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

Instituto de Astronomía y Física del Espacio (UBA, CONICET), CC 67, Suc. 28, 1428 Buenos Aires, Argentina
e-mail: lsuad@iafe.uba.ar

Received: 3 May 2022
Accepted: 1 September 2022

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 E_k = (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.