First X-ray polarization measurement confirms the low black-hole spin in LMC X-3
Abstract
X-ray polarization is a powerful tool to investigate the geometry of accreting material around black holes, allowing independent measurements of the black hole spin and orientation of the innermost parts of the accretion disk. We perform the X-ray spectro-polarimetric analysis of an X-ray binary system in the Large Magellanic Cloud, LMC X-3, that hosts a stellar-mass black hole, known to be persistently accreting since its discovery. We report the first detection of the X-ray polarization in LMC X-3 with the Imaging X-ray Polarimetry Explorer, and find the average polarization degree of 3.2% +- 0.6% and a constant polarization angle -42 deg +- 6 deg over the 2-8 keV range. Using accompanying spectroscopic observations by NICER, NuSTAR, and the Neil Gehrels Swift observatories, we confirm previous measurements of the black hole spin via the X-ray continuum method, a ~ 0.2. From polarization analysis only, we found consistent results with low black-hole spin, with an upper limit of a < 0.7 at a 90% confidence level. A slight increase of the polarization degree with energy, similar to other black-hole X-ray binaries in the soft state, is suggested from the data but with a low statistical significance.
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Cite
@article{arxiv.2309.10813,
title = {First X-ray polarization measurement confirms the low black-hole spin in LMC X-3},
author = {Jiří Svoboda and Michal Dovčiak and James F. Steiner and Fabio Muleri and Adam Ingram and Anastasiya Yilmaz and Nicole Rodriguez Cavero and Lorenzo Marra and Juri Poutanen and Alexandra Veledina and Mehrnoosh Rahbardar Mojaver and Stefano Bianchi and Javier Garcia and Philip Kaaret and Henric Krawczynski and Giorgio Matt and Jakub Podgorný and Martin C. Weisskopf and Fabian Kislat and Pierre-Olivier Petrucci and Maimouna Brigitte and Michal Bursa and Sergio Fabiani and Kun Hu and Sohee Chun and Guglielmo Mastroserio and Romana Mikušincová and Ajay Ratheesh and Roger W. Romani and Paolo Soffitta and Francesco Ursini and Silvia Zane and Iván Agudo and Lucio A. Antonelli and Matteo Bachetti and Luca Baldini and Wayne H. Baumgartner and Ronaldo Bellazzini and Stephen D. Bongiorno and Raffaella Bonino and Alessandro Brez and Niccolo Bucciantini and Fiamma Capitanio and Simone Castellano and Elisabetta Cavazzuti and Chien-Ting Chen and Stefano Ciprini and Enrico Costa and Alessandra De Rosa and Ettore Del Monte and Laura Di Gesu and Niccolo Di Lalla and Alessandro Di Marco and Immacolata Donnarumma and Victor Doroshenko and Steven Ehlert and Teruaki Enoto and Yuri Evangelista and Riccardo Ferrazzoli and Shuichi Gunji and Kiyoshi Hayashida and Jeremy Heyl and Wataru Iwakiri and Svetlana G. Jorstad and Vladimír Karas and Takao Kitaguchi and Jeffery Kolodziejczak and Fabio La Monaca and Luca Latronico and Ioannis Liodakis and Simone Maldera and Alberto Manfreda and Frédéric Marin and Andrea Marinucci and Alan P. Marscher and Herman L. Marshall and Francesco Massaro and Ikuyuki Mitsuishi and Tsunefumi Mizuno and Michela Negro and C. -Y. Ng and Stephen L. O'Dell and Nicola Omodei and Chiara Oppedisano and Alessandro Papitto and George Pavlov and Abel Peirson and Matteo Perri and Melissa Pesce-Rollins and Maura Pilia and Andrea Possenti and Simonetta Puccetti and Brian D. Ramsey and John Rankin and Oliver Roberts and Carmelo Sgro and Patrick Slane and Gloria Spandre and Douglas A. Swartz and Toru Tamagawa and Fabrizio Tavecchio and Roberto Taverna and Yuzuru Tawara and Allyn F. Tennant and Nicholas E. Thomas and Francesco Tombesi and Alessio Trois and Sergey S. Tsygankov and Roberto Turolla and Jacco Vink and Kinwah Wu and Fei Xie},
journal= {arXiv preprint arXiv:2309.10813},
year = {2024}
}
Comments
14 pages, 8 figures, submitted to ApJ