TITLE: GCN CIRCULAR NUMBER: 6174 SUBJECT: GRB 070306: IR observations and candidate afterglow DATE: 07/03/07 00:01:25 GMT FROM: Andrew Levan at U.of Leicester E. Rol (Leicester), A. Levan (Warwick), N. Tanvir (Leicester), M. Schirmer (ING), A.J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger collaboration, report: "We observed the location of GRB 070306 (Pandey et al. GCNC 6169) using the 4.2m WHT (+LIRIS) in the JHK bands beginning at 19:57 UT, roughly 3.27 hours after the burst. Within the X-ray localisation of Page et al. (GCNC 6172) we find a single source, which is also present in the SDSS pre-observations of the field (Cool et al. GCNC 6170). The location of this source is RA: 09:52:23.31 (J2000) DEC: +10:28:55.26 (J2000) with errors of 0.3" in each coordinate. Preliminary photometry implies K=17.9 +/- 0.1. Compared to the measured SDSS magnitudes this implies r-K~5. This is unusually red for a GRB host galaxy and may indicate a contribution from the IR afterglow. Further observations will be necessary to ascertain any variability."