Accretion onto a black hole in a string cloud background

Apratim Ganguly, Sushant G. Ghosh, and Sunil D. Maharaj
Phys. Rev. D 90, 064037 – Published 23 September 2014

Abstract

We examine the accretion process onto the black hole with a string cloud background, where the horizon of the black hole has an enlarged radius rH=2M/(1α), due to the string cloud parameter α (0α<1). The problem of stationary, spherically symmetric accretion of a polytropic fluid is analyzed to obtain an analytic solution for such a perturbation. Generalized expressions for the accretion rate M˙, critical radius rs, and other flow parameters are found. The accretion rate M˙ is an explicit function of the black hole mass M, as well as the gas boundary conditions and the string cloud parameter α. We also find the gas compression ratios and temperature profiles below the accretion radius and at the event horizon. It is shown that the mass accretion rate, for both the relativistic and the nonrelativistic fluid by a black hole in the string cloud model, increases with increase in α.

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  • Received 14 February 2014

DOI:https://doi.org/10.1103/PhysRevD.90.064037

© 2014 American Physical Society

Authors & Affiliations

Apratim Ganguly1,*, Sushant G. Ghosh1,2,†, and Sunil D. Maharaj1,‡

  • 1Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
  • 2Centre for Theoretical Physics, Jamia Millia Islamia, New Delhi 110025, India

  • *ganguly@ukzn.ac.za
  • sghosh2@jmi.ac.in
  • maharaj@ukzn.ac.za

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Vol. 90, Iss. 6 — 15 September 2014

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