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How hot is the molecular gas in the Galactic Center?

Published online by Cambridge University Press:  09 February 2017

Katharina Immer ,
Jens Kauffmann ,
Thushara Pillai ,
Adam Ginsburg  and
Karl M. Menten
Katharina Immer
Affiliation:
European Southern Observatory Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany email: kimmer@eso.org
Jens Kauffmann
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
Thushara Pillai
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
Adam Ginsburg
Affiliation:
European Southern Observatory Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany email: kimmer@eso.org
Karl M. Menten
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
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Abstract

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The molecular clouds in the Central Molecular Zone of our Galaxy (CMZ; inner ~200 pc) show systematically higher gas than dust temperatures (>50 K vs <30 K) in recent H2CO line and dust continuum surveys. This discrepancy is puzzling since gas and dust temperatures should become equal over short times at the high densities observed in these clouds. In deep H2CO(3–2) and (4–3) observations of seven clouds in the CMZ, we detected not only large temperature differences between the clouds but also large gradients within the clouds. Comparing the temperatures and the main H2CO lines at 218 and 291 GHz, we found a positive correlation between those two parameters, indicating that turbulence plays an important role in the heating of the gas. As a follow-up, we mapped the temperature tracers CH3CCH and CH3CN in these seven clouds to derive multiple temperature estimates and test the accuracy of high gas temperatures.

Keywords

Galaxy: centerISM: moleculesISM: structureISM: cloudsSubmillimeter: ISM
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 11 , Symposium S322: The Multi-Messenger Astrophysics of the Galactic Centre , July 2016 , pp. 111 - 114
Copyright
Copyright © International Astronomical Union 2017 

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