GCN Circular 32355

Subject

GRB 220708B: Nanshan/NEXT optical upper limits

Event

GRB 220708B

Date

2022-07-09T03:18:20Z (4 years ago)

From

Dong Xu at NAOC/CAS <dxu@nao.cas.cn>

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

We observed the field of GRB 220708B detected by Swift/BAT-GUANO 
(Tohuvavohu et al., GCN 32345Loading...
 
 ) using the NEXT-0.6m telescope located at 
Nanshan, Xinjiang, China. We obtained 10x200 s frames in the Sloan 
r-band and 9x200 s frames in Sloan z-band, starting at 19:15:57.859 UT 
on 2022-07-08,i.e.,17.15 hr after the BAT trigger.

No optical source is detected in our stacked images at the  XRT 
afterglow position (Osborne et al., GCN 32350Loading...
 
 ), with upper limits as 
follows:

T_mid-T0 (hr)    Filter   Upper limit(3-sigma)
    17.42               r         >21.60
    17.96               z         >19.54

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