TITLE:   GCN CIRCULAR
NUMBER:  36115
SUBJECT: GRB 240414A: Swift/UVOT Detection
DATE:    24/04/15 13:29:21 GMT
FROM:    Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>

M. H. Siegel (PSU) and R. Caputo (GSFC) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240414A
9754s after the BAT trigger (Caputo et al., GCN Circ. 36083). A source consistent
with the XRT position (Obsorne et al., GCN Circ. 36102) and the previously reported
optical counterpart (Schneider et al., GCN Circ. 36084, Aryan et al., GCN Circ. 36094,
Dutton et al., GCN Circ. 36097, Xu et al., GCN Circ. 36105, Pankov et al., GCN Circ. 36113)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  12:19:08.09 = 184.78370 (deg.)
    Dec (J2000) = +56:44:28.6  =  56.74127 (deg.)
with an estimated uncertainty of 0.4 arc sec. (radius, 90% confidence).

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

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
b                 9754        10628          853      19.23+/-0.07
uvm2             15403        16303          885            >20.33
u                22136        22862          707      19.29+/-0.11
v                62457        62769          302            >19.60
uvw1             16310        22129         1262      20.04+/-0.18
uvw2             26698        27465          755            >20.54

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).