[vsnet-grb-info 23696] GRB 190919B: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25795
SUBJECT: GRB 190919B: Swift/UVOT Upper Limits
DATE:    19/09/20 20:58:25 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall at milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and A. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190919B
28564 s after the INTEGRAL trigger (Mereghetti et al., GCN Circ. 25788).
No optical afterglow consistent with the optical position
(Bolmer, GCN Circ. 25789; Tyurina et al. GCN Circ. 25791)
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

u_FC             28987        29196          206         >20.3
v                30258        36440          225         >19.6
b                29201        36022          301         >20.2
u                28987        35920          301         >20.7
w1               28564        35819          602         >20.8
m2               30471        30737          262         >20.3
w2               29416        36416         1204         >21.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).