The molecular mass function of the local Universe
Abstract
Aims: We construct the molecular mass function using the bivariate K-band-mass function (BMF) of the Herschel Reference Survey (HRS), which is a volume-limited sample that has already been widely studied at the entire electromagnetic spectrum.
Methods: The molecular mass function was derived from the K-band and the gas mass cumulative distribution using a copula method, which is described in detail in our previous papers.
Results: The H2 mass is relatively strongly correlated with the K-band luminosity because of the tight relation between the stellar mass and the molecular gas mass within the sample with a scatter, which is likely due to those galaxies which have lost their molecular content because of environmental effects or because of a larger gas consumption due to past star formation processes. The derived H2 MF samples the molecular mass range from ∼4 × 106 M⊙ to ∼1010 M⊙, and when compared with theoretical models, it agrees well with the theoretical predictions at the lower end of the mass values; whereas at masses larger than 1010 M⊙, the HRS sample may miss galaxies with a large content of molecular hydrogen and the outcomes are not conclusive. The value of the local density of the molecular gas mass inferred from our analysis is ∼1.5 × 107 M⊙ Mpc-3, and it is compared with the results at larger redshifts, confirming the lack of strong evolution for the molecular mass density between z = 0 and z = 4.
Conclusions: This is the first molecular mass function that has been derived on a complete sample in the local Universe, which can be used as a reliable calibration at redshift z = 0 for models aiming to predict the evolution of the molecular mass density.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 2020
- DOI:
- 10.1051/0004-6361/202038675
- arXiv:
- arXiv:2008.11134
- Bibcode:
- 2020A&A...643L..11A
- Keywords:
-
- ISM: molecules;
- submillimeter: galaxies;
- galaxies: statistics;
- galaxies: luminosity function;
- mass function;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- submitted to A&