AAS 195th Meeting, January 2000
Session 73. ISM: Molecular Gas
Display, Friday, January 14, 2000, 9:20am-6:30pm, Grand Hall

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[73.04] Direct Detection CO 7-6 Spectroscopy of the Galactic Center and Starburst Galaxies: SPIFI at the JCMT

C.M. Bradford, G.J. Stacey, T. Nikola, M.R. Swain (Cornell University), A.D. Bolatto, J.M. Jackson (Boston University), M.L. Savage, J.A. Davidson (USRA, NASA Ames Research Center)

We present the results of the first two observing runs with our new submillimeter spectrometer, the South Pole Imaging Fabry-Perot Interferometer (SPIFI). SPIFI is the first of its kind -- a direct-detection imaging spectrometer for use in the submillimeter. Our first two runs were through the 350 \mu m telluric window on the 15 m James Clerk Maxwell Telescope (JCMT), but SPIFI can also access the 200, 450, and 600 \mu m windows available to the JCMT and the AST/RO telescope at the South Pole.

Despite mediocre weather on our first two runs (atmospheric transmission < 10%), we mapped the entire Galactic Center circumnuclear ring (CNR) in CO (J=7-6) at 7 arcsec resolution (about 200 spectra). The high-J CO emission traces warm, dense molecular gas, and especially highlights shocks. We observe bright emission in both the CNR itself and in kinematically distinct infalling material such as the +70 km/s cloud and the northern arm. We also carried out the first extragalactic CO (7-6) obsevations, in the starburst galaxies NGC 253 and M82. The line intensities indicate that these starburst systems, especially NGC 253, are exciting large amounts of dense molecular gas to T ~ 100 K.

SPIFI's sensitivity at the telescope was very close to predicted. We measured system temperatures around 10,000 K with an atmospheric transmission of 8.5 %, which, accounting for the efficiencies, is equivalent to Trec (DSB) < 100 K. We intend to continue to improve SPIFI's performance, and good-weather projects in the near future include [CI] 370 \mu m mapping in the Galactic Center, starburst galaxies, dwarf galaxies, and ULIGs, as well as the first observations of far-IR fine structure lines in high-redshift systems.

If you would like more information about this abstract, please follow the link to http://astrosun.tn.cornell.edu/research/projects/spifi.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: bradford@astrosun.tn.cornell.edu

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