A. Rossi, E. Maiorano, and E. Palazzi (INAF-OAS) report on behalf of the CIBO collaboration:
We observed the field of the long GRB 230328B detected by Fermi-GBM (Fermi GBM Team, GCN 33526; Dalessi et al., GCN 33531), Swift-BAT (Gropp et al., GCN 33527), AstroSat-CZTI (Waratkar et al., GCN 33532), GRBAlpha (Dafcikova et al., GCN 33543), and Konus-Wind (Svinkin et al., GCN 33544). We obtained 20 min of g'- and r'-band imaging with the LBC camera mounted on LBT (Mt Graham, AZ, USA) on 2023-06-23, ~3 months after the burst trigger. Observations were performed under mediocre weather conditions with a strong SW wind and thus an average seeing of ~2".
At the location of the optical afterglow (Pankov et al., GCN 33528; Belkin et al., GCN 33530; Lu et al., GCN 33534; Catapano et al., GCN 33535; Suresh et al., GCN 33536; Adami et al., GCN 33537; Gompertz et al., GCN 33538; Komesh et al., GCN 33539; Kumar et al., GCN 33547; Kugel et al., GCN 33550; Siegel et al., 33556; Pozanenko et al., GCN 33559), we detect a faint source which is likely the GRB host galaxy. We measure the following AB magnitudes:
g 24.2 +- 0.3
r 23.8 +- 0.2
calibrated against PanSTARRS field stars, and not corrected for the foreground Galactic extinction.
We acknowledge the excellent support from the LBTO and LBT-INAF staff, particularly D. Thompson, D. Gonzalez Huerta, F. Cusano and D. Paris, in obtaining these observations.