CO Excitation, Molecular Gas Density, and Interstellar Radiation Field in Local and High-redshift Galaxies
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
CO Excitation, Molecular Gas Density, and Interstellar Radiation Field in Local and High-redshift Galaxies. / Liu, Daizhong; Daddi, Emanuele; Schinnerer, Eva; Saito, Toshiki; Leroy, Adam; Silverman, John D.; Valentino, Francesco; Magdis, Georgios E.; Gao, Yu; Jin, Shuowen; Puglisi, Annagrazia; Groves, Brent.
In: Astrophysical Journal, Vol. 909, No. 1, 56, 03.2021.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - CO Excitation, Molecular Gas Density, and Interstellar Radiation Field in Local and High-redshift Galaxies
AU - Liu, Daizhong
AU - Daddi, Emanuele
AU - Schinnerer, Eva
AU - Saito, Toshiki
AU - Leroy, Adam
AU - Silverman, John D.
AU - Valentino, Francesco
AU - Magdis, Georgios E.
AU - Gao, Yu
AU - Jin, Shuowen
AU - Puglisi, Annagrazia
AU - Groves, Brent
PY - 2021/3
Y1 - 2021/3
N2 - We study the carbon monoxide (CO) excitation, mean molecular gas density, and interstellar radiation field (ISRF) intensity in a comprehensive sample of 76 galaxies from local to high redshift (z similar to 0-6), selected based on detections of their CO transitions J = 2 -> 1 and 5 -> 4 and their optical/infrared/(sub)millimeter spectral energy distributions (SEDs). We confirm the existence of a tight correlation between CO excitation as traced by the CO (5-4)/(2-1) line ratio R-52 and the mean ISRF intensity <U > as derived from infrared SED fitting using dust SED templates. By modeling the molecular gas density probability distribution function (PDF) in galaxies and predicting CO line ratios with large velocity gradient radiative transfer calculations, we present a framework linking global CO line ratios to the mean molecular hydrogen gas density and kinetic temperature Tkin. Mapping in this way observed R-52 ratios to and T-kin probability distributions, we obtain positive <U >- and <U >-T-kin correlations, which imply a scenario in which the ISRF in galaxies is mainly regulated by T-kin and (nonlinearly) by . A small fraction of starburst galaxies showing enhanced could be due to merger-driven compaction. Our work demonstrates that ISRF and CO excitation are tightly coupled and that density-PDF modeling is a promising tool for probing detailed ISM properties inside galaxies.
AB - We study the carbon monoxide (CO) excitation, mean molecular gas density, and interstellar radiation field (ISRF) intensity in a comprehensive sample of 76 galaxies from local to high redshift (z similar to 0-6), selected based on detections of their CO transitions J = 2 -> 1 and 5 -> 4 and their optical/infrared/(sub)millimeter spectral energy distributions (SEDs). We confirm the existence of a tight correlation between CO excitation as traced by the CO (5-4)/(2-1) line ratio R-52 and the mean ISRF intensity <U > as derived from infrared SED fitting using dust SED templates. By modeling the molecular gas density probability distribution function (PDF) in galaxies and predicting CO line ratios with large velocity gradient radiative transfer calculations, we present a framework linking global CO line ratios to the mean molecular hydrogen gas density and kinetic temperature Tkin. Mapping in this way observed R-52 ratios to and T-kin probability distributions, we obtain positive <U >- and <U >-T-kin correlations, which imply a scenario in which the ISRF in galaxies is mainly regulated by T-kin and (nonlinearly) by . A small fraction of starburst galaxies showing enhanced could be due to merger-driven compaction. Our work demonstrates that ISRF and CO excitation are tightly coupled and that density-PDF modeling is a promising tool for probing detailed ISM properties inside galaxies.
U2 - 10.3847/1538-4357/abd801
DO - 10.3847/1538-4357/abd801
M3 - Journal article
VL - 909
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 56
ER -
ID: 258081537