GCN Circular 32335

Subject

GRB 220706A: Nanshan/NEXT optical upper limits

Event

GRB 220706A

Date

2022-07-07T02:45:18Z (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 220706A detected by Swift (D'Ai et al., GCN 
32329Loading...
 
 ) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, 
China. We obtained 7x200 s frames in the Sloan r-band and 5x200 s frames 
in the Sloan z-band, starting at 20:21:09 UT on 2022-07-06, i.e., 4.2 hr 
after the BAT trigger.

No optical source is detected in our stacked images at the enhanced XRT 
position (Goad et al., GCN 32333Loading...
 
 ), with upper limits as follows:

T_mid-T0 (hr)    Filter   Upper limit(3-sigma)
    4.41                 r          >20.7
    4.79                 z          >18.8

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