Atomic carbon as a powerful tracer of molecular gas in the high-redshift Universe: perspectives for ALMA

Abstract

We use a high-resolution hydrodynamic simulation that tracks the non-equilibrium abundance of molecular hydrogen within a massive high-redshift galaxy to produce mock Atacama Large Millimeter Array (ALMA) maps of the fine-structure lines of atomic carbon, CI 1-0 and CI 2-1. Inspired by recent observational and theoretical work, we assume that CI is thoroughly mixed within giant molecular clouds and demonstrate that its emission is an excellent proxy for H2. Nearly all of the H2 associated with the galaxy can be detected at redshifts z<4 using a compact interferometric configuration with a large synthesized beam (that does not resolve the target galaxy) in less than 4 h of integration time. Low-resolution imaging of the \CI lines (in which the target galaxy is resolved into three to four beams) will detect ~80 per cent of the H2 in less than 12 h of aperture synthesis. In this case, the resulting data cube also provides the crucial information necessary for determining the dynamical state of the galaxy. We conclude that ALMA observations of the CI 1-0 and 2-1 emission are well-suited for extending the interval of cosmic look-back time over which the H2 distributions, the dynamical masses, and the Tully-Fisher relation of galaxies can be robustly probed.

5 pages, 4 figures, accepted for publication in MNRAS Letters

References in corpus (5)

• The Stellar, Gas and Dynamical Masses of Star-Forming Galaxies at z~2
• Modelling [CI] emission from turbulent molecular clouds
• Physical conditions of molecular gas in the Circinus galaxy: Multi-J CO and CI 1-0 observations
• Clumpy photon-dominated regions in Carina. I. [CI] and mid-J CO lines in two 4'x4' fields
• Simulating the H2 content of high-redshift galaxies

Cited by in corpus (11)

• Effective destruction of CO by cosmic rays: implications for tracing H${}_2$ gas in the Universe
• ALMA observations of atomic carbon in z~4 dusty star-forming galaxies
• Turbulent Gas in Lensed Planck-selected Starbursts at redshifts 1-3.5
• Neutral carbon and CO in 76 (U)LIRGs and starburst galaxy centers A method to determine molecular gas properties in luminous galaxies
• An ALMA multi-line survey of the ISM in two quasar host-companion galaxy pairs at $z>6$
• Molecular hydrogen in IllustrisTNG galaxies: carefully comparing signatures of environment with local CO & SFR data
• A High-Resolution Investigation of the Multi-Phase ISM in a Galaxy during the First Two Billion Years
• ALMA Observations of Atomic Carbon [C I] (${{}^3\mathrm{P}}_1\to {{}^3\mathrm{P}}_0$) and Low-$J$ CO Lines in the Starburst Galaxy NGC 1808
• ALMA Datacubes and Continuum Maps of the Irradiated Western Wall in Carina
• The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder IV. Neutral Carbon Detection in the SPIRE FTS Spectra
• The molecular-gas properties in the gravitationally lensed merger HATLAS J142935.3-002836