Molecular Gas at High Redshift

Solomon, P. M.; Bout, P. A. Vanden

doi:10.1146/annurev.astro.43.051804.102221

Cited by 864 publications

(1,076 citation statements)

References 126 publications

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“…The CO(2-1) transition, in fact, traces the gas which is in a slightly denser phase (e.g. Solomon & Vanden Bout 2005), and therefore provides a less accurate estimate of the total molecular gas reservoir. In addition, the IRAM beam size at 2 mm is characterized by a FWHM of 11 arcsec, and is therefore sensitive to the gas which only resides in the innermost part of the galaxy ( 8 kpc).…”

Section: Co Luminosities and Molecular Gas Massesmentioning

confidence: 99%

Galaxy pairs in the SDSS – XIII. The connection between enhanced star formation and molecular gas properties in galaxy mergers

Violino

Ellison

Sargent

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We investigate the connection between star formation and molecular gas properties in galaxy mergers at low redshift (z 0.06). The study we present is based on IRAM 30-m CO(1-0) observations of 11 galaxies with a close companion selected from the Sloan Digital Sky Survey (SDSS). The pairs have mass ratios 4, projected separations r p 30 kpc and velocity separations ∆V 300 km s −1 , and have been selected to exhibit enhanced specific star formation rates (sSFR). We calculate molecular gas (H 2 ) masses, assigning to each galaxy a physically motivated conversion factor α CO , and we derive molecular gas fractions and depletion times. We compare these quantities with those of isolated galaxies from the extended CO Legacy Data base for the GALEX Arecibo SDSS Survey sample (xCOLDGASS, Saintonge et al. 2017) with gas quantities computed in an identical way. Ours is the first study which directly compares the gas properties of galaxy pairs and those of a control sample of normal galaxies with rigorous control procedures and for which SFR and H 2 masses have been estimated using the same method. We find that the galaxy pairs have shorter depletion times and an average molecular gas fraction enhancement of 0.4 dex compared to the mass matched control sample drawn from xCOLDGASS. However, the gas masses (and fractions) in galaxy pairs and their depletion times are consistent with those of non-mergers whose SFRs are similarly elevated. We conclude that both external interactions and internal processes may lead to molecular gas enhancement and decreased depletion times.

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Section: Co Luminosities and Molecular Gas Massesmentioning

confidence: 99%

Galaxy pairs in the SDSS – XIII. The connection between enhanced star formation and molecular gas properties in galaxy mergers

Violino

Ellison

Sargent

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…(1) where X CO = 2 × 10 20 cm −2 ( K km s −1 ) −1 in the Milky Way disk (Solomon et al 1987;Solomon & Vanden Bout 2005;Bolatto, Wolfire & Leroy 2013), D L is the luminosity distance, and z is the redshift of the BCG. However, the Galactic conversion factor is not expected or observed to be universal (eg.…”

Section: Molecular Gas Massmentioning

confidence: 99%

ALMA observations of cold molecular gas filaments trailing rising radio bubbles in PKS 0745−191

Russell

McNamara

Fabian

et al. 2016

Mon. Not. R. Astron. Soc.

105

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We present ALMA observations of the CO(1-0) and CO(3-2) line emission tracing filaments of cold molecular gas in the central galaxy of the cluster PKS 0745-191. The total molecular gas mass of 4.6±0.3×10 9 M , assuming a Galactic X CO factor, is divided roughly equally between three filaments each extending radially 3 − 5 kpc from the galaxy centre. The emission peak is located in the SE filament ∼ 1 arcsec (2 kpc) from the nucleus. The velocities of the molecular clouds in the filaments are low, lying within ±100 km s −1 of the galaxy's systemic velocity. Their FWHMs are less than 150 km s −1 , which is significantly below the stellar velocity dispersion. Although the molecular mass of each filament is comparable to a rich spiral galaxy, such low velocities show that the filaments are transient and the clouds would disperse on < 10 7 yr timescales unless supported, likely by the indirect effect of magnetic fields. The velocity structure is inconsistent with a merger origin or gravitational free-fall of cooling gas in this massive central galaxy. If the molecular clouds originated in gas cooling even a few kpc from their current locations their velocities would exceed those observed. Instead, the projection of the N and SE filaments underneath X-ray cavities suggests they formed in the updraft behind bubbles buoyantly rising through the cluster atmosphere. Direct uplift of the dense gas by the radio bubbles appears to require an implausibly high coupling efficiency. The filaments are coincident with low temperature X-ray gas, bright optical line emission and dust lanes indicating that the molecular gas could have formed from lifted warmer gas that cooled in situ.

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“…Typically, at low and high redshifts, CO emission is used as a tracer for the molecular gas phase (e.g. review by Solomon and Vanden Bout 2005). It is important to keep in mind though, that, at the highest z, only the very high rotational lines of CO will be observable with ALMA.…”

Section: Carbon Monoxide (Co)mentioning

confidence: 99%

Detecting the most distant (z>7) objects with ALMA

Walter

Carilli

2007

Astrophys Space Sci

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Detecting and studying objects at the highest redshifts, out to the end of Cosmic Reionization at z > 7, is clearly a key science goal of ALMA. ALMA will in principle be able to detect objects in this redshift range both from high-J (J > 7) CO transitions and emission from ionized carbon, [CII], which is one of the main cooling lines of the ISM. ALMA will even be able to resolve this emission for individual targets, which will be one of the few ways to determine dynamical masses for systems in the Epoch of Reionization. We discuss some of the current problems regarding the detection and characterization of objects at high redshifts and how ALMA will eliminate most (but not all) of them.

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Molecular Gas at High Redshift

Cited by 864 publications

References 126 publications

Galaxy pairs in the SDSS – XIII. The connection between enhanced star formation and molecular gas properties in galaxy mergers

Galaxy pairs in the SDSS – XIII. The connection between enhanced star formation and molecular gas properties in galaxy mergers

ALMA observations of cold molecular gas filaments trailing rising radio bubbles in PKS 0745−191

Detecting the most distant (z>7) objects with ALMA

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