Astrophys. J., 799, 92 (2015/January-3)
Sub-millimeter telescope CO (2-1) observations of nearby star-forming galaxies.
JIANG X.-J., WANG Z., GU Q., WANG J. and ZHANG Z.-Y.
Abstract (from CDS):
We present CO J = 2-1 observations toward 32 nearby gas-rich star-forming galaxies selected from the ALFALFA and Wide-field Infrared Survey Explorer (WISE) catalogs, using the Sub-millimeter Telescope (SMT). Our sample is selected to be dominated by intermediate-M*galaxies. The scaling relations between molecular gas, atomic gas, and galactic properties (stellar mass, NUV - r, and WISE color W3 - W2) are examined and discussed. Our results show the following. (1) In the galaxies with stellar mass M* ≤ 1010 M☉, the H I fraction (f_ H I_≡ M_H I/M*_) is significantly higher than that of more massive galaxies, while the H2gas fraction (fH2 ≡ MH2/M*) remains nearly unchanged. (2) Compared to fH2, f_H I_correlates better with both M*and NUV - r. (3) A new parameter, WISE color W3 - W2 (12-4.6 µm), is introduced, which is similar to NUV - r in tracing star formation activity, and we find that W3 - W2 has a tighter anti-correlation with log fH2 than the anti-correlation of (NUV - r)-f_ H I_, (NUV - r)-fH2, and (W3 - W2)-f_H I_. This indicates that W3 - W2 can trace the H2fraction in galaxies. For the gas ratio MH2/M_H I_, only in the intermediate-M*galaxies it appears to depend on M*and NUV - r. We find a tight correlation between the molecular gas mass MH2 and 12 µm (W3) luminosities (L_12 µm_), and the slope is close to unity (1.03±0.06) for the SMT sample. This correlation may reflect that the cold gas and dust are well mixed on a global galactic scale. Using the all-sky 12 µm (W3) data available in WISE, this correlation can be used to estimate CO flux for molecular gas observations and can even predict H2mass for star-forming galaxies.
galaxies: evolution - galaxies: ISM - infrared: galaxies - ISM: molecules - radio lines: galaxies
View the reference in ADS
To bookmark this query, right click on this link: simbad:2015ApJ...799...92J and select 'bookmark this link' or equivalent in the popup menu