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Center for Astrophysics Research and Technologies Seminar Series Information

 

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Starless Clumps and the Earliest Phases of High-mass Star Formation in the Milky Way

Thursday November 1, 2018
2:00 pm


 Presenter:  Brian Svoboda, NRAO
 Series:  Center for Astrophysics Research and Technologies Seminar Series
 Abstract:  High-mass stars are key to regulating the interstellar medium, star formation activity, and overall evolution of galaxies, but their formation remains an open problem in astrophysics. In order to understand the physical conditions during the earliest phases of high-mass star formation, I will discuss observational studies we have carried out on dense starless clump candidates (SCCs) that show no signatures of star formation activity. We identify 2223 SCCs from the 1.1 mm Bolocam Galactic Plane Survey, systematically analyse their physical properties, and show that the starless phase is not represented by a single timescale, but evolves more rapidly with increasing clump mass. To investigate the sub-structure in SCCs at high spatial resolution, we investigate the 12 most high-mass SCCs within 5 kpc using ALMA. We find previously undetected low-luminosity protostars in 11 out of 12 SCCs, fragmentation equal to the thermal Jeans length of the clump, and no starless cores exceeding 30 solar masses. While uncertainties remain concerning the star formation efficiency in this sample, these observational facts are consistent with models where high-mass stars form from initially low- to intermediate-mass protostars that accrete most of their mass from the surrounding clump. I will also briefly present on-going research studying the magnetic fields in SCCs with SOFIA and gas inflow signatures with the VLA and ALMA.
 Host:  Ylva Pihlström
 Location:  Room 190, Physics & Astronomy

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