GCN Circular 15181

S. T. Holland (STScI) and Dirk Grupe (PSU)
report on behalf of the Swift/UVOT team:

     The Swift/UVOT began observations of the field of GRB 130903A
starting 44.1 ks after the INTEGRAL/IBAS trigger (Mereghetti et
al. 2013, GCNC 15169).  We do not detect any new source consistent
with the GROND afterglow position (Tanga et al. 2013, GCNC 15177) in
any of the UVOT exposures.  Preliminary 3-sigma upper limits using the
UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358,
373) for the summed exposures are presented below.

---------------------------------------------------
Filter       TSTART      TSTOP    Exposure      Mag
---------------------------------------------------
    v        44,128     51,114        2461    >21.2
    u        45,378     51,795        1442    >21.3
---------------------------------------------------

     The quoted upper limits have not been corrected for the expected
extinction due to the Galactic reddening along the line of sight to
this burst of E(B-V) = 0.12 mag (Schlafly et al. 2011, ApJS, 737,
103).