AROUND THE RING WE GO: THE COLD, DENSE RING OF MOLECULAR GAS IN NGC 1614

Journal Article · Thu Nov 20 04:00:00 EST 2014 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/796/1/L15· OSTI ID:22364512

Sliwa, Kazimierz; Wilson, Christine D. ^[1]; Iono, Daisuke ^[2]; Peck, Alison ^[3]; Matsushita, Satoki ^[4]

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1. Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)
2. National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)
3. National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
4. Academia Sinica Institute of Astronomy and Astrophysics, PO Box 23-141, Taipei 10617, Taiwan (China)

We present high-resolution archival Atacama Large Millimeter/submillimeter Array (ALMA) {sup 12}CO J = 3-2 and J = 6-5 and HCO{sup +} J = 4-3 observations and new CARMA {sup 12}CO and {sup 13}CO J = 1-0 observations of the luminous infrared galaxy NGC 1614. The high-resolution maps show the previously identified ring-like structure while the {sup 12}CO J = 3-2 map shows extended emission that traces the extended dusty features. We combined these new observations with previously published Submillimeter Array {sup 12}CO and {sup 13}CO J = 2-1 observations to constrain the physical conditions of the molecular gas at a resolution of 230 pc using a radiative transfer code and a Bayesian likelihood analysis. At several positions around the central ring-like structure, the molecular gas is cold (20-40 K) and dense (>10{sup 3.0} cm{sup –3}). The only region that shows evidence of a second molecular gas component is the ''hole'' in the ring. The {sup 12}CO-to-{sup 13}CO abundance ratio is found to be greater than 130, more than twice the local interstellar medium value. We also measure the CO-to-H{sub 2} conversion factor, α{sub CO}, to range from 0.9 to 1.5 M {sub ☉} (K km s{sup –1} pc{sup 2}){sup –1}.

• OSTI ID: 22364512
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 796; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CARBON 12
CARBON 13
CARBON MONOXIDE
CONVERSION
GALAXIES
HYDROGEN
ISOTOPE RATIO
RADIANT HEAT TRANSFER
STAR CLUSTERS