Abstract Details

Name: Manash Samal
Affiliation: Physical Research Laboratory ( PRL )
Conference ID: ASI2020_46
Title : Insights into the structure of Galactic molecular clouds and star formation within them with the study of bipolar HII regions
Authors and Co-Authors : Manash Samal
Abstract Type : Invited
Abstract Category : Stars, ISM and Galaxy
Abstract : A growing body of evidence indicates that interstellar sheets and filaments play a vital role in the star formation process, including the formation of massive stars. Once a massive star forms, it photoionises its surroundings, forming an HII region. HII regions show ring-like cavity or bubble-like structures at 8.0 micron. Our understanding of the evolution and physics of HII regions comes mostly from studies that assume spherical symmetry of molecular clouds. Classical HII regions also show cometary and bipolar morphologies. The formation and evolution of spherical and cometary or blister HII regions have been relatively well-studied. To date, little numerical work has been devoted to the modelling and simulation of bipolar HII regions, primarily because no adequate attention has been paid to the identification and characterisation of such nebulae. Using Spitzer-GLIMPSE survey, and the Herschel Hi-GAL survey, we have identified 16 bipolar HII regions in a zone of the Galactic plane between ±60° in longitude and ±1° in latitude. In this talk, I shall discuss the structure of the star-forming clouds based on the detected bipolar HII regions, roles of filaments and sheets in the formation and evolution of such regions, and the impact of bipolar HII regions on the subsequent star formation processes of the parental cloud. In particular, I shall highlight their role on the formation of second generation massive stars and clusters that we observed at the waist of these HII regions.