Open AccessOn the interpretation of the multicolour disc model for black hole candidates
Author(s) -
Merloni A.,
Fabian A. C.,
Ross R. R.
Publication year - 2000
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 - 10.1046/j.1365-8711.2000.03226.x
Subject(s) - physics , astrophysics , radius , accretion (finance) , redshift , radiative transfer , accretion disc , spectral line , black hole (networking) , doppler effect , astronomy , galaxy , optics , computer network , routing protocol , routing (electronic design automation) , computer security , computer science , link state routing protocol
We present a critical analysis of the usual interpretation of the multicolour disc model parameters for black hole candidates in terms of the inner radius and temperature of the accretion disc. Using a self‐consistent model for the radiative transfer and the vertical temperature structure in a Shakura–Sunyaev disc, we simulate the observed disc spectra, taking into account Doppler blurring and gravitational redshift, and fit them with multicolour models. We show not only that such a model systematically underestimates the value of the inner‐disc radius, but that when the accretion rate and/or the energy dissipated in the corona are allowed to change, the inner edge of the disc, as inferred from the multicolour model, appears to move even when it is in fact fixed at the innermost stable orbit.