GRB 051109B
GCN Circular 5441
Subject
GRB051109B: Late-time Radio Observations
Date
2006-08-12T19:23:53Z (19 years ago)
From
Alicia Soderberg at Caltech <ams@astro.caltech.edu>
A. M. Soderberg (Caltech), D. A. Frail (NRAO) and P. Chandra (UVA/NRAO)
report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We re-observed the field of GRB 051109B (GCN 4222) centered on the
revised XRT position (GCN 5387) using the VLA on August 9.5 UT 2006 (t~9
months after the burst) at a frequency of 1.43 GHz. Comparison with our
previous VLA observations (GCN 4245) reveals no new sources within the
revised XRT error circle. We place a 3-sigma limit of 0.21 mJy.
Adopting a redshift of z=0.08 for the putative host galaxy (GCN 5387),
this limit corresponds to a radio luminosity 100 times fainter than that
observed for GRB 030329 at a comparable epoch (Frail et al. 2003, ApJ,
619, 944).
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 5387
Subject
GRB 051109B: Bright spiral host galaxy at low redshift
Date
2006-08-02T04:51:03Z (19 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, R. J. Foley, J. S. Bloom and N. R. Butler (UCB) report:
On the night of 2006 July 25 (UT), we imaged the field of GRB051109B
(GCN 4222) for 630 seconds in g' and 600 seconds in R using Keck I (+
LRIS). There is a bright (R ~ 14.5) spiral galaxy close to the XRT
position (GCN 4226), also visible in DSS and other surveys. In our
imaging, the galaxy is observed to be a barred spiral of type SBa. The
presence of a faint tidal bridge indicates that the galaxy has recently
interacted with a neighboring galaxy 60" to the north.
Using 25 X-ray sources and 51 DSS sources in the field, we calculate an
improved XRT position of RA = 23:01:50.21, dec = +38:40:46.0 (with a 90%
uncertainty radius of 2.2", including an estimate of the systematic
error.) This position lies inside an outer spiral arm of the galaxy,
identifying it as the GRB host. In addition, both our position and the
original XRT error circle include a faint optical point-like source at
RA = 23:01:50.30, dec = +38:40:46.7 (0.5" uncertainty).
We obtained spectroscopy of the host galaxy and optical source the
following night. The galaxy is observed to be at a redshift of z =
0.080, and lacks any strong emission features. Spectroscopy of the
point source inside the XRT error circle shows no evidence for a
nebular-phase supernova; however, there are emission lines indicating
active star formation in this region.
The offset of the position of the optical source to the galaxy center is
14.1", or 20.9 kpc at the observed redshift. This is the largest offset
yet seen in a long GRB in angular or physical scale. Using the 15-150
keV gamma-ray fluence (GCN 4237), E_iso for this GRB is 4.1 x 10^48
ergs, comparable to that observed for GRB980425 but less than that of
any other GRB. GRB980425/SN1998bw was also seen in a spiral galaxy at
large offset, and also lacked a detected optical afterglow.
Given the low redshift of this system, inspection of archival images for
the presence or absence of supernova emission is strongly encouraged.
We also encourage radio and X-ray observations to look for a late-time
afterglow or supernova.
Additional information on this GRB, including an image of the field, is
available at:
http://lyra.berkeley.edu/~dperley/051109b/host.html
GCN Circular 4296
Subject
GRB 051109B: GAO 150cm telescope Optical limit
Date
2005-11-22T06:13:34Z (20 years ago)
From
Kenzo Kinugasa at Gunma Astro. Obs/Japan <kinugasa@astron.pref.gunma.jp>
K. Kinugasa (Gunma Astronomical Observatory) and K. Torii (Osaka U.) report:
The error region of GRB 051109B (Tagliaferri, et al. GCN 4222) was imaged
with the LN2 cooled CCD Camera atattched on the 150 cm telescope of the
Gunma Astronomical Observatory. Starting at 15:28 UT (6.8 hours after the
burst), V, Rc, and Ic frames were acquired.
We do not identify an optical counterpart for the X-ray afterglow (Campana,
et al. GCN 4226). Following 3-sigma upper limits are derived for the stacked
frames relative to USNO-B1.0 magnitudes.
---------------------------------
MidUT Filter Mag Exposure
---------------------------------
15:54 Rc >20.2 180s x 5
16:10 Ic >18.4 60s x 10
---------------------------------
GCN Circular 4277
Subject
GRB 051109B : Nainital upper limits
Date
2005-11-16T14:55:42Z (20 years ago)
From
Kuntal Mishra at ARIES,Nainital,India <kuntal@aries.ernet.in>