T. Poole (MSSL), C. Hurkett (Leicester), S. Hunsberger (PSU), A. Breeveld
(MSSL), P. Boyd (GSFC), N. Gehrels (GSFC), K. Mason (MSSL), J. Nousek
(PSU), on behalf of the Swift UVOT team
The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of
GRB050509a on May 09, 2005 at 01:47:20.5 UT, 52 seconds after the initial
Swift BAT trigger (Hurkett et al., GCN 3379). The XRT error circle
(Kennea et al., GCN 3380) falls partially on a known source from the DSS.
We detect no new sources at the Swift XRT position (Kennea et al, GCN
3380). The limiting magnitudes (in 6" radius apertures) in each of the
UVOT filters are as follows:
Filter Lim_Mag Lim_mag Total duration T_start T_mid
5sigma 3sigma (s) (s) (s)
V 18.23 18.79 191 52 1853
UVW1 18.97 19.52 210 5722 5827
UVM2 20.29 20.84 921 3763 4739
UVOT only observed GRB050509b in V, UVW1 and UVM2 because it's run of
observations were interrupted by GRB050509b.
The magnitudes are based on preliminary zero-points, measured in
orbit, and will require refinement with further calibration.
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