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| Paper: |
Properties of Molecular Gas in Star-Forming Galaxies at z∼1.4 with ALMA |
| Volume: |
499, Revolution in Astronomy with ALMA: The Third Year |
| Page: |
43 |
| Authors: |
Seko, A.; Ohta, K.; Hatsukade, B.; Yabe, K. |
| Abstract: |
We made CO(J=5-4) observations of 20 star-forming galaxies at z∼1.4 with ALMA to study properties of molecular gas with respect to the stellar mass and metallicity. Almost all of our sample galaxies are on the main sequence of star-forming galaxies at this redshift. Uniqueness of the sample is gas phase metallicity is known for each galaxy. The metallicities of our sample galaxies are derived from near-infrared spectroscopic observations with Subaru/FMOS. The ranges of metallicity (12+log(O/H)) and stellar mass are 8.2-8.9 and 4×109-4×1011 M☉, respectively. The stellar mass range covers lower mass than that in previous studies. We detected CO emission lines from 11 galaxies. Molecular gas mass is derived by adopting metallicity-dependent CO-to-H2 conversion factor. The derived molecular gas masses of detected galaxies are (3-11)×1010 M☉. The molecular gas mass fractions are 0.25-0.94, and the fraction is lower in a more massive galaxy or a galaxy with higher metallicity. However, it is difficult to conclude which of stellar mass and metallicity is a main cause for the relations. We try to constrain the inflow and outflow rate by using an analytic chemical evolution model. |
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