GCN Circular 10143
Subject
GRB 091109: Swift/UVOT observations
Date
2009-11-09T12:24:27Z (15 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (MSSL-UCL) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began observerving the field of GRB 091109 156s
after the BAT trigger (Oates et al., GCN Circ. 10138). We detect the
optical afterglow in the white filter only, which faded rapidly.
The refined UVOT position is:
RA (J2000) 20:37:01.80
Dec (J2000) -44: 9:29.6
with an estimated uncertainty of 0.7 arcsec (radius, 90% confidence).
This position is consistent with the XRT refined position (Beardmore
et al., GCN Circ 10140).
Preliminary magnitudes and the 3 sigma upper limits are reported below.
Filter T_start(s) T_stop(s) Exposure Mag Err
###########################################################
white 156 306 147 19.88 +\- 0.14
white 5371 5571 197 > 21.26
v 4345 5981 393 > 19.94
b 5166 5365 197 > 20.49
u 314 6572 615 > 20.97
uvw1 4755 6392 393 > 20.59
uvm2 4550 6186 393 > 20.46
uvw2 4140 5777 393 > 20.68
###########################################################
The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.03 mag (Schlegel et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric system
described in Poole et al. (2008, MNRAS, 383,627).