From interstellar dust to filaments - Key results from Herschel Gould Belt Sirvey

		Recent Herschel observations of nearby star forming molecular clouds carried out as a part of the Herschel Gould Belt Survey (HGBS) at submillimeter wavelengths have revolutionized our understanding about the initial conditions of early stages of prestellar core formation. Recent analysis of Herschel data have put observational constraints on number of key astrophysical questions related to low mass star formation such as the link of Core Mass Function (CMF) and the IMF, the star formation efficiency, threshold of prestellar core formation. These studies clearly demonstrate that all of these astrophysical phenomena have a common connection with the physics of filamentary structures of the interstellar medium. The Herschel images with a unprecedented sensitivity and resolution have not only revealed the ubiquity of filamentary structures over a wide range in column density but also resolved the inner width of such structures in nearby molecular clouds. While all of the filamentary structures tend to maintain a characteristic quasi-universal sub-parsec inner width (0.1 pc), the thermally supercritical filaments fragment due to gravitational instability to form prestellar cores. Herschel observations have suggested that the sub-solar mass scale at which the CMF peaks can be explained by the simple gravitational fragmentation of thermally supercritical filaments, however, the development of the Salpeter-like power-law tail toward the high-mass end can be understood from the physics of initial density fluctuations with a characteristic power spectrum slope along filaments. In this talk, I will also discuss about the observational constrain on the submillimeter dust opacity obtained from the Herschel data.