Mapping the circumnuclear regions of the Circinus galaxy with the Imaging X-ray Polarimetry Explorer
Articolo
Data di Pubblicazione:
2023
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.
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
galaxies: active; galaxies: individual: Circinus; galaxies: Seyfert; polarization; scattering; X-rays: galaxies
Elenco autori:
Ursini F.; Marinucci A.; Matt G.; Bianchi S.; Marin F.; Marshall H.L.; Middei R.; Poutanen J.; Rogantini D.; De Rosa A.; Di Gesu L.; Garcia J.A.; Ingram A.; Kim D.E.; Krawczynski H.; Puccetti S.; Soffitta P.; Svoboda J.; Tombesi F.; Weisskopf M.C.; Barnouin T.; Perri M.; Podgorny J.; Ratheesh A.; Zaino A.; 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.; Ciprini S.; Costa E.; Del Monte E.; Di Lalla N.; Di Marco A.; Donnarumma I.; Doroshenko V.; Dovciak M.; Ehlert S.R.; Enoto T.; Evangelista Y.; Fabiani S.; Ferrazzoli R.; Gunji S.; Heyl J.; Iwakiri W.; Jorstad S.G.; Karas V.; Kitaguchi T.; Kolodziejczak J.J.; La Monaca F.; Latronico L.; Liodakis I.; Maldera S.; Manfreda A.; Marscher A.P.; Mitsuishi I.; Mizuno T.; Muleri F.; Ng C.Y.; O'Dell S.L.; Omodei N.; Oppedisano C.; Papitto A.; Pavlov G.G.; Peirson A.L.; Pesce-Rollins M.; Petrucci P.-O.; Pilia M.; Possenti A.; Ramsey B.D.; Rankin J.; Romani R.W.; Sgro C.; Slane P.; Spandre G.; Tamagawa T.; Tavecchio F.; Taverna R.; Tawara Y.; Tennant A.F.; Thomas N.E.; Trois A.; Tsygankov S.S.; Turolla R.; Vink J.; Wu K.; Xie F.; Zane S.
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