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IAUC 7133: 1999bc, 1999bd; XTE J1723-376

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                                                  Circular No. 7133
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/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)


SUPERNOVAE 1999bc AND 1999bd
     P. Nugent, Lawrence Berkeley Laboratory, on behalf of the
Supernova Cosmology Project and the Near-Earth Asteroid Tracking
project (cf. IAUC 7125, 7128), reports two supernovae discoveries
on unfiltered CCD frames:

SN      1999 UT     R.A. (2000.0) Decl.      Mag.    Offset
1999bc  Feb. 19    8 28 31.08  +17 28 15.4   18.9:   4".2 W, 17".1 N
1999bd  Feb. 19    9 30 29.17  +16 26 07.8   17.7:      ?

A CCD spectrum (range 420-850 nm) of SN 1999bc, located in UGC
4433, taken by G. Aldering on Mar. 5 UT at the MDM 2.4-m telescope,
showed a few narrow emission features (463, 537, and 586 nm) about
4000 km/s across, along with some contamination from a superposed H
II region.  A CCD spectrum (range 365-930 nm) taken by M. M.
Phillips on Mar. 22 with the Las Campanas 2.5-m duPont telescope
shows that these features have broadened somewhat over this time
period.  Phillips classifies SN 1999bc as a type-Ic supernova at a
redshift of 0.022, the spectrum being similar to that of SN 1983V
at about 30 days after peak brightness.
     SN 1999bd has no apparent host on the discovery images
(limiting mag about 19).  A CCD spectrum obtained at the ARC 3.5-m
telescope on Mar. 10 by G. Richards, H. Newberg, and S. Kent showed
a blue continuum with several narrow features and H-alpha emission,
strongly absorbed by the atmospheric A band.  Phillips took another
spectrum of this object (range 365-930) on Mar. 22, and he
classifies it as a type-II supernova at a redshift of 0.151.  Once
again, several narrow features are present in the spectrum, along
with a weak, broad component visible below H-alpha.


XTE J1723-376
     F. E. Marshall, Goddard Space Flight Center (GSFC); Y. Ueda,
Institute of Space and Astronautical Science; and C. B. Markwardt,
National Academy of Sciences/National Research Council and GSFC,
report an improved position for XTE J1723-376 (IAUC 7103):  R.A. =
17h23m38s, Decl. = -37o39'.7 (equinox 2000.0; estimated uncertainty
0'.5, from an ASCA observation on Mar. 4 UT).  The x-ray spectrum
is typical of low-mass x-ray binaries, and the absorption is about
4 x 10E22 cmE-2.  Type-1 x-ray bursts were observed with the RXTE
PCA on Feb. 3.942 and 4.055, with peak intensities of 0.51 and 0.43
Crab.  These results indicate that the source is at a distance
comparable to that of the Galactic Center.  The most recent RXTE
observation shows a persistent flux of 0.05 Crab on Mar. 22.9.

                      (C) Copyright 1999 CBAT
1999 March 27                  (7133)            Daniel W. E. Green

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