Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6735: GRB 970828; USNO 1425.09823278; C/1996 J1

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 6734 SEARCH Read IAUC 6736

View IAUC 6735 in .dvi or .ps format.
IAUC number 

                                                 Circular No. 6735
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)


GRB 970828
     S. C. Odewahn, S. G. Djorgovski, and S. R. Kulkarni,
California Institute of Technology; and D. A. Frail, National Radio
Astronomy Observatory, report: "We examined CCD images of the field
of GRB 970828 obtained at the Palomar 5-m Hale telescope by T.
Herter, F. Fang, X. Xu, and O. Pevunova on Aug. 29 UT, and by C.
Steidel, K. Adelberger, and M. Kellog on Aug. 30, 31, and Sept. 1.
Our preliminary analyis shows, within the ASCA/RXTE/IPN error box,
no objects brighter than magnitude R about 24.5 whose brightness
changed by > 0.2 mag/day in a statistically significant manner.
This places a severe limit on the peak brightness of any possible
optical transient associated with this burst, about a factor of 100
lower than the optical transient associated with GRB 970508."
     K. Z. Stanek, M. R. Garcia, and M. Krockenberger, Harvard-
Smithsonian Center for Astrophysics, communicate:  "Analysis of
images centered on the error box of the x-ray counterpart to GRB
970828 detected by RXTE (IAUC 6726, 6728) reveals no significantly-
variable objects to a magnitude limit of R = 22.  The variability
for the 460 point sources in the field with 15.5 < R < 22 is rms <
0.3 mag.  The field contains numerous well-resolved galaxies.  The
images were obtained with the 1.2-m telescope of the F. L. Whipple
Observatory on Aug. 30.18, 30.19, Sept. 2.26, 2.27, 3.23, 3.24,
4.12, and 4.14 UT in the Cousins R filter (15-min exposures).  The
images cover an area 11' x 11' and are available as FITS files by
anonymous ftp at cfa-ftp.harvard.edu, in pub/kstanek/GRB970828, or
through the WWW at http://cfa-www.harvard.edu/~kstanek/.  The faint
(R = 24.5 +/- 0.5) optical object coincident with the variable
radio source (IAUC 6730) is undetected on all of our individual and
daily-summed images, which reach a detection threshold of R about
22.  Note that the position of this radio source is outside the 30"
revised ASCA error radius (IAUC 6732)."


USNO 1425.09823278
     Visual magnitude estimate (cf. IAUC 6731) by P. Schmeer,
Bischmisheim, Germany:  Sept. 5.021 UT, 13.5.


COMET C/1996 J1 (EVANS-DRINKWATER)
     Visual m_1 estimates by R. J. Bouma, Groningen, The
Netherlands (0.25-m reflector):  Aug. 5.98 UT, 13.7; 6.99, 13.6;
Sept. 1.07, 13.7.

                      (C) Copyright 1997 CBAT
1997 September 5               (6735)            Daniel W. E. Green

Read IAUC 6734 SEARCH Read IAUC 6736

View IAUC 6735 in .dvi or .ps format.

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!