[AAVSO-HEN] GRB 070509: Swift/UVOT Upper Limits

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  6404
SUBJECT: GRB 070509: Swift/UVOT Upper Limits
DATE:    07/05/10 16:00:38 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland at milkyway.gsfc.nasa.gov>

S. T. Holland (CRESST/GSFC/USRA) and L. Vetere (PSU)
report on the behalf of the Swift UVOT team:


       The Swift/UVOT observed the field of GRB 070509 starting 73 s
after the BAT trigger (Vetere et al. 2007, GCN Circ. 6394).  We do
not find any source, in any of the UVOT observations, inside the
refined XRT error circle (Vetere et al., 2007 GCN Circ. 6400).

       The 3-sigma upper limits for detecting a source anywhere inside
the refined XRT error circle in the co-added frames are:


Filter    T_start   T_stop    Exp(s)    Mag (3-sigma upper limit)
-----------------------------------------------------------------
V             179     6074      1003    20.6
B             657     1468        39    18.6
U             633     1443        58    18.4
UVW1          609     1419        58    18.0
UVM2          584     6085        65    17.5
UVW2          686     5869       236    19.3
White          73     1482       225    21.1
-----------------------------------------------------------------

The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E_{B-V} = 0.14 mag towards
the direction of the burst (Schlegel et al. 1998).