Beneath the Baselines: Detecting Molecular Emission from Submillimeter Galaxies with the GBT
Abstract
We report the first detection of a submillimeter galaxy (SMG) in CO(1 →0) emission using the GBT. We identify a line with Δv_(FWHM) ~1000 kms^(−1) in the 1 cm spectrum of SMM J13120+4242 at z = 3.408, which is significantly greater than the width of the previously detected CO(4→3) line. If the observed CO(1→0) line profile arises from a single object and not several merging objects, the CO(4 →3)/CO(1→0) brightness temperature ratio of ~0.26 suggests n(H_2) > 10^3 cm^(−3) and the presence of sub-thermally excited gas. The 10σ integrated line flux implies a cold molecular gas mass M(H2) ~10^(11)M_⊙, comparable to the dynamical mass estimate and four times larger than the H_2 mass found from the CO(4 →3) line. While our observations confirm that this SMG is massive and highly gas-rich, they also suggest that J_(upper) > 3 transitions of CO may not accurately trace cold, diffuse molecular gas in SMGs.
Additional Information
© 2007 Astronomical Society of the Pacific. We acknowledge with gratitude the assistance and patience of R. Maddalena and A. Minter at NRAO-Green Bank in calibrating the GBT K-band data. LJH acknowledges the support of the GBT Graduate Funding program during this work. AWB acknowledges support from the Alfred P. Sloan Foundation and the Research Corporation.Attached Files
Published - Hainline2007p9106From_Z-Machines_To_Alma__Sub__Millimeter_Spectroscopy_Of_Galaxies.pdf
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Additional details
- Eprint ID
- 20004
- Resolver ID
- CaltechAUTHORS:20100917-093653291
- GBT Graduate Funding program
- Alfred P. Sloan Foundation
- Research Corporation
- Created
-
2010-09-17Created from EPrint's datestamp field
- Updated
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2019-10-03Created from EPrint's last_modified field
- Series Name
- ASP Conference Series
- Series Volume or Issue Number
- 375