TITLE: GCN CIRCULAR NUMBER: 11095 SUBJECT: Swift/UVOT observations of GRB100814A DATE: 10/08/14 15:26:23 GMT FROM: Patricia Schady at MPE/Swift M. De Pasquale (MSSL-UCL) and C.J. Saxton (MSSL-UCL) report on the behalf of the Swift UVOT team:  The Swift/UVOT began settled observations of the field of GRB 100814A 153 s after the BAT trigger  (Beardmore et al. 2010, GCN Circ. 11087) with a finding chart in the u filter. We detect the optical afterglow in all filters except uvw2. The refined UVOT position is  RA  (J2000) = 01h 29m 53.61s = 22.47338  Dec (J2000) = -17d 59m 43.6s = -17.99545 with an estimated uncertainty of 0.6 arcsec (radius, 90% confidence, statistical + systematic). This is about 1.5 arcsec north of the UVOT-enhanced XRT position (Beardmore et al. 2010, GCN Circ. 11092).  Preliminary magnitudes, and 3-sigma upper limits for detecting a source in the finding charts and in co-added images are Filter      T_start   T_stop    Exp(s)      Mag   Err ---------------------------------------------------------------------    u (fc)      153      403       246     16.80 0.06    v           458      627        39      17.91 0.32    b           408      721        53      21.22 0.20    u           153      701      285      16.84 0.06  uvw1        507      676        39       17.33 0.20  uvm2       483     651       39      17.86 0.31  uvw2        434     602       39    >18.52  3-sigma UL  white      3858     4211       344      18.63 0.07 -----------------------------------------------------------  The quoted magnitudes and upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.02 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).