Filaments, Clumps, and Disks: Investigating the Origins of Star- and Planet-Forming Structures in Molecular Clouds

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Star formation occurs within the densest gas of molecular clouds and planets form out of even denser gas surrounding protostars. In this proposal, I describe plans to exploit the newest observational technologies to determine the origins of substructure in molecular clouds that promote the formation of stars and planets, i.e., filaments, clumps, and disks.  With these projects, Canada will continue its leading role in probing the origins of stars and planets.  These projects will also be undertaken primarily by students under my direct supervision.****The Herschel Space Observatory recently revealed that significant mass in clouds is found in filaments, with the densest examples being the predominant locations of compact pockets of gas, i.e., dense cores, and protostars.   These data indicate the pivotal role of filaments in the star formation process, i.e, providing the conditions from which star formation is most efficient.  Understanding their origins is therefore important, and can be explored with further data of their kinematics. For example, are filaments equilibrium or non-equilibrium structures?  Though some compelling data of a few filamentary regions have been obtained, I propose to use line data of CO, 13CO, and C18O from the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey to probe the kinematics of a wide variety of filaments and through model comparisons determine their dynamical states and origins.****Herschel also revealed that filaments may be implicated in the formation of stellar clusters, as compact pockets of gas more massive than cores that may fragment into tight associations of cores, i.e., clumps, are found at the intersections of filaments.  This arrangement provides an elegant solution to cluster formation, as increased avenues of mass flow are available to grow a specific region to high densities.  Nevertheless, the kinematics of filaments associated with clumps require investigation to determine if this scenario is realistic, e.g., are intersections physical connections of filaments?  I propose to use the U.S. National Radio Astronomy Observatory's Green Bank Telescope (GBT) and Jansky Very Large Array (JVLA) to observe NH3 line emission towards such examples of filament intersection in nearby clouds, specifically those with little to no star formation, and assess their kinematics.***Finally, I propose to address the formation of the flattened structures near protostars from which planets form, i.e., disks.  Observations of disks at their earliest epochs will inform the initial conditions of disk evolution and any subsequent planet formation. Herschel and JCMT, however, do not have the angular resolution to probe such structures.  Instead, I propose to use continuum and (N2H+ and H2D+) line data from the new Atacama Large Millimeter Array (ALMA) to investigate the densities and velocities of dense gas in the centers of cores on the verge or just beyond the star formation event. **** **