Central Bureau for Astronomical Telegrams
IAUC 6785: GRB 971208; SNe; 1997dn, 1997dq
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Circular No. 6785
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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Phone 617-495-7244/7440/7444 (for emergency use only)
GRB 971208
V. Connaughton, National Academy of Sciences/National Research
Council and Marshall Space Flight Center (MSFC); and R. M. Kippen
and R. Preece, University Alabama at Huntsville and MSFC, for the
BATSE team; and K. Hurley, University of California at Berkeley,
for the Ulysses team, write that an unusually long and smooth
single-peaked gamma-ray burst (GRB) was detected by BATSE on the
Compton Gamma-Ray Observatory on Dec. 8.335 UT (trigger 6526) and
was detected also by Ulysses. A duration of nearly 800 s makes it
longer by an order of magnitude than any other single-peaked GRB
observed by BATSE. It is also the longest single episode of
emission in a BATSE GRB. Its intensity rose over an interval of 60
s to a maximum flux of 8.97 +/- 0.3 x 10E-7 erg cmE-2 sE-1 (between
25 and 1800 keV; integration time 2.048 s) and decayed with a power
law of roughly -0.4 over the following 700 s. The total fluence of
the event above 25 keV is estimated to be 1.86 +/- 0.03 x 10E-4 erg
cmE-2. The BATSE location centroid for the GRB is R.A. = 23h45m50s,
Decl. = +77o56'.4 (equinox 2000.0) with a 1-sigma statistical error
of 1.2 deg. A preliminary joint BATSE/Ulysses InterPlanetary
Network annulus is described by a center at R.A. = 23h25m39s, Decl.
= -11o52'.4, with a radius of 87.906 deg (half-width 0.224 deg). A
sky map of the event is available at
http://www.batse.msfc.nasa.gov/~kippen/batserbr/brbr_obs.html.
SUPERNOVAE
S. Deustua, Lawrence Berkeley Laboratory (LBL); R. McMillan,
Apache Point Observatory; H. Newberg, Fermi National Accelerator
Laboratory; P. Nugent, C. Pennypacker, and S. Perlmutter, LBL; and
M. Strauss, Princeton University, report redshifts (+/- 0.002) for
the host galaxies of four supernovae announced on IAUC 6782; the
following redshifts were estimated from emission features in
spectra obtained with the 3.5-m ARC Telescope at Sunspot, NM, on
the respective dates: SN 1997eb, Nov. 23 UT, 0.085; SN 1997ec, 23,
0.124; SN 1997ed, 24, 0.152; SN 1997ee, 29, 0.166. SN 1997ee is a
normal type-Ia supernova near maximum light, and SN 1997ed may be a
type-II event.
SUPERNOVAE 1997dn AND 1997dq
Unfiltered CCD magnitude estimates (GSC reference stars) from
S. Moretti and S. Tomaselli, Forli, Italy: SN 1997dn (cf. IAUC
6763), Dec. 8.02 UT, 16.6; SN 1997dq (cf. IAUC 6770), Dec. 8.04,
16.2.
(C) Copyright 1997 CBAT
1997 December 10 (6785) Daniel W. E. Green
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