[vsnet-grb-info 25432] GRB 200410A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27532
SUBJECT: GRB 200410A: Swift/UVOT Detection
DATE:    20/04/10 21:38:49 GMT
FROM:    Paul Kuin at MSSL  <npkuin at gmail.com>

N. P. M. Kuin (UCL-MSSL) and K. K. Simpson (PSU) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 200410A
104 s after the BAT trigger (Simpson et al., GCN Circ. 27518).
A source consistent with the XRT position (Goad et al. GCN Circ. 27522)
is detected in the initial UVOT exposures.

The uvot position has been determined from the first white image to be
RA  = 19:58:35.3
Dec = +51:46:53.0
or 299.64717 =51.78138 Deg (J2000) with an error estimate of 0.5".
There are two nearby stars visible at 4 and 6 arcsec.


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              104          254          147         19.51 +/- 0.14
v                 5051         6869          396         21.23 +/- 0.90
b                  572         1519           98         19.61 +/- 0.32
u                  317          567          246         20.39 +/- 0.37
w1                 696         1294           57        >19.8
m2                 671         1220           57        >20.0
w2                 622         1270           57        >19.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.15 in the direction of the burst
(Schlegel et al. 1998).