Bibcode
Bandyopadhyay, R. M.; Shahbaz, T.; Charles, P. A.; Naylor, T.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 306, Issue 2, pp. 417-426.
Advertised on:
6
1999
Citations
93
Refereed citations
83
Description
Using CGS4 on UKIRT, we have obtained 2.00-2.45 mu m infrared spectra of
a number of low-mass X-ray binaries including Sco X-1, Sco X-2 and GX1
3+1. Sco X-1 shows emission lines only, supporting our previous
conclusion that the spectral type of the evolved secondary must be
earlier than G5. Emission lines are also seen in the spectrum of Sco
X-2, confirming the identity of the IR counterpart. We report the
detection of CO bands in GX1 3+1, and estimate the most likely spectral
type of the secondary to be K5III. We also find P Cygni-type profiles in
the Brackett gamma lines of Sco X-1 and GX1 3+1, indicating the presence
of high-velocity outflows in these systems. We present spectra of
candidate IR counterparts to several other elusive X-ray binaries.
Finally, implications for the nature and classification of these systems
are discussed.