The Role of the CMB in Redshift Related Departures from the Gao–Solomon Relation

Tunnard, R.; Greve, T. R.

doi:10.3847/1538-4357/aa8e4d

Cited by 6 publications

(7 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The CMB produces a non-negligible radiation field at z = 4, where T CMB = 13.7 K; this reduces the observed sub-mm/mm flux densities relative to their intrinsic values (e.g. da Cunha et al 2013;Zhang et al 2016;Tunnard & Greve 2017;Jin et al 2019). Observed 97-GHz flux densities correspond to rest-frame 650 μm.…”

Section: Gas Mass Estimatesmentioning

confidence: 96%

ALMA unveils wider environment of distant red protocluster core

Ivison

Biggs

Bremer

et al. 2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We report observations with the Atacama Large Millimetre Array (ALMA) of six submillimetre galaxies (SMGs) within 3 arcmin of the Distant Red Core (DRC) at z = 4.0, a site of intense cluster-scale star formation, first reported by Oteo et al. We find new members of DRC in three SMG fields; in two fields, the SMGs are shown to lie along the line of sight towards DRC; one SMG is spurious. Although at first sight this rate of association is consistent with earlier predictions, associations with the bright SMGs are rarer than expected, which suggests caution when interpreting continuum overdensities. We consider the implications of all 14 confirmed DRC components passing simultaneously through an active phase of star formation. In the simplest explanation, we see only the tip of the iceberg in terms of star formation and gas available for future star formation, consistent with our remarkable finding that the majority of newly confirmed DRC galaxies are not the brightest continuum emitters in their immediate vicinity. Thus, while ALMA continuum follow-up of SMGs identifies the brightest continuum emitters in each field, it does not necessarily reveal all the gas-rich galaxies. To hunt effectively for protocluster members requires wide and deep spectral-line imaging to uncover any relatively continuum-faint galaxies that are rich in atomic or molecular gas. Searching with short-baseline arrays or single-dish facilities, the true scale of the underlying gas reservoirs may be revealed.

show abstract

Section: Gas Mass Estimatesmentioning

confidence: 96%

ALMA unveils wider environment of distant red protocluster core

Ivison

Biggs

Bremer

et al. 2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Considering the HCN/CO ration, even though the CO(1-0) emission is more susceptible to the CMB temperature, Tunnard & Greve (2017) do not find that the observed HCN/CO ratios at z = 3 are significantly overestimated. However, their models consider relatively compact cold gas reservoir sizes (scale radius 1.4 kpc); CO(1-0) emission from very extended (≥ 10 kpc) cold gas reservoirs seen in some DSFGs might be suppressed more efficiently (da Cunha et al 2013;Zhang et al 2016).…”

Section: Appendix B: Attenuation Of Dense-gas Tracers Due To the Cosm...mentioning

confidence: 55%

“…However, the local thermal equilibrium approximation can not be easily extended to the scales of entire galaxies, which might exhibit significant temperature, density and optical depth gradients on kpc-scales. The impact of the CMB temperature on high-z observations of HCN, CO, and FIR continuum in this more complex scenario was explored by Tunnard & Greve (2017). in particular, they used both single-line-of-sight and galaxy-scale toy models coupled with the Radex (van der Tak et al 2007) radiative transfer calculations.…”

Section: Appendix B: Attenuation Of Dense-gas Tracers Due To the Cosm...mentioning

confidence: 99%

Prussic

Rybak

Hodge

Greve

et al. 2022

A&A

Self Cite

View full text Add to dashboard Cite

Dusty star-forming galaxies (DSFGs) at redshift z ≥ 1 are among the most vigorously star-forming galaxies in the Universe. However, their dense (≥ 10 5 cm −3 ) gas phase -typically traced by HCN(1-0) -remains almost entirely unexplored: only two DSFGs have been detected in HCN(1-0) to date. We present results of a JVLA survey of the J=1-0 transition of HCN, HCO + , and HNC(1-0) in six strongly lensed DSFGs at z = 2.5 − 3.3, effectively doubling the number of DSFGs with deep observations of these lines. We detect HCN(1-0) emission in one source (J1202+5354, 4.4σ), with a tentative HCO + (1-0) detection in another (J1609+6045, 3.3σ). Spectral stacking yields strict upper limits on the HCN/FIR (≤ 3.6 × 10 −4 ) and HCN/CO(1-0) ratios (≤0.045). The inferred HCN/FIR ratios (a proxy for the star-formation efficiency) are consistent with those in z ∼ 0 FIR-luminous starbursts. However, the HCN/CO ratios -a proxy for the dense-gas fraction -are a factor of a few lower than suggested by the two previous DSFG detections. Our results imply that most DSFGs have low dense-gas fractions. A comparison with Krumholz & Thompson (2007) models of star-forming galaxies indicates that the bulk of gas in DSFGs is at lower densities (≈10 2 cm −3 ), similar to "normal" star-forming galaxies, rather than ultraluminous starbursts.

show abstract

“…We do not correct for cosmic microwave background (CMB) effects (i.e., the observational contrast against the CMB and the enhanced excitation of the CO or other line transitions), since this requires extensive modelling of the ISM conditions and exceeds the scope of this paper, particularly since it is not a large correction at these redshifts (da Cunha et al 2013;Zhang et al 2016;Tunnard & Greve 2017). The velocity-width FWHM of our sources ranges between 110 and 1290 km s −1 .…”

Section: Line Fluxesmentioning

confidence: 99%

Bright extragalactic ALMA redshift survey (BEARS) III: detailed study of emission lines from 71Herscheltargets

Hagimoto

Bakx

Serjeant

et al. 2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We analyse the molecular and atomic emission lines of 71 bright Herschel-selected galaxies between redshifts 1.4 to 4.6 detected by the Atacama Large Millimetre/submillimetre Array. These lines include a total of 156 CO, [C i], and H2O emission lines. For 46 galaxies, we detect two transitions of CO lines, and for these galaxies we find gas properties similar to those of other dusty star-forming galaxy (DSFG) samples. A comparison to photo-dissociation models suggests that most of Herschel-selected galaxies have similar interstellar medium conditions as local infrared-luminous galaxies and high-redshift DSFGs, although with denser gas and more intense far-ultraviolet radiation fields than normal star-forming galaxies. The line luminosities agree with the luminosity scaling relations across five orders of magnitude, although the star-formation and gas surface density distributions (i.e., Schmidt-Kennicutt relation) suggest a different star-formation phase in our galaxies (and other DSFGs) compared to local and low-redshift gas-rich, normal star-forming systems. The gas-to-dust ratios of these galaxies are similar to Milky Way values, with no apparent redshift evolution. Four of 46 sources appear to have CO line ratios in excess of the expected maximum (thermalized) profile, suggesting a rare phase in the evolution of DSFGs. Finally, we create a deep stacked spectrum over a wide rest-frame frequency (220–890 GHz) that reveals faint transitions from HCN and CH, in line with previous stacking experiments.

show abstract

The Role of the CMB in Redshift Related Departures from the Gao–Solomon Relation

Cited by 6 publications

References 48 publications

ALMA unveils wider environment of distant red protocluster core

ALMA unveils wider environment of distant red protocluster core

Prussic

Bright extragalactic ALMA redshift survey (BEARS) III: detailed study of emission lines from 71Herscheltargets

Contact Info

Product

Resources

About