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 - 25.2km s- 1. It is located at 3.2 ± 1.0 kpc from the Sun and has a kinetic energy of Ek = (2.1 ± 1.3) × 1050 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 Hii 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 Hii 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 Hii 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.