Polarization constraints on the X-ray corona in Seyfert Galaxies: MCG-05-23-16
Antonelli, L. A.; Costa, E.; Bianchi, S.; Baldini, L.; Bellazzini, R.; Brez, A.; Ciprini, S.; Latronico, L.; Mizuno, T.; Omodei, N.; Pesce-Rollins, M.; Romani, R. W.; Spandre, G.; Cavazzuti, E.; Tavecchio, F.; Vink, J.; Tombesi, F.; Possenti, A.; Tsygankov, S. S.; Pilia, M.; Capitanio, F.; Bachetti, M.; Papitto, A.; Zane, S.; Matt, G.; Liodakis, I.; Turolla, R.; Petrucci, P. O.; De Rosa, A.; Doroshenko, V.; Perri, M.; Puccetti, S.; Middei, R.; Tamagawa, T.; Bonino, R.; Fabiani, S.; Poutanen, J.; Ursini, F.; Muleri, F.; Agudo, I.; Baumgartner, W. H.; Bongiorno, S. D.; Bucciantini, N.; Castellano, S.; Del Monte, E.; Di Gesu, L.; Di Lalla, N.; Di Marco, A.; Donnarumma, I.; Ehlert, S. R.; Enoto, T.; Evangelista, Y.; Ferrazzoli, R.; Garcia, J. A.; Gunji, S.; Hayashida, K.; Heyl, J.; Iwakiri, W.; Jorstad, S. G.; Karas, V.; Kitaguchi, T.; Kolodziejczak, J. J.; Krawczynski, H.; La Monaca, F.; Maldera, S.; Manfreda, A.; Marin, F.; Marscher, A. P.; Marshall, H. L.; Mitsuishi, I.; Ng, C. -Y.; O'Dell, S. L.; Oppedisano, C.; Pavlov, G. G.; Peirson, A. L.; Ramsey, B. D.; Rankin, J.; Ratheesh, A.; Slane, P.; Soffitta, P.; Taverna, R.; Tawara, Y.; Tennant, A. F.; Thomas, N. E.; Trois, A.; Weisskopf, M. C.; Wu, K.; Xie, F.; Marinucci, A.; Ingram, A.; Veledina, A.; Madejski, G.; Barnouin, T.; Podgorny, J.; Dovciak, M.; Zhang, W.; Panagiotou, C.; Harper, D.; Rodriguez, N. Cavero; Sgrš, C.
Italy, Czech Republic, France, United States, United Kingdom, Finland, Sweden, Russia, China, Spain, Germany, Japan, Canada, Hong Kong SAR, Netherlands
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°.