GCN Circular 17868
S. Dichiara, C. Guidorzi (U. Ferrara), C.G. Mundell (Bath U.), A. Gomboc (U. Ljubljana) on behalf of a larger collaboration report: The 1-m LCOGT unit in Cerro Tololo began observing Fermi GBM and LAT GRB 150523A (Yu et al GCN 17863; Bissaldi et al. GCN 17864) on May 23 at 23:17 UT (~13.8 hours after the burst trigger) with SDSS r and i filters. Inside the Swift-XRT error circle (Beardmore et al GCN 17866) we detect an uncatalogued object at the following position: RA(J2000) = 07:41:08.68 Dec(J2000)= -45:25:12.3 with an uncertainty of ~1" and a magnitude of R=20.2 +-0.1 calibrated against nearby USNOB-1 stars. Presently we cannot establish whether the source is fading.