TITLE: GCN CIRCULAR NUMBER: 30000 SUBJECT: Short GRB 210323A: likely host galaxy detection DATE: 21/05/12 14:38:46 GMT FROM: Daniele B Malesani at DTU Space Daniele B. Malesani (DTU Space), Luca Izzo (DARK/NBI) and Andrea Rossi (INAF/OAS) report on behalf of a larger collaboration. We observed again the field of the short GRB 210323A (Gropp et al., GCN 29699). We used the ALFOSC camera at the Nordic Optical Telescope (NOT). Observations were carried out during the night of 2021 May 4, approximately 42.3 days after the GRB, and consisted of 5x600 s exposure in the r band. The optical source detected in our earlier observation (Malesani et al., GCN 29703; see also Pozanenko et al., GCN 29708; de Ugarte Postigo et al., GCN 29717; Rastinejad et al., GCN 29720) has clearly faded, confirming it is the afterglow of GRB 210323A. Directly underneath the position of the optical transient, a faint source is visible in the stack of our images, which is likely the host galaxy of the GRB (see also Rastinejad et al., GCN 29720). We measure for the host an AB magnitude r = 24.6 +- 0.3, calibrated against nearby stars from the Pan-STARRS catalogue. We acknowledge expert help from the support astronomer at the NOT, Amanda Djupvik.