The JCMT Nearby Galaxies Legacy Survey Journal Articles uri icon

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  • We present a first complete 12 CO J=3-2 map of M81, observed as part of the Nearby Galaxies Legacy Survey being carried out at the James Clerk Maxwell Telescope. We detect 9 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 H-alpha map obtained using the Isaac Newton Telescope and archival HI, 24 microns and FUV images to uncover a correlation between the molecular gas and star forming regions in M81. 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 (10^3-10^4) cm^{-3}. We also estimated the amount of hydrogen produced in photo-dissociation regions near the locations where CO J=3-2 was detected.


  • Sánchez-Gallego, JR
  • Knapen, JH
  • Heiner, JS
  • Wilson, Christine D
  • Warren, BE
  • Allen, RJ
  • Azimlu, M
  • Barmby, P
  • Bendo, GJ
  • Comerón, S
  • Israel, FP
  • Serjeant, S
  • Tilanus, RPJ
  • Vlahakis, C
  • van der Werf, P

publication date

  • March 2011