TITLE:   GCN CIRCULAR
NUMBER:  33540
SUBJECT: GRB 230328B: Nanshan/NEXT 2nd optical observation
DATE:    23/03/30 01:53:10 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

T.H. Lu, S.Q. Jiang, S.Y. Fu, X. Liu (NAOC), Z.P. Zhu (NAOC, HUST), D. 
Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:

We observed the field of GRB 230328B detected by Swift (Gropp et al., 
GCN 33527) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, 
China. We obtained 12x300 s frames in the Sloan r-band, starting at 
14:49:11 UT on 2023-03-29 (i.e., 23.9 hr after the BAT trigger).

The optical afterglow (e.g., 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) is not detected in our stacked image. 
Preliminary photometric result is as follows:

T_mid-T0 (hr)   Filter   Upper limit(3-sigma)
    24.42             r           >21.0

calibrated with the nearby PanSTARRS field and not corrected for 
Galactic extinction.