J/A+A/695/A163 CO LF and molecular gas mass density (Bollo+, 2025)
ALMACAL. XIII. Evolution of the CO luminosity function and the molecular gas
mass density out to z ∼ 6.
Bollo V., Peroux C., Zwaan M., Hamanowicz A., Chen J., Weng S.,
Lagos C. del P., Bravo M., Ivison R.J., Biggs A.
<Astron. Astrophys. 695, A163 (2025)>
=2025A&A...695A.163B 2025A&A...695A.163B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Molecular clouds ; Interstellar medium ;
Carbon monoxide
Keywords: evolution - galaxy evolution - intergalactic medium - galaxies: ISM -
galaxies: luminosity function - mass function
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 z∼6. The cosmic
molecular gas mass density increases with redshift, peaking around
z∼1.5, then slowly declines towards higher redshifts by ∼1dex. Our
findings confirm the key role of molecular gas in fueling star
formation. We provide new insights into the redshift evolution of
baryonic components in the Universe. The ratio of molecular
gas-to-stellar mass density is consistent with the so-called
'bathtub model' of baryons, indicating 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.
Description:
This work uses the latest data release, which comprises
the ALMA calibrator data taken up until 2022 May, so-called ALMACAL-22
(Bollo et al., 2024A&A...690A.258B 2024A&A...690A.258B).
The final catalogue was created after a thorough visual inspection
of all detections, along with an analysis of the spectra and the
integrated emission-line map across the spectral range of the detected
lines. We select candidates with S/N>4 and a clear peak in the moment
map compared to the background noise. Duplicate detections - e.g.
those offset by only a few pixels but originating from the same region
- were excluded. The final catalogue of CO emitters includes 87
sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 208 87 Physical properties of the ALMACAL-22 detections
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See also:
J/MNRAS/478/1512 : ALMA calibrator continuum observations catalog
(Bonato+, 2018)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Object name (JHHMM+DDMM)
12- 14 I3 --- NID Object identifier
16- 33 F18.14 GHz Freq Observed frequency
35- 53 F19.15 mJy.km/s Flux Median flux density
55- 74 F20.16 mJy.km/s e_Flux Negative error on flux
76- 99 E24.16 mJy.km/s E_Flux Positive error on flux
101-120 F20.15 km/s FWHM Median full-width at half maximum
122-141 F20.16 km/s e_FWHM Negative error on FWHM
143-163 F21.16 km/s E_FWHM Positive error on FWHM
165-169 F5.2 --- S/N Signal-to-noise ratio
171-188 F18.16 % Compl Sample completeness factor
190-208 F19.17 % Rel Reliability of detection
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Acknowledgements:
Victoria Bollo, victoria.bollo(at)eso.org
References :
Oteo et al., Paper I 2016ApJ...822...36O 2016ApJ...822...36O
Oteo et al., Paper II 2017ApJ...837..182O 2017ApJ...837..182O
Klitsch et al., Paper III 2018MNRAS.475..492K 2018MNRAS.475..492K
Bonato et al., Paper IV 2018MNRAS.478.1512B 2018MNRAS.478.1512B, Cat. J/MNRAS/478/1512
Klitsch et al., Paper V 2019MNRAS.482L..65K 2019MNRAS.482L..65K
Klitsch et al., Paper VI 2019MNRAS.490.1220K 2019MNRAS.490.1220K
Klitsch et al., Paper VII 2020MNRAS.495.2332K 2020MNRAS.495.2332K
Hamanowicz et al., Paper VIII 2023MNRAS.519...34H 2023MNRAS.519...34H
Chen et al., Paper IX 2023MNRAS.518.1378C 2023MNRAS.518.1378C
Klitsch et al., Paper X 2023MNRAS.523L..46K 2023MNRAS.523L..46K
Chen et al., Paper XI 2023A&A...675L..10C 2023A&A...675L..10C
Bollo et al., Paper XII 2024A&A...690A.258B 2024A&A...690A.258B
(End) Patricia Vannier [CDS] 12-Feb-2025