Spatially Resolved CO SLED of the Luminous Merger Remnant NGC 1614 with ALMA
Artikel i vetenskaplig tidskrift, 2017

We present high-resolution (1.?0) Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO (1-0) and CO (2-1) rotational transitions toward the nearby IR-luminous merger NGC 1614 supplemented with ALMA archival data of CO (3-2) and CO (6-5) transitions. The CO (6-5) emission arises from the starburst ring (central 590 pc in radius), while the lower-J CO lines are distributed over the outer disk (?3.3 kpc in radius). Radiative transfer and photon-dominated region (PDR) modeling reveals that the starburst ring has a single warmer gas component with more a intense far-ultraviolet radiation field (nh2 ? 104.6 cm-3, Tkin ?42 K, and G0 ?102.7) relative to the outer disk (nh2 ? 105.1 cm-3, Tkin ? 22 K, and G0 ?100.9 cm-3, K, and ). A two-phase molecular interstellar medium with a warm and cold (>70 and ?19 K) component is also an applicable model for the starburst ring. A possible source for heating the warm gas component is mechanical heating due to stellar feedback rather than PDR. Furthermore, we find evidence for non-circular motions along the north-south optical bar in the lower-J CO images, suggesting a cold gas inflow. We suggest that star formation in the starburst ring is sustained by the bar-driven cold gas inflow and that starburst activities radiatively and mechanically power the CO excitation. The absence of a bright active galactic nucleus can be explained by a scenario where cold gas accumulating on the starburst ring is exhausted as the fuel for star formation or is launched as an outflow before being able to feed to the nucleus.

submillimeter: galaxies

galaxies: interactions

radiative transfer

Arp 186)

galaxies: ISM

galaxies: individual (NGC 1614

Författare

Toshiki Saito

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

University of Tokyo

D. Iono

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

Sokendai Graduate University for Advanced Studies

C. K. Xu

California Institute of Technology

Kazimierz Sliwa

Max Planck-institutet

Junko Ueda

Harvard-Smithsonian Center for Astrophysics

D. Espada

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

Sokendai Graduate University for Advanced Studies

Hiroyuki Kaneko

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

Sabine König

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

K. Nakanishi

Sokendai Graduate University for Advanced Studies

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

Minju Lee

University of Tokyo

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

Min S. Yun

University of Massachusetts

Susanne Aalto

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

John E. Hibbard

National Radio Astronomy Observatory

Takuji Yamashita

JAXA Institute of Space and Astronautical Science

Kentaro Motohara

University of Tokyo

R. Kawabe

Sokendai Graduate University for Advanced Studies

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

University of Tokyo

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 835 174

Ämneskategorier

Atom- och molekylfysik och optik

DOI

10.3847/1538-4357/835/2/174