A Caltech Library Service

Beneath the Baselines: Detecting Molecular Emission from Submillimeter Galaxies with the GBT

Hainline, Laura J. and Blain, Andrew and Greve, Thomas and Chapman, Scott and Smail, Ian and Ivison, Rob J. (2007) Beneath the Baselines: Detecting Molecular Emission from Submillimeter Galaxies with the GBT. In: From Z-machines to ALMA : (sub)millimeter spectroscopy of galaxies. ASP Conference Series. No.375. Astronomical Society of the Pacific , San Francisco, CA, pp. 157-165. ISBN 978-1-58381-311-9.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


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.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Blain, Andrew0000-0001-7489-5167
Smail, Ian0000-0003-3037-257X
Ivison, Rob J.0000-0001-5118-1313
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.
Funding AgencyGrant Number
GBT Graduate Funding programUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Research CorporationUNSPECIFIED
Series Name:ASP Conference Series
Issue or Number:375
Record Number:CaltechAUTHORS:20100917-093653291
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20004
Deposited By: Tony Diaz
Deposited On:17 Sep 2010 21:36
Last Modified:03 Oct 2019 02:04

Repository Staff Only: item control page