Two-phase spectral modelling of 1E1740.7-2942

Combined ASCA and SIGMA data of 1E1740.7-2942 during the standard state (September 1993 and 1994) were fitted with two-phase models (ISMBB/Poutanen at al. and ADAF/Narayan et al.). In ISMBB's, the radius of the spherical hot (Te = 150 - 200 KeV) corona lies between 200 - 250 km where it joins the classical inner disc. The disc radiates 40 per cent of the total luminosity with 1.7 per cent of the Eddington accretion rate of 10 solar mass black hole. ADAF's need an extra component to reproduce the soft part of the spectrum. However, the origin of the soft excess remains somewhat uncertain, although special care was taken in the background elimination.