[vsnet-grb-info 21883] GRB 190320A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23982
SUBJECT: GRB 190320A: Swift/UVOT Upper Limits
DATE:    19/03/20 16:22:03 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall at milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190320A
2834 s after the BAT trigger (Gropp et al., GCN Circ. 23973).
No optical afterglow consistent with the XRT position
(Lipunov et al. GCN Circ. 23976)
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          2834         2984          147         >20.0
white             2834        16112         1213         >21.4
v                 2992        21862         1645         >20.4
b                 3812        15216         1082         >20.8
u                 3607         3807          197         >19.6
w1                3402         3602          197         >19.5
m2                3196        22200          524         >19.8
w2                4223        20949         1776         >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.23 in the direction of the burst
(Schlegel et al. 1998).