TITLE: GCN CIRCULAR NUMBER: 32647 SUBJECT: GRB 221009A: Nanshan/NEXT photometry and Xinglong-2.16m spectroscopy DATE: 22/10/10 09:19:26 GMT FROM: Dong Xu at NAOC/CAS D. Xu, S.Q. Jiang, S.Y. Fu, X. Liu (NAOC), Z.P. Zhu (NAOC, HUST), T.H. Lu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report: We observed the field of the optical counterpart of Swift J1913.1+1946 or GRB 221009A detected by Swift (Dichiara, GCN 32632), using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. Observations started at 14:25:55 UT on 2022-10-09, i.e., 762 s after the Swift/BAT trigger. A series of frames in the Sloan r- and z- filters were obtained. The optical counterpart is clearly detected in each of our images, which decays from r ~ 14.93 to r ~ 16.50 within ~ four hours, with a decay index of \alpha ~ 0.5 (F_t ~ t^-\alpha), calibrated the nearby PS1 stars. The decaying behavior is consistent with that for conventional GRBs. Spectroscopy of the optical counterpart was performed at the 2.16m telescope equipped with the BFOSC camera at Xinglong, Hebei, China. The spectrum covers the wavelength range 3800-9000 AA. The observation mid time is 2022 Oct 10.63 UT, i.e., 0.95 hr after the BAT trigger. The spectrum is dominated by a red continuum due to very high Galactic extinction, and no prominent absorption feature can be identified. Given the detections by Swift/UVOT as well as spectral continuum, the event could be real GRB 221009A at a rather low redshift. We thank the great support of the Xinglong-2.16m staff, in particular Junjun Jia, Min He, Aiying Zhou, and Jie Zheng.