Submillimeter Array 12CO (2-1) Imaging of the NGC 6946 Giant Molecular Clouds

Ya Lin Wu, Kazushi Sakamoto, Hsi An Pan

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


We present a 12CO (2-1) mosaic map of the spiral galaxy NGC 6946 by combining data from the Submillimeter Array and the IRAM 30 m telescope. We identify 390 giant molecular clouds (GMCs) from the nucleus to 4.5 kpc in the disk. GMCs in the inner 1 kpc are generally more luminous and turbulent, some of which have luminosities >106 K km s-1 pc2 and velocity dispersions >10 km s-1. Large-scale bar-driven dynamics likely regulate GMC properties in the nuclear region. Similar to the Milky Way and other disk galaxies, GMC mass function of NGC 6946 has a shallower slope (index > -2) in the inner region, and a steeper slope (index < -2) in the outer region. This difference in mass spectra may be indicative of different cloud formation pathways: gravitational instabilities might play a major role in the nuclear region, while cloud coalescence might be dominant in the outer disk. Finally, the NGC 6946 clouds are similar to those in M33 in terms of statistical properties, but they are generally less luminous and turbulent than the M51 clouds.

Original languageEnglish
Article number6
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 2017 Apr 10
Externally publishedYes


  • ISM: clouds
  • galaxies: ISM
  • galaxies: individual (NGC 6946)
  • galaxies: spiral

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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