Uncovering the geometry of the hot X-ray corona in the seyfert galaxy NGC 4151 with IXPE

DOI: 
10.1093/mnras/stad1697
Publication date: 
13/06/2023
Main author: 
Gianolli, V. E.
IAA authors: 
Agís-González, B.;Agudo, I.
Authors: 
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.;O'Dell, 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.
Journal: 
Monthly Notices of the Royal Astronomical Society
Publication type: 
Article
Pages: 
4468
Abstract: 
We present an X-ray spectro-polarimetric analysis of the bright Seyfert galaxy NGC 4151. 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 Π = 4.9 ± 1.1% and angle Ψ = 86<SUP>○</SUP> ± 7<SUP>○</SUP> 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 (&gt;38%) polarization degree. Assuming more reasonable values, a polarization degree of the hot corona ranging from ~4 to ~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. NGC 4151 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.
Database: 
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023MNRAS.523.4468G/abstract
ADS Bibcode: 
2023MNRAS.523.4468G
Keywords: 
galaxies: active;galaxies: Seyfert;galaxies: individual: NGC 4151;polarization;Astrophysics - Astrophysics of Galaxies;Astrophysics - High Energy Astrophysical Phenomena