ALMACAL XIII. Evolution of the CO luminosity function and the molecular gas mass density out to ~ 6
arXiv:2502.06778 · doi:10.1051/0004-6361/202453223
Abstract
Cold molecular gas, largely traced by CO emission, is the primary fuel for star formation, making it essential for understanding galaxy evolution. ALMA has made significant progress in the study of the cosmic evolution of cold molecular gas. Here, we exploit the ALMACAL survey to address issues relating to small sample sizes and cosmic variance, utilising calibration data from ALMA to compile a statistically significant and essentially unbiased sample of CO-selected galaxies. By employing a novel statistical approach to emission-line classification using semi-analytical models, we place strong constraints on the CO luminosity function and the cosmic evolution of molecular gas mass density () back to . The cosmic molecular gas mass density increases with redshift, peaking around , then slowly declines towards higher redshifts by dex. Our findings confirm the key role of molecular gas in fuelling star formation. The new estimates allow us to revisit the cosmic baryon cycle, showing that the ratio of molecular gas-to-stellar mass density is consistent with the so-called 'bathtub model' of baryons, which implies a continuous replenishment of gas. The cosmic gas depletion timescale, estimated on a global scale, is shown to be fairly constant at all redshifts. We emphasise the importance of surveys using multiple small fields rather than a single contiguous area to mitigate the effects of cosmic variance.
Main text 18 pages, 7 figures. Appendix 7 pages, 4 figures. Accepted for publication in Astronomy & Astrophysics
References in corpus (26)
- Cosmic Star Formation History
- EAZY: A Fast, Public Photometric Redshift Code
- The Circumgalactic Medium
- CASA, the Common Astronomy Software Applications for Radio Astronomy
- xCOLD GASS: the complete IRAM-30m legacy survey of molecular gas for galaxy evolution studies
- The Cosmic Baryon and Metal Cycles
- SoFiA: a flexible source finder for 3D spectral line data
- ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Survey Description
- Reionization Era Bright Emission Line Survey: Selection and Characterization of Luminous Interstellar Medium Reservoirs in the z>6.5 Universe
- The cold interstellar medium of galaxies in the Local Universe
- SoFiA 2 -- An automated, parallel HI source finding pipeline for the WALLABY survey
- Automated Mining of the ALMA Archive in the COSMOS Field (A3COSMOS): II. Cold Molecular Gas Evolution out to Redshift 6
- ALMA spectroscopic survey in the Hubble Ultra Deep Field: CO luminosity functions and the evolution of the cosmic density of molecular gas
- CO line emission from galaxies in the Epoch of Reionization
- COLDz: A High Space Density of Massive Dusty Starburst Galaxies ~1 Billion Years after the Big Bang
- VLA-ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (VLASPECS): Total Cold Gas Masses and CO Line Ratios for z=2-3 "Main Sequence" Galaxies
- SURFS: Riding the waves with Synthetic UniveRses For Surveys
- CONCERTO: High-fidelity simulation of millimeter line emissions of galaxies and [CII] intensity mapping
- A NOEMA molecular line scan of the Hubble Deep Field North: Improved constraints on the CO luminosity functions and cosmic density of molecular gas
- Atomic and molecular gas from the epoch of reionization down to redshift 2
- The Astrophysical Consequences of Intervening Galaxy Gas on Fast Radio Bursts
- ColdSIM predictions of [C II] emission in primordial galaxies
- CO in the ALMA Radio-Source Catalogue (ARC): the molecular gas content of radio galaxies as a function of redshift
- ALMACAL VIII: A pilot survey for untargeted extragalactic CO emission lines in deep ALMA calibration data
- Spritz is sparkling: simulated CO and [CII] luminosities
- Intertwined Formation of , Dust, and Stars in Cosmological Simulations