EDP Sciences
Free access
Volume 421, Number 1, July I 2004
Page(s) 13 - 15
Section Astrophysical processes
DOI http://dx.doi.org/10.1051/0004-6361:20034569

A&A 421, 13-15 (2004)
DOI: 10.1051/0004-6361:20034569

Research Note

Mass accretion rate of the galactic black hole A0620-00 in its quiescent state

S. Pal1 and S. K. Chakrabarti1, 2

1  Centre for Space Physics, Chalantika 43, Garia Station Rd., Kolkata, 700084, India
2  S. N. Bose National Centre for Basic Sciences, Salt Lake, Kolkata, 700098, India
    e-mail: chakraba@bose.res.in

(Received 24 October 2003 / Accepted 14 March 2004 )

Our recent radio observation using the Giant Meter Radio Telescope (GMRT) of the galactic black hole transient A0620-00 at 1.280 GHz revealed a micro-flare of a few milli-Jansky. Assuming an equipartition of magnetic energy and the gravitational potential energy of accreting matter, it is possible to estimate the upper limit of the accretion rate. Assuming a black hole mass of $10~M_\odot$ residing at the center, we find this to be at most ${\dot M} = (8.5 \pm 1.4) \times 10^{-11}
~M_\odot$  yr -1. This is consistent with earlier estimates of accretion rates based on optical and X-ray observations.

Key words: black hole physics -- accretion, accretion disks -- magnetic fields -- radio continuum: general -- techniques: photometric -- methods: observational

Offprint request: S. Pal, space_phys@vsnl.com

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