Central Bureau for Astronomical Telegrams
IAUC 6666: GRB 970508; V485 Cen; 1997bp
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 6667
.dvi or
.ps format.
Circular No. 6666
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 970508
M. Morris, N. Mastrodemos, B. Zuckerman, C. McCarthy, E.
Becklin, P. Lowrance, and R. Chary, University of California at Los
Angeles; and C. Barnbaum, Space Telescope Science Institute, report:
"We imaged the optical transient associated with GRB 970508 (cf.
IAUC 6649, 6654, 6655) with the Keck I telescope (+ NIRC camera +
K_s filter). The K_s magnitudes of the variable on May 13.25 and
16.25 UT were 18.43 +/- 0.05 and 19.21 +/- 0.06, respectively,
corresponding to fluxes of 28.3 +/- 1.3 and 13.8 +/- 1.7 microJy.
The gradient of the decline in this interval is similar to that
reported in the r band in the preceding 3-day interval (IAUC 6658,
6660). The May 13.25 K_s flux is slightly above the contemporaneous
r-band flux, giving an r-K_s color of +2.3 +/- 0.2. In these brief
(about 10-min) images, the limit on the K_s flux from any associated
galaxy within a 1".2-2".4 annulus around the transient is 5 microJy."
M. Donahue, K. C. Sahu, M. Livio, and L. Petro, Space Telescope
Science Institute; J. T. Stocke, University of Colorado; P. Groot,
University of Amsterdam (UoA); and J. van Paradijs, UoA and
University of Alabama, write: "A 15-min exposure in the I band
taken on May 9.15 UT at the Kitt Peak 4-m telescope was used to get
relative photometry of the optical counterpart of GRB 970508 (IAUC
6654, 6655, 6658), yielding I = 20.4 +/- 0.1, assuming the magnitude
of the 'standard' star of Schaefer et al. (IAUC 6658) to be I = 18.4
+/- 0.1."
V485 CENTAURI
A. Olech, Warsaw University Observatory, writes: "CCD
observations of the dwarf nova V485 Cen during its recent outburst,
collected with the 1.3-m Warsaw telescope at Las Campanas
Observatory as a subproject of the OGLE-2 project, indicate that
this star belongs to the SU UMa group of cataclysmic variables. A
3-hr I-band observation on May 17.1 UT shows three well-developed
typical superhumps with an amplitude of 0.25 mag and period 57.7
min. Thus, V485 Cen has the shortest known period among SU UMa-
type stars, with a period as much as 25 percent shorter than
previously known objects."
SUPERNOVA 1997bp IN NGC 4680
Unfiltered CCD magnitude estimate by S. Moretti and S.
Tomaselli, Forli, Italy: May 14.92 UT, 15.6 (GSC comparison stars).
(C) Copyright 1997 CBAT
1997 May 21 (6666) Daniel W. E. Green
Read IAUC 6667
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
