TITLE: GCN CIRCULAR NUMBER: 10687 SUBJECT: GRB 100424A: Liverpool Telescope Upper Limits DATE: 10/04/25 14:25:15 GMT FROM: Zach Cano at ARI/John Moores Liverpool Z. Cano, A. Melandri (Liverpool JMU), C. Guidorzi (U. Ferrara), C. Mundell, R.J. Smith, D. Bersier, I.A. Steele, S. Kobayashi, C.J. Mottram, (Liverpool JMU), A. Gomboc (U. Ljubljana) report, on behalf of a larger collaboration: We observed the field of GRB 100424A (Hoversten et al. GCNC 10667) with the Liverpool Telescope starting 20:54 UT on April 24, 2010. We do not detect the NIR afterglow discovered by Cenko et al. (GCN 10682), nor any other object within the enhanced XRT error circle (Evans, GCN 10668; Evans et al., GCN 10669) down to the following limits: ------------------------------------------------------------------- Mid Exposure Total T-To (hrs) Exposure Time (min) Filter upper limit ------------------------------------------------------------------- 6.91 30 B >21.5 6.92 50 I >21.8 8.38 20 R >21.7 ------------------------------------------------------------------- The upper limits are for an isolated object in our images and are calibrated using nearby stars in the USNO-B1 catalogue. No correction for Galactic extinction has been made.