Latest OIR observations of GRO J1655-40

ATel #608; Michelle Buxton (Columbia Univ.) and Charles Bailyn (Yale Univ.)
on 16 Sep 2005; 01:01 UT
Credential Certification: Michelle Buxton (buxton@astro.yale.edu)

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We have been monitoring the black-hole X-ray transient GRO J1655-40 in optical and infrared (OIR) bands since the beginning of the current outburst (ATEL #414, #418). Observations are made daily (when possible) with the SMARTS 1.3m telescope at CTIO using the ANDICAM instrument. For approximately the last 130 days, GRO J1655-40 has remained at somewhat constant magnitudes, perhaps with a very gradual decline, in B, V, I, J and K bands. The largest overall difference observed over all bands is approximately 0.8 magnitude, although this represents the extreme difference over the past 130 days. There seems to be no obvious change in these bands in the past few days, unlike that seen recently in the X-rays (ATEL #607). We will continue monitoring GRO J1655-40 on a daily basis, when possible. Our latest light curves will be posted as soon as possible at : http://www.astro.yale.edu/buxton/smarts/light_curves/oir_gro.jpg