Bibcode
Shahbaz, T.; Smale, A. P.; Naylor, T.; Charles, P. A.; van Paradijs, J.; Hassall, B. J. M.; Callanan, P.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 282, Issue 4, pp. 1437-1453.
Fecha de publicación:
10
1996
Número de citas
56
Número de citas referidas
52
Descripción
We have obtained broad-band optical spectra of a sample of 15 low-mass
X-ray binaries (LMXBs) in the range 4000-9000A and fitted them with
combinations of standard accretion disc models plus secondary star
templates. For the sample of LMXBs in which we determine the power-law
indices of the accretion disc flux distribution, we can explain the
steepness of the slopes in terms of an optically thick accretion disc
and X-ray heating of the outer parts of the disc. We present for the
first time optical spectra of X1705-250, XB1905+00 and XB1916-053.
Optical line emission was detected in most of the sample. The Balmer
lines Hα and Hβ were generally the strongest lines with mean
equivalent widths of 3.7 and 1.9A, respectively. The HeII lambda4686 and
the Bowen CIII/NIII blend at lambda4640 were also observed, with
equivalent widths of 3.0 and 4.1A, respectively. The Paschen lines were
also present in CenX-4, GS2000+25, and for the first time detected in
AqlX-1. The only systems in which stellar features were detected were
those in which the companions were evolved e.g. GX1+4, CygX-2 and the
source in which the mass accretion rate is low i.e. CenX-4.