IR OBSERVATIONS OF SGR-1806-20 DURING THE NOVEMBER 1996 ACTIVE PERIOD

Following the announcement of a new period of activity of the soft gam ma-ray repeater SGR 1806-20 in 1996 November, we have performed follow -up observations of the LR counterpart, which has been proposed as a l uminous blue variable or B[e] star. We have found that no variability larger than 0.1 mag in the K-band is present in the data. No variation in the K-band flux is found either when comparing our observations (1 996 November 6 & 10) with a previous one (1996 July 3), nor any variat ion larger than 0.1 mag was detected in the K-band on 6 November at th e 1-second timescale. Assuming that a faint burst (with fluence S simi lar to 10(-9) erg cm(-2)) occurred during our observation, we can set an upper limit to the fluences rate (assuming a 1-s IR burst) as SIR(K -band)/Sgamma(25-130 keV) less than or equal to 10(-2). There is a mod est chance that no burst at all could have occurred during our observa tion. In that case the upper limit quoted here is considerably worse. Photometry revealed that the HK magnitudes are consistent with the val ues reported by Kulkarni et al. (1995) in 1993 October, but the J valu e is slightly different by about 0.4 mag.