The Quiescent X-ray Spectrum of Accreting Black Holes

Understand

The quiescent state is the dominant accretion mode for black holes on all mass scales.

• Our knowledge of the X-ray spectrum is limited due to the characteristic low luminosity in this state.
• Herein, we present an analysis of the sample of dynamically-confirmed stellar-mass black holes observed in quiescence in the \textit{Chandra/XMM-Newton/Suzaku} era resulting in a sample of 8 black holes with $\sim$ 570 ks of observations.
• In contrast to the majority of AGN where observations are limited by contamination from diffuse gas, the stellar-mass systems allow for a clean study of the X-ray spectrum resulting from the accretion flow alone.