[vsnet-grb-info 4243] GRB 070125: UVOT Detection in Ultraviolet Filters

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6041
SUBJECT: GRB 070125: UVOT Detection in Ultraviolet Filters
DATE:    07/01/26 22:04:19 GMT
FROM:    Frank Marshall at GSFC  <marshall at milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC), D. E. vanden Berk (PSU), and 
J. Racusin (PSU) report on behalf of the Swift team:

The afterglow of GRB 070125 (Hurley et al., GCN Circ. 6024)
has now been detected in all 6 UVOT filters ranging from
V (central wavelength of 546 nm) to UWW2
(central wavelength of 193 nm).
The decay in the V filter is consistent
with a 1/t decay rate. Detection in the UVW2
filter requires a redshift of < 1.5, which
is consistent with earlier suggestions by
Prochaska et al. (GCN 6031 and 6032) and
Pelangeon and Atteia (GCN 6033).

The table below gives the measured magnitudes. 
T_start and T_end are the start and stop
times of the summed exposures in seconds from the trigger.
No correction has been made for the expected
Galactic reddening of E(B-V) = 0.05.

Filter  T_start   T_end  Exposure  Mag   Error
V       46685     53261   1736    18.54  0.06
V       58269     63986   1590    18.74  0.07
V      116966    117176    205    19.26  0.27
B       47550     54163   1674    18.92  0.03
B       59126     59947    798    19.03  0.06
UVW2   116119    116959    840    19.26  0.10