Far-ultraviolet study of the local supershell GSH 006-15+7

TL;DR

This study uses far-ultraviolet observations and simulations to analyze the large supershell GSH 006-15+7, estimating its distance, dust scattering properties, and molecular hydrogen content, revealing insights into its structure and composition.

Contribution

It provides the first detailed FUV analysis of GSH 006-15+7, estimating its distance and physical properties through combined observational and simulation approaches.

Findings

Distance to supershell estimated at 1300 ± 800 pc.

Detected molecular hydrogen fluorescence indicating PDR presence.

Derived high hydrogen density of approximately 30 cm^{-3}.

Abstract

We have analyzed the archival data of FUV observations for the region of GSH 006-15+7, a large shell-like structure discovered by Moss et al. (2012) from the H I velocity maps. FUV emission is seen to be enhanced in the lower supershell region. The FUV emission is considered to come mainly from the scattering of interstellar photons by dust grains. A corresponding Monte Carlo simulation indicates that the distance to the supershell is 1300 +- 800 pc, which is similar to the previous estimation of 1500 +- 500 pc based on kinematic considerations. The spectrum at lower Galactic latitudes of the supershell exhibits molecular hydrogen fluorescence lines; a simulation model for this candidate photodissociation region (PDR) yields an H_2 column density of N(H_2) = 10^{18.0-20.0} cm^{-2} with a rather high total hydrogen density of n_H ~ 30 cm^{-3}.