TITLE: GCN CIRCULAR NUMBER: 10856 SUBJECT: GRB 100615A: Swift/UVOT Upper Limits DATE: 10/06/15 19:21:44 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA) and V. D'Elia (ASDC) report on the behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 100615A starting 53 s after the BAT trigger (D'Elia, et al., 2010, GCN Circ. 10841). Settled observations started at 72 s. We do not find any new source, relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT afterglow (Goad, et al. 2010, GCN Circ. 10848). Preliminary 3-sigma upper limits for detecting a source in the finding charts, and in the co-added images, using a 2.5 arcsecond radius circular aperture, are Filter T_start T_stop Exp(s) Mag -------------------------------------------- white (fc) 72 222 147 >21.5 864 1014 147 >21.5 u (fc) 284 534 246 >20.7 v 613 7037 510 >20.6 b 539 6422 490 >21.1 u 284 6216 539 >21.1 uvw1 663 7436 499 >21.1 uvm2 813 7242 413 >20.7 uvw2 589 6832 471 >21.1 white 72 6627 785 >22.2 -------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.05 mag (Schlegel, et al., 1998, ApJS, 500, 525). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627).