TY - JOUR
T1 - CONSTRAINT on the INFLOW/OUTFLOW RATES in STAR-FORMING GALAXIES at z ∼ 1.4 from MOLECULAR GAS OBSERVATIONS
AU - Seko, Akifumi
AU - Ohta, Kouji
AU - Yabe, Kiyoto
AU - Hatsukade, Bunyo
AU - Akiyama, Masayuki
AU - Tamura, Naoyuki
AU - Iwamuro, Fumihide
AU - Dalton, Gavin
N1 - Funding Information:
K.O. is supported by a Grant-in-Aid for Scientific Research (C) (16K05294) from JSPS. K.Y. is supported by a Grant-in-Aid for Young Scientists (B) (JP16K17659) from JSPS. Kavli IPMU is supported by the World Premier International Research Center Initiative (WPI), MEXT, Japan.
PY - 2016/12/10
Y1 - 2016/12/10
N2 - We constrain the rate of gas inflow into and outflow from a main-sequence star-forming galaxy at z ∼ 1.4 by fitting a simple analytic model for the chemical evolution in a galaxy to the observational data of the stellar mass, metallicity, and molecular gas mass fraction. The molecular gas mass is derived from CO observations with a metallicity-dependent CO-to-H2 conversion factor, and the gas metallicity is derived from the Hα and [N II]λ 6584 emission line ratio. Using a stacking analysis of CO integrated intensity maps and the emission lines of Hα and [N II], the relation between stellar mass, metallicity, and gas mass fraction is derived. We constrain the inflow and outflow rates with least-chi-square fitting of a simple analytic chemical evolution model to the observational data. The best-fit inflow and outflow rates are ∼1.7 and ∼0.4 in units of star formation rate (SFR), respectively. The inflow rate is roughly comparable to the sum of the SFR and outflow rate, which supports the equilibrium model for galaxy evolution; i.e., all inflow gas is consumed by star formation and outflow.
AB - We constrain the rate of gas inflow into and outflow from a main-sequence star-forming galaxy at z ∼ 1.4 by fitting a simple analytic model for the chemical evolution in a galaxy to the observational data of the stellar mass, metallicity, and molecular gas mass fraction. The molecular gas mass is derived from CO observations with a metallicity-dependent CO-to-H2 conversion factor, and the gas metallicity is derived from the Hα and [N II]λ 6584 emission line ratio. Using a stacking analysis of CO integrated intensity maps and the emission lines of Hα and [N II], the relation between stellar mass, metallicity, and gas mass fraction is derived. We constrain the inflow and outflow rates with least-chi-square fitting of a simple analytic chemical evolution model to the observational data. The best-fit inflow and outflow rates are ∼1.7 and ∼0.4 in units of star formation rate (SFR), respectively. The inflow rate is roughly comparable to the sum of the SFR and outflow rate, which supports the equilibrium model for galaxy evolution; i.e., all inflow gas is consumed by star formation and outflow.
KW - galaxies: ISM
KW - galaxies: evolution
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U2 - 10.3847/1538-4357/833/1/53
DO - 10.3847/1538-4357/833/1/53
M3 - Article
AN - SCOPUS:85006371746
VL - 833
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 53
ER -