Circular No. 6803
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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XTE J0053-724 AND AX J0051-722
     R. Corbet, Goddard Space Flight Center (GSFC) and Universities
Space Research Association (USRA); F. E. Marshall, GSFC; J. C.
Lochner, GSFC and USRA; and M. Ozaki and Y. Ueda, Institute of
Space and Astronautical Science, report: "Further analysis of the
ASCA observation of 1WGA J0053.8-7226 = XTE J0053-724 (IAUC 6788,
6789) reveals that there are two transient pulsing sources in this
image.  1WGA J0053.8-7226, whose location was given on IAUC 6788,
in fact has a period of 46.63 +/- 0.04 s, rather than about 92 s as
initially reported.  A second source, AX J0051-722, located at R.A.
= 0h51m04s, Decl. = -72o13'44" (equinox 2000.0; +/- 1'.2, 90-
percent confidence) with a 2-10-keV flux of 1.05 x 10E-11 erg sE-1
cmE-2, exhibits the 91.12-s (+/- 0.05 s) pulsations first detected
with RXTE.  Initial misidentification arose due to the approximate
2 to 1 ratio of these periods.  Additional analysis of the first
RXTE observation (IAUC 6777) shows, in addition to the 46.6-s and
91.1-s pulsations, an indication of additional modulation at a
period of 74.8 +/- 0.4 s from a possible third pulsar within the
2-deg FWZI field-of-view centered on SMC X-3.  However, no
corresponding ASCA source can be identified.  A ROSAT observation
on 1997 Dec. 11 detected both AX J0051-722 and 1WGA J0053.8-7226 at
R.A. =  0h50m55s.8, Decl. = -72o13'38", and at R.A. = 0h53m55s.0,
Decl. = -72o26'47" (+/- 10"), respectively."


GRB 971227
     S. A. Ilovaisky and C. Chevalier, Observatoire de Haute-
Provence (OHP), write:  "R-band CCD images of the SAX error box
reported on IAUC 6797 were obtained with the 1.2-m OHP telescope on
Jan. 3.14 UT.  Analysis of the resulting median frame of three 30-
min exposures shows no object at the position reported by Castro-
Tirado et al. (IAUC 6800) down to a limiting R_c magnitude slightly
fainter than 22.  A group of faint galaxies with R_c about 21.5
appears a few arcsec northwest of that position."


SUPERNOVAE
     S. Moretti and S. Tomaselli, Forli, Italy, report unfiltered
CCD magnitudes (GSC reference stars):  SN 1997dn in NGC 3451, 1997
Dec. 29.94 UT, 16.7; SN 1997dq in NGC 3810, Dec. 29.9, 16.4; SN
1997ef in UGC 4107, Dec. 29.85, 16.8.

                      (C) Copyright 1997 CBAT
1997 January 6                 (6803)            Daniel W. E. Green