GCN Circular 8509
Subject
GRB 081109A: Possible Swift-UVOT detection
Date
2008-11-10T01:35:23Z (15 years ago)
From
Stefan Immler at NASA/GSFC <stefan.m.immler@nasa.gov>
S. Immler (CRESST/UMD/GSFC), N. P. M. Kuin (MSSL/UCL), and S. T. Holland
(CRESST/USRA/GSFC) report on behalf of the Swift UVOT team:
Further analysis of Swift Ultraviolet/Optical Telescope (UVOT) data of
GRB 081109A (Immler et al., GCN Circ. 8500), starting 75 sec after the
BAT trigger, gives a tentative detection of an optical source at the
reported REM position (D'Avanzo et al., GCN Circ 8501) in the white
filter at a 3.3-sigma level of confidence. The source is not detected in
any of the other UVOT filters at the limiting magnitudes reported below.
Filter Tstart(s) Tstop(s) Exp(s) Magnitude
wh 75 6592 745 21.6+/-0.3
u 287 6181 501 >21.5 (3-sigma UL)
b 543 6387 452 >20.9 (3-sigma UL)
uvw2 593 5362 274 >21.6 (3-sigma UL)
v 617 5566 274 >20.9 (3-sigma UL)
uvm2 641 5771 274 >21.5 (3-sigma UL)
uvw1 666 5976 255 >21.5 (3-sigma UL)
The possible detection in the white filter, combined with the lack of a
detection in the v filter, is consistent with the source having a
redshift greater than 5.5.
Follow-up observations, especially in the infrared, are encouraged.