Impact of the returning radiation on the analysis of the reflection spectra of black holes

Understand

A fraction of the electromagnetic radiation emitted from the surface of a geometrically thin and optically thick accretion disk of a black hole returns to the disk because of the strong light bending in the vicinity of the compact object (returning radiation).

• While such radiation clearly affects the observed spectrum of the source, it is often neglected in theoretical models.
• In the present paper, we study the impact of the returning radiation on relativistic reflection spectra.
• Assuming neutral material in the disk, we estimate the systematic uncertainties on the measurement of the properties of the system when we fit the data with a theoretical model that neglects the returning radiation.