TITLE:   GCN CIRCULAR
NUMBER:  8669
SUBJECT: Possible GRB 081211B: Swift/UVOT Upper Limits
DATE:    08/12/15 17:27:44 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland@milkyway.gsfc.nasa.gov>

S. T. Holland (CRESST/GSFC/USRA) reports, on the behalf of the Swift
UVOT team:

       The Swift/UVOT observed the field of the possible BAT Slew
Survey burst GRB 081211B (Copete et al., GCN Circ. 8661) starting 81.7
ks after the start of the slew that this source was detected in.  We
find no new source, relative to the DSS, USNO-B1.0, or 2MASS, or a
variable source, inside the UVOT-enhanced XRT error circle (Page et
al. 2008, GCN Circ. 8666).  Preliminary 3-sigma upper limits for
detecting a source in the co-added images, using an aperture-corrected
2.5 arcsecond radius circular aperture, are

Filter   T_start   T_stop  Exp(s)      Mag
------------------------------------------
    v      81,651  132,774    2318    >21.4
    b      85,687  126,980    1770    >22.5
  uvm2    132,780  133,265     478    >20.8
  uvw2     87,513  128,664    1426    >21.8
  white    86,600  127,893    1770    >23.1
------------------------------------------

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} = 0.01 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).