Abstract Details
| Name: Tapas Baug Affiliation: Post-Doctoral Fellow, TIFR, Mumbai Conference ID: ASI2016_417 Title : Galactic bubble N37 and surrounding star formation activity Authors and Co-Authors : D.K. Ojha, TIFR, Mumbai. L.K. Dewangan, PRL, Ahmedabad. J.P. Ninan, TIFR, Mumbai. Abstract Type : Oral Abstract Category : Stars, The Milky Way Galaxy and its neighbours Abstract : In spite of their vast importance in the evolution of their host galaxies, formation and evolution of massive stars are not yet well understood. They are the main source of heavy elements and ultra-violet radiations. They influence the galactic evolution and replenish interstellar medium by their strong winds, outflows, expanding H II regions and supernova explosions. Processes like "collect and collapse" and radiative driven implosion (RDI) found to occur around H II regions and lead to further star formation. Massive stars are often found to be associated with mid-infrared bubbles, elongated columns of gas (i.e, pillars) pointing towards the ionizing sources. Understanding the interplay between the ionizing radiation and surrounding dense gas is important for characterizing triggered star formation. We studied star formation activity around a Galactic bubble (N37; Churchwell et al., 2006) possibly developed by several massive stars. We analysed multi-wavelength data starting from optical to radio to look for detailed processes going on in this region. From our observed optical spectra from 2-meter Himalayan Chandra Telescope, we identified two sources as early-B/late-O type stars. It is apparent from the 20 cm Multi-Array Galactic Plane Imaging Survey (MAGPIS) map that the expansion of H II region has led to formation of this bubble. The bubble is also found to be associated with pillar-like structures. Pillars are generally formed because of shadowing the ionizing radiation by an inhomogeneous density field. These pillars are also believed to be probable sight of triggered star formation via RDI. Starlight polarization data provide the information about the orientation of the magnetic field on the plane-of-sky, and hence, alignment of dust particle. Variation in mean polarization position angle around the bubble is noticed in the GPIPS near-infrared H-band polarization, suggestive of expansion of the surrounding gas. A large scale accumulation (clump) of mass (> 30000 M_sun) at the edge of the bubble N37 is evident from the Herschel column density map and 13CO molecular line data. Young stellar sources, identified using Spitzer IRAC bands and UKIDSS NIR band magnitudes, are mostly seen towards the massive clump and at the edge of the bubble. Overall analysis of this region suggests that the presence of massive stars at the center of the bubble has probably induced triggered star formation on the surrounding material. |