[vsnet-grb-info 27110] GRB 201229A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29213
SUBJECT: GRB 201229A: Swift/UVOT Detection
DATE:    21/01/01 02:06:07 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18 at psu.edu>

M. H. Siegel (PSU) and B. Sbarufatti (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 201229A
117 s after the BAT trigger (Sbarufatti et al., GCN Circ. 29192).
A source consistent with the XRT position
(Osborne et al. GCN Circ. 29193) is detected in the initial UVOT exposures, consistent
with the optical transient reported in the initial circular and confirmed by
SAO (Moskvitin et al., GCN Circ. 29203) and AbAO (Pankov et al., GCN Circ. 29205).

The preliminary UVOT position is:
    RA  (J2000) =  14:02:45.40 = 210.68916 (deg.)
    Dec (J2000) = +48:11:53.3  =  48.19814 (deg.)
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white (fc)         117          266          147      18.22 +/- 0.05
white              555          749           38      18.50+/-0.13
white              879         1029          147      19.17+/-0.13
white             1182         1548           58      19.42+/-0.34
white            23280        24102          801      20.88+/-0.22
v                  605         1597          116     >18.48
v                17146        34853         1217     >20.39
b                  531         1523           97     >19.33
b                22367        23274          885     >21.24
u (fc)             275          525          245      18.13+/-0.09
u                  680         5086          107      18.57+/-0.25
u                12362        29756         1220      20.54+/-0.34
uvw1               654         5071          254      19.04+/-0.25
uvw1             28021        28921          885     >20.45
uvw2             16239        34408         1771      20.27+/-0.21

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).