THE INCLINATION OF THE SOFT X-RAY TRANSIENT A0620-00 AND THE MASS OF ITS BLACK HOLE
- Department of Astronomy, Yale University. P.O. box 208101, New Haven, CT 06520 (United States)
- Department of Astronomy, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1221 (United States)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Kavli Institute for Astrophysics and Space Research, MIT, Cambridge, MA 02139 (United States)
- Center for Astrophysics and Space Astronomy, University of Colorado, 593 UCB, Boulder, CO 80309-0593 (United States)
- Harvard University Department of Astronomy, 60 Garden Street, MS-10 Cambridge, MA 02138 (United States)
We analyze photometry of the soft X-ray transient A0620 - 00 spanning nearly 30 years, including previously published and previously unpublished data. Previous attempts to determine the inclination of A0620 using subsets of these data have yielded a wide range of measured values of i. Differences in the measured value of i have been due to changes in the shape of the light curve and uncertainty regarding the contamination from the disk. We give a new technique for estimating the disk fraction and find that disk light is significant in all light curves, even in the infrared. We also find that all changes in the shape and normalization of the light curve originate in a variable disk component. After accounting for this disk component, we find that all the data, including light curves of significantly different shapes, point to a consistent value of i. Combining results from many separate data sets, we find i = 51.{sup 0}0 +- 0.{sup 0}9, implying M = 6.6 +- 0.25 M{sub sun}. Using our dynamical model and zero-disk stellar VIH magnitudes, we find d = 1.06 +- 0.12 kpc. Understanding the disk origin of nonellipsoidal variability may assist with making reliable determinations of i in other systems, and the fluctuations in disk light may provide a new observational tool for understanding the three-dimensional structure of the accretion disk.
- OSTI ID:
- 21394457
- Journal Information:
- Astrophysical Journal, Vol. 710, Issue 2; Other Information: DOI: 10.1088/0004-637X/710/2/1127; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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