PI: Takeshi Oka, University of Chicago, firstname.lastname@example.org
Address: Department of Astronomy and Astrophysics, 5735 South Ellis Avenue, Chicago, Illinois 60637, USA
CoI: Thomas R. Geballe, Gemini Observatory
CoI: Benjamin J. McCall, University of Illinois, Urbana-Champaign
Title: Studies of Warm and Diffuse Gas near the Galactic Center using H_3^+ and CO
Abstract: \hspace0.4 in Using an infrared absorption line from the metastable (J, K)=(3, 3) rotational level of H_3^+ together with other lines of H_3^+ and CO, we have recently discovered a vast amount of high temperature (~ 250 K) and low density (~ 100 cm^- 3) gas in the Central 200 pc radius Molecular Zone (CMZ) of the Galaxy. The discovery is based on observations of eight infrared sources within 30 pc of the center. We suspect that this previously unknown warm and diffuse gas exists through much of the CMZ; if so its mass is far greater than that of molecular clouds in the CMZ. We propose to extend our observations to wider regions of the CMZ, using as probes fourteen young massive stars with Galactic longitude up to 1 degree, selected from the catalogue of YSO candidates in the recent ISOGAL survey. The data will allow us to obtain an overall picture of the distribution and physical state of the warm and diffuse gas in the CMZ.
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