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The ALMA Spectroscopic Survey in the HUDF: the Molecular Gas Content of Galaxies and Tensions with IllustrisTNG and the Santa Cruz SAM
- Source :
- The Astrophysical Journal, The Astrophysical Journal, 2019, 882 (2), pp.137. ⟨10.3847/1538-4357/ab30f2⟩, The Astrophysical Journal, American Astronomical Society, 2019, 882 (2), pp.137. ⟨10.3847/1538-4357/ab30f2⟩, Astrophysical Journal (0004-637X), Astrophysical journal, 2019, Vol.882(2), pp.137 [Peer Reviewed Journal], Astrophysical Journal (0004-637X), 882(2), 137
- Publication Year :
- 2019
- Publisher :
- HAL CCSD, 2019.
-
Abstract
- The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (ASPECS) provides new constraints for galaxy formation models on the molecular gas properties of galaxies. We compare results from ASPECS to predictions from two cosmological galaxy formation models: the IllustrisTNG hydrodynamical simulations and the Santa Cruz semi-analytic model (SC SAM). We explore several recipes to model the H$_2$ content of galaxies, finding them to be consistent with one another, and take into account the sensitivity limits and survey area of ASPECS. For a canonical CO-to-H$_2$ conversion factor of $��_{\rm CO} = 3.6\,\rm{M}_\odot/(\rm{K}\,\rm{km/s}\,\rm{pc}^{2})$ the results of our work include: (1) the H$_2$ mass of $z>1$ galaxies predicted by the models as a function of their stellar mass is a factor of 2-3 lower than observed; (2) the models do not reproduce the number of H$_2$-rich ($M_{\rm H2} > 3\times 10^{10}\,\rm{M}_\odot$) galaxies observed by ASPECS; (3) the H$_2$ cosmic density evolution predicted by IllustrisTNG (the SC SAM) is in tension (only just agrees) with the observed cosmic density, even after accounting for the ASPECS selection function and field-to-field variance effects. The tension between models and observations at $z>1$ can be alleviated by adopting a CO-to-H$_2$ conversion factor in the range $��_{\rm CO} = 2.0 - 0.8\,\rm{M}_\odot/(\rm{K}\,\rm{km/s}\,\rm{pc}^{2})$. Additional work on constraining the CO-to-H$_2$ conversion factor and CO excitation conditions of galaxies through observations and theory will be necessary to more robustly test the success of galaxy formation models.<br />Re-submitted to ApJ after addressing the first round of comments by the referee, other comments welcome
- Subjects :
- Physics
COSMIC cancer database
010504 meteorology & atmospheric sciences
Stellar mass
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics
Galaxies: Evolution-galaxies: Formation-galaxies: High-redshift-galaxies: Ism-ism: Molecules
Hubble Ultra-Deep Field
Astrophysics - Astrophysics of Galaxies
01 natural sciences
Galaxy
[SDU]Sciences of the Universe [physics]
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
0103 physical sciences
Content (measure theory)
Galaxy formation and evolution
010303 astronomy & astrophysics
ComputingMilieux_MISCELLANEOUS
Density evolution
0105 earth and related environmental sciences
Subjects
Details
- Language :
- English
- ISSN :
- 0004637X and 15384357
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal, The Astrophysical Journal, 2019, 882 (2), pp.137. ⟨10.3847/1538-4357/ab30f2⟩, The Astrophysical Journal, American Astronomical Society, 2019, 882 (2), pp.137. ⟨10.3847/1538-4357/ab30f2⟩, Astrophysical Journal (0004-637X), Astrophysical journal, 2019, Vol.882(2), pp.137 [Peer Reviewed Journal], Astrophysical Journal (0004-637X), 882(2), 137
- Accession number :
- edsair.doi.dedup.....eff7e284d2747e58ab0b1037ff7bfbe9