Polarization of reflected X-ray emission from Sgr A molecular complex: multiple flares, multiple sources?
Polarization of reflected X-ray emission from Sgr A molecular complex: multiple flares, multiple sources?
Extended X-ray emission observed in the direction of several molecular clouds in the Central Molecular Zone (CMZ) of our Galaxy exhibits spectral and temporal properties consistent with the `X-ray echo' scenario. It postulates that the observed signal is a light-travel-time delayed reflection of a short ($δt<$1.5 yr) and bright ($L_{\rm X}>10^{39}~{\rm erg~s^{-1}}$) flare, most probably produced a few hundred years ago by Sgr A*. This scenario also predicts a distinct polarization signature for the reflected X-ray continuum, with the polarization vector being perpendicular to the direction towards the primary source and polarization degree (PD) being determined by the scattering angle. We report the results of two deep observations of the currently brightest (in reflected emission) molecular complex Sgr A taken with the Imaging X-ray Polarimetry Explorer (IXPE) in 2022 and 2023. We confirm the previous polarization measurement for a large region encompassing Sgr A complex with higher significance, but also reveal an inconsistent polarization pattern for the brightest reflection region in its center. X-ray polarization from this region is almost perpendicular to the expected direction in the case of Sgr A* illumination and shows a smaller PD compared to the large region. This could indicate the simultaneous propagation of several illumination fronts throughout the CMZ, with the origin of one of them not being Sgr A*. The primary source could be associated with the Arches stellar cluster or a currently unknown source located in the closer vicinity of the illuminated cloud, potentially lowering the required luminosity of the primary source. Although significantly deeper observations with IXPE would be required to unequivocally distinguish between the scenarios, a combination of high-resolution imaging and micro-calorimetric spectroscopy offers an additional promising path forward.
Roberto Turolla、Jacco Vink、Martin C. Weisskopf、Kinwah Wu、Fei Xie、Silvia Zane、Ildar Khabibullin、Eugene Churazov、Riccardo Ferrazzoli、Philip Kaaret、Jeffery J. Kolodziejczak、Frédéric Marin、Rashid Sunyaev、Jiri Svoboda、Alexey Vikhlinin、Thibault Barnouin、Chien-Ting Chen、Enrico Costa、Laura Di Gesu、Alessandro Di Marco、Steven R. Ehlert、William Forman、Dawoon E. Kim、Ralph Kraft、W. Peter Maksym、Giorgio Matt、Juri Poutanen、Paolo Soffitta、Douglas A. Swartz、Ivan Agudo、Lucio Angelo Antonelli、Luca Baldini、Wayne H. Baumgartner、Ronaldo Bellazzini、Stefano Bianchi、Stephen D. Bongiorno、Raffaella Bonino、Alessandro Brez、Niccolo Bucciantini、Fiamma Capitanio、Simone Castellano、Elisabetta Cavazzuti、Stefano Ciprini、Alessandra De Rosa、Ettore Del Monte、Niccolò Di Lalla、Immacolata Donnarumma、Victor Doroshenko、Michal Dovciak、Teruaki Enoto、Yuri Evangelista、Sergio Fabiani、Javier A. Garcia、Shuichi Gunji、Kiyoshi Hayashida、Jeremy Heyl、Wataru Iwakiri、Svetlana G. Jorstad、Vladimir Karas、Fabian Kislat、Takao Kitaguchi、Henric Krawczynski、Fabio La Monaca、Luca Latronico、Ioannis Liodakis、Simone Maldera、Alberto Manfreda、Alan P. Marscher、Herman L. Marshall、Francesco Massaro、Ikuyuki Mitsuishi、Tsunefumi Mizuno、Fabio Muleri、Michela Negro、Chi-Yung Ng、Stephen L. O'Dell、Nicola Omodei、Chiara Oppedisano、Alessandro Papitto、George G. Pavlov、Abel Lawrence Peirson、Melissa Pesce-Rollins、Pierre-Olivier Petrucci、Maura Pilia、Andrea Possenti、Simonetta Puccetti、Brian D. Ramsey、John Rankin、Ajay Ratheesh、Oliver J. Roberts、Roger W. Romani、Carmelo Sgro、Patrick Slane、Gloria Spandre、Toru Tamagawa、Fabrizio Tavecchio、Roberto Taverna、Yuzuru Tawara、Allyn F. Tennant、Nicholas E. Thomas、Francesco Tombesi、Alessio Trois、Sergey S. Tsygankov
天文学
Roberto Turolla,Jacco Vink,Martin C. Weisskopf,Kinwah Wu,Fei Xie,Silvia Zane,Ildar Khabibullin,Eugene Churazov,Riccardo Ferrazzoli,Philip Kaaret,Jeffery J. Kolodziejczak,Frédéric Marin,Rashid Sunyaev,Jiri Svoboda,Alexey Vikhlinin,Thibault Barnouin,Chien-Ting Chen,Enrico Costa,Laura Di Gesu,Alessandro Di Marco,Steven R. Ehlert,William Forman,Dawoon E. Kim,Ralph Kraft,W. Peter Maksym,Giorgio Matt,Juri Poutanen,Paolo Soffitta,Douglas A. Swartz,Ivan Agudo,Lucio Angelo Antonelli,Luca Baldini,Wayne H. Baumgartner,Ronaldo Bellazzini,Stefano Bianchi,Stephen D. Bongiorno,Raffaella Bonino,Alessandro Brez,Niccolo Bucciantini,Fiamma Capitanio,Simone Castellano,Elisabetta Cavazzuti,Stefano Ciprini,Alessandra De Rosa,Ettore Del Monte,Niccolò Di Lalla,Immacolata Donnarumma,Victor Doroshenko,Michal Dovciak,Teruaki Enoto,Yuri Evangelista,Sergio Fabiani,Javier A. Garcia,Shuichi Gunji,Kiyoshi Hayashida,Jeremy Heyl,Wataru Iwakiri,Svetlana G. Jorstad,Vladimir Karas,Fabian Kislat,Takao Kitaguchi,Henric Krawczynski,Fabio La Monaca,Luca Latronico,Ioannis Liodakis,Simone Maldera,Alberto Manfreda,Alan P. Marscher,Herman L. Marshall,Francesco Massaro,Ikuyuki Mitsuishi,Tsunefumi Mizuno,Fabio Muleri,Michela Negro,Chi-Yung Ng,Stephen L. O'Dell,Nicola Omodei,Chiara Oppedisano,Alessandro Papitto,George G. Pavlov,Abel Lawrence Peirson,Melissa Pesce-Rollins,Pierre-Olivier Petrucci,Maura Pilia,Andrea Possenti,Simonetta Puccetti,Brian D. Ramsey,John Rankin,Ajay Ratheesh,Oliver J. Roberts,Roger W. Romani,Carmelo Sgro,Patrick Slane,Gloria Spandre,Toru Tamagawa,Fabrizio Tavecchio,Roberto Taverna,Yuzuru Tawara,Allyn F. Tennant,Nicholas E. Thomas,Francesco Tombesi,Alessio Trois,Sergey S. Tsygankov.Polarization of reflected X-ray emission from Sgr A molecular complex: multiple flares, multiple sources?[EB/OL].(2025-08-06)[2025-08-18].https://arxiv.org/abs/2508.04862.点此复制
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