Center for Astrophysics Research and Technologies Seminar Series
Extreme (and not so extreme!) gas properties in the center of our Galaxy
Presented by Betsy Mills (NRAO)
As the nearest galactic nucleus, the center of our galaxy offers a unique opportunity for detailed study of the extreme processes which shape the gas in galactic nuclei, and at high redshifts. Gas in the central parsecs of our Galaxy is subject to a harsh environment, including the close proximity of a supermassive black hole, supernova remnants, and massive star clusters. By characterizing the molecular gas conditions in this region, we can quantify the effect that the resulting shocks, x-rays, and cosmic rays have on gas properties and eventually star formation in such an extreme environment. I will present a combination of results from radio and mm telescopes which place new limits on the large densities, temperatures, and turbulent line widths found in the molecular gas in the central 100 parsecs. Close to the black hole, we use data from the APEX telescope, to study the gas density in the Circumnuclear disk (CND), finding that it is not stable against tidal disruption. Almost all clumps appear to be transient and unlikely to form stars. We additionally find that reprocessed dust radiation from the central star cluster appears to be contributing to radiative excitation of HCN in the CND, which may lower the gas densities inferred using this molecule. Farther from the black hole, I will present larger scale VLA and GBT surveys of gas temperatures and turbulence in Galactic center clouds, including new detections of a 400 K gas component which may be shock heated, and finally new hints of cooler and less turbulent clumps embedded within these clouds. Together, these studies place new constraints on the most extreme conditions found in Galactic center molecular gas, and the processes which are responsible
2:00 pm, Thursday, February 20, 2014
PAIS-2540, PAIS
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