Abstract:
We report GHz observations beginning 4.5 days after the discovery of RS
Ophiuchi undergoing its 2006 recurrent nova outburst. Observations over
the first 60 days are included, enabling us to follow spectral development
throughout the three phases of the remnant development. We see dramatic
brightening on days 4 to 7 at 6 GHz and an accompanying increase in other
bands, particularly 1.46 GHz, consistent with transition from the initial
phase to the adiabatic expansion phase. This is complete by day 13 when
the brightness at 5 GHz is apparently declining from an early maximum
(compared with 1985 observations). The flux recovered to a second peak by
approximately day 40, consistent with behaviour observed in 1985. At all
times the spectral index is consistent with combined thermal and
non-thermal components. The emission requires at least 4±2×10/sup−7M
of ejecta.
