[vsnet-grb-info 2942] Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4779
SUBJECT: Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
DATE:    06/02/18 17:01:28 GMT
FROM:    Frank Marshall at GSFC  <marshall at milkyway.gsfc.nasa.gov>

F. Marshall (GSFC), S. Immler (GSFC/USRA) and G. Cusumano (IASF-Pa INAF)
report on behalf of the Swift team:

The UVOT source reported by Cusumano et al. (GCN 4775) is detected in all
four UVOT finding chart exposures ranging from 153s to 1036s
from the burst trigger as shown in the table below. There is marginal
evidence for brightening in the V filter. The revised source position is
03:21:39.71 +16:52:02.6 (J2000) with an estimated 1-sigma error of about 1.0".
This position is within the XRT error circle (Kennea et al. GCN 4776).
We note the existence of a source in the USNO-B1 catalog
at 03:21:39.69 +16:52:02.2 with a B2 magnitude of 20.67
and an R2 magnitude of 20.3. Further UVOT observations
are underway to search for fading of this afterglow candidate.

T_start  Exposure   Filter   Mag   Mag. Range (1-sigma)
 153       200       V      19.6    19.1 - 20.3
 359       155       B      19.4    19.2 - 19.6
 830       127       B      19.3    19.1 - 19.5
1036       148       V      18.4    18.2 - 18.6