[vsnet-grb-info 5046] GRB070810B: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6755
SUBJECT: GRB070810B: Swift/UVOT Upper Limits
DATE:    07/08/11 19:32:53 GMT
FROM:    Peter Brown at PSU  <pbrown at astro.psu.edu>

P.J. Brown and F.E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 070810B (trigger #287409)
starting 65 s after the BAT trigger (Marshall et al., GCN Circ. 6743).
We do not find any new source in the UVOT observations inside the
refined BAT error circle (Sakamoto et al., GCN Circ. 6753) including
the two low significance XRT sources (Starling et al., GCN Circ. 6754).
The galaxy 2MASX J00355339+0849273 (= LEDA 1354367) is visible in
all filters except uvm2, but does not show signs of variability.
The 3-sigma upper limits for detecting a source in the first
finding chart (FC) exposure and co-added frames are:

Filter       T_start(s)   T_stop(s)     Exp(s)     Mag (3-sigma UL)

white (FC)   66           165           98         >20.5
white        66           13134         1345       >22.0
v            172          7372          1296       >20.4
b            653          12222         1299       >21.2
u            628          7987          549        >20.3
uvw1         604          7782          549        >20.5
uvm2         579          7577          549        >20.4
uvw2         683          13859         1237       >21.1

The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E(B-V) = 0.053 mag towards
the direction of the burst (Schlegel et al. 1998).