ALMA observations of warm molecular gas and cold dust in NGC 34

Journal Article · Tue May 20 00:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/787/1/48· OSTI ID:22356848

Xu, C. K.; Cao, C.; Lu, N.; Mazzarella, J. M.; Diaz-Santos, T.; Zhao, Y. -H.; Appleton, P.; Armus, L.; Lord, S.; Murphy, E. J.; Schulz, B. ^[1]; Gao, Y. ^[2]; Van der Werf, P.; Meijerink, R. ^[3]; Evans, A. S.; Stierwalt, S. ^[4]; Chu, J.; Sanders, D. B. ^[5]; Haan, S. ^[6]

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1. Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States)
2. Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China)
3. Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)
4. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)
5. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96816 (United States)
6. CSIRO Astronomy and Space Science, ATNF, P.O. Box 76, Epping 1710 (Australia)

We present Atacama Large Millimeter Array (ALMA) Cycle-0 observations of the CO (6-5) line emission (rest-frame frequency = 691.473 GHz) and of the 435 μm dust continuum emission in the nuclear region of NGC 34, a local luminous infrared galaxy at a distance of 84 Mpc (1'' = 407 pc) which contains a Seyfert 2 active galactic nucleus (AGN) and a nuclear starburst. The CO emission is well resolved by the ALMA beam (0.''26 × 0.''23), with an integrated flux of f {sub CO(6-5)} = 1004 (± 151) Jy km s{sup –1}. Both the morphology and kinematics of the CO (6-5) emission are rather regular, consistent with a compact rotating disk with a size of 200 pc. A significant emission feature is detected on the redshifted wing of the line profile at the frequency of the H{sup 13}CN (8-7) line, with an integrated flux of 17.7 ± 2.1(random) ± 2.7(systematic) Jy km s{sup –1}. However, it cannot be ruled out that the feature is due to an outflow of warm dense gas with a mean velocity of 400 km s{sup –1}. The continuum is resolved into an elongated configuration, and the observed flux corresponds to a dust mass of M {sub dust} = 10{sup 6.97±0.13} M {sub ☉}. An unresolved central core (radius ≅ 50 pc) contributes 28% of the continuum flux and 19% of the CO (6-5) flux, consistent with insignificant contributions of the AGN to both emissions. Both the CO (6-5) and continuum spatial distributions suggest a very high gas column density (≳ 10{sup 4} M {sub ☉} pc{sup –2}) in the nuclear region at radius ≲ 100 pc.

• OSTI ID: 22356848
• Journal Information: Astrophysical Journal, Vol. 787, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CARBON MONOXIDE
CONFIGURATION
DENSITY
DUSTS
EMISSION
EVOLUTION
GALAXIES
GHZ RANGE
INTERACTIONS
MASS
RANDOMNESS
RED SHIFT
SPATIAL DISTRIBUTION
T-10 TOKAMAK
VELOCITY