GS 121–05–037: A new Galactic chimney candidate with signs of triggered star formation

Abstract

Aims. The goal of this study is to analyze the H i supershell GS 121−05−037 and its role in triggering star formation. Methods. To characterize the supershell, we analyzed the H i 21-cm line and the far-infrared emission distributions. In addition, to study the star formation processes related to GS 121−05−037, we used the Gaia survey, together with spectrophotometric calculations, and derived a method to look for massive OB-type stars.Results. The H i characterization of GS 121−05−037 shows an expanding structure centered at (l, b) ∼ (121 • .3, −4 • .8) in the velocity range from −47.8 to −25.2 km s −1 . It is located at 3.2 ± 1.0 kpc from the Sun and has a kinetic energy of E k = (2.1 ± 1.3) × 10 50 erg. GS 121−05−037 presents, in the H i emission distribution, an open morphology toward the Galactic halo. The analysis of the IR emission reveals the presence of 32 H ii regions seen projected into the borders of GS 121−05−037. A spectrophotometric analysis to look for the ionizing stars of these regions reveals that 12 of them would be located at a similar distance to GS 121−05−037. Conclusions. The relative location between GS 121−05−037 and the H ii regions, together with their age difference, led us to conclude that the ionizing stars could have been created due to the expansion of the H i supershell. On the other hand, the H ii regions located on the interface of two or more supershells could have originated from the collision of the H i structures. Finally, the open morphology of GS 121−05−037 toward the halo suggests that this large structure could be a Galactic chimney.