Spectral signature of mass loss from (and mass gain by) an accretion disk around a black hole

Abstract

Accretion and outflows are common in systems that include black holes. Assuming that outflows are primarily produced at the centrifugal pressure-supported boundary layer at the inner disk, the hard X-ray spectrum is softened in the presence of winds. Conversely, the spectrum would be hardened when mass gain takes place at the inner disk. We first demonstrate these changes in the spectrum from theoretical consideration. We then give examples of the spectra of a few black hole candidates that indicate that a significant mass loss or mass gain may be taking place in short timescales, causing changes is spectral slopes.