[vsnet-grb-info 7374] GRB 090305: Swift/UVOT Upper Limits
GCN Circulars
gcncirc at capella.gsfc.nasa.gov
Fri Mar 6 21:49:32 JST 2009
TITLE: GCN CIRCULAR
NUMBER: 8938
SUBJECT: GRB 090305: Swift/UVOT Upper Limits
DATE: 09/03/06 12:49:24 GMT
FROM: Stephen Holland at USRA/NASA/GSFC/SSC <sholland at milkyway.gsfc.nasa.gov>
S. T. Holland (CRESST/GSFC/USRA) and A. P. Beardmore (U Leicester)
report on the behalf of the Swift UVOT team:
The Swift/UVOT observed the field of GRB 090305 starting 78 s
after the BAT trigger (Beardmore, et al. 2009, GCN Circ. 8932).
Settled exposures started at T+96 s. We do not find any new source,
relative to the DSS, USNO-B1.0, or 2MASS, or any variable source at
the position of the GMOS-S afterglow (Cenko, et al. 2009, GCN
Circ. 8933). Preliminary 3-sigma upper limits for detecting a source
in the white finding chart, and the co-added images, using a 2.5
arcsecond radius circular aperture, are
Filter T_start T_stop Exp(s) Mag
------------------------------------------
white 96 198 100 >20.6
v 3503 11,765 1034 >20.6
b 4323 15,980 1278 >21.8
u 4118 5755 393 >20.6
uvw1 3913 5550 393 >20.6
uvm2 3708 5345 393 >20.3
uvw2 4734 17,549 1723 >21.6
white 4528 16,892 1982 >22.7
------------------------------------------
The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.21 mag (Schlegel, et al., 1998, ApJS, 500,
525). All photometry is on the UVOT photometry system described in
Poole et al. (2008, MNRAS, 383, 627).
The GMOS-S afterglow is located in the wings of the B = 13.72
mag USNO-B1.0 star 0584-0391760. UVOT photometry at this location is
contaminated by this star.
Please update my e-mail address in your Address Book to <Stephen.T.Holland at nasa.gov
>.
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