paper

Milliarcsecond X-ray astrometry to resolve inner regions of AGN at using gravitational lensing

arXiv:2203.04245 · doi:10.3847/1538-4357/ac68eb

Abstract

We report the localization of the X-ray emission from two strongly lensed AGN, CLASS B0712+472 () and CLASS B1608+656 (). We obtain milliarcsecond X-ray astrometry by developing a novel method that combines parametric lens modelling with a Bayesian analysis. We spatially locate the X-ray sources in CLASS B0712+472 and CLASS B1608+656 within 11 mas and 9 mas from the radio source, respectively. For CLASS B0712+472, we find that the X-ray emission is co-spatial with the radio and optical emission. While, in CLASS B1608+656, the X-ray emission is co-spatial with radio, but displaced with respect to the optical emission at 1 level, which positions this source as an offset AGN candidate. This high astrometric precision improves on the limitations of existing X-ray instruments by two orders of magnitude. The demonstrated method opens a path to search for offset and binary AGN at , and to directly test supermassive black hole formation models in a redshift range that has been mostly underconstrained to date.

16 pages, 7 figures. Accepted for publication in ApJ

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