학술논문
Uncovering the geometry of the hot X-ray corona in the Seyfert galaxy NGC4151 with IXPE
Document Type
Working Paper
Author
Gianolli, V. E.; Kim, D. E.; Bianchi, S.; Agís-González, B.; Madejski, G.; Marin, F.; Marinucci, A.; Matt, G.; Middei, R.; Petrucci, P-O.; Soffitta, P.; Tagliacozzo, D.; Tombesi, F.; Ursini, F.; Barnouin, T.; De Rosa, A.; Di Gesu, L.; Ingram, A.; Loktev, V.; Panagiotou, C.; Podgorny, J.; Poutanen, J.; Puccetti, S.; Ratheesh, A.; Veledina, A.; Zhang, W.; Agudo, I.; Antonelli, L. A.; Bachetti, M.; Baldini, L.; Baumgartner, W. H.; Bellazzini, R.; Bongiorno, S. D.; Bonino, R.; Brez, A.; Bucciantini, N.; Capitanio, F.; Castellano, S.; Cavazzuti, E.; Chen, C. -T.; Ciprini, S.; Costa, E.; Del Monte, E.; Di Lalla, N.; Di Marco, A.; Donnarumma, I.; Doroshenko, V.; Dovčiak, M.; Ehlert, S. R.; Enoto, T.; Evangelista, Y.; Fabiani, S.; Ferrazzoli, R.; García, J. A.; Gunji, S.; Heyl, J.; Iwakiri, W.; Jorstad, S. G.; Kaaret, P.; Karas, V.; Kislat, F.; Kitaguchi, T.; Kolodziejczak, J. J.; Krawczynski, H.; La Monaca, F.; Latronico, L.; Liodakis, I.; Maldera, S.; Manfreda, A.; Marscher, A. P.; Marshall, H. L.; Massaro, F.; Mitsuishi, I.; Mizuno, T.; Muleri, F.; Negro, M.; Ng, C. -Y.; ODell, S. L.; Omodei, N.; Oppedisano, C.; Papitto, A.; Pavlov, G. G.; Peirson, A. L.; Perri, M.; Pesce-Rollins, M.; Pilia, M.; Possenti, A.; Ramsey, B. D.; Rankin, J.; Roberts, O. J.; Romani, R. W.; Sgrò, C.; Slane, P.; Spandre, G.; Swartz, D. A.; Tamagawa, T.; Tavecchio, F.; Taverna, R.; Tawara, Y.; Tennant, A. F.; Thomas, N. E.; Trois, A.; Tsygankov, S. S.; Turolla, R.; Vink, J.; Weisskopf, M. C.; Wu, K.; Xie, F.; Zane, S.
Source
Subject
Language
Abstract
We present an X-ray spectro-polarimetric analysis of the bright Seyfert galaxy NGC4151. The source has been observed with the Imaging X-ray Polarimetry Explorer (IXPE) for 700 ks, complemented with simultaneous XMM-Newton (50 ks) and NuSTAR (100 ks) pointings. A polarization degree ${\Pi} = 4.9 {\pm} 1.1 \%$ and angle ${\Psi}= 86{\deg} {\pm} 7{\deg}$ east of north ($68\%$ confidence level) are measured in the 2-8 keV energy range. The spectro-polarimetric analysis shows that the polarization could be entirely due to reflection. Given the low reflection flux in the IXPE band, this requires however a reflection with a very large ($> 38 \%$) polarization degree. Assuming more reasonable values, a polarization degree of the hot corona ranging from ${\sim}4$ to ${\sim}8\%$ is found. The observed polarization degree excludes a spherical lamppost geometry for the corona, suggesting instead a slab-like geometry, possibly a wedge, as determined via Monte Carlo simulations. This is further confirmed by the X-ray polarization angle, which coincides with the direction of the extended radio emission in this source, supposed to match the disc axis. NGC4151 is the first AGN with an X-ray polarization measure for the corona, illustrating the capabilities of X-ray polarimetry and IXPE in unveiling its geometry.
Comment: 9 pages, 4 figures
Comment: 9 pages, 4 figures