Open AccessEvidence for two‐component flows around the black hole candidate XTE J1550−564 from spectral features during its 1998–1999 outburst
Author(s) -
Dutta Broja G.,
Chakrabarti Sandip K.
Publication year - 2010
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2010.16428.x
Subject(s) - physics , astrophysics , accretion (finance) , black hole (networking) , accretion disc , astronomy , halo , galaxy , computer network , routing protocol , routing (electronic design automation) , computer science , link state routing protocol
We study the spectral properties of the accretion disc in the Galactic black hole candidate XTE J 1550− 564 during the 1998–1999 outburst when the source exhibited double‐peaked eruptions. This outburst lasted for 250 d and the 2.5–25.0 keV spectral state varied smoothly from one to another several times. We show that the spectral features of the 1998–1999 outburst could be clearly understood by a two‐component (Keplerian and sub‐Keplerian) advective flow (TCAF). We concentrate on the spectral data from a Proportional Counter Array instrument on the RXTE satellite for the black hole XTE J 1550− 564 and fit them quite satisfactorily using TCAF model. From the spectral fit we calculate the disc parameters, such as the Keplerian rate, the sub‐Keplerian rate (halo rate), the shock location and the inner edge of the Keplerian disc. This observation points to the presence of two independent components in the accretion flow and that the accretion rate at all radii need not be constant in an evolving disc.