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Surveying Star Formation in the Galaxy

Adam Ginsburg

Thesis work conducted at: Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, Colorado, USA

Current address: 391 UCB Boulder, CO, USA 80309

Address as of October 2013: Karl-Schwarzschild-Straße 2, 85748 Garching bei München, Germany

Electronic mail: [email protected]

Ph.D dissertation directed by: John Bally

Ph.D degree awarded: April 2013

I studied the formation of massive stars and clusters via millimeter, radio, and infrared observations. The Bolocam Galactic Plane Survey (BGPS) was the first millimeter-wave blind survey of the plane of our Galaxy. I wrote the data reduction pipeline for this survey and produced the final publicly released data products. I ran extensive tests of the pipeline, using simulations to probe its performance.

The BGPS detected over 8000 1.1 mm sources, the largest sample at this wavelength ever detected. As a single-wavelength continuum survey, the BGPS serves as a finder chart for millimeter and radio observations. I therefore performed follow-up surveys of BGPS sources in CO 3-2 and , and others did similar follow-ups to measure velocities and distances towards these sources.

observations of ultracompact HII regions and other millimeter-bright sources were used to measure the local molecular gas density. These measurements hint that density within molecular clouds does not follow a simple lognormal distribution. They also show that star-forming clouds all contain gas at density \(\gtrsim10^4\) .

I used the BGPS source catalog to identify the most massive compact clumps within the galaxy, identifying 18 with masses \(M>10^4\) in the first quadrant of the Galactic plane. As these objects are all actively star-forming, the starless timescale of massive proto-cluster clumps must be relatively short, with lifetimes \(\lesssim0.6\) Myr.