Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-09-18
Abe et al. 2005, PASJ 57 p.629
Astronomy and Astrophysics
Astrophysics
24 pages, 9 figures, to appear in PASJ 57 p.629
Scientific paper
We studied a time history of X-ray spectral states of a black-hole candidate, 4U 1630-47, utilizing data from a number of monitoring observations with the Rossi X-Ray Timing Explorer over 1996--2004. These observations covered five outbursts of 4U 1630-47, and most of the data recorded typical features of the high/soft states. We found that the spectra in the high/soft states can be further classified into three states. The first spectral state is explained by a concept of the standard accretion disk picture. The second state appears in the so-called very high state, where a dominant hard component is seen and the disk radius apparently becomes too small. These phenomena are explained by the effect of inverse Compton scattering of disk photons, as shown by Kubota, Makishima, & Ebisawa (2001, ApJ, 560, L147) for GRO J1655-40. The third state is characterized in such a way that the disk luminosity varies in proportion to $T_{\rm in}^2$, rather than $T_{\rm in}^4$, where $T_{\rm in}$ is the inner-disk temperature. This state is suggested to be an optically-thick and advection-dominated slim disk, as suggested by Kubota & Makishima (2004, ApJ, 601, 428) for XTE J1550-564. The second and third states appear, with good reproducibility, when $T_{\rm in}$ and the total X-ray luminosity are higher than 1.2 keV and $\sim2.5\times10^{38}(D/10\quad{\rm kpc})^2\l eft[\cos{\theta}/(1/\sqrt{3})]^{-1}$ erg s$^{-1}$, respectively, where $D$ is the distance to the object and $\theta$ is the inclination angle to the disk. The present results suggest that these three spectral states commonly appear among black-hole binaries under high accretion rates.
Abe Yukiko
Fukazawa Yasushi
Kasama Daisuke
Kubota Aya
Makishima Kazuo.
No associations
LandOfFree
Three Spectral States of the Disk X-Ray Emission of the Black-Hole Candidate 4U 1630-47 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Three Spectral States of the Disk X-Ray Emission of the Black-Hole Candidate 4U 1630-47, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three Spectral States of the Disk X-Ray Emission of the Black-Hole Candidate 4U 1630-47 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-654347