[vsnet-grb-info 21620] GRB 190114A: Swift/UVOT Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23719
SUBJECT: GRB 190114A: Swift/UVOT Observations
DATE:    19/01/15 16:52:55 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18 at psu.edu>

M. H. Siegel (PSU) and S. J. LaPorte (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190114A
258 s after the BAT trigger (LaPorte et al., GCN Circ. 23677).
We confirm a source consistent with the XRT position (Evans et al. GCN
Circ. 23681) as initially reported in UVOT (Siegel \& LaPorte, GCN Circ. 23678)
 and later detected by GROND (Bolmer \& Schady, GCN Circ. 23682), OSN (de Ugarte
Postigo et al., GCN Circ. 23687) and NOT (Selsing et al., GCN Circ. 23697).
Notably, the optical counterpart was not seen in the initial finding chart and
had faded beyond detectability by the second orbit. The lack of detection in any
of the NUV filters would be consistent with the redshift of 3.4 reported by
de Ugarte Postigo et al. (GCN Circ. 23680).

The preliminary UVOT position is:
   RA  (J2000) =  04:22:10.55 =  65.54397 (deg.)
   Dec (J2000) = +02:11:29.6  =   2.19157 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).

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 (fc)         258          408          147        >20.58
white              514         1701          264         19.69+/-0.13
v                  564         1752          136         18.33+/-0.22
b                  490         1676          136         19.57+/-0.27
u                  465         1825          155        >19.64
uvw1               440         1801          155        >19.17
uvm2              5866         7502          393        >19.66
uvw2               540         1726          136        >19.12


The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.22 in the direction of the burst
(Schlegel et al. 1998).