[vsnet-grb-info 9186] GRB 100424A: WHT z-band observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10672
SUBJECT: GRB 100424A: WHT z-band observations
DATE:    10/04/25 02:12:06 GMT
FROM:    Andrew Levan at U.of Leicester  <A.J.Levan at warwick.ac.uk>

A.J. Levan, C. Copperwheat, E. Breedt (U. Warwick), D. Malesani
(DARK/NBI) report on behalf of a larger collaboration:

"We observed the localization of GRB 100424A (Hoversten et al. GCN
10667) using the WHT and ACAM. Observations begin at April 25 00:18,
approximately 9 hours after the burst. We obtained 4x200s exposures
in the z-band. No source is visible within the enhanced XRT location
(Evans et al. GCN 10669)  to a limiting magnitude of z>23.2, calibrated
against SDSS. 

The deep z-band limit, coupled with apparently bright early X-ray
afterglow is suggestive of either a highly extinguished, or high
redshift burst."