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Hubble Space Telescope Observations of the Black Hole X-ray Transient GRO J0422+32 Near Quiescence

R. I. Hynes·C. A. Haswell
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Abstract

We present HST/FOS ultraviolet and optical spectroscopy of the black hole X-ray transient GRO J0422+32 shortly before the system reached quiescence. We find that the accretion spectrum from 2500-9000A can be very well fit by a self-absorbed synchrotron model, with superposed HI and MgII emission lines. The explanations we suggest for this spectrum are that it is either due to active coronal regions above a geometrically thin accretion disc, or that the disc is evaporated into an advective flow.

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R. I. Hynes, C. A. Haswell. 1998-09-10. Hubble Space Telescope Observations of the Black Hole X-ray Transient GRO J0422+32 Near Quiescence. https://doi.org/10.1046/j.1365-8711.1999.02227.x

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