[vsnet-grb-info 3018] GRB060219: Liverpool Telescope observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4855
SUBJECT: GRB060219: Liverpool Telescope observations
DATE:    06/03/09 14:11:34 GMT
FROM:    Evert Rol at U.Leicester  <er45 at star.le.ac.uk>

E. Rol (U of Leicester), N. Tanvir (U of Hertsfordshire) and
C. Mundell (Liverpool JMU), report on behalf of a larger
collaboration:

We have observed the X-ray position of GRB060219 (Moretti, GCN4788,
GCN4797) with the 2m Liverpool Telescope, on two nights in r'- and
i'-bands. Within the images, we detect the SDSS-source mentioned by
Moretti (GCN4801). In the first epoch r'-band, a very faint source
just outside the XRT error circle can be seen as well, with r' ~ 23.4.
Image subtraction of the r'-band images between the two epochs shows
no variability of the galaxy. The faint source is not visible on the
second epoch image, but the second observation is slightly shallower
than the first observation, and its estimated source magnitude is
around the limiting magnitude of that image.
The defringed i'-band images unfortunately suffer from residual
fringing and could therefore not be used for image subtraction. No
sign of the faint source is seen in these images.

Our 3-sigma limiting magnitudes, measured in a aperture equal to 1
times the estimated seeing, and calibrated to the SDDS-r' and i'
magnitudes, are as follows:

       time             filter          limiting 
(days post trigger)                    magnitude
      0.220               r'             23.7
      4.15                r'             23.5
      0.276               i'             22.9
      4.17                i'             22.6

We note that the galaxy inside the XRT error circle appears to have
slightly different magnitudes than those quoted by Moretti
(GCN4801). According to the SDSS derived model magnitudes (Cool,
GCN4789), its magnitudes are u' = 25.105, g' = 22.698, r' = 21.941, i'
= 21.153 and z' = 20.491. The r' and i' magnitudes are in agreement
with the estimates from our photometry.