We offer a brief description of the bulk motion Comptonization (BMC) model for accretion onto black holes, illustrated by its application to observational data for LMC X-1 and Nova Muscae 1991. We then extract some physical parameters of these systems from observables within the context of the BMC model, drawing from results on GRO J1655-40, for which we presented extensive analysis previously. We derive estimates of the mass, (16+/-1)M_solarx[0.5/cos(i)]^1/2, and mass accretion rate in the disk in Eddington units (m_d~=2) for LMC X-1 and (24+/-1)M_solarx[0.5/cos(i)]^1/2d_5.5 and (m_d~=3) for Nova Muscae 1991, where cos(i) and d_5.5 are the inclination angle cosine and distance in 5.5 kpc units, respectively. Differences between these estimates and previous estimates based on dynamical studies are discussed. It is further shown that the disk inner radius increases with the high-to-low-state transition in Nova Muscae 1991. Specifically, our analysis suggests that the inner disk radius increases to r_in~=17 Scwarzschild radii as the transition to the low-hard state occurs.

Mass Determination of Black Holes in LMC X-1 and Nova MUSCAE 1991 from Their High-Energy Spectra

TITARCHUK, Lev
1999

Abstract

We offer a brief description of the bulk motion Comptonization (BMC) model for accretion onto black holes, illustrated by its application to observational data for LMC X-1 and Nova Muscae 1991. We then extract some physical parameters of these systems from observables within the context of the BMC model, drawing from results on GRO J1655-40, for which we presented extensive analysis previously. We derive estimates of the mass, (16+/-1)M_solarx[0.5/cos(i)]^1/2, and mass accretion rate in the disk in Eddington units (m_d~=2) for LMC X-1 and (24+/-1)M_solarx[0.5/cos(i)]^1/2d_5.5 and (m_d~=3) for Nova Muscae 1991, where cos(i) and d_5.5 are the inclination angle cosine and distance in 5.5 kpc units, respectively. Differences between these estimates and previous estimates based on dynamical studies are discussed. It is further shown that the disk inner radius increases with the high-to-low-state transition in Nova Muscae 1991. Specifically, our analysis suggests that the inner disk radius increases to r_in~=17 Scwarzschild radii as the transition to the low-hard state occurs.
C., Shrader; Titarchuk, Lev
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11392/532940
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 28
  • ???jsp.display-item.citation.isi??? 37
social impact