P. D'Avanzo (INAF-OAB), V. D'Elia (INAF/OAR & ASI/ASDC), V. Lorenzi, G. Mainella, W. Boschin, A. Garcia de Gurtubai Escudero (INAF-TNG) report on behalf of a larger collaboration:
We observed the field of GRB 150101B/Swift J123205.1-105602 (Cummings GCN 17267; Stanbro GCN 17276) using the NICS near-infrared camera on the 3.6m TNG Telescope (La Palma, Canary Islands).
We obtained two epochs of imaging observations in the J band on Jan 11 and Jan 16 at mean times of 9.62 and 14.56 days after the trigger, respectively.
In both epochs we covered about 50% of the the BAT error circle (Cummings GCN 17267) including the positions of the X-ray, optical and radio sources reported by Cummings et al. (GCN 17268), Fong et al. (GCN 17271), van der Horst et al. (GCN 17286), Fong (GCN 17288), Troja et al (GCN 17289), Campana (GCN 17318) and Levan et al. (GCN 17321).
Digital image subtraction between these two epochs carried out with the ISIS package (Alard 2000, A&AS, 144, 363) reveals no variable source within the field of view.
The 3sigma limiting magnitude is J > 20.8 for epoch #1 and J > 21.5 for epoch #2 (Vega system, calibrated against the 2MASS catalogue).