Understanding spectral states of sub-Keplerian accretion discs around compact objects as transitions between steady states

TL;DR

This paper introduces a hydrodynamic model that explains spectral states of sub-Keplerian accretion discs around compact objects as transitions between steady states, providing insights into variability and corona formation.

Contribution

The study presents a novel phenomenological model linking steady state transitions in sub-Keplerian accretion flows to spectral states and corona formation.

Findings

Correlations between steady states explain spectral variability.

Steady state transitions can produce corona/outflows.

Model offers insights into environmental effects on accretion discs.

Abstract

We present here a simple hydrodynamic model based on a sequence of steady states of the inner sub-Keplerian accretion disc to model its spectral states. Correlations between different hydrodynamic steady states are studied with a goal to understand the origin of, e.g., the aperiodic variabilities. The plausible source of corona/outflow close to the central compact object is shown to be a consequence of steady state transition in the underlying accretion flow. We envisage that this phenomenological model can give insight on the influence of environment on the inner sub-Keplerian accretion disc.