Central Bureau for Astronomical Telegrams
IAUC 6285: GRO J1744-28; OB AND X-RAY BINARY CANDIDATES
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Circular No. 6285
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)
GRO J1744-28
M. H. Finger, Compton Observatory Science Support Center; R.
B. Wilson and B. A. Harmon, Marshall Space Flight Center, NASA; K.
Hagedon, University Space Research Association; and T. A. Prince,
California Institute of Technology, report for the Compton
Observatory BATSE team: "Pulsations with a period of 467 ms are
being detected in the energy band 25-45 keV from a source in the
galactic-center region. The pulsed flux is about 40 percent of the
total flux observed from the hard x-ray transient GRO J1744-28
(IAUC 6284). Absence of any other persistent source consistent
with the direction and flux of the observed pulsed emission implies
that the pulsations are from GRO J1744-28. The 31-ms-resolution
data in which the pulsations were observed excluded time intervals
containing outbursts from the possibly separate burst source in the
same region (IAUC 6272, 6275, 6276). On Jan. 6.0 UT, the measured
barycentric pulse frequency was 2.1409720(5) Hz."
OB AND X-RAY BINARY CANDIDATES
C. Motch and M. Pakull, CNRS, Observatoire Astronomique de
Strasbourg; F. Haberl and K. Dennerl, Max-Planck-Institut fur
Extraterrestrische Physik, report the discovery of several new
galactic OB/x-ray binary candidates: "These massive systems were
selected from a cross-correlation of the ROSAT all-sky survey (|b|
< 20o) with OB star catalogues, and display significant excess x-
ray emission (range 0.1-2.4 keV) over the expected stellar level.
Follow-up optical and ROSAT observations yield four very likely new
massive x-ray binaries: the O star LS 5039 (RX J1826.2-1450) and
the Be stars BSD 24-491 (RX J0440.9+4431), LS 992 (RX J0812.4-3114)
and LS 1698 (RX J1037.5-5647). LS 992 exhibited an x-ray outburst
during survey observations (1990 Oct. 28.5-31.1 UT; x-ray
luminosity 1.3 x 10E35 erg/s, assuming d = 9.2 kpc), and LS 1698 is
probably identical to the hard x-ray transient 4U 1036-56. The new
candidates have x-ray luminosity > 6 x 10E33 erg/s, indicating the
presence of an accreting neutron star or black hole. Two further
Be/x-ray binary candidates, HD 161103 and SAO 49725 require
confirmation of their x-ray excess (x-ray luminosity 1-5 x 10E32
erg/s) and could be Be + accreting white dwarf systems."
(C) Copyright 1996 CBAT
1996 January 10 (6285) Daniel W. E. Green
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