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The Galactic Central Molecular Zone is full of hot molecular gas

Event Details

Event Dates: 

Friday, July 10, 2015 - 12:00pm

Seminar Location: 

  • CASA Conference Room C324

Speaker Name(s): 

Adam Ginsburg

Speaker Affiliation(s): 

Seminar Type/Subject

Scientific Seminar Type: 

  • Astrophysics Lunch Seminar

Event Details & Abstract: 

Star formation laws are observed to hold over a wide range of conditions and appear to be universal in integrated light from galaxies and in resolved Galactic disks. However, there are differences in Galactic central regions, especially in our own Galaxy's CMZ. Star formation appears to be suppressed in the CMZ, with normal indicators falling an order of magnitude below the usual dense gas-star formation relations. The deficiency may occur because of stochasticity or intrinsic differences in interstellar processes in the Galactic center. I will present newly acquired maps of the gas temperature within the dense gas in the CMZ. These maps show that the dense (n~10^5 cm^-3) gas is preferentially warm (>60 K) in the inner 500 pc of our Galaxy. These high temperatures are in stark contrast to disk clouds, with typical temperatures ~10-20 K. These high temperatures should affect core fragmentation, and therefore may change the core mass function. The cause of the high temperatures remains a mystery, though: is it from cosmic ray heating, X-ray heating, or turbulence dissipation? Determining the relevant physical mechanism is crucial for applying our detailed understanding of the CMZ to other galaxies, and I will discuss the constraints we can place on each mechanism.