Polarization constraints on the X-ray corona in Seyfert Galaxies: MCG-05-23-16
Andrea Marinucci, Fabio Muleri, Michal Dovčiak, S. Bianchi, Frédéric Marin, G. Matt, F. Ursini, R. Middei, Herman L. Marshall, L. Baldini, Thibault Barnouin, Nicole Cavero Rodriguez, A De Rosa, L Di Gesu, D Harper, Adam Ingram, V. Karas, H. Krawczynski, G. Madejski, Christos Panagiotou, Pierre-Olivier Petrucci, Jakub Podgorný, Simonetta Puccetti, Francesco Tombesi, Alexandra Veledina, Wenda Zhang, I. Agudo, L. A. Antonelli, Matteo Bachetti, W. H. Baumgartner, R. Bellazzini, Stephen D. Bongiorno, R. Bonino, A. Brez, N. Bucciantini, Fiamma Capitanio, Simone Castellano, E. Cavazzuti, S. Ciprini, E. Costa, E. Del Monte, N Di Lalla, A Di Marco, I. Donnarumma, Victor Doroshenko, Steven R. Ehlert, Teruaki Enoto, Y. Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Javier A. García, Shuichi Gunji, Kentaro Hayashida, Jeremy Heyl, W. Iwakiri, Svetlana G. Jorstad, T. Kitaguchi, Jeffery J. Kolodziejczak, Fabio La Monaca, L. Latronico, Ioannis Liodakis, S. Maldera, Alberto Manfreda, Alan P. Marscher, Ikuyuki Mitsuishi, Tsunefumi Mizuno, C-Y Ng, Stephen L. O’Dell, N. Omodei, C. Oppedisano, Alessandro Papitto, George G. Pavlov, Abel L. Peirson, M. Perri, M. Pesce-Rollins, M. Pilia, Andrea Possenti, Juri Poutanen, Brian D. Ramsey, John Rankin, Ajay Ratheesh, Roger W. Romani, C Sgrš, Patrick Slane, P. Soffitta, G. Spandre, Toru Tamagawa, F. Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, A. Trois, Sergey S. Tsygankov, R. Turolla, Jacco Vink, Martin C. Weisskopf, Kinwah Wu, Fei Xie, Silvia Zane
Abstract
ABSTRACT We report on the first observation of a radio-quiet active galactic nucleus (AGN) in polarized X-rays: the Seyfert 1.9 galaxy MCG-05-23-16. This source was pointed at with the Imaging X-ray Polarimetry Explorer (IXPE) starting on 2022 May 14 for a net observing time of 486 ks, simultaneously with XMM-Newton (58 ks) and NuSTAR (83 ks). A polarization degree Π smaller than 4.7 per cent (at the 99 per cent confidence level) is derived in the 2–8 keV energy range, where emission is dominated by the primary component ascribed to the hot corona. The broad-band spectrum, inferred from a simultaneous fit to the IXPE, NuSTAR, and XMM-Newton data, is well reproduced by a power law with photon index Γ = 1.85 ± 0.01 and a high-energy cutoff EC = 120 ± 15 keV. A comparison with Monte Carlo simulations shows that a lamp-post and a conical geometry of the corona are consistent with the observed upper limit, a slab geometry is allowed only if the inclination angle of the system is less than 50°.