TITLE:   GCN CIRCULAR
NUMBER:  31980
SUBJECT: GRB 220430A: CAHA 2.2m telescope optical limit
DATE:    22/05/01 09:53:15 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, T.-R. Sun, M. D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia and A. J. Castro-Tirado (IAA-CSIC), R. Minguez and I. Vico (CAHA) on behalf of a larger collaboration, report:

Following the detection of GRB 220430A by Swift (Ambrosi et al. GCNC 31972) and AGILE (Ursi et al. GCNC 31975), we triggered the 2.2m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almeria, Spain). Images were gathered after the twilight starting on Apr. 30 20:15 UT (i.e. 6.4 hrs post trigger) in Sloan-gri at high airmass. On the co-added Sloan-i band image (8x60s), no optical transient down to 22.1 mag is detected at the X-ray afterglow candidate position reported by Swift/XRT (Ambrosi et al. GCNC 31972, J.P. Osborne et al. GCNC 31973). This non-detection is consistent with the report from Groot et al. (GCNC 31974), Pankov et al.(GCNC 31976), Dornic et al. (GCNC 31977) and V. Lipunov et al.(GCNC 31978).

We thank the staff at Calar Alto observatory for their excellent support.