TITLE: GCN CIRCULAR NUMBER: 19945 SUBJECT: GRB 160925A: Bassano Bresciano Photometry of MASTER optical transient DATE: 16/09/27 09:44:27 GMT FROM: Ulisse Quadri at Bassano Bresciano Obs U.Quadri, L.Strabla and R.Girelli report: The photometrical observations of the MASTER optical transient (GCN 19938, 19939, 19941) Is it a possible optical counterpart to the FERMI GBM trigger 496473540 (GRB160925A). The optical transient has the ID MASTER OT J222817.90-145657.4. Observations made by the 250 mm F/4.8 Newton robotic telescope of (IAU station 565) Bassano Bresciano Observatory. Observations started on 2016-09-26 at 20h 04m UT and ended 2016-09-26 at 22h 32m UT Exposures time of 60 sec each. Reference star is: UCAC4 376-178184 Chk Star is: UCAC4 375-181914 ------------------------------------ CV Mag. T (JD)" OT Chk1 ------------------------------------ 2457658.33643518 16.089 13.981 2457658.33721064 15.947 13.953 2457658.33797453 16.051 13.976 2457658.33875000 16.019 13.962 2457658.33952546 16.026 13.991 2457658.34030092 15.986 13.963 2457658.34107638 16.060 13.968 2457658.34185185 16.065 13.969 2457658.34262731 16.132 13.977 2457658.34339120 16.060 13.991 2457658.34439814 16.072 13.973 2457658.34516203 15.988 13.983 2457658.34592592 16.043 13.959 2457658.34668981 16.069 13.981 2457658.34745370 15.963 14.002 2457658.34840277 16.083 13.969 2457658.34916666 16.035 13.958 2457658.34991898 16.068 13.963 2457658.35069444 16.054 13.989 2457658.35144675 15.944 13.975 2457658.35239583 15.962 13.986 2457658.35315972 16.040 14.013 2457658.35392361 16.072 13.995 2457658.35468749 15.956 13.976 2457658.35543981 15.983 13.990 2457658.35638888 15.992 13.980 2457658.35715277 16.010 13.969 2457658.35791666 15.996 13.990 2457658.35868055 15.974 13.971 2457658.35944444 15.992 13.989 2457658.36039351 16.111 13.952 2457658.36114583 16.004 14.008 2457658.36190972 15.980 13.991 2457658.36267361 15.939 13.978 2457658.36343749 16.035 14.001 2457658.36438657 15.972 13.985 2457658.36515046 16.028 13.989 2457658.36591435 16.055 13.989 2457658.36667824 16.063 13.989 2457658.36743055 16.015 13.987 2457658.36837962 16.036 13.976 2457658.36914351 15.971 13.997 2457658.36990740 15.935 13.997 2457658.37067129 16.016 13.963 2457658.37143518 16.077 14.017 2457658.37238425 15.977 13.968 2457658.37314814 15.985 13.995 2457658.37391203 15.905 13.959 2457658.37466435 15.941 13.974 2457658.37542824 15.998 13.982 2457658.37637731 16.002 13.971 2457658.37714120 15.934 13.970 2457658.37790509 15.859 13.949 2457658.37866898 15.994 13.950 2457658.37942129 16.021 13.966 2457658.38037037 16.015 13.978 2457658.38113425 16.142 13.966 2457658.38189814 15.944 14.019 2457658.38266203 16.022 13.975 2457658.38342592 16.174 13.992 2457658.38436342 16.119 14.019 2457658.38512731 16.109 13.959 2457658.38589120 16.112 13.966 2457658.38665509 15.908 13.963 2457658.38740740 16.054 13.975 2457658.38835648 16.030 13.987 2457658.38912037 16.184 13.968 2457658.39633101 16.020 14.001 2457658.39709490 15.941 13.967 2457658.39785879 16.160 13.989 2457658.39863425 15.937 13.958 2457658.39938657 16.069 13.992 2457658.40033564 16.051 13.993 2457658.40262731 16.062 13.963 2457658.40908564 15.910 14.006 2457658.40984953 16.049 13.979 2457658.41061342 16.024 13.953 2457658.41231481 16.074 13.989 2457658.41307870 16.090 13.996 2457658.41384259 15.901 13.986 2457658.41460648 16.137 13.986 2457658.41537037 16.033 13.994 2457658.41631944 16.053 13.972 2457658.41708333 16.132 13.979 2457658.41783564 16.025 13.963 2457658.41859953 16.029 13.968 2457658.41936342 16.067 13.987 2457658.42031250 16.031 13.965 2457658.42107638 16.007 13.978 2457658.42184027 16.031 13.950 2457658.42260416 15.986 13.958 2457658.42335648 16.055 13.939 2457658.42430555 16.011 13.949 2457658.42506944 15.992 13.983 2457658.42583333 15.966 13.978 2457658.42736111 16.004 13.967 2457658.42829861 16.053 13.975 2457658.42906250 16.132 13.953 2457658.42982638 15.971 13.933 2457658.43059027 16.006 13.955 2457658.43135416 16.138 13.985 2457658.43229166 15.972 13.962 2457658.43305555 15.962 13.966 2457658.43381944 16.082 13.962 2457658.43458333 15.992 13.944 2457658.43534722 15.873 13.947 2457658.43628472 15.986 13.972 2457658.43781250 16.153 13.968 2457658.43857638 16.018 13.957 Magnitudes were estimated with the UCAC4 cat. and are not corrected for galactic dust extinction. Reference: http://www.osservatoriobassano.org/GRB.asp The message may be cited.