[vsnet-grb-info 27350] GRB 210209A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29453
SUBJECT: GRB 210209A: Swift/UVOT Upper Limits
DATE:    21/02/10 14:39:45 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld at ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and S. L. Laha (GSFC/UMBC/CRESST) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210209A 127 s after the BAT trigger 
(Laha et al., GCN Circ. 29442).
No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 29443) is detected in 
the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. 
Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:

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

white_FC           127          276          147         >20.3
u_FC               285          535          246         >19.4
white              127          952          275         >20.4
v                  615         4730          236         >19.1
b                  540          733           39         >18.8
u                  285         5225          345         >19.8
w1                 664         5140          236         >19.7
m2                 639         4934          236         >19.4
w2                 590         4525          236         >20.5

The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of 
E(B-V) = 0.286 in the direction of the burst (Schlegel et al. 1998).