{
  "bibcode": "2007GCN..6629....1K",
  "body": "D. A. Kann & A. C. Wilson (TLS Tautenburg) report:\n\nWe reobserved the field of GRB 070616 (Starling et al., GCN 6542) with the \nTautenburg 1.34m Schmidt telescope. We obtained 6 x 300 second images in \nthe I band in good observing conditions but with a few passing clouds. \nUsing the same USNOB1.0 star as used by Kann et al. (GCN 6545), we \ndetermine the following limiting magnitude:\n\ndate            time (days)     exp. time       Ic limit\n070715.00750    28.32031        6 x 300         21.6\n\nUsing this star and three other unsaturated, isolated stars, we determine \ndifferential magnitudes between the star that is blended with the \nafterglow (de Pasquale et al., GCN 6557) and these stars at both epochs.\n\nWe find that between the two epochs the star has become fainter by 0.064, \n0.023, 0.041 and 0.001 magnitudes in comparison to the other four stars. \nThe typical errors are 0.02 magnitudes.\n\nWe therefore conclude that we detect no significant fading between epoch \none (star + possibly blended afterglow) and epoch two (star only), placing \na limit of Ic > 20 on the afterglow at the first epoch (Kann et al., GCN \n6545).\n\nThis message may be cited.",
  "circularId": 6629,
  "createdOn": 1184515588000,
  "email": "kann@tls-tautenburg.de",
  "eventId": "GRB 070616",
  "subject": "GRB 070616: No Evidence for I Band Afterglow",
  "submitter": "Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>"
}