GCN Circular 28331

L. Izzo (DARK/NBI) reports:

We observed the field of GRB 200829A (Siegel et al., GCN #28307; Ursi et al., GCN #28314; Ridnaia et al., GCN #28323; Lesage & Meegan, GCN #28326) with the IO:O camera mounted on the 2-m Liverpool Telescope located in La Palma, Spain. Observations started on August 29 at 20:31:39 UT (0.272 days after the GRB trigger) and a second epoch was obtained on August 30 at 22:38:42 UT (1.362 days). In both epochs, we obtained a series of 5x60s images in the griz filters.
The optical afterglow (Siegel et al., GCN #28307, Pozanenko et al., GCN #28308; Kuin & Siegel, GCN #28311; Lipunov et al., GCN #28315; Vinko et al., GCN #28316; Hentunen et al., GCN #28318; Moskvitin et al., GCN #28322, GCN #28328, Zhu et al., GCN #28324, GCN #28330; Pankov et al., GCN #28329) is visible in the stacked images in both epochs. We measure the following preliminary AB magnitudes, calibrated against Pan-STARRS catalog stars:

Filter      mag     err     MJD

SDSS-g  18.91  0.05  (59090.855)
SDSS-g  21.17  0.09  (59091.944)
SDSS-r  18.76  0.04  (59090.860)
SDSS-r  21.34  0.10  (59091.948)
SDSS-i  18.65  0.04  (59090.865)
SDSS-i  21.25  0.09  (59091.953)
SDSS-z  18.57  0.04  (59090.870)
SDSS-z  20.50  0.08  (59091.958)