Modeling CO emission from hydrodynamic simulations of nearby spirals, starbursting mergers, and high-redshift galaxies

Autor: C. Mastropietro, Emanuele Daddi, Romain Teyssier, Florent Renaud, Axel Weiß, Frédéric Bournaud
Přispěvatelé: Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Max-Planck-Institut für Radioastronomie (MPIFR), Department of Physics, University of Surrey, University of Surrey (UNIS), Institute for Computational science, Universität Zürich [Zürich] = University of Zurich (UZH), The simulations presented in this work were performed at the Très Grand Centre de Calcul of CEA under GENCI allocations 2013-GEN 2192 and 2014-GEN2192 and on SuperMuc at the LRZ under a PRACE allocation, European Project: 257720,EC:FP7:ERC,ERC-2010-StG_20091028,GALSICO(2011), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universität Zürich [Zürich] (UZH), University of Zurich
Rok vydání: 2015
Předmět:
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Opacity
530 Physics
FOS: Physical sciences
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
7. Clean energy
01 natural sciences
Spectral line
1912 Space and Planetary Science
0103 physical sciences
Emission spectrum
galaxies: ISM / galaxies: star formation
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Physics
010308 nuclear & particles physics
Velocity gradient
Star formation
Astronomy and Astrophysics
Astrophysics - Astrophysics of Galaxies
Redshift
Galaxy
Interstellar medium
13. Climate action
Space and Planetary Science
10231 Institute for Computational Science
galaxies: star formation
Astrophysics of Galaxies (astro-ph.GA)
3103 Astronomy and Astrophysics
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
galaxies: ISM
Astrophysics - Cosmology and Nongalactic Astrophysics
Zdroj: Astronomy and Astrophysics-A&A
Astronomy and Astrophysics-A&A, EDP Sciences, 2015, 575, pp.A56. ⟨10.1051/0004-6361/201425078⟩
Astronomy and Astrophysics-A&A, 2015, 575, pp.A56. ⟨10.1051/0004-6361/201425078⟩
ISSN: 1432-0746
0004-6361
DOI: 10.1051/0004-6361/201425078
Popis: We model the intensity of emission lines from the CO molecule, based on hydrodynamic simulations of spirals, mergers, and high-redshift galaxies with very high resolutions (3pc and 10^3 Msun) and detailed models for the phase-space structure of the interstellar gas including shock heating, stellar feedback processes and galactic winds. The simulations are analyzed with a Large Velocity Gradient (LVG) model to compute the local emission in various molecular lines in each resolution element, radiation transfer and opacity effects, and the intensity emerging from galaxies, to generate synthetic spectra for various transitions of the CO molecule. This model reproduces the known properties of CO spectra and CO-to-H2 conversion factors in nearby spirals and starbursting major mergers. The high excitation of CO lines in mergers is dominated by an excess of high-density gas, and the high turbulent velocities and compression that create this dense gas excess result in broad linewidths and low CO intensity-to-H2 mass ratios. When applied to high-redshift gas-rich disks galaxies, the same model predicts that their CO-to-H2 conversion factor is almost as high as in nearby spirals, and much higher than in starbursting mergers. High-redshift disk galaxies contain giant star-forming clumps that host a high-excitation component associated to gas warmed by the spatially-concentrated stellar feedback sources, although CO(1-0) to CO(3-2) emission is overall dominated by low-excitation gas around the densest clumps. These results overall highlight a strong dependence of CO excitation and the CO-to-H2 conversion factor on galaxy type, even at similar star formation rates or densities. The underlying processes are driven by the interstellar medium structure and turbulence and its response to stellar feedback, which depend on global galaxy structure and in turn impact the CO emission properties.
Comment: A&A in press
Databáze: OpenAIRE
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