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IAUC 6603: GRS 1737-31; 4U 1812-12; 1E 1740.7-2942 AND GRO J1744-28

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                                                 Circular No. 6603
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, 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)
URL http://cfa-www.harvard.edu/cfa/ps/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)


GRS 1737-31
     F. E. Marshall, Goddard Space Flight Center; and D. M. Smith,
University of California, Berkeley, report for the RXTE team:
"Recent scans over the position of the new x-ray transient GRS
1737-31 (IAUC 6599) with the Proportional Counter Array on the
Rossi X-ray Timing Explorer reveal that the outburst began between
Feb. 17.0 and 20.4 UT and peaked about 2 weeks later.
The following fluxes in milliCrabs (2-10 keV) were detected:  Feb.
17.0, < 3; 20.4, 10; 27.1, 14; 27.9, 25; Mar. 6.1, 23; 9.9, 25;
11.0, 20; 19.9, 17.  A pointed observation with the PCA and HEXTE
was carried out during Mar. 21.69-21.73."


4U 1812-12
     L. Burderi, N. Robba, Istituto di Fisica, Universita di
Palermo; M. Guainazzi, D. Ricci, M. Capalbi, G. Celidonio, A.
Coletta, R. Ricci, and M. Smith, BeppoSax, Rome; and A. R. King, G.
A. Wynn, and U. Kolb, Astronomy Group, University of Leicester,
report:  "On Mar. 12.220949 UT, the Wide Field Camera No. 1 onboard
the BeppoSAX satellite detected an x-ray burst in the energy range
1.5-26.0 keV.  The burst was seen in the ratemeter as a single
peak, showing a moderately fast rise (of the order of 10 s) and an
exponential decay lasting for about 70 s (the decay time is of the
order of 20 s).  The burst intensity was 1.2 Crab in the band 1.5-
10.0 keV and 0.6 Crab in the band 10.0-26.0 keV.  The derived
position is R.A. = 18h14m41s.8, Decl. = -11o52'17" (equinox 2000.0)
with an estimated error radius of about 18'.  The error box
contains the source 4U 1812-12 (R.A. = 18h15m12s.0, Decl. =
-12o04'59", equinox 2000.0), which is classified as a low-mass x-
ray-binary bursting source.  No other x-ray binary sources are
contained within 60' radius.  This implies that the identification
with 4U 1812-12 is quite robust."


1E 1740.7-2942 AND GRO J1744-28
     Further to the item concerning GRS 1737-31 on IAUC 6599, R.
Sunyaev reports for the GRANAT/SIGMA Team:  "Other sources detected
in the galactic-center field during preliminary analysis of the
data are 1E 1740.7-2942 (fluxes 96 +/- 16 and 94 +/- 19 mCrab in
the bands 35-75 and 75-150 keV, respectively) and GRO J1744-28
(fluxes 107 +/- 16 and 10 +/- 18 mCrab, respectively).  GRANAT will
continue observations of the galactic-center region until the end
of March."

                      (C) Copyright 1997 CBAT
1997 March 26                  (6603)            Daniel W. E. Green

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