The Discovery of a New Massive Molecular Gas Component Associated with the Submillimeter Galaxy SMM J02399-0136

• Published in: The Astrophysical journal 2018-06, Vol.860 (2), p.87
• Main Authors: Frayer, David T., Maddalena, Ronald J., Ivison, R. J., Smail, Ian, Blain, Andrew W., Bout, Paul Vanden
• Format: Article
• Language: English
• Subjects: Active galactic nuclei; Astrophysics; Galaxies; galaxies: active; galaxies: evolution; galaxies: high-redshift; galaxies: individual (SMM J02399-0136); galaxies: starburst; Luminosity; Molecular gases; Quasars; Radio telescopes; Stars & galaxies
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/aac49a

We present CO(1-0), CO(3-2), and CO(7-6) observations using the Green Bank Telescope (GBT) and the Atacama Large Millimeter Array (ALMA) of the z = 2.8 submillimeter galaxy SMM J02399−0136. This was the first submillimeter-selected galaxy discovered and remains an archetype of the class, comprising a merger of several massive and active components, including a quasar-luminosity AGN and a highly obscured, gas-rich starburst spread over a ∼25 kpc extent. The GBT CO(1-0) line profile is comprised of two distinct velocity components separated by about 600 km s−1 and suggests the presence of a new component of molecular gas that had not been previously identified. The CO(3-2) observations with ALMA show that this new component, designated W1, is associated with a large extended structure stretching 13 kpc westward from the AGN. W1 is not detected in the ALMA CO(7-6) data, implying that this gas has much lower CO excitation than the central starburst regions, which are bright in CO(7-6). The molecular gas mass of W1 is about 30% of the total molecular gas mass in the system, depending on the CO-to-H2 conversion factor. W1 is arguably a merger remnant; alternatively, it could be a massive molecular outflow associated with the AGN, or perhaps inflowing metal-enriched molecular gas fueling the ongoing activity.