The HI supershell GS118+01-44 and its role in the interstellar medium

SUAD, L. A.; CICHOWOLSKI, S.; NORIEGA-CRESPO, A.; ARNAL, E. M.; TESTORI, J. C.; FLAGEY, N.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2015

0004-6361

Aims. We carry out a multiwavelength study to characterize the Hi supershell designated GS 118+01−44, and to analyse its possibleorigin.Methods. A multiwavelength 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.Results. The Canadian Galactic Plane Survey (CGPS) Hi data reveals that GS 118+01−44 is centred at (l, b) = (117.◦7, 1.◦4) witha systemic velocity of −44.3 kms−1. 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 thetemperature spectral index distribution shows that in the region there is a predominance of non-thermal emission. Infrared emissionshows that cool temperatures dominate the area of the supershell. Concerning the origin of the structure, we found that even thoughseveral OB stars belonging to CasOB5 are located in the interior of GS 118+01−44, an analysis of the energy injected by these starsthrough their stellar winds indicates that they do not have sufficient energy to create GS 118+01−44. Therefore, an additional energysource is needed to explain the genesis of GS 118+01−44. On the other hand, the presence of several HII regions and young stellarobject candidates in the edges of GS 118+01−44 shows that the region is still active in forming new stars.