Geometry of the X-ray source 1H 0707-495

TL;DR

This study constrains the size and location of the X-ray source in 1H 0707-495, revealing it to be very compact and close to the black hole, challenging the idea of an extended corona.

Contribution

Developed a new modeling code and applied it to archival data, demonstrating the X-ray source is compact rather than extended in 1H 0707-495.

Findings

X-ray source is at most a gravitational radius in size

The source is located within a few gravitational radii of the black hole

Reflection is stronger than expected for an extended corona

Abstract

We investigate constraints for the size and location of the X-ray source in 1H 0707-495 determined from the shape of the relativistically smeared reflection from the accretion disc. We develop a new code to model an extended X-ray source and we apply it to all archival XMM observations of 1H 0707-495. Contrary to Wilkins et al. we find that the relativistic reflection in this source is not consistent with an extended uniform corona. Instead, we find that the X-ray source must be very compact, with the size of at most a gravitational radius, and located at most at a few gravitational radii from the black hole horizon. A uniform extended corona does indeed produce an emissivity which is like a twice broken power law, but the inner emissivity is fixed by the source geometry rather than being a free parameter. In 1H0707-495, reflection from the inner disc is much stronger than expected for a uniformly extended source. Including the effect of ionised absorption from a wind does not change this conclusion, but including scattered emission (and more complex absorption) from the wind can dramatically change the reflection parameters.