GRB200925B

We observed the location of the SWIFT GRB 200925B (trigger number #997453) with 0,7 m NUTTelA-TAO telescope at Assy-Turgen observatory, Almaty, Kazakhstan. The telescope started observation of the field of GRB 200925B 45 s after GRB trigger time (2020-09-25 21:50:37 UT).

Additional analysis of aperture photometry gives the following for the very early light curve in 45 s co-adds, where a negative mag is 5 sigma upper limit:

tc-t0 g’ sigma r’ sigma i’ sigma

67.5 -17.65 0.000 -18.40 0.000 18.32 0.303

136.5 -18.17 0.000 18.50 0.127 17.60 0.088

181.5 -17.80 0.000 -18.52 0.000 18.22 0.245

226.5 -18.27 0.000 18.04 0.084 17.50 0.076

271.5 -18.24 0.000 18.07 0.086 17.54 0.077

316.5 -18.32 0.000 18.23 0.097 17.52 0.079

361.5 -18.37 0.000 18.33 0.107 17.71 0.084

406.5 -18.18 0.000 18.29 0.117 17.61 0.088

Note well these values are not color corrected.

Note that the uncertainties have not been proven for all conditions and ranges of brightness.

Further reduction – improving uncertainty estimates and doing color corrections, is ongoing.