Abstract Details
| Name: Archana Affiliation: Korea Astronomy & Space Science Institute (KASI) Conference ID: ASI2016_512 Title : Investigation of galactic star forming regions and young stellar objects Authors and Co-Authors : Dr. Maheswar G., ARIES, Nainital; Dr. Chang Won Lee, KASI, Republic of Korea; Prof. H. C. Bhatt, IIA, Bangalore Abstract Type : Oral Abstract Category : Thesis Abstract : The study of magnetic fields in molecular clouds formed in various environments have enormous potential towards understanding the underlying physics behind the role played by the magnetic fields in the formation of molecular clouds and the subsequent star formation. The closer and isolated molecular clouds provide the fascinating laboratories where the importance of magnetic fields can be explored towards ongoing activities like evolution of the cloud and star formation. The focus of this thesis is to explore the magnetic fields morphologies and strength in various environments of molecular clouds to understand the open issue of the role played by magnetic fields in interstellar medium (ISM). The regions where we have mapped the magnetic fields are broadly classified into the categories viz. triggered star forming and spontaneous star forming sites. In triggered star forming regions, we have chosen the multiple bright-rimmed clouds (BRCs) and cometary globules (CGs) associated to some HII regions surrounded by a high mass star in the center. The radiation driven implosion process explains the photoionization induced collapse of a dense, isolated cloud that is illuminated from one side by a source of ionizing radiation. In the presence of magnetic fields, the dynamical evolution of the globule and ionized gas streaming out of the globule surface get modified significantly depending on the strength and the orientation of the magnetic field. These HII regions are selected because of their structural simplicity and proximity to the sun. It has been widely accepted that the magnetic fields play an important role in the spontaneous star formation process. In a magnetic field dominated scenario for isolated low mass star formation, the cores are envisaged to gradually condense out of a magnetically sub- critical background cloud, through ambipolar diffusion. To understand the evolution of magnetic fields in the cores of different ages (ages deter- mined based onto the chemical evolution), we have studied the magnetic fields in a number of prestellar cores. Magnetic fields morphologies in some of the cores harboring very low luminosity objects (VeLLOs) have also been made in this thesis. These studies will help in understanding the standard models of low mass star formation and key role played by the magnetic fields in these processes. In order to understand the disk formation in the low mass stars, we have studied the magnetic field structure and following alignment/misalignment between the mean magnetic field direction and the rotation axis (the outflow axis is presumed to be the rotation axis of the core) in a core with a proto-brown dwarf candidate. Magnetic field strength have been estimated using the modified Chandrasekhar-Fermi (CF) relation. We have tried to constrain the standard models of low mass star formation through observations. |