TY - JOUR
T1 - The JCMT Nearby Galaxies Legacy Survey VI. The distribution of gas and star formation in M81
AU - Sanchez-Gallego, J.R.
AU - Knapen, J.H.
AU - Heiner, J.S.
AU - Wilson, C.D.
AU - Warren, Bradley
AU - Allen, R.J.
AU - Azimlu, M.
AU - Barmby, P.
AU - Bendo, G.J.
AU - Comeron, S.
AU - Israel, F.P.
AU - Serjeant, S.
AU - Tilanus, R.P.J.
AU - Vlahakis, C.
AU - Van Der Werf, P.
PY - 2011
Y1 - 2011
N2 - We present the first complete (CO)-C-12 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 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 Ha map obtained using the Isaac Newton Telescope and archival HI, 24 mu m, 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.
AB - We present the first complete (CO)-C-12 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 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 Ha map obtained using the Isaac Newton Telescope and archival HI, 24 mu m, 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.
U2 - 10.1051/0004-6361/201014930
DO - 10.1051/0004-6361/201014930
M3 - Article
VL - 527
SP - 10pp
JO - ASTRONOMY & ASTROPHYSICS
JF - ASTRONOMY & ASTROPHYSICS
SN - 0004-6361
ER -