TITLE: GCN CIRCULAR NUMBER: 10793 SUBJECT: GRB 100522A: GROND observations, upper limits DATE: 10/05/23 16:03:15 GMT FROM: Sylvio Klose at TLS Tautenburg P. Afonso (MPE Garching), S. Klose (TLS Tautenburg), and J. Greiner (MPE Garching), report on behalf of the GROND team: GROND (Greiner et al. 2008, PASP 120, 405), the 7-channel imager mounted at the 2.2m ESO/MPI telescope on La Silla, started follow-up observations of the Swift/Fermi burst GRB 100522A (Troja et al. 2010, GCN 10784; McBreen 2010, GCN 10790) on May 23 at 09:18 UT (about 29.5 hrs after the burst), and continued for about 1 hour. Within the enhanced XRT 1.5 arcsec error circle reported by Osborne et al. (GCN 10787) we do not find any afterglow candidate. Based on 50 min of total exposures in g'r'i'z' and 40 min in JHK, preliminary measured upper limits are (in the AB system, 3 sigma): g' > 24.8, r' > 24.4, i' > 23.6, z' > 23.3, J > 21.7, H > 20.9, K > 20.6, using GROND zeropoints and the 2MASS catalog.