[vsnet-grb-info 2409] GRB 051008 Tautenburg Supernova Search

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4246
SUBJECT: GRB 051008 Tautenburg Supernova Search
DATE:    05/11/10 19:24:04 GMT
FROM:    Sylvio Klose at TLS Tautenburg  <klose at tls-tautenburg.de>

D. A. Kann, P. Ferrero, B. Stecklum, S. Klose, Thueringer
Landessternwarte Tautenburg, Germany, report:

The XRT position (Perri et al., GCN 4073) of GRB 051008 (Marshall et
al., GCN 4069, Golenetskii et al., GCN 4078) was reobserved with the
Tautenburg 1.34m Schmidt telescope on October 29, 30 and 31, in good
conditions but near dawn. We obtained 30x60 second Rc-band images in
each epoch. The total exposure of the stacked images is 90 minutes
(meantime 21.5 days after the burst). The flux of the bright star
HD 117710 close to the XRT error circle was carefully removed.

The potential host galaxy (Rumyantsev et al., GCN 4081, 4087) is
clearly detected. At the position of the probable afterglow
(Rumyantsev et al., GCN 4087), no source is detected down to a
limiting magnitude of Rc = 22.5.

Under the assumption that this burst is at a low redshift (Ferrero et
al., GCN 4085), the failure to detect a supernova rebrightening
implies either an underluminous supernova in comparison to SN 1998bw,
which is not unusual (cf. Zeh et al. 2004, ApJ, 609, 952), or a large
amount of source frame extinction, which is indicated by the very high
excess N_H column density along the line of sight (30 times the
Galactic column density, Perri et al., GCN 4080). This situation is
comparable to the bright GRB 051022 for which no afterglow was
detected and a large amount of source frame extinction was implied
from X-ray observations (Butler et al., GCN 4170, and references
therein).

Spectroscopic observations of the putable host galaxy are encouraged.

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