Spectral properties of two-component advective flows with standing shocks in the presence of comptonization

Santanu Mondal, Sandip K. Chakrabarti

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


We study self-consistently the hydrodynamic and spectral properties of a general class of steady-state accretion discs where we couple both the hydrodynamics and the radiative transfer. We consider a two-component accretion flow in which the Keplerian disc is immersed inside an accreting low angular momentum flow (halo) around a black hole. The injected soft photons from the Keplerian disc are reprocessed by the electrons in the halo. We study the transonic properties of such a Comptonized flow. We use the Rankine-Hugoniot relation to obtain the shock locations in the disc and compute the radiated spectrum from this shocked disc. We identify the boundary of the parameter space spanned by the specific energy and angular momentum which allows the formation of the standing shocks. We show how the boundary changes in the presence of Compton cooling. Due to the radiative loss, some energy is removed from the accreting matter and the shock moves towards the black hole to maintain the pressure balance condition. We solve the two-temperature equations with Coulomb energy exchange between the protons and the electrons, and the radiative processes such as the bremsstrahlung and thermal Comptonization. We study the variation of the hydrodynamical and spectral properties as a function of the accretion rates of the Keplerian and sub-Keplerian components. Ours is the most accurate transonic solution of an inviscid flow around a black hole to date.

Original languageEnglish
Pages (from-to)2716-2722
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - 1 Jan 2013
Externally publishedYes


  • Accretion
  • Accretion discs
  • Black hole physics
  • Hydrodynamics
  • Shock waves

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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