GCN Circular 6755
Subject
GRB070810B: Swift/UVOT Upper Limits
Event
Date
2007-08-11T19:32:53Z (18 years ago)
From
Peter Brown at PSU <pbrown@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).