Portal de Periódicos da CAPES

Mapping the circumnuclear regions of the Circinus galaxy with the Imaging X-ray Polarimetry Explorer

2022; Oxford University Press; Volume: 519; Issue: 1 Linguagem: Inglês

10.1093/mnras/stac3189

1365-2966

F. Ursini, Andrea Marinucci, G. Matt, S. Bianchi, Frédéric Marin, Herman L. Marshall, R. Middei, Juri Poutanen, D Rogantini, Alessandra De Rosa, Laura Di Gesu, Javier A. García, A Ingram, Dawoon E. Kim, H. Krawczynski, Simonetta Puccetti, P Soffitta, Jiří Svoboda, F Tombesi, M. C. Weisskopf, Thibault Barnouin, M. Perri, Jakub Podgorný, Ajay Ratheesh, A. Zaino, I. Agudo, L. A. Antonelli, Matteo Bachetti, L. Baldini, W. H. Baumgartner, R. Bellazzini, Stephen D. Bongiorno, R. Bonino, A Brez, N. Bucciantini, Fiamma Capitanio, S Castellano, E. Cavazzuti, S. Ciprini, E. Costa, E. Del Monte, N Di Lalla, Alessandro Di Marco, I. Donnarumma, Victor Doroshenko, Michal Dovčiak, Steven R. Ehlert, Teruaki Enoto, Y. Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Shuichi Gunji, J Heyl, W. Iwakiri, Svetlana G. Jorstad, V. Karas, T Kitaguchi, J J Kolodziejczak, Fabio La Monaca, L. Latronico, Ioannis Liodakis, S. Maldera, Alberto Manfreda, A P Marscher, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Fabio Muleri, C. Y. Ng, Stephen L O'Dell, N. Omodei, C. Oppedisano, Alessandro Papitto, George G. Pavlov, Abel L. Peirson, M. Pesce-Rollins, P-O Petrucci, M. Pilia, Andrea Possenti, B. D. Ramsey, John Rankin, Roger W. Romani, C. Sgrò, Patrick Slane, G. Spandre, T. Tamagawa, F. Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, A Trois, Sergey S. Tsygankov, R. Turolla, J Vink, Kinwah Wu, Fei Xie, Silvia Zane,

Astrophysics and Cosmic Phenomena

ABSTRACT We report on the Imaging X-ray Polarimetry Explorer (IXPE) observation of the closest and X-ray brightest Compton-thick active galactic nucleus (AGN), the Circinus galaxy. We find the source to be significantly polarized in the 2–6 keV band. From previous studies, the X-ray spectrum is known to be dominated by reflection components, both neutral (torus) and ionized (ionization cones). Our analysis indicates that the polarization degree is 28 ± 7 per cent (at 68 per cent confidence level) for the neutral reflector, with a polarization angle of 18° ± 5°, roughly perpendicular to the radio jet. The polarization of the ionized reflection is unconstrained. A comparison with Monte Carlo simulations of the polarization expected from the torus shows that the neutral reflector is consistent with being an equatorial torus with a half-opening angle of 45°–55°. This is the first X-ray polarization detection in a Seyfert galaxy, demonstrating the power of X-ray polarimetry in probing the geometry of the circumnuclear regions of AGNs, and confirming the basic predictions of standard Unification Models.