Dense Gas Towards the RXJ1713.7−3946 Supernova Remnant

Abstract

Abstract: We present results from a Mopra 7 mm-wavelength survey that targeted the dense gas-tracing CS(1-0) transition towards the young γ-ray-bright supernova remnant, RX J1713.7−3946 (SNR G 347.3−0.5). In a hadronic γ-ray emission scenario, where cosmic ray protons interact with gas to produce the observed γ-ray emission, the mass of potential cosmic ray target material is an important factor. We summarise newly-discovered dense gas components, towards Cores G and L, and Clumps N1, N2, N3 and T1, which have masses of 1- 104 M. We argue that these components are not likely to contribute significantly to γ-ray emission in a hadronic γ-ray emission scenario. This would be the case if RX J1713.7−3946 were at either the currently favoured distance of ∼1 kpc or an alternate distance (as suggested in some previous studies) of ∼6 kpc. This survey also targeted the shock-tracing SiO molecule. Although no SiO emission corresponding to the RX J1713.7−3946 shock was observed, vibrationally-excited SiO(1-0) maser emission was discovered towards what may be an evolved star. Observations taken one year apart confirmed a transient nature, since the intensity, line-width and central velocity of SiO(J=1-0,v=1,2) emission varied significantly.