TITLE: GCN CIRCULAR NUMBER: 32471 SUBJECT: GRB 220813A: VLT optical observations and possible host galaxy DATE: 22/08/14 12:52:42 GMT FROM: Dong Xu at NAOC/CAS dxu@nao.cas.cn

H. Fausey (GWU), Z.P. Zhu (NAOC, HUST), P. D'Avanzo (INAF-OAB), D. B. Malesani (Radboud Univ. and DAWN/NBI), L. Izzo (DARK/NBI), D. A. Kann (IAA-CSIC), D. Xu (NAOC) report on behalf of the Stargate collaboration:

We observed the field of GRB 220813A (Bernardini et al., GCN 32465) using the ESO VLT/UT3 equipped with the X-shooter acquisition camera. Observations started at 08:06:45 UT on 2022-08-14 (i.e., ~12.73 hr after the BAT trigger) and consisted of 3x60 s, 4x60 s, 3x60 s exposures in the Sloan g-/r-/z- bands, respectively.

The previously reported optical afterglow (Bernardini et al., GCN 32465; Kuin & Bernardini, GCN 32470) is marginally detected in the stacked r-band image with r ~ 21.8 mag (AB), and is not detected in g-band and z-band with upper limits of g > 22.1 and z > 19.9, respectively (both AB).

In addition, we note that from Legacy Survey there exists a source at coordinates R.A. (J2000) = 05:26:07.5 and Dec.(J2000) = -33:00:59.2, being consistent with the Swift/UVOT position, which has photometric magnitudes of g ~ 24.99, r ~ 24.28 and z ~ 23.76 as well as photometric redshift of z ~ 0.82, which is the likely host galaxy of GRB 220813A.

We thank the great support of the ESO VLT staff, in particular Steffen Mieske and Michael Abdul-Masih.