TITLE:   GCN CIRCULAR
NUMBER:  31425
SUBJECT: GRB 220101A: Additional Liverpool telescope photometry
DATE:    22/01/09 20:17:08 GMT
FROM:    Daniel Perley at Liverpool JMU  <d.a.perley@ljmu.ac.uk>

D. A. Perley (LJMU) reports:

We acquired additional multicolor imaging of the optical afterglow of 
GRB 220101A (Tohuvavohu et al., GCN 31347) using the IO:O camera of the 
2m robotic Liverpool Telescope, on the nights (UT) of 2022-01-02, 
2022-01-03, 2022-01-04, 2022-01-05, and 2022-01-07.

Photometry with reference to SDSS secondary standard stars in
the field gives the following magnitudes:

dt(d)   filter	mag   unc
1.5924	r   	21.17 0.06
1.5958	i   	19.70 0.04
1.5991	z   	19.48 0.05
2.7070	z   	19.97 0.12
2.7120	i   	20.39 0.08
2.7154	r   	21.58 0.17
3.6932	z   	20.61 0.12
3.6983	r   	22.31 0.17
3.7032	i   	20.89 0.09
4.5961	z   	20.63 0.11
4.6011	i   	21.25 0.11
4.6045	r   	23.13 0.34
6.7021	i   	21.34 0.19

Magnitudes are given in the SDSS system and uncorrected for extinction.
Times are referenced to the BAT trigger time.





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