[vsnet-grb-info 4404] GRB 070309: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6185
SUBJECT: GRB 070309: Swift/UVOT Upper Limits
DATE:    07/03/09 20:54:28 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland at milkyway.gsfc.nasa.gov>

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

     Swift/UVOT observed the field of GRB 070309 (Paizis, et al. 2007,
GCN Circ. 6182) starting 13,906 s after the INTEGRAL/IBAS trigger.
UVOT did not detect any source inside the INTEGRAL error circle,
relative to the DSS, down to the following 3 sigma upper limits.

Filter  t_start(s)  t_stop(s)  Exp(s)  Mag 3-sig UL

    V      14,525     14,868      274      19.3
    B      14,215     14,365      147      20.0
    U      14,061     14,211      147      19.7
  UVW1     13,906     14,056      147      19.6
  UVM2     14,930     15,080      147      19.5
  UVW2     14,371     14,446      147      19.8

These upper limits are not corrected for the Galactic extinction,
corresponding to a reddening of E_{B-V} = 1.46 mag (Schlegel et
al. 1998), in the direction of this burst.  We note that this
burst lies in the Galactic plane towards the Galactic centre and
the field is very crowded.