UCL Discovery Stage
UCL home » Library Services » Electronic resources » UCL Discovery Stage

Mapping the circumnuclear regions of the Circinus galaxy with the Imaging X-ray Polarimetry Explorer

Ursini, F; Marinucci, A; Matt, G; Bianchi, S; Marin, F; Marshall, HL; Middei, R; ... Zane, S; + view all (2022) Mapping the circumnuclear regions of the Circinus galaxy with the Imaging X-ray Polarimetry Explorer. Monthly Notices of the Royal Astronomical Society 10.1093/mnras/stac3189. (In press). Green open access

[thumbnail of Zane_stac3189.pdf]
Preview
Text
Zane_stac3189.pdf - Accepted Version

Download (1MB) | Preview

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.

Type: Article
Title: Mapping the circumnuclear regions of the Circinus galaxy with the Imaging X-ray Polarimetry Explorer
Open access status: An open access version is available from UCL Discovery
DOI: 10.1093/mnras/stac3189
Publisher version: https://doi.org/10.1093/mnras/stac3189
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: galaxies: active, galaxies: individual: Circinus, galaxies: Seyfert, polarization, scattering, X-rays: galaxies
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery-pp.ucl.ac.uk/id/eprint/10159158
Downloads since deposit
1,512Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item