[vsnet-grb-info 11512] GRB 120202A: Swift/XRT and UVOT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12911
SUBJECT: GRB 120202A: Swift/XRT and UVOT observations
DATE:    12/02/03 21:55:00 GMT
FROM:    Giulia Stratta at ASDC  <giulia.stratta at gmail.com>

S. Holland (NASA/GSFC), V. D'Elia (ASDC), G. Stratta (ASDC),
R. Starling (U. Leicester) report on behalf of the Swift team:

We have analysed 4.5 ks of XRT data for the INTEGRAL-detected burst:
GRB 120202A (Mereghetti et al., GCN Circ. 12909), from 33.9 ks to 58.6 ks
after the INTEGRAL trigger.
The data are entirely in Photon Counting (PC) mode.
An X-ray source is detected within the INTEGRAL error circle at:
RA, Dec = 203.503595, 22.773873 deg which is equivalent to:

RA (J2000): 13h 34m 00.86s
Dec(J2000): +22d 46' 25.94"

with an uncertainty of 4.8 arcsec (radius, 90% confidence).
The source count rate is 3.26E-03+/-1.1E-03 cts/s (1 sigma error).
This position is 10.1 arcsec from the INTEGRAL position.
We note that there is a bright SDSS galaxy at about 32 arcseconds
from the burst position, within the INTEGRAL error circle.
At the present time we can not assess whether the source is fading or not.

The Swift/UVOT observed the field of GRB 120202A starting 33,899 s
after the INTEGRAL/IBAS trigger.
We do not detect an optical afterglow inside the XRT error circle.
Preliminary 3-sigma upper limits for detecting a source in the the co-added
images are

Filter       TSTART       TSTOP  EXPOSURE       Mag
---------------------------------------------------
v            35,727      64,596       485     >20.0
u            33,899      64,484      2884     >22.0
white        34,522      64,580      1305     >22.4
---------------------------------------------------

The quoted magnitudes and upper limits have not been corrected for
the Galactic extinction along the line of sight to this burst of
E_{B-V} = 0.02 mag (Schlegel et al. 1998, ApJS, 500, 525).