The first X-ray polarimetric observation of the black hole binary LMC X-1
Abstract
We report on an X-ray polarimetric observation of the high-mass X-ray binary LMC X-1 in the high/soft state, obtained by the Imaging X-ray Polarimetry Explorer (IXPE) in October 2022. The measured polarization is below the minimum detectable polarization of 1.1 per cent (at the 99 per cent confidence level). Simultaneously, the source was observed with the NICER, NuSTAR and SRG/ART-XC instruments, which enabled spectral decomposition into a dominant thermal component and a Comptonized one. The low 2-8 keV polarization of the source did not allow for strong constraints on the black-hole spin and inclination of the accretion disc. However, if the orbital inclination of about 36 degrees is assumed, then the upper limit is consistent with predictions for pure thermal emission from geometrically thin and optically thick discs. Assuming the polarization degree of the Comptonization component to be 0, 4, or 10 per cent, and oriented perpendicular to the polarization of the disc emission (in turn assumed to be perpendicular to the large scale ionization cone orientation detected in the optical band), an upper limit to the polarization of the disc emission of 1.0, 0.9 or 0.9 per cent, respectively, is found (at the 99 per cent confidence level).
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@article{arxiv.2303.12034,
title = {The first X-ray polarimetric observation of the black hole binary LMC X-1},
author = {Jakub Podgorny and Lorenzo Marra and Fabio Muleri and Nicole Rodriguez Cavero and Ajay Ratheesh and Michal Dovciak and Romana Mikusincova and Maimouna Brigitte and James F. Steiner and Alexandra Veledina and Stefano Bianchi and Henric Krawczynski and Jiri Svoboda and Philip Kaaret and Giorgio Matt and Javier A. Garcia and Pierre-Olivier Petrucci and Alexander A. Lutovinov and Andrey N. Semena and Alessandro Di Marco and Michela Negro and Martin C. Weisskopf and Adam Ingram and Juri Poutanen and Banfsheh Beheshtipour and Sohee Chun and Kun Hu and Tsunefumi Mizuno and Zhang Sixuan and Francesco Tombesi and Silvia Zane and Ivan 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 Immacolata Donnarumma and Victor Doroshenko and Steven R. Ehlert and Teruaki Enoto and Yuri Evangelista and Sergio Fabiani and Riccardo Ferrazzoli and Shuichi Gunji and Kiyoshi Hayashida and Jeremy Heyl and Wataru Iwakiri and Svetlana G. Jorstad and Vladimir Karas and Fabian Kislat and Takao Kitaguchi and Jeffery J. Kolodziejczak and Fabio La Monaca and Luca Latronico and Ioannis Liodakis and Simone Maldera and Alberto Manfreda and Frederic Marin and Andrea Marinucci and Alan P. Marscher and Herman L. Marshall and Francesco Massaro and Ikuyuki Mitsuishi and Chi-Yung Ng and Stephen L. O'Dell and Nicola Omodei and Chiara Oppedisano and Alessandro Papitto and George G. Pavlov and Abel L. 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 J. Roberts and Roger W. Romani and Carmelo Sgro and Patrick Slane and Paolo Soffitta and Gloria Spandre and Doug A. Swartz and Toru Tamagawa and Fabrizio Tavecchio and Roberto Taverna and Yuzuru Tawara and Allyn F. Tennant and Nicholas E. Thomas and Alessio Trois and Sergey S. Tsygankov and Roberto Turolla and Jacco Vink and Kinwah Wu and Fei Xie},
journal= {arXiv preprint arXiv:2303.12034},
year = {2023}
}
Comments
12 pages, 9 figures, 4 tables. Accepted for publication in MNRAS