New optical images of the young supernova remnant ( SNR ) G292.0+1.8 , obtained from the 0.9-m telescope at CTIO , show a more extensive network of filaments than had been known previously .
Filaments emitting in [ O iii ] Â are distributed throughout much of the 8 arcmin diameter shell seen in X-ray and radio images , including a few at the very outermost shell limits .
In addition to the extensive [ O iii ] Â filaments , we have detected four small complexes of filaments that show [ S ii ] Â emission along with the oxygen lines .
In a single long-slit spectrum we find variations of almost an order of magnitude in the relative strengths of oxygen and sulfur lines , which must result from abundance variations .
None of the filaments , with or without [ S ii ] , shows any evidence for hydrogen , so all appear to be fragments of pure supernova ejecta .
The [ S ii ] Â filaments provide the first evidence for undiluted products of oxygen burning in the ejecta from the supernova that gave rise to G292.0+1.8 .
Some oxygen burning , either hydrostatic or explosive , must have occurred , but the paucity of [ S ii ] -emitting filaments suggests that either the oxygen burning was not extensive or that most of its products have yet to be excited .
Most of the outer filaments exhibit radial , pencil-like morphologies that suggest an origin as Rayleigh-Taylor fingers of ejecta , perhaps formed during the explosion .
Simulations of core-collapse supernovae predict the development of such fingers , but these have never before been so clearly observed in a young SNR .
Following careful subtraction of the stars in the field , we have measured the total flux in [ O iii ] \ > \lambda 5007 as 5.4 \times 10 ^ { -12 } \ > { ergs\ > cm ^ { -2 } \ > s ^ { -1 } } .
Using a distance of 6 kpc and an extinction correction corresponding to E ( B - V ) = 0.6 Â mag ( lower than previous values but more consistent both with our data and with X-ray and radio measurements of the hydrogen column density ) leads to a luminosity of 1.6 \times 10 ^ { 35 } \ > { ergs\ > s ^ { -1 } } Â in the 5007 Ã Â line .