One year of monitoring of the 2006 outburst in optical and low radio frequencies

Abstract

The evolution of the optical spectrum of RS Ophiuchi was monitored beginning 1 day since the 2006 outburst discovery to over a year after the outburst. The evolution of the spectrum is found to be similar to previous outbursts. The outburst was also monitored in the low radio frequency region, in the 0.610 GHz, 0.325 GHz and 0.240 GHz bands. The radio observations began ˜ 20 days after the discovery and continued until ˜ 400 days. The outburst was detected, for the first time at frequencies below 1 GHz. The low frequency radio emission is non-thermal and is well-explained by a synchrotron spectrum of index α ˜ -0.8 (S ∝ ν/sup^α) suffering foreground absorption due to the pre-existing, ionized, warm, clumpy red giant wind.