Central Bureau for Astronomical Telegrams
IAUC 6526: GRB 960720; 22P
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 6527
.dvi or
.ps format.
Circular No. 6526
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
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)
Phone 617-495-7244/7440/7444 (for emergency use only)
GRB 960720
C. Luginbuhl and F. Vrba, U.S. Naval Observatory, Flagstaff
Station; R. Hudec, P. Pravec, and L. Sarounova, Astronomical
Institute, Ondrejov; J. Greiner, Max-Planck-Institut fur
Extraterrestrische Physik, Garching; and G. Tovmassian, Instituto
de Astronomia, Universidad Nacional Autonoma de Mexico (UNAM),
report: "Broadband BVR CCD frames taken at the Ondrejov 0.65-m
telescope have revealed a single very blue object within the 10'-
radius Beppo-SAX error circle for GRB 960720 (cf. IAUC 6467) at
R.A. = 17h29m24s.73, Decl. = +49o06'22".0 (equinox 2000.0); these
images do not reach deep enough to detect the fainter objects seen
on the POSS images. Broadband UBVI photometric observations of
this object obtained at the Flagstaff Station 1.0-m telescope on
Oct. 9 and 10 UT show this object to have colors typical of
quasistellar objects (QSOs), with V = 18.25 +/- 0.01, U-B = -0.31
+/- 0.08, B-V = +1.21 +/- 0.05, V-I = +1.36 +/- 0.02. An optical
spectrum (range 400--670 nm) obtained on Oct. 19 with the UNAM
2.15-m telescope at Cananea confirms the QSO (which was outside the
1'-radius error circle of the quiescent x-ray source discussed on
IAUC 6481), showing a strong, broad emission line at 418 nm and two
fainter broad lines at 442 and 515 nm, which we interpret as the
redshifted lines of C IV] at 155 nm, He II at 164 nm, and C III] at
191 nm, resulting in a redshift of z = 1.7 (see
http://www.rosat.mpe-garching.mpg.de/~jcg/grb.html). This QSO is
the likely counterpart of RX J1729.4+4906, mentioned (but not
specificially designated) on IAUC 6487. From the Boyle et al.
(1988, MNRAS 235, 935) QSO statistics, the likelihood of finding a
QSO of this brightness or brighter within the Beppo-SAX
localization by chance alone is 0.08. The Flagstaff Station
observations also covered the other seven ROSAT sources within the
Beppo-SAX localization described on IAUC 6487. For the Seyfert
galaxy reported within the RX J1729.5+4904 error circle, our
measures indicate a possible variation at U of 0.50 +/- 0.16 mag
between the two successive nights with mean photometric values of V
= 20.39 +/- 0.05, U-B = -0.59 +/- 0.25, B-V = +0.28 +/- 0.05, V-I =
+0.40 +/- 0.17. Follow-up observations of this Seyfert object are
encouraged to confirm and characterize any variation."
COMET 22P/KOPFF
G. Cremonese, Astronomical Observatory, Padua, informs us that
the account of this comet's splitting is in error and that the part
of the report on IAUC 6521 discussing the splitting should be
ignored.
(C) Copyright 1996 CBAT
1996 December 21 (6526) Daniel W. E. Green
Read IAUC 6527
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
