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SN2017ckj: A linearly declining Type IIb supernova with a relatively massive hydrogen envelope

ArXiv 2510.22989 (2025)

Authors:

L-H Li, S Benetti, Y-Z Cai, B Wang, A Pastorello, N Elias-Rosa, A Reguitti, L Borsato, E Cappellaro, A Fiore, M Fraser, M Gromadzki, J Harmanen, J Isern, T Kangas, E Kankare, P Lundqvist, S Mattila, P Ochner, Z-H Peng, TM Reynolds, I Salmaso, S Srivastav, MD Stritzinger, L Tomasella, G Valerin, Z-Y Wang, J-J Zhang, C-Y Wu

ZTF25abjmnps (AT2025ulz) and S250818k: A Candidate Superkilonova from a Sub-threshold Sub-Solar Gravitational Wave Trigger

ArXiv 2510.23732 (2025)

Authors:

Mansi M Kasliwal, Tomas Ahumada, Robert Stein, Viraj Karambelkar, Xander J Hall, Avinash Singh, Christoffer Fremling, Brian D Metzger, Mattia Bulla, Vishwajeet Swain, Sarah Antier, Marion Pillas, Malte Busmann, James Freeburn, Sergey Karpov, Aleksandra Bochenek, Brendan O'Connor, Daniel A Perley, Dalya Akl, Shreya Anand, Andrew Toivonen, Sam Rose, Theophile Jegou du Laz, Chang Liu, Kaustav Das, Sushant Sharma Chaudhary, Tyler Barna, Aditya Pawan Saikia, Igor Andreoni, Eric C Bellm, Varun Bhalerao, S Bradley Cenko, Michael W Coughlin, Daniel Gruen, Daniel Kasen, Adam A Miller, Samaya Nissanke, Antonella Palmese, Jesper Sollerman, Niharika Sravan, GC Anupama, Smaranika Banerjee, Sudhanshu Barway, Joshua S Bloom, Tomas Cabrera, Tracy Chen, Chris Copperwheat, Alessandra Corsi, Richard Dekany, Nicholas Earley, Matthew Graham, Patrice Hello, George Helou, Lei Hu, Yves Kini, Ashish Mahabal, Frank Masci, Tanishk Mohan, Natalya Pletskova, Josiah Purdum, Yu-Jing Qin, Nabeel Rehemtulla, Anirudh Salgundi, Yuankun Wang

Symbolic Regression and Differentiable Fits in Beyond the Standard Model Physics

ArXiv 2510.20453 (2025)

Authors:

Shehu AbdusSalam, Steven Abel, Deaglan Bartlett, Miguel Crispim Romão

Symbolic Emulators for Cosmology: Accelerating Cosmological Analyses Without Sacrificing Precision

ArXiv 2510.18749 (2025)

Authors:

Deaglan J Bartlett, Shivam Pandey

Gamma-ray lines, electron–positron annihilation, and possible radio emission in X-ray pulsars

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 543:4 (2025) 3993-4002

Authors:

Alexander A Mushtukov, Emir Tataroglu, Alex J Cooper, Sergey S Tsygankov

Abstract:

ABSTRACT Accretion on to neutron stars (NSs) in X-ray pulsars (XRPs) results in intense X-ray emission, and under specific conditions, high-energy nuclear interactions that produce gamma-ray photons at discrete energies. These interactions are enabled by the high free-fall velocities of accreting nuclei near the NS surface and give rise to characteristic gamma-ray lines, notably at 2.2, 5.5, and 67.5 MeV. We investigate the production mechanisms of these lines and estimate the resulting gamma-ray luminosities, accounting for the suppression effects of radiative deceleration in bright XRPs and the creation of electron–positron pairs in strong magnetic fields. The resulting annihilation of these pairs leads to a secondary emission line at ${\sim} 511$ keV. We also discuss the possibility that non-stationary pair creation in the polar cap region could drive coherent radio emission, though its detectability in accreting systems remains uncertain. Using a numerical framework incorporating general relativistic light bending and magnetic absorption, we compute the escape fraction of photons and distinguish between actual and apparent gamma-ray luminosities. Our results identify the parameter space – defined by magnetic field strength, accretion luminosity, and NS compactness – where these gamma-ray signatures may be observable by upcoming MeV gamma-ray missions. In particular, we highlight the diagnostic potential of detecting gravitationally redshifted gamma-ray lines and annihilation features for probing the mass–radius relation and magnetospheric structure of NSs.