GCN Circular 1091
Subject
GRB000926, Host Galaxy Observations
Date
2001-09-08T07:45:25Z (23 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
S. Dodonov, T. Fatkhullin, V. Sokolov (SAO RAS), Andrew Fruchter (STScI),
V. Komarova, A. Moiseev (SAO RAS), A. Cherepashchuk, K. Postnov (SAI-MSU Moscow)
report:
"On July 24 and 25, 2001 UT, we have observed the field of the optical
transient of GRB 000926 (Fynbo et al., 2001, A&A, 373, 796).
We have obtained B, V, Rc, Ic images with the SCORPIO
(http://www.sao.ru/~moisav/scorpio/scorpio.html) at the
6-m telescope of SAO RAS. Photometric conditions were good and
the seeing was about 1.3 arcsec. Photometric calibration was
performed using Stetson standards in Landolt standard field PG1633.
At the position of the optical transient we have detected an object -
a host galaxy. At about 3" to the East from the OT position an extended
emission is clearly seen. This extended emission is most likely the galaxy
seen in early HST image (see Price et al., 2001, ApJ, 549, L7) and its
association with the host is unclear.
The exposure times and magnitudes of the object are:
Filter Exposure (sec.) Magnitude Aperture
---------------------------------------------------------
B 2500 26.13 +/- 0.17 2.0 arcsec
V 1500 25.85 +/- 0.22 2.0 arcsec
Rc 1260 26.31+/- 0.25 2.0 arcsec
Ic 1800 24.7 +/- 0.4 2.0 arcsec
---------------------------------------------------------
The faint R-band magnitude can be explained by a graphite band
as on the Galactic extinction curves. Indeed, for the redshift z=2.0369
(Castro et al., GCN #851) this band (2200A) goes to the observed R-band.
If so, then this is the second case of direct observations of this
feature (see Sokolov et al., 2001, A&A, 372, 438, the case of the HG
GRB 980703).
We also performed the photometry of entire system of the objects using
an aperture of 4.5 arcsec. Below we present the obtained magnitudes:
Filter Exposure (sec.) Magnitude Aperture
---------------------------------------------------------
B 2500 24.73 +/- 0.11 4.5 arcsec
V 1500 24.81 +/- 0.19 4.5 arcsec
Rc 1800* 24.38+/- 0.10 4.5 arcsec
Ic 1800 23.68 +/- 0.30 4.5 arcsec
---------------------------------------------------------
* The R-band data obtained on 25 Aug. are coadded.
Images can be seen at
http://www.sao.ru/~sokolov/GRB/HOSTS/GRB000926/GRB000926.html
This message may be cited".
-Vladimir Sokolov, on behalf of the RAS Special Astrophysical Observatory
GRB followup team.