* Astronomy

Title: Soft X-ray Spectroscopy of the Cygnus Loop Supernova Remnant
Authors: Randall L. McEntaffer, Webster Cash

The Cygnus X-ray Emission Spectroscopic Survey (CyXESS) sounding rocket payload was launched from White Sands Missile Range on 2006 November 20 and obtained a high resolution spectrum of the Cygnus Loop supernova remnant in the soft X-rays. The novel X-ray spectrograph incorporated a wire-grid collimator feeding an array of gratings in the extreme off-plane mount which ultimately dispersed the spectrum onto Gaseous Electron Multiplier (GEM) detectors. This instrument recorded 65 seconds of usable data between 43-49.5 A in two prominent features. The first feature near 45 A is dominated by the He-like triplet of O7 in second order with contributions from Mg10 and Si9-Si12 in first order, while the second feature near 47.5 A is first order S9 and S10. Fits to the spectra give an equilibrium plasma at \log(T)=6.2 (kT_e=0.14 keV) and near cosmic abundances. This is consistent with previous observations, which demonstrated that the soft x-ray emission from the Cygnus Loop is dominated by interactions between the initial blast wave with the walls of a precursor formed cavity surrounding the Cygnus Loop and that this interaction can be described using equilibrium conditions.

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