Southern Serpents: The Internal Structure of Interstellar Filaments in the Fourth-Quadrant of the Milky Way

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

The birthplace of nearly all stars lies within the interstellar molecular clouds that reside in the disk of the Milky Way Galaxy. Previous observations of the Galactic disk suggest that many of these clouds are filamentary over a wide range of physical scales. While astronomers agree that stars form within the densest regions of interstellar clouds, they currently do not understand the importance of interstellar filaments for the process of star formation. The only way to measure the three-dimensional structure of interstellar clouds is through spectroscopic radio observations. The investigator will use three spectroscopic surveys in concert to probe both the atomic and molecular internal structure of interstellar filaments within the southern Galactic plane. The main research objectives are to 1) characterize the velocity structure of the filaments and compare this to numerical models to draw conclusions about their lifetimes, stability and star-formation efficiencies, 2) trace the turbulent structure of the filaments using higher order statistics on both the atomic and molecular observations. The investigator volunteers with the University of Wisconsin-Madison McNair Scholars Program as a Science Technology Engineering and Mathematics (STEM) Professional Advisor aimed at preparing first-generation, low-income, and minority undergraduates for graduate school and beyond. This research will also provide training and mentoring opportunities for undergraduate students. If filamentary clouds are the only structures with densities large enough to form stars, then the theory of Galactic star formation needs to be focused on the formation and evolution of filamentary molecular clouds, including filamentary sub-structures where proto-stellar activity occurs. This research project will make a contribution by directly identifying and characterizing interstellar filaments through spectroscopic observations of both their molecular gas and atomic envelopes. One of the main data products will be a catalog of filaments, along with the results from the dynamical studies done on them. This will allow future research on where proto-stellar activity resides in relation to filamentary structure.