TITLE: GCN CIRCULAR
NUMBER: 9308
SUBJECT: GRB 090429A: Swift/UVOT Upper Limits
DATE: 09/04/30 15:15:24 GMT
FROM: Stephen Holland at USRA/NASA/GSFC/SSC <Stephen.T.Holland at nasa.gov>
M. M. Chester (PSU), S. T. Holland (CRESST/GSFC/USRA) and
C. B. Markwardt (CRESST/GSFC/UMD) report on the behalf of the Swift
UVOT team:
The Swift/UVOT observed the field of GRB 090429A starting 49 s
after the BAT trigger (Markwardt, et al., 2009, GCN Circ. 9280).
Settled exposures started at T+67 s. We do not find any new source,
relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT
afterglow (Evans, et al. 2009, GCN Circ. 9297). 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
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white (fc) 67 217 147 >21.7
v 35,736 58,902 114 >19.8
b 40,727 63,010 1697 >22.1
u 52,833 53,121 284 >21.0
uvw1 50,447 86,297 3336 >22.2
uvm2 44,777 47,341 659 >20.9
uvw2 34,829 57,197 1746 >21.9
white 63,015 63,137 120 >21.5
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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} = 0.06 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).