演講資訊

摘要：

Incoming light from a number of distant astronomical sources get polarized due to several astrophysical processes. Among them, differential extinction or dichroism, according to which un-polarized light get partially linearly polarized (up to few percent) due to an ensemble of aligned, non-spherical and spinning dust grains with respect to the Galactic magnetic field, is one of the most promising tool to understand the properties of dust grains and to map the line of sight averaged, plane of the sky magnetic field orientation. Polarimetry of reddened background stars of starless and star- forming cloud regions enable us to map the magnetic field geometry in and around these regions. During my PhD, I have studied a number of star-clusters/star-forming regions, and molecular clouds that are distributed at different distances, reddened by different amount extinction values, characterized by different extinction laws, and having different levels of star-formation activity. Field stars and the cluster members have been identified using both optical color-color ((U-B) versus (B-V)) and Stokes plane (Q versus U) diagrams. The distribution and properties of dust grains, distribution of the magnetic field orientation, and the polarization efficiency of the dust grains have been studied. Magnetic fields are one of the important constituents of the ISM, and are believed to play an important, perhaps even crucial, role in the formation and evolution of the molecular clouds, their collapse, star- formation in them, and the feed back processes (formation and evolution of outflows, mid-infrared bubbles, and bright rimmed clouds). In this colloquium, I will present important results on my past and ongoing research work. Finally, I will present a brief outline about my proposed research work at IANCU.