The JCMT nearby galaxies legacy survey VI. The distribution of gas and star formation in M 81

J. R. Sánchez-Gallego, J. H. Knapen, J. S. Heiner, C. D. Wilson, B. E. Warren, R. J. Allen, M. Azimlu, P. Barmby, G. J. Bendo, S. Comerón, F. P. Israel, S. Serjeant, R. P.J. Tilanus, C. Vlahakis, P. Van Der Werf

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We present the first complete 12CO J = 3-2 map of M 81, observed as part of the Nearby Galaxies Legacy Survey being carried out at the James Clerk Maxwell Telescope. We detect nine regions of significant CO emission located at different positions within the spiral arms, and confirm that the global CO emission in the galaxy is low. We combine these data with a new Hα map obtained using the Isaac Newton Telescope and archival H i, 24 μm, and FUV images to uncover a correlation between the molecular gas and star forming regions in M 81. For the nine regions detected in CO J = 3-2, we combine our CO J = 3-2 data with existing CO J = 1-0 data to calculate line ratios. We find that the ratio J = (3-2)/(1-0) is in agreement with the range of typical values found in the literature (0.2-0.8). Making reasonable assumptions, this allows us to constrain the hydrogen density to the range (103-104)cm -3. We also estimated the amount of hydrogen produced in photo-dissociation regions near the locations where CO J = 3-2 was detected.

Original languageEnglish (US)
Article numberA16
JournalAstronomy and astrophysics
Volume527
DOIs
StatePublished - Mar 1 2011
Externally publishedYes

Keywords

  • Galaxies: ISM
  • Galaxies: star formation
  • H ii regions
  • ISM: atoms
  • Ism: molecules

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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