Black hole mass determination in the X-ray binary 4U 1630–47: scaling of spectral and variability characteristicsстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 2 сентября 2014 г.
Аннотация:We present the results of a comprehensive investigation on the evolution of spectral and timing properties of the Galactic black hole candidate 4U 1630–47 during its spectral transitions. In particular, we show how a scaling of the correlation of the photon index of the Comptonized spectral component Γ with low frequency of quasi-periodic oscillations (QPO), ν_L and mass accretion rate,
dotM can be applied to the black hole mass and the inclination angle estimates. We analyze the transition episodes observed with the Rossi X-ray Timing Explorer (RXTE) and BeppoSAX satellites. We find that the broadband X-ray energy spectra of 4U 1630–47 during all spectral states can be modeled by a combination
of a thermal component, a Comptonized component and a red-skewed iron line component. We also establish that Γ monotonically increases during transition from the low-hard state to the high-soft state and then saturates for high mass accretion rates. The index saturation levels vary for different transition episodes. Correlations of Γ versus νL also shows saturation at Γ ∼ 3. Γ−dotM and Γ−ν_L correlations with their index saturation revealed in 4U 1630–47 are similar to those established in a number of other BHCs and can be considered as an observational evidence for the presence of a black hole in these sources. The
scaling technique, which relies on XTE J1550–564, GRO 1655-40 and H 1743-322 as reference sources, allows us to evaluate a black hole mass in 4U 1630–47 yielding M_BH ∼ 10 ± 0.1 solar masses, and to constrain the inclination angle of i∼< 70◦.