Bibcode
Castro-Tirado, A. J.; Gorosabel, J.; Hammersley, P.
Referencia bibliográfica
Astronomy and Astrophysics, v.330, p.1067-1069 (1998)
Fecha de publicación:
2
1998
Revista
Número de citas
3
Número de citas referidas
2
Descripción
Following the announcement of a new period of activity of the soft
gamma-ray repeater SGR 1806-20 in 1996 November, we have performed
follow-up observations of the IR counterpart, which has been proposed as
a luminous 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 (1996
November 6 & 10) with a previous one (1996 July 3), nor any
variation larger than 0.1 mag was detected in the K-band on 6 November
at the 1-second timescale. Assuming that a faint burst (with fluence S ~
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 S_IR ({sl
K-band)}/S_{gamma (25-130 keV)} <= 10(-2) . There is a modest
chance that no burst at all could have occurred during our observation.
In that case the upper limit quoted here is considerably worse.
Photometry revealed that the HK magnitudes are consistent with the
values reported by Kulkarni etal. (1995) in 1993 October, but the J
value is slightly different by about 0.4 mag. Based on observations made
with the Carlos Sánchez Telescope operated on the island of
Tenerife in the Spanish Observatorio del Teide of the Instituto de
Astrof\'{i