University of Connecticut

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Astronomy Seminar

Wednesday, September 18, 2019
2:00pm – 3:00pm

Storrs Campus
GS-119

Dr. Michael Mattern,Max Planck Institute for Radio Astronomy, Germany

Massive filamentary clouds and their role in star formation

Filamentary structures are ubiquitous in the interstellar medium of the Milky Way. They are observed within star-forming and quiescent molecular clouds and representing molecular clouds themselves. Therefore, filamentary structures play an important role in the early phases of star formation. Filaments in nearby (<500pc) molecular clouds were found to be thermally stable against gravitational collapse, fragmenting into star-forming clumps. However, the evolution of filaments with masses above the thermally critical value is unknown.

Here, I will present the analyzes of the kinematics of 283 filamentary molecular cloud candidates in the Galactic Plane using the 13CO(2–1) and C18O(2–1) data of the SEDIGISM (Structure, Excitation, and Dynamics of the Inner Galactic Inter Stellar Medium) survey. To do so, we developed an automated algorithm to derive size, mass, and kinematic properties towards all candidates. We find two-third of the filament candidates are coherent structures. Also, we find a correlation between the mass per unit length and the velocity dispersion of the filament.

Further, I present the fragmentation characteristics and kinematics of the extremely long, massive Nessie filament. The fragmentation characteristics are derived from a combined near- and mid-infrared dust extinction map, and then compared with predictions from gravitational fragmentation models. We find that the characteristics of the fragments at all scales are similar to the predictions of one model. The kinematics provided by the SEDIGISM survey reveal Nessie as a single physical object, despite several morphological differences along the filament.

Contact:

Dr. A. Huang

Physics Department (primary), College of Liberal Arts and Sciences

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