Fatkhullin, T. A.; Komarova, V. N.; Sokolov, V. V.; Moskvitin, A. S.; Gorosabel, J.; Sota, A.; Castro-Tirado, A. J.; de Ugarte Postigo, A.
GRB Coordinates Network, Circular Service, 11419, 1 (2010)
"Following the detection of the optical afterglow to the INTEGRAL GRB 101112A (Gotz et al., GCNC 11396), we have undertaken observations of the region with the 1.5-m telescope at Sierra Nevada Obs. (Spain) on Nov 13 and with the 6.0-m BTA at SAO-RAS in Zelenchukskaia (Russia) on Nov 14 and Nov 15. At the location of the optical afterglow (Guidorzi et al., GCNC 11397, de Ugarte Postigo et al., GCNC 11398) a faint source with R-band magnitude about 23 was detected on Nov 14.766 UT, which was below the detection limit on Nov 15.838 UT. This value should be compared with R = 15.6, as derived from the BOOTES-2/TELMA early time
images on Nov 12.9260 UT (a value that supersedes the one given on GCNC 11398 which was based on a wrong photometric calibration). The fact that the optical counterpart is blended (1."2) with a brighter star (with R about 18) has made useless the attempted spectroscopy on Nov 14.8 UT."
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