TITLE: GCN CIRCULAR NUMBER: 43893 SUBJECT: GRB 260228A: CAHA 2.2m telescope optical upper limit DATE: 26/03/01 22:42:20 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es> S. Guziy (IAA-CSIC), Y.-D. Hu (GXU), M.D. Caballero-García, M. Gritsevich, I. Pérez-García, R. Sánchez-Ramírez, S-Y. Wu (IAA-CSIC), G. García-Segura (UNAM), M. Blazek, I. Vico (CAHA) and A.J. Castro-Tirado (IAA-CSIC), on behalf of a larger collaboration, report: Following the detection of GRB 260228A by SVOM/ECLAIRs (Julakanti et al., GCNC 43882), we triggered the 2.2 m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almería, Spain). Images were obtained starting on Mar. 1 at 03:34 UT (i.e., ~6.7 hours after the trigger) in the Sloan griz bands covering the entire error region. In the co-added images (60 × 6 s), no optical transient is detected down to limiting magnitudes of 22.1 mag (r') and 21.0 (i'). This non-detection is consistent with the reports from SVOM/VT (Li et al., GCNC 43886) and SVOM/COLIBRÍ (Mandarakas et al. GCNC 43892). We thank the staff at Calar Alto Observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/43893. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...