Comptonizing Efficiencies of IGR 17091-3624 and its similarity to GRS 1915+105

TL;DR

This study compares the Comptonizing Efficiency (CE) of IGR 17091-3624 with GRS 1915+105, revealing similar CE patterns despite different black hole masses, suggesting CE-based variability classification is mass-independent.

Contribution

The paper demonstrates that CE patterns are similar across different black hole systems, indicating a potential universal method for classifying variability independent of black hole mass.

Findings

CE patterns of IGR 17091-3624 are similar to GRS 1915+105

CE-based variability classification is likely mass-independent

Size scaling of seed photon sources and corona explains similarities

Abstract

Variability classes in the enigmatic black hole candidate GRS 1915+105 are known to be correlated with the variation of the Comptonizing Efficiency (CE) which is defined to be the ratio between the number of power-law (hard) photons and seed (soft) photons injected into the Compton cloud. Similarities of light curves of several variability classes of GRS 1915+105 and IGR 17091-3624, some of which are already reported in the literature, motivated us to compute CE for IGR 17091-3624 as well. We find that they are similar to what were reported earlier for GRS 1915+105, even though masses of these objects could be different. The reason is that the both the sizes of the sources of the seed photons and of the Comptonizing corona scale in the same way as the mass of the black hole. This indicates that characterization of variability classes based on CE is likely to be black hole mass independent, in general.