TITLE: GCN CIRCULAR NUMBER: 6435 SUBJECT: GRB070521 : Faulkes Telescope North Observations DATE: 07/05/21 07:55:27 GMT FROM: Andrea Melandri at Liverpool John Moores U A. Melandri, I. A. Steele, C. G. Mundell, C. Guidorzi, D. Carter, R. J. Smith, C. J. Mottram, D. F. Bersier, S. Kobayashi, M. F. Bode (Liverpool JMU), A. Gomboc (Ljubljana), P. O'Brien, E. Rol, N. Bannister (Leicester) report The 2-m Faulkes Telescope North robotically followed up GRB070521 (Guidorzi et al., GCN 6431, trigger=279935) beginning ~2.5 minutes after the GRB trigger time (UT:06:51:10). No new object has been detected inside the XRT error circle (Guidorzi et al., GCN 6431) down to a limiting magnitude of R~19.3 (texp = 30 sec) and I~18.5 (texp = 10 sec), at a mean epoch of ~3 and ~6 minutes after the burst, respectively (comparison with respect to the USNO B1 catalog). Further observations are ongoing.