GCN Circular 33329

B. Gendre, E. Moore, F. Panther, D. Coward, J. A. Moore (OzGrav-UWA),
A. Klotz (IRAP-CNRS-OMP), and P. Thierry (AGORA), report:

We imaged the field of GRB 230216A detected by SWIFT (trigger 1154815,
Klingler et al. GCN #33328
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 ) with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia.

The observations started 164.1s after the GRB trigger
(130.9s after the notice). The elevation of the field decreased from
64 degrees above horizon and weather conditions
were good.

The field is crowded and the star USNO-B1 0819-0175793 lies within the XRT
error box of the possible counterpart, making the analysis complex.
However, on a serie of exposures taken between T0+164s and T0+3006s,
the PSF of USNO-B1 0819-0175793 increases toward the North axis before
returning to a value compatible with the other nearby stars.

We would tentatively conclude that the optical afterglow is located
behind that star.
The coordinates of the afterglow would then be
RA = 07h35m50.1s (J2000)
DEC = -08d00m42.5s (J2000)

At the moment it is impossible to estimate the magnitude of the
afterglow; the limiting
magnitude of the images is R ~ 19. Further observations are planned.

N.B. Galactic coordinates are lon=225.1876 lat= +6.0956
and the galactic extinction in R band is 0.0 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

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