TITLE:   GCN CIRCULAR
NUMBER:  32217
SUBJECT: GRB220611A: Gemini Optical Afterglow Confirmation
DATE:    22/06/18 13:24:01 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>

B. O’Connor (UMD/GWU), E. Troja (U Tor Vergata/ASU) , S. Dichiara (PSU),
and S. B. Cenko (NASA/GSFC) report on behalf of a larger collaboration:

We carried out additional target of opportunity observations of GRB220611A
(Cenko et al.
GCN 32191) with the Gemini Multi Object Spectrograph (GMOS) mounted on the
Gemini-South
telescope. The observations began 5.7 d after the GRB trigger, and were
performed in
i-band for a total exposure of 540 s.

We detect the source reported by O’Connor et al. (GCN 32203) with magnitude
i~21 AB.
This source is not detected in archival images from the Dark Energy Survey
(Abbott et
al. 2021), and is likely the GRB afterglow. We determine that the X-ray,
optical,
and infrared data (O’Connor et al. GCN 32203, Rastinejad et al. GCN 32208)
can be
modeled by a power-law with spectral index beta~1.

Further observations are planned.

We thank the Gemini staff for rapid scheduling of these observations.