FAR-ULTRAVIOLET STUDY OF THE LOCAL SUPERSHELL GSH 006-15+7

Abstract

We have analyzed the archival data of far-UV (FUV) observations for the region of GSH 006-15+ 7, a large shell-like structure discovered by Moss et al. 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 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) similar to 30 cm(-3).