GCN Circular 8790
Subject
GRB 090107B: Swift/UVOT Observations
Event
Date
2009-01-07T21:41:56Z (18 years ago)
From
Frank Marshall at GSFC <marshall@milkyway.gsfc.nasa.gov>
F.E. Marshall (NASA/GSFC)
reports on behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 090107B starting 4396 s after
the INTEGRAL trigger (Gotz et al., GCN Circ. 8786). No optical afterglow
is detected in the initial UVOT exposures at the position
of the candidate X-ray afterglow (Perri et al., GCN Circ. 8789).
There is also no obvious optical afterglow candidate
elsewhere in the INTEGRAL error circle.
The 3-sigma upper limits in the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for detecting
a source at the position of the XRT candidate are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 5420 5535 113 >20.9
v 4396 4595 197 >19.6
b 5216 5415 197 >20.3
u 5010 5209 197 >20.1
uvw1 4806 5005 197 >20.3
uvm2 4600 4799 197 >20.3
uvw2 4191 4390 197 >20.6
The values quoted above are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.046 in the direction of the burst
(Schlegel et al. 1998).