[vsnet-grb-info 4839] GRB 070621: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6573
SUBJECT: GRB 070621: Swift/UVOT Upper Limits
DATE:    07/06/22 17:22:32 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland at milkyway.gsfc.nasa.gov>

S. T. Holland (CRESST/GSFC/USRA) and B. Sbarufatti (INAF-IASFPA)
report on the behalf of the Swift UVOT team:


        The Swift/UVOT observed the field of GRB 070621 starting 120 s
after the BAT trigger (Sbarufatti, et al. 2007, GCN Circ. 6560).  We
do not find any source, in any of the UVOT observations, inside the
refined XRT error circle (Sbarufatti, et al., 2007 GCN Circ. 6567), or
at the location of the NOT source (Malesani, et al. 2007, GCN
Circ. 6565).

        The 3-sigma upper limits for detecting a source inside the
refined XRT error circle in the initial data products are:


Filter    T_start   T_stop    Exp(s)    Mag (3-sigma upper limit)
-----------------------------------------------------------------
V             226     1360       806    20.2
B             702      714        10    18.6
U             680     4799        88    19.7
UVW1          656     4744       236    20.3
UVM2          631      802        38    18.8
UVW2          733      752        19    18.1
White         120      954       204    21.3
-----------------------------------------------------------------

The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E_{B-V} = 0.05 mag in the
direction of the burst (Schlegel et al. 1998).