN spectral energy distribution (SED) model with state-of-the-art observations to reassess the contribution of AGNs to cosmic reionization. Our findings indicate that adopting a more sophisticated AGN SED model could substantially increase the predicted ionizing photon output by a factor of 3$\sim$4, elevating AGNs to a more significant role ($\approx$20\%) in maintaining reionization than previously estimated. The inclusion of abundant faint AGNs further amplifies this contribution by a factor of a few. These conclusions remain robust across a wide range of accretion rates and ionizing photon escape fractions. Collectively, our results suggest that AGNs may have played a more prominent and previously underestimated role in the reionization of the Universe.
[abstract 19 / 32] (score: 2) - Title: Cosmic wallflowers: the circumgalactic origins of isolated ultra-compact star clusters at $z>7$Authors: Floor van Donkelaar, Lucio Mayer, Pedro R. Capelo, Debora Sijacki, Angela Adamo,Comments: 14 pages, 11 figures, submitted to MNRASSubjects: astro-ph.GA astro-ph.HECreated: 2026-01-08; Updated: 2026-01-12; Datestamp: 2026-01-12
The discovery of gravitationally lensed stellar clusters at high redshift with the James Webb Space Telescope (JWST) has revealed extremely compact, massive star-forming systems in galaxies at $z > 6$, providing a new window into early cluster formation. In this work, we investigate star cluster formation in the circumgalactic environments of gas-rich galaxies with stellar masses spanning between $\sim$$10^{8}$ - $10^{11}$ M$_{\odot}$ at $z > 7$, using the MassiveBlackPS cosmological hydrodynamical simulation with 2 pc resolution. We identify 55 baryon-dominated clusters forming outside galactic discs but within the virial radius of the primary halo. Star formation in these systems proceeds rapidly, reaching peak stellar surface densities above $10^{5}$ M$_{\odot}$ pc$^{-2}$, closely matching the compact clusters recently discovered by JWST in the lensed Cosmic Gems Arc at $z \approx 9.6$. Such extreme densities are a key pre-requisite to trigger runaway stellar collisions, indicating that a subset of our clusters would be a likely host of intermediate-mass BLACK HOLEs (IMBHs). We find that massive star clusters can form efficiently in the circumgalactic medium at early times through filament fragmentation, whereby high gas densities lead to rapid local collapse via a combination of thermal and gravitational instabilities. This formation pathway implies that some compact clusters formed in the quiet outskirts of forming galaxies rather than within their discs. Small variations in filament properties, including metallicity, density, and dark-matter content, influence the likelihood of a star cluster being able to form an IMBH seed. The formation of clusters in circumgalactic environments points to a potential evolutionary pathway connecting early off-disc clusters, present-day globular clusters, and the seeds of massive BHs.
[abstract 20 / 32] (score: 2) - Title: Development of Design for the STS Extraction Magnet SystemAuthors: V. Chernenok, S. Cheban, D. J Harding, V. Kashikhin, T. Strauss, B. Szabo, M. Allitt, L. Boyd,Comments: 2025 International Conference on Magnet Technology (MT29)Subjects: physics.acc-phCreated: 2026-01-08; Updated: 2026-01-12; Datestamp: 2026-01-12
The Oak Ridge National Laboratory STS Project will enhance the Spallation Neutron Source by adding a new neutron source. The upgrade includes a 30% increase in beam energy and a 50% boost in beam current, doubling the accelerator's power capability to 2.8 MW. The Ring-to-Second-Target Beam Transport (RTST) system is vital in directing high-energy proton beams to the new second target station. New MAGNETs have to fit into a restricted space within the existing beamline to add the new extraction line. New, fast kicker MAGNETs (Pulsed Dipole), a focusing quad with an aperture for both beamlines (Large Quad) and the replacement of existing 21Q40 Quads with 'Narrow Quads' having identical fields as the existing design are FERMIlab's responsibility. The design of these MAGNETs poses unique challenges, as in addition to the high requirements on the quality of MAGNETic fields, they are subject to major restrictions related to their dimensions.
[abstract 21 / 32] (score: 2) - Title: Similarity Theory and Scaling Networks for ElectroMAGNETic Wave-Driven PlasmasAuthors: Hanyang Li, Yulia Sharova, Denis Eremin, Yangyang Fu,Comments: 5 pages, 4 figuresSubjects: physics.plasm-phCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
We demonstrate the scale-invariant behavior of electroMAGNETic wave-driven radio-frequency plasmas across different dimensional scales. Using two-dimensional electroMAGNETic particle-in-cell simulations, we show that plasma uniformity remains the same in similar discharges. Building on the concept of similarity laws, we develop scaling networks that effectively relate plasma parameters across varying operating conditions. These results establish a generalized similarity theory derived from the Boltzmann equation coupled with the full set of Maxwell equations, extending the theoretical framework of similarity laws into electroMAGNETic regimes.
[abstract 22 / 32] (score: 2) - Title: The Hadronization Impact on $J/ψ$ Energy Correlators: A Pythia8 Study from Partonic to Hadronic ObservablesAuthors: Jin-peng Zhang, Qian Yang, Wen-Chao Zhang, Yu-jiao Zhao,Comments: 8 pages, 5 figuresSubjects: hep-phCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
A comprehensive study of the $J/ψ$ energy correlator as a probe of non-perturbative hadronization in color-octet $c\bar{c}$ production is performed. The energy correlator measures the energy flow as a function of the angular distance ($χ$) from the identified $J/ψ$ meson. Using the PYTHIA 8 Monte Carlo event generator, the correlator is computed at both parton and hadron levels. At high $J/ψ$ transverse momentum ($p_T > 7\ \text{GeV}/c$), the parton-level correlator in the $\cosχ> 0$ region is dominated by soft gluon emission during the hadronization of the color-octet state, a contribution clearly distinguishable from other partonic sources, such as underlying multi-parton interactions. The transition to the hadron level, however, introduces substantial modifications, suppressing the correlator in this region by approximately an order of magnitude and underscoring the complexity of the hadronization mapping. Further analysis reveals that the hadron-level observable exhibits notable sensitivity to model parameters: increasing the mass splitting between colored $c\bar{c}$ pre-resonances and the $J/ψ$ meson from 0.2 to 0.8 GeV/$c^{2}$ enhances the correlator by up to $60\%$, while extending the color RECONNECTion range yields a milder enhancement of about $10\%$. These findings demonstrate that precise measurements of the hadron level $J/ψ$ energy correlator, when interpreted within robust event-generator frameworks, can provide novel constraints on hadronization dynamics and help clarify the production mechanisms of $J/ψ$ state.
[abstract 23 / 32] (score: 2) - Title: Conservative formulation of the drift-reduced fluid plasma modelAuthors: Brenno De Lucca, Paolo Ricci, Micol Bassanini, Sergio García Herreros, Zeno Tecchiolli,Comments: 17 pages, 0 figuresSubjects: physics.plasm-phCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
A conservative formulation of the drift-reduced fluid plasma model is constructed by analytically inverting the implicit relation defining the polarisation velocity as a function of the time-derivative of the electric field. The obtained model satisfies exact conservation laws for energy, mass, charge and momentum, in arbitrary MAGNETic geometry, also when electroMAGNETic fluctuations are included.
[abstract 24 / 32] (score: 2) - Title: Energy Bounds from Relative Magnetic Helicity in Spherical ShellsAuthors: Anthony R. Yeates, Gunnar Hornig,Comments: 17 pages, 7 figures, accepted for publication in ApJSubjects: astro-ph.SR physics.plasm-phCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
Relative MAGNETic helicity is commonly used in solar physics to avoid the well known gauge ambiguity of standard MAGNETic helicity in MAGNETically open domains. But its physical interpretation is difficult owing to the invocation of a reference field. For the specific case of spherical shell domains (with potential reference field), relative helicity may be written intrinsically in terms of the MAGNETic field alone, without the need to calculate the reference field or its vector potential. We use this intrinsic expression to prove that non-zero relative helicity implies lower bounds for both MAGNETic energy and free MAGNETic energy, generalizing the important Arnol'd inequality known for closed-field MAGNETic helicity. Further, we derive a stronger energy bound by spatially decomposing the relative helicity over a MAGNETic partition of the domain to obtain a new ideal invariant which we call unsigned helicity. The bounds are illustrated with analytical linear force-free fields (that maximize relative helicity for given boundary conditions) as well as a non-potential data-driven model of the solar corona. These bounds confirm that both relative helicity and the unsigned helicity can influence the dynamics in the solar corona.
[abstract 25 / 32] (score: 2) - Title: A nonlinear voice from GW250114 ringdownAuthors: Yi-Fan Wang, Sizheng Ma, Neev Khera, Huan Yang,Comments: 9 pages, 6 figures. Data release at https://github.com/yi-fan-wang/nonlinear-ringdown-GW250114. Comments welcome!Subjects: gr-qc astro-ph.HECreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
The detection of quadratic quasi-normal modes would provide a direct probe into BLACK HOLE nonlinear perturbations. We report the first observational evidence of a set of quadratic quasi-normal modes in the gravitational-wave ringdown of a binary BLACK HOLE merger. Analyzing the signal from GW250114, we detect six nonlinear modes from the quadratic coupling of the fundamental $(2,2,0)$ mode and its first two overtones. At 5 final mass ($M_\mathrm{f}$) after the merger, the evidence for these nonlinear modes reaches a Bayes factor of 74. To single out these contributions, we employ recent theoretical progress to compute the waveforms and subtract the corresponding nonlinear modes from a numerical relativity surrogate waveform. Our data analysis uses a novel method that incorporates inspiral-merger inference results as a highly constraining prior for the ringdown inference. We further perform a test allowing for phenomenological deviations for the theoretically predicted amplitudes of the quadratic modes. The results show that an amplitude of zero is excluded at $3.0~σ$ significance level, while the theoretical expectation is consistent with the inference. This detection marks a first step towards observationally characterizing nonlinear perturbations in the ringdown of a BLACK HOLE.
[abstract 26 / 32] (score: 2) - Title: Fading into darkness: A weak mass ejection and low-efficiency fallback accompanying BLACK HOLE formation in M31-2014-DS1Authors: Kishalay De, Morgan MacLeod, Jacob E. Jencson, Ryan M. Lau, Andrea Antoni, Maria Jose Colmenares Diaz, Jane Huang, Megan Masterson, Viraj R. Karambelkar, Mansi M. Kasliwal, Abraham Loeb, Christos Panagiotou, Eliot Quataert,Comments: 14 pages, 5 figures + 1 figure (Appendix), 1 table, submitted to ApJ Letters. Comments welcome!Subjects: astro-ph.SR astro-ph.GA astro-ph.HECreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
Stellar-mass BLACK HOLEs (BHs) can form from the near-complete collapse of massive stars, causing them to abruptly disappear. The star M31-2014-DS1 in the Andromeda galaxy was reported to exhibit such a disappearance between 2014 and 2022, with properties consistent with the failed explosion of a $\approx 12 - 13$ M$_\odot$ yellow supergiant leading to the formation of a $\approx 5$ M$_\odot$ BH. We present mid-infrared (MIR) observations of the remnant obtained with the James Webb Space Telescope (JWST) and X-ray observations from the Chandra X-ray Observatory in 2024. The JWST MIRI/NIRSpec data reveal an extremely red source, showing strong blueshifted absorption from molecular gas (CO, CO$_2$, H$_2$O, SO$_2$) and deep silicate dust features. Modeling the dust continuum confirms continued bolometric fading of the central source to $\log(L/L_\odot)\approx3.88$ ($\approx7-8$% of the progenitor luminosity), surrounded by a dust shell spanning $\approx40-200$ au. Modeling of the molecular gas indicates $\sim 0.1$ M$_\odot$ of gas expanding at $\approx 100$ km s$^{-1}$ near the inner edge of the dust shell. No X-ray source is detected down to a luminosity limit of $L_X\lesssim1.5\times10^{35}$ erg s$^{-1}$. We show that the panchromatic observations are explained by (i) a low-energy ($\approx10^{46}$ erg) ejection of the outer H-rich progenitor envelope and (ii) a fading central BH powered by inefficient ($\sim0.1$% in mass) accretion of loosely bound fallback material. The analysis robustly establishes the bolometric fading of M31-2014-DS1 and provides the first cohesive insights into BH formation via low-energy explosions and long-term fallback.
[abstract 27 / 32] (score: 2) - Title: Dynamics of ion temperature gradient modes in burning plasma conditions in the presence of energetic particlesAuthors: Roman Ivanov, Alessandro Biancalani, Alberto Bottino, Didier Gossard, Thomas Hayward-Schneider, Alexey Mishchenko, Ruoyuan Wu,Comments: Submitted to Nuclear Fusion; under reviewSubjects: physics.plasm-phCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
The interaction between energetic particles (EPs) and ion temperature gradient (ITG) modes is studied using the global particle in cell ORB5 code. In this work, we extend previous studies to a broader range of EP temperatures, including the burning plasma regime and to wider variety of EP distribution functions. Two main stabilization mechanisms are found to be effective in ITG stabilization confirming previous studies: direct dispersion relation modification (DDRM) effective only at intermediate EP temperatures and dilution effect (DE) which is independent of EP temperature and becomes dominant in burning plasma regime ($T_f > 50T_i$). The study is further extended to slowing-down EP distributions which in contrast exhibit no DDRM-related stabilization. The findings are further validated in an ITER pre-fusion operation scenario and additionally compared with electroMAGNETic effects. In this scenario EP stabilization is found to be weaker than $β$-stabilization. Overall, these results provide better understanding of EP-ITG interactions over a wider range of EP parameters relevant to burning plasma regime which is important for predicting turbulence and confinement in future devices such as ITER.
[abstract 28 / 32] (score: 2) - Title: Feasibility of event-by-event primary mass discrimination using radio observables and supervised machine learningAuthors: Washington R. de Carvalho, Lech Wiktor Piotrowski,Comments:Subjects: astro-ph.HECreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
In this work, we investigate the feasibility of event-by-event primary mass discrimination using radio observables only. Although the analysis does not require an explicit reconstruction of the shower maximum ($X_{max}$), the discrimination power still arises from the sensitivity of the radio observables to the longitudinal development of the extensive air shower (EAS). Such radio-based approaches could be particularly relevant for radio-only experiments, such as GRAND. To assess this feasibility, we obtained conservative upper limits for the discrimination accuracy using a supervised machine-learning (ML) algorithm, namely a random forest (RF). The input features used were the peak electric fields and the spectral slopes, which have complementary discrimination power, along with the antenna distances to the shower axis. The RF was trained and tested using large event sets generated by the fast radio emission simulation and simplified detector response implemented in the RDSim framework. We obtained discrimination accuracies between 81\% and 96\% over the studied zenith range, even after normalizing each shower by its own electroMAGNETic energy. Since the analysis includes deliberately conservative choices, such as a large 10\% uncertainty on the reconstructed EM energy, these quoted values should be interpreted as conservative upper limits suitable for a feasibility assessment. Our results demonstrate that event-by-event primary mass discrimination using radio observables is, in principle, feasible.
[abstract 29 / 32] (score: 2) - Title: Comment on Nuclear Fusion 66, 016012 (2026) and arXiv:2508.03561 by Richard Fitzpatrick, A Simple Model of Current Ramp-Up and Ramp-Down in TokamaksAuthors: Allen H Boozer,Comments: The article being commented on is arXiv:2508.03561 as well as Nuclear Fusion 66, 016012 (2026)Subjects: physics.plasm-phCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
The article Nuclear Fusion \textbf{66}, 016012 (2026) by Richard Fitzpatrick is based on fundamental errors in the physics of the poloidal MAGNETic flux in tokamaks. His paper was inspired by an article that I posted on arXiv in various versions [arXiv:2507.05456]. The September 9, 2025 version was submitted to the Physics of Plasmas, which flatly rejected the article. Before I can resubmit, the Physics of Plasmas stated that the issues with the Fitzpatrick article must be explained. Not only did Fitzpatrick make numerous fundamental errors in science, he totally misrepresented my views as clearly stated in my article and even more explicitly in email exchanges, called ``private communication" in his paper. Enquiries were made to the journal Nuclear Fusion staring on November 24, 2025 of the consistency of Fitzpatrick's article with the scientific and ethical standards of the journal. On January 5, 2026, Nuclear Fusion said they had "no evidence of intentional misrepresentation," but others may disagree after reading the emails. Both grants and the publication of an important paper make the public availability of this Comment urgent.
[abstract 30 / 32] (score: 2) - Title: Self-organization of local streamline structures and energy transfer rate in compressible plasma turbulenceAuthors: Simone Benella, Virgilio Quattrociocchi, Emanuele Papini, Andrea Verdini, Simone Landi, Maria Federica Marcucci, Giuseppe Consolini,Comments:Subjects: physics.space-ph physics.plasm-phCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
We examine how local streamline topology and energy cascade rate self-organize in plasma turbulence for both compressible and incompressible regimes. Using a fully-compressible Hall-MAGNETohydrodynamic simulation, we quantify the subgrid-scale energy transfer and analyze its relationship to streamline structures by means of grandient tensor geometric invariants of the velocity field. Our results highlight how streamline topology is crucial for diagnosing turbulence: for nearly-incompressible fluctuations the energy is primarily transferred to smaller scales through strain-dominated and stable-vortical structures, while is back-transferred towards larger scales through unstable-vortical structures. Compressible fluctuations, on the contrary, do not show a clear topological selection of the energy transfer since the overall direction of the local cascade rate is found to be determined by the sign of $-\nabla\cdot u$ (plasma volumetric compression or expansion).
[abstract 31 / 32] (score: 2) - Title: Probing Cosmic Expansion and Early Universe with Einstein TelescopeAuthors: Angelo Ricciardone, Mairi Sakellariadou, Archisman Ghosh, Alessandro Agapito, M. Celeste Artale, Michael Bacchi, Tessa Baker, Marco Baldi, Nicola Bartolo, Andrea Begnoni, Enis Belgacem, Marek Biesiada, Jose J. Blanco-Pillado, Tomasz Bulik, Marica Branchesi, Gianluca Calcagni, Giulia Capurri, Carmelita Carbone, Roberto Casadio, J. A. R. Cembranos, Andrea Cozzumbo, Ivan De Martino, Jose M. Diego, Emanuela Dimastrogiovanni, Guillem Domènech, Ulyana Dupletsa, Hannah Duval, Gabriele Franciolini, Andrea Giusti, Giuseppe Greco, Lavinia Heisenberg, Alexander C. Jenkins, Sumit Kumar, Gaetano Lambiase, Michele Maggiore, Michele Mancarella, Federico Marulli, Sabino Matarrese, Isabela Santiago de Matos, Michele Moresco, Riccardo Murgia, Ilia Musco, Gabriele Perna, Michele Punturo, Diego Rubiera-Garcia, Javier Rubio, Alexander Sevrin, Riccardo Sturani, Matteo Tagliazucchi, Nicola Tamanini, Alessandro Tronconi, Ville Vaskonen, Daniele Vernieri, Stoytcho Yazadjiev, Ivonne Zavala,Comments: 4 pages. White paper submitted to the ESO Expanding Horizons Call on behalf of ET OSB Div2 - CosmologySubjects: astro-ph.CO gr-qcCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
Over the next two decades, gravitational-wave (GW) observations are expected to evolve from a discovery-driven endeavour into a precision tool for astrophysics, cosmology, and fundamental physics. Current second-generation ground-based detectors have established the existence of compact-binary mergers and enabled GW multi-messenger astronomy, but they remain limited in sensitivity, redshift reach, frequency coverage, and duty cycle. These limitations prevent them from addressing many fundamental open questions in cosmology. By the 2040s, wide-field electroMAGNETic surveys will have mapped the luminous Universe with unprecedented depth and accuracy. Nevertheless, key problems including the nature of DARK MATTER, the physical origin of cosmic acceleration, the properties of gravity on cosmological scales, and the physical conditions of the earliest moments after the Big Bang will remain only partially constrained by electroMAGNETic observations alone. Progress on these fronts requires access to physical processes and epochs that do not emit light. Gravitational waves provide a unique and complementary observational channel: they propagate over cosmological distances largely unaffected by intervening matter, probe extreme astrophysical environments, and respond directly to the geometry of spacetime. In this context, next-generation GW observatories such as the Einstein Telescope (ET) will be transformative for European astronomy. Operating at sensitivities and frequencies beyond existing detectors, ET will observe binary BLACK HOLEs and neutron stars out to previously inaccessible redshifts, enable continuous high signal-to-noise monitoring of compact sources, and detect gravitational-wave backgrounds of astrophysical and cosmological origin. Together with space-based detectors, ET will play a central role in advancing our understanding of cosmic evolution and fundamental physics.
[abstract 32 / 32] (score: 2) - Title: Weak lensing of bright standard sirens: prospects for $σ_8$Authors: Ville Vaskonen,Comments: 7 pages, 5 figuresSubjects: astro-ph.COCreated: 2026-01-09; Updated: 2026-01-12; Datestamp: 2026-01-12
Gravitational wave events with electroMAGNETic counterparts provide direct measurements of the Hubble diagram. We demonstrate that incorporating weak lensing into bright standard siren analyses allows measurements of cosmological parameters that do not influence the mean luminosity distance-redshift relation but do impact the cosmic structures. In particular, we examine the prospects for measuring the standard deviation of matter perturbations $σ_8$, in addition to the Hubble constant and the matter abundance. We find that a $10\%$ measurement of $σ_8$ would be feasible with ET, provided a population of $300$ neutron star binaries with electroMAGNETic counterparts is observed. With LISA, the measurement of $σ_8$ would have $30\%$ accuracy, assuming a population of $12$ massive BLACK HOLE binaries with electroMAGNETic counterparts is observed.
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