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Spatially Resolved CO SLED of the Luminous Merger Remnant NGC 1614 with ALMA

Saito, Toshiki and Iono, Daisuke and Xu, Cong K. and Sliwa, Kazimierz and Ueda, Junko and Espada, Daniel and Kaneko, Hiroyuki and König, Sabine and Nakanishi, Kouichiro and Lee, Minju and Yun, Min S. and Aalto, Susanne and Hibbard, John E. and Yamashita, Takuji and Motohara, Kentaro and Kawabe, Ryohei (2017) Spatially Resolved CO SLED of the Luminous Merger Remnant NGC 1614 with ALMA. Astrophysical Journal, 835 (2). Art. No. 174. ISSN 0004-637X.

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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 (n_(H_2) ~ 10^(4.6) Cm^(−3), T_(kin) ~ 42 K, and G_0 ~ 10^(2.7)) relative to the outer disk (N_(H_2) ~ 10^(5.1) cm^(−3), T_(kin) ~ 22 K, and G_0 ~ 10^(0.9)). 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Iono, Daisuke0000-0002-2364-0823
Nakanishi, Kouichiro0000-0002-6939-0372
Yun, Min S.0000-0001-7095-7543
Yamashita, Takuji0000-0002-4999-9965
Kawabe, Ryohei0000-0002-8049-7525
Additional Information:© 2017 The American Astronomical Society. Received 2016 October 23; revised 2016 December 9; accepted 2016 December 21; published 2017 January 30. The authors thanks an anonymous referee for comments that improved the contents of this paper. T.S. thanks N. Lu, E.W. Pellegrini, and E. Schinnerer for useful discussion. T.S. and the other authors thank the ALMA staff for their kind support and H. Nagai for the instruction of ALMA data reduction. T.S. and M.L. are financially supported by a Research Fellowship from the Japan Society for the Promotion of Science for Young Scientists. T.S. was supported by the ALMA Japan Research Grant of NAOJ Chile Observatory, NAOJ-ALMA-0114. D.I. was supported by the ALMA Japan Research Grant of NAOJ Chile Observatory, NAOJ-ALMA-0011, and JSPS KAKENHI grant No. 15H02074. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00182.S, ADS/JAO.ALMA#2011.0.00768.S, ADS/JAO.ALMA#2013.1.00991.S, and ADS/JAO.ALMA#2013.1.01172.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. This research has made extensive use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
National Astronomical Observatory of Japan (NAOJ)NAOJ-ALMA-0114
National Astronomical Observatory of Japan (NAOJ)NAOJ-ALMA-0011
Japan Society for the Promotion of Science (JSPS)15H02074
Subject Keywords:galaxies: individual (NGC 1614, Arp 186) – galaxies: interactions – galaxies: ISM – radiative transfer – submillimeter: galaxies
Issue or Number:2
Record Number:CaltechAUTHORS:20170130-131755306
Persistent URL:
Official Citation:Toshiki Saito et al 2017 ApJ 835 174
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73823
Deposited By: Tony Diaz
Deposited On:30 Jan 2017 21:50
Last Modified:09 Mar 2020 13:19

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