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IAUC 6690: 1997ct; GRB 970616; N Sco 1997

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IAUC number

                                                 Circular No. 6690
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/cfa/ps/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)

     J. Mueller reports her discovery of a supernova (mag about 17)
located 8".7 east and 4" south of the center of a galaxy at R.A. =
14h07m24s, Decl. = +70o26'.1 (equinox 2000.0).  SN 1997ct was found
on a IV-N plate taken on June 29 with the 1.2-m Oschin Schmidt
Telescope by Mueller and J. D. Mendenhall in the course of the
second Palomar Sky Survey.  No object appears at the position on
the digitized sky survey or on a red sky survey plate taken on 1991
June 7.  An uncalibrated spectrogram taken on July 1 by S. R.
Kulkarni, J. C. Clemens, A. Sivaramakrishnan, and D. A. Frail with
the Hale 5-m telescope (+ double spectrograph) shows the object to
be a supernova.

GRB 970616
     A. Udalski, Warsaw University Observatory, reports on behalf
of the OGLE-2 collaboration:  "I-band CCD images of the entire
XTE/IPN error box of the GRB 970616 field were obtained with the
1.3-m Warsaw telescope at the Las Campanas Observatory on June
22.400 and 23.403 UT.  A comparison of images revealed the presence
of a faint object, close to detection limit (I about 21), with
coordinates R.A. = 1h18m28s.00, Decl. = -5o28'05".5 (equinox
2000.0) on the 180-s image from June 22, but not visible on the
180-s image taken on June 23.  The object was not detected on
additional, much deeper 900-s images taken on June 24.408 and
25.431; it is marginally visible on the 900-s image taken on June
30.416, so it must have faded by at least 1.5 mag during that time.
The object is located about 4'.5 away from the southern edge of the
XTE/IPN error box, and hence it is not likely to be the afterglow
of GRB 970616.  This was the only fast fading object in the GRB
970616 field on our frames.  Apparently the background of variable
objects is high, and it may contribute significantly to false
afterglow detections.  Images may be retrieved from
ftp://sirius.astrouw.edu.pl/pub/udalski/grb or

     Photometry by A. C. Gilmore, obtained with the Mount John
0.6-m f/16 reflector on June 27.506 UT:  V = 12.82 +/- 0.03, U-B =
-0.22 +/- 0.03, B-V = +0.57 +/- 0.07, V-R = +1.61 +/- 0.04, V-I =
+1.47 +/- 0.06 (comparison stars E790, E782, and E739 from Cousins'
E region).

                      (C) Copyright 1997 CBAT
1997 July 1                    (6690)            Daniel W. E. Green

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