The H i  supershell GS 118+01−44  and its role in the interstellar medium

¹ Instituto Argentino de Radioastronomía (CCT-La Plata, CONICET), CC 5, 1894, Villa Elisa, Argentina
e-mail: lasuad@iar.unlp.edu.ar
² Instituto de Astronomía y Física del Espacio (CONICET-UBA), Cuidad Universitaria, C.A.B.A, Argentina
³ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore DM 21218, USA
⁴ Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, La Plata, Argentina
⁵ Canada-France-Hawaii Telescope Corporation, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743, USA

Received: 26 November 2014
Accepted: 16 October 2015

Abstract

Aims. We carry out a multiwavelength study to characterize the H i  supershell designated GS 118+01−44, and to analyse its possible origin.

Methods. A multiwavelength study has been carried out to study the supershell and its environs. We performed an analysis of the H i, CO, radio continuum, and infrared emission distributions.

Results. The Canadian Galactic Plane Survey (CGPS) H i  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^-1. According to Galactic rotation models this structure is located at 3.0 ± 0.6 kpc from the Sun. There are several H ii  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 H ii  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.