Victor Doroshenko


Nov 03, 2022

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

And another IXPE paper. We report observation of the closest and X-ray brightest Compton-thick active galactic nucleus (AGN), the Circinus galaxy. This time significant polarization is detected at a level of ~30 per cent (at 68 per cent confidence level) for the neutral reflector, with a polarization angle of 18 deg, roughly perpendicular to the radio jet. 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.