X-ray polarization evidence for a 200 years-old flare of Sgr A$^*$
Abstract
The center of the Milky Way Galaxy hosts a 4 million solar mass black hole (Sgr A) that is currently very quiescent with a luminosity many orders of magnitude below those of active galactic nuclei. Reflection of X-rays from Sgr A by dense gas in the Galactic Center region offers a means to study its past flaring activity on times scales of hundreds and thousands of years. The shape of the X-ray continuum and the strong fluorescent iron line observed from giant molecular clouds in the vicinity of Sgr A are consistent with the reflection scenario. If this interpretation is correct, the reflected continuum emission should be polarized. Here we report observations of polarized X-ray emission in the direction of the Galactic center molecular clouds using the Imaging X-ray Polarimetry Explorer (IXPE). We measure a polarization degree of 31\% 11\%, and a polarization angle of 48 11. The polarization angle is consistent with Sgr A being the primary source of the emission, while the polarization degree implies that some 200 years ago the X-ray luminosity of Sgr A was briefly comparable to a Seyfert galaxy.
Keywords
Cite
@article{arxiv.2304.06967,
title = {X-ray polarization evidence for a 200 years-old flare of Sgr A$^*$},
author = {Frédéric Marin and Eugene Churazov and Ildar Khabibullin and Riccardo Ferrazzoli and Laura Di Gesu and Thibault Barnouin and Alessandro Di Marco and Riccardo Middei and Alexey Vikhlinin and Enrico Costa and Paolo Soffitta and Fabio Muleri and Rashid Sunyaev and William Forman and Ralph Kraft and Stefano Bianchi and Immacolata Donnarumma and Pierre-Olivier Petrucci and Teruaki Enoto 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 Niccolò Bucciantini and Fiamma Capitanio and Simone Castellano and Elisabetta Cavazzuti and Chien-Ting Chen and Stefano Ciprini and Alessandra De Rosa and Ettore Del Monte and Niccolò Di Lalla and Victor Doroshenko and Michal Dovciak and Steven R. Ehlert and Yuri Evangelista and Sergio Fabiani and Javier A. Garcia and Shuichi Gunji and Kiyoshi Hayashida and Jeremy Heyl and Adam Ingram and Wataru Iwakiri and Svetlana G. Jorstad and Philip Kaaret and Vladimir Karas and Takao Kitaguchi and Jeffery J. Kolodziejczak and Henric Krawczynski and Fabio La Monaca and Luca Latronico and Ioannis Liodakis and Simone Maldera and Alberto Manfreda and Andrea Marinucci and Alan P. Marscher and Herman L. Marshall and Francesco Massaro and Giorgio Matt 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 G. Pavlov and Abel L. Peirson and Matteo Perri and Melissa Pesce-Rollins and Maura Pilia and Andrea Possenti and Juri Poutanen and Simonetta Puccetti and Brian D. Ramsey and John Rankin and Ajay Ratheesh and Oliver J. Roberts and Roger W. Romani and Carmelo Sgrò and Patrick Slane and Gloria Spandre and Doug 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 Martin C. Weisskopf and Kinwah Wu and Fei Xie and Silvia Zane},
journal= {arXiv preprint arXiv:2304.06967},
year = {2023}
}
Comments
24 pages, 5 figures, 4 tables, author's version of the paper accepted for publication in Nature