Far-ultraviolet Emission-line Morphologies of the Supernova Remnant G65.3+5.7

TL;DR

This study presents the first far-ultraviolet emission-line morphologies of supernova remnant G65.3+5.7, revealing shock distributions, evolutionary asymmetries, and its advanced radiative stage compared to other remnants.

Contribution

It provides new FUV morphological data of G65.3+5.7, linking FUV features with optical and X-ray images, and offers insights into its evolutionary stage and shock structures.

Findings

FUV morphologies correlate with optical and X-ray images.

Differences in C IV and [O III] suggest resonant scattering and dust effects.

G65.3+5.7 is in a radiative evolutionary stage, with low X-ray luminosity.

Abstract

We present the first far-ultraviolet (FUV) emission-line morphologies of the whole region of the supernova remnant (SNR) G65.3+5.7 using the FIMS/SPEAR data. The morphologies of the C IV {\lambda}{\lambda}1548, 1551, He II {\lambda}1640, and O III] {\lambda}{\lambda}1661, 1666 lines appear to be closely related to the optical and/or soft X-ray images obtained in previous studies. Dramatic differences between the C IV morphology and the optical [O III] {\lambda}5007 image provide clues to a large resonant-scattering region and a foreground dust cloud. The FUV morphologies also reveal the overall distribution of various shocks in different evolutionary phases and an evolutionary asymmetry between the east and the southwest sides in terms of Galactic coordinates, possibly due to a Galactic density gradient in the global scale. The relative X-ray luminosity of G65.3+5.7 to C IV luminosity is considerably lower than those of the Cygnus Loop and the Vela SNRs. This implies that G65.3+5.7 has almost evolved into the radiative stage in the global sense and supports the previous proposal that G65.3+5.7 has lost its bright X-ray shell and become a member of mixed-morphology SNRs as it has evolved beyond the adiabatic stage.