[57.03] Optical Spectroscopy of the Black-Hole Candidate GX 339-4

AAS 201st Meeting, January, 2003
Session 57. Stellar Black Holes
Oral, Tuesday, January 7, 2003, 10:00-11:30am, 6AB

[57.03D] Optical Spectroscopy of the Black-Hole Candidate GX 339-4

M.M. Buxton (RSAA, ANU/Yale), S. Vennes (SMS, ANU)

I will present optical spectroscopic observations of GX 339-4 obtained during the high state in 1998 and the low state in 1999. Analysis of the radial velocities, equivalent widths and V/R ratios of H-alpha and HeII 4686 show modulation on the 14.86 hr orbital period. This is the first time that the orbital period has been confirmed since it was first published by Callanan et al. (1992, MNRAS, 259, 395).

Using the semi-amplitude of the radial velocities of H-alpha (14 kms^-1) and the orbital period, the mass of the black hole is calculated to be 5 Msun assuming M₂ = 0.7 Msun and i = 15^o. This places GX 339-4 into the black hole category.

The line profiles of H-alpha and HeII 4686 clearly show variations on the orbital period but also exhibit changes which occur over a much longer timescale. In particular, there are significant differences in the gross profile shape between the high and low X-ray states. I will mention possible scenarios which may explain this profile behavior and raise questions which should be pursued in future observations of GX 339-4.

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