The HI supershell GS 118+01-44 and its role in the interstellar medium

TL;DR

This study characterizes the HI supershell GS 118+01-44 using multiwavelength data, analyzing its properties, origin, and star formation activity, revealing it is not solely formed by OB stars but is still an active star-forming region.

Contribution

It provides a detailed multiwavelength analysis of GS 118+01-44, assessing its origin and star formation activity, and concludes additional energy sources are needed beyond OB stars.

Findings

GS 118+01-44 is located at 3.0 +- 0.6 kpc from the Sun.

OB stars alone cannot account for the supershell's formation.

The region shows ongoing star formation at its edges.

Abstract

We carry out a multiwavelength study to characterize the HI supershell designated GS 118+01-44, and to analyse its possible origin. A multiwavlength study has been carried out to study the supershell and its environs. We performed an analysis of the HI, CO, radio continuum, and infrared emission distributions. The Canadian Galactic Plane Survey (CGPS) HI data reveals that GS 118+01-44 is centred at (l, b) = (117.7, 1.4) with a systemic velocity of -44.3 km/s. According to Galactic rotation models this structure is located at 3.0 +- 0.6 kpc from the Sun. There are several HII regions and three supernova remnants (SNRs) catalogued in the region. On the other hand, the analysis of the temperature spectral index distribution shows that in the region there is a predominance of non-thermal emission. Infrared emission shows that cool temperatures dominate the area of the supershell. Concerning the origin of the structure, we found that even though several OB stars belonging to Cas OB5 are located in the interior of GS 118+01-44, an analysis of the energy injected by these stars through their stellar winds indicates that they do not have sufficient energy to create GS 118+01-44. Therefore, an additional energy source is needed to explain the genesis of GS 118+01-44. On the other hand, the presence of several HII regions and young stellar object candidates in the edges of GS 118+01-44 shows that the region is still active in forming new stars.