Pith. sign in

REVIEW 3 major objections 5 minor 288 references

The canonical CO-to-H2 factor of 0.8 for early dusty galaxies is not forced by the data; two gas-mass methods and realistic size estimates leave near-Milky-Way values (2–4.3) dynamically viable.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

T0 review · deepseek-v4-flash

2026-08-01 15:22 UTC pith:TM6H3OCC

load-bearing objection A careful, honest paper showing alpha_CO=0.8 is not uniquely required for unlensed DSFGs, but its near-Galactic alpha_CO claim rests on one untested pivot: G/D=100. the 3 major comments →

arxiv 2607.18440 v1 pith:TM6H3OCC submitted 2026-07-20 astro-ph.GA

Vz-GAL Dusty Star-Forming Galaxies: Revisiting the CO-H2 Conversion Factor Tension

classification astro-ph.GA
keywords CO-to-H2 conversion factordusty star-forming galaxieshigh-redshift galaxiesmolecular gasvirial dynamical massesradiative transfer modelingCO(1-0) emissiongas-to-dust ratio
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper confronts a long-standing tension in measuring how much molecular gas early dusty galaxies really hold. Astronomers translate CO line luminosity into gas mass through a conversion factor α_CO, and for dusty starbursts at redshifts 1–4 a low value of 0.8 has been standard because larger values seemed to exceed the galaxies' dynamical mass. Using the largest homogeneous sample of 21 unlensed such galaxies — CO(1–0) detections from the Vz-GAL survey plus resolved millimeter dust imaging — the authors derive gas masses two independent ways: dust-spectral-energy-distribution fitting and the TUNER radiative-transfer framework, both assuming a solar gas-to-dust ratio of 100. Both methods give α_CO ≈ 1.5–11.5, clustering near the Milky Way value of 4.3, and the apparent conflict with dynamics disappears once realistic cold-gas extents replace compact dust radii in the standard isotropic virial estimate. The conclusion: current data do not force α_CO = 0.8, and if near-Galactic values hold, these galaxies hold roughly five times more molecular gas than commonly assumed.

Core claim

The paper establishes that the canonical α_CO = 0.8 conversion factor is not uniquely favored by dynamical constraints on high-redshift dusty star-forming galaxies. For 12 unlensed Vz-GAL sources, dust-SED and TUNER large-velocity-gradient modeling give mutually consistent gas masses, α_CO ≈ 1.5–11.5, medians near 3.4 and 5.1. With realistic cold-gas radii (radiative-transfer or 2.5× dust radii), the isotropic virial estimate yields upper limits α_CO ≤ 4.5 and ≤ 10.6, encompassing the gas-based values. The GN20 case study shows resolved gas geometry and kinematics recover the mass a "mixed" rotating-disk estimator misses, reconciling LVG-derived α_CO with dynamics.

What carries the argument

Two dynamical estimators carry the argument: the isotropic virial estimator, M_dyn ∝ (FWHM)² R_eff, treats the galaxy as a pressure-supported sphere, while the proposed "mixed" estimator, M_dyn = (v_rot² + kσ₀²)R_eff/G with k = 3, models a rotating turbulent thick disk. The decisive input is the effective radius: compact dust radii suppress dynamical masses and force low α_CO, whereas radiative-transfer (LVG) radii — about twice the dust radius — or a fiducial 2.5×R_dust restore consistency. The gas masses come from two methods sharing a fixed gas-to-dust ratio of 100: dust-SED (GMBB) fitting anchored by resolved dust sizes, and the TUNER large-velocity-gradient code jointly fitting the CO l

Load-bearing premise

The entire near-Galactic conclusion rests on fixing the gas-to-dust mass ratio at 100 in both gas-mass methods: if the true ratio were much lower, as for metal-poor gas, both methods would yield α_CO ≈ 0.8–1.0 and the claimed tension would vanish, and the paper sets aside its own free-G/D fits (150–380) as unrealistic without direct metallicity measurements.

What would settle it

Two observations would settle the claim. First, resolve the CO(1–0) emission of the 12 modeled galaxies: if the cold-gas radii match the compact dust radii rather than the assumed ~2× larger extents, the isotropic virial upper limits fall back below the gas-based α_CO and the near-Galactic conclusion collapses. Second, measure metallicities (e.g., via far-infrared fine-structure lines or dust-to-metal calibration) for a handful of these sources: a gas-to-dust ratio near 25–30 would rescale both gas masses down ~3–4×, putting α_CO back at roughly 0.8–1.0.

Watch this falsifier — get emailed when new claim-graph text bears on it.

If this is right

  • If α_CO is near-Galactic rather than 0.8, the molecular gas masses of these dusty galaxies are roughly a factor of five larger, implying lower star-formation efficiencies and longer gas-depletion times than commonly quoted.
  • Realistic cold-gas extents push the isotropic virial upper limits to α_CO ≤ 4.5 (narrow-line group) and ≤ 10.6 (broad-line group), fully bracketing the gas-based values, so no dynamical argument uniquely favors the low conversion factor.
  • α_CO appears to vary from source to source with ISM conditions; applying a universal 0.8 indiscriminately would systematically underestimate molecular gas reservoirs in many high-redshift dusty galaxies.
  • Inclinations inferred from dust morphology can misrepresent the gas disk (GN20: dust implies ~67°, resolved gas ~30°), so disk-based dynamical masses need resolved cold-gas kinematics to be reliable.
  • Multi-phase ISM structure, with low-J CO tracing extended diffuse gas and higher-J lines tracing dense gas, makes single-transition α_CO calibrations an oversimplification for extreme starbursts.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The near-Galactic conclusion rests entirely on the fixed gas-to-dust ratio of 100: direct metallicity measurements showing sub-solar abundances (G/D ~ 25–30) would rescale both gas-mass methods down to α_CO ≈ 0.8–1.0, dissolving the tension in the opposite direction — a test the paper's own free-G/D fits anticipate but cannot resolve.
  • The radius logic yields a sharp, checkable prediction: resolved CO(1–0), [CI], or [CII] mapping of these 21 galaxies should reveal cold-gas disks roughly twice the dust radii; if the gas turns out to be as compact as the dust, the dynamical case for α_CO > 2 largely evaporates.
  • If near-Galactic α_CO survives, the implied gas fractions and depletion times for early-universe starbursts must be revised upward, shifting estimates of the cosmic molecular gas budget at z ~ 2–4 — a consequence the paper gestures at but does not quantify.
  • The "mixed" estimator's failure on unresolved data — it needs implausibly face-on inclinations to match the virial estimator — is a caution that generalizes beyond DSFGs to any survey deriving disk dynamical masses from integrated linewidths alone.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The paper uses the largest homogeneous sample of 21 unlensed Vz-GAL DSFGs at z~1-4 with VLA CO(1-0) detections and resolved ALMA 1mm dust sizes, down-selecting 12 galaxies for robust gas-mass modeling. Molecular gas masses are derived with two methods: a general modified blackbody (GMBB) dust SED fit with fixed G/D=100, and the TUNER LVG radiative-transfer framework using the same G/D and dust opacity normalization. Both yield α_CO ~1.5-11.5, with medians ~3-5, in contrast to the commonly adopted α_CO=0.8. These gas masses are compared with isotropic virial and 'mixed' rotating thick-disk dynamical mass estimators using dust, LVG, and fiducial 2.5×R_dust radii. The paper concludes that current data do not require α_CO=0.8 and that intermediate to near-Galactic values remain dynamically viable once gas geometry, dust properties, and G/D uncertainties are considered.

Significance. If the main conclusion is accepted, the paper is important because it challenges the routine adoption of α_CO=0.8 for high-z DSFGs and does so with a homogeneous, carefully selected sample that includes CO(1-0) luminosities and resolved dust sizes. Strengths include the transparent statement of shared assumptions between methods, a very useful GN20 case study that decomposes the impact of individual parameters on dynamical α_CO limits, and a clear demonstration that the isotropic virial estimator with realistic gas extents yields upper limits that encompass the gas-based values. The weaker, but defensible, claim that current dynamical data do not exclude near-Galactic α_CO is significant. However, the quantitative gas-based medians are conditional on an untested G/D=100 and on a single dust-opacity normalization, so the paper is best read as a viability argument rather than a measurement of α_CO. With the sensitivity analysis recommended below, the manuscript would make a solid contribution to the α_CO debate.

major comments (3)
  1. [§3.2.1–§3.2.2, Tables 3, 6, 8] The quantitative backbone of the conclusion is the fixed G/D=100 plus the Draine et al. (2014) dust opacity normalization. Both gas-mass estimators scale linearly with G/D, so the median α_CO values ~3–5 are directly proportional to this assumed ratio. The paper itself reports that leaving G/D free in TUNER yields G/D~150–380 and α_CO~7–22 (§3.2.2), and excludes these as unrealistic based on literature expectations rather than sample metallicity measurements. No direct metallicity or G/D constraint is presented for the Vz-GAL objects. A true ratio in the range 25–50 would bring the gas-based α_CO to ~0.8–1.5 and dissolve the claimed tension; the §3.2.3 statement that the results 'statistically favor' a Milky Way-like value is therefore not supported by the data as presented. At minimum, the paper needs a sensitivity analysis propagating the G/D uncertainty (and ideally external metallici
  2. [§3.2.2, Eq. (6), Table 6, Fig. 6] The TUNER-based α_CO is not an independent gas-mass estimate in the way the 'two complementary methods' framing implies. The model is fit to the observed CO(1–0) and higher-J CO lines, and α_CO,LVG is defined as M_H2,LVG / L'_CO(1-0),LVG, where the model CO(1–0) luminosity is matched to the observed value within ~0.1 dex for most sources. The agreement between method-1 and method-2 is therefore partly by construction: both share G/D=100 and κ_ν, and the CO luminosity enters the TUNER fit itself. The text acknowledges the non-independence, but the consistency argument should be downweighted or a version of the TUNER analysis that does not feed the observed CO(1–0) luminosity into the α_CO determination should be presented.
  3. [§4.2, Table 8] The mixed estimator is shown to systematically underestimate M_dyn for unresolved data, and the paper ultimately relies on the isotropic virial estimator with enlarged radii for its headline upper limits. This is transparent, but it leaves the quantitative α_CO upper limits (Table 8, columns g–h) resting on R_LVG or 2.5×R_dust. R_LVG comes from the same TUNER model whose G/D and opacity assumptions are at issue, and 2.5×R_dust is a fiducial literature factor, not a measured cold-gas size for this sample. The central claim should be phrased as 'these values are not excluded by current dynamical constraints' rather than as a positive preference for near-Galactic α_CO, and the illustrative character of the enlarged-radius limits should be stated in the abstract or summary.
minor comments (5)
  1. [Title/affiliations] The running title contains typographical artifacts: 'F orming' and 'F actor T ension'; the affiliation carries 'Departement' instead of 'Department'.
  2. [Table 2, note g] Using the CO(5–4) linewidth for HerBS-191 instead of the CO(1–0) FWHM affects the Group-2 dynamical limits. This is important enough to be stated in the main text, not only in a table note.
  3. [Fig. 6 caption] The phrase 'median underestimation of ~0.10 dex' should be 'median underprediction' to make clear it is the model, not the data, that lies low.
  4. [Table 8] The repeated column labels (a)–(h) in the table notes are confusing. Please use distinct column identifiers or a clearer shorthand in the caption and notes.
  5. [§4.3, Table 7] The 'Difference [dex]' column is ambiguous regarding sign convention. Specify explicitly whether positive values correspond to increases or decreases in α_CO relative to the baseline.

Circularity Check

2 steps flagged

TUNER-based α_CO divides by the model-fitted CO(1-0) luminosity, and the free-G/D fit that would give α_CO~7-22 is discarded in favor of a fixed G/D=100; the near-Galactic α_CO result is therefore partly loaded into the input calibration rather than independently measured.

specific steps
  1. fitted input called prediction [§3.2.2, Eq. (6), Table 6, Fig. 6 (right)]
    "MH2,L VG=α CO,L VG·L′ CO(1−0),L VG (Eq. 6). ... Our best-fit models fit the observed CO(1–0) line luminosities within the error bars, with a median underestimation of∼0.10 dex."

    The LVG-derived conversion factor is defined as the ratio of the model-inferred gas mass to the model-reproduced CO(1-0) luminosity. Because TUNER is fitted to the observed CO(1-0) line (along with the higher-J SLED and dust SED), L'_CO(1-0),LVG is not an independent observable. Thus α_CO,LVG is partly a re-expression of the fitting procedure and of the assumed G/D=100, rather than an independent measurement of the CO-to-H2 conversion factor. The dust-SED method (method 1) does not share this particular issue because it uses the observed L'_CO in the denominator.

  2. other [§3.2.2 (free-G/D test; fixed G/D adopted; Eqs. 5-6)]
    "We have also fixed the G/D ratio to 100, i.e., the same as that used in §3.2.1. We further tested TUNER L VG models with the G/D ratio left as a free parameter. The resulting fits produced median G/D ratios of∼150–380, with 9/12 sources favoring values above 200. These solutions implyα CO values of∼7–22 ... Given that such large G/D ratios are not generally expected ... we chose to adopt a fixed G/D ratio of 100."

    By Eq. (5), M_gas = G/D × M_dust and α_CO = M_gas/L'_CO, so every gas-based α_CO in Tables 3 and 6 scales linearly with the adopted G/D. The paper first fits G/D freely and obtains α_CO ~7-22, then rejects those fits as unrealistic and fixes G/D=100, yielding α_CO ~3-5. The headline 'intermediate to near-Galactic values remain viable' is therefore to first order enforced by the choice G/D=100 rather than independently inferred from the data. This is a partially circular/assumption-forced step, although the dynamical upper limits provide some independent constraint.

full rationale

The paper contains substantial independent content: it uses observed CO(1-0) luminosities, ALMA-resolved dust sizes, and dynamical estimators built from observed FWHMs, and it tests the interpretation against the resolved GN20 case. The dust-SED method (Eq. 5) is not circular in the strict sense: it combines an observed CO luminosity with a continuum-derived dust mass and an externally assumed G/D=100. The isotropic virial upper limits are also a legitimate, partly independent check. However, two steps undermine the claim that the near-Galactic α_CO values are a 'prediction' rather than a consequence of the input calibration. First, the TUNER-derived α_CO (Eq. 6) uses the model-fitted CO(1-0) luminosity as its denominator; because TUNER is fitted to the observed CO(1-0) line, this α_CO is a re-expression of the fit rather than an independent measurement. Second, the paper explicitly fits G/D as a free parameter, obtains α_CO~7-22, declares those G/D values unrealistic, and fixes G/D=100; since all gas masses scale linearly with G/D, the resulting α_CO~3-5 is largely imposed by that fixed input. The paper is transparent about the G/D dependence and states that the conclusion is conditional, which keeps this from being fully circular, but the central 'near-Galactic' result is partly loaded into the assumed gas-to-dust ratio. Hence a score of 4 is appropriate: there is real independent content, but some of the derived α_CO values reduce by construction to the adopted calibration.

Axiom & Free-Parameter Ledger

7 free parameters · 5 axioms · 0 invented entities

The central claim depends on a handful of calibrated constants (G/D, κ_ν) and structural assumptions (gas extent, inclination, linewidth decomposition). No new physical entities are introduced. The most fragile input is G/D=100, because it scales both gas-mass methods linearly and the data do not directly constrain it.

free parameters (7)
  • Gas-to-dust mass ratio (G/D) = 100
    Fixed to 100 for all sources; linear scaling factor for both gas-mass methods. Free-G/D TUNER fits give 150-380, which is rejected as unrealistic. If G/D were lower (~25-30), α_CO would drop to ~0.8–1.0.
  • Dust opacity normalization (κ_ν) = 0.047 m^2/kg at 850 µm
    Taken from Draine et al. (2014); directly affects dust masses and hence gas masses.
  • Intrinsic disk thickness (q0) = 0.2
    Assumed to convert observed axis ratios into inclinations; affects all inclination-dependent dynamical masses.
  • Pressure-support coefficient (k) = 3
    Assumed in the 'mixed' dynamical estimator for rotating, pressure-supported thick disks; not empirically constrained.
  • Rotation-to-FWHM factor = 0.5
    Assumed v_rot = 0.5 × FWHM / sin(i); the unresolved CO linewidth cannot be decomposed into rotation and dispersion.
  • Velocity dispersion (σ0) = 31-38 km/s
    Adopted from the redshift-dependent relation of Rizzo et al. (2024), not measured for each source.
  • Fiducial gas-to-dust size ratio = 2.5
    Used as a test radius for dynamical consistency; not directly measured for the sample.
axioms (5)
  • standard math Spatially flat ΛCDM cosmology (Planck 2020)
    Used for angular distance and kpc scales; standard background assumption.
  • domain assumption Dust emission traces a circular inclined disk
    Assumed to derive R_dust and inclinations from ALMA axis ratios; no direct cold-gas geometry for most sources.
  • domain assumption Molecular gas is smoothly distributed on scales exceeding the dust radius
    Invoked to justify using LVG-inferred radii (or 2.5×R_dust) as the true cold-gas extent; only GN20 has direct resolved CO size evidence.
  • domain assumption Solar metallicity (G/D=100) in high-z DSFGs
    Fixed G/D=100; direct metallicity measurements are unavailable and free-G/D fits are rejected as unrealistic.
  • standard math Virial estimator factor 6.7
    Adopted from Binney & Tremaine via Förster Schreiber et al. (2009) for the isotropic virial mass formula.

pith-pipeline@v1.3.0-alltime-deepseek · 46635 in / 9199 out tokens · 71842 ms · 2026-08-01T15:22:31.125597+00:00 · methodology

0 comments
read the original abstract

The CO luminosity-to-H$_2$ mass conversion factor ($\alpha_{CO}$) remains a debated uncertainty in determining molecular gas masses of high-redshift dusty star-forming galaxies (DSFGs). Dynamical mass constraints have often favored $\alpha_{CO}=0.8$~$M_{\odot}~{(K~km~{s}^{-1}~{pc}^{2})}^{-1}$, whereas dust- and radiative-transfer-based methods imply higher values. We revisit this ``tension" using the largest homogeneous sample of 21 unlensed $z\sim1-4$ DSFGs, with securely measured \coonezero luminosities from the VLA \vzgal survey and resolved ($\sim{0.1}^{\prime\prime}$) ALMA 1~mm dust continuum imaging. For 12 galaxies with robust modeling constraints, we derive molecular gas masses using dust spectral energy distribution modeling and the TUNER LVG framework, adopting a solar-metallicity gas-to-dust mass ratio of 100. Although not fully independent due to shared assumptions on dust properties, these approaches yield mutually consistent gas masses corresponding to $\alpha_{CO}\sim1.5-11.5$, with a median near the Galactic $\alpha_{CO}=4.3$. Isotropic virial dynamical masses agree with these gas masses when realistic molecular gas sizes are adopted, while our proposed ``mixed" (rotating, pressure-supported, thick-disk) estimator systematically underestimates dynamical masses, producing low $\alpha_{CO}$ limits. Using GN20 ($z=4.055$) as a case study, we show that resolved gas geometry and kinematics reconcile the discrepancy with LVG-derived $\alpha_{CO}$. Our results suggest that current data do not require $\alpha_{CO}=0.8$, and intermediate to near-Galactic values remain dynamically viable given uncertainties in gas geometry, dust properties, and gas-to-dust ratios. Further progress in calibrating $\alpha_{CO}$ in the early universe will require resolved molecular gas observations, physically motivated ISM modeling, and stringent constraints on dust properties.

Figures

Figures reproduced from arXiv: 2607.18440 by Amelie Saintonge, Andrew J. Baker, Asantha Cooray, Axel Weiss, Bethany Jones, Chentao Yang, Diana Ismail, Dominik Riechers, Edoardo Borsato, Emilio Romano-Diaz, Hiddo S. B. Algera, Kirsty M. Butler, Leindert A. Boogaard, Matthew Lehnert, Paul van der Werf, Pierre Cox, Prachi Prajapati, Roberto Neri, Stefano Berta, Tom J. L. C. Bakx.

Figure 1
Figure 1. Figure 1: Classification of the Vz -GAL high-z dusty galaxies as lensed or unlensed sources, their CO(1–0) line fluxes and redshift distribution. We find that DSFGs at lower line fluxes show a higher fraction of unlensed galaxies, as expected. We find 19 Herschel fields with 27 isolated dusty galaxies ( [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: ALMA 1 mm dust contours of the selected Vz -GAL unlensed sources ( [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Left panel: Observed major and minor axes of the targets using ALMA 1 mm observations. Right panel: Dust inclination angle distribution of the sources as compared to their derived dust sizes. The median inclination angle is consistent with that expected for randomly oriented disks in the sky, corresponding to ⟨i⟩ = 1 (i = 57.3 ◦ ) or ⟨sin2 (i)⟩ = 2/3 (i = 54.7 ◦ ). These values should not be confused with … view at source ↗
Figure 4
Figure 4. Figure 4: Correlation between inclination angle and ellipticity of a disk. Both parameters depend on the observed axis ratio ‘q’. Left panel: Variation in inclination-angle contribution to the dynamical mass (Mdyn) — via sin−2 (i) factor (M. S. Bothwell et al. 2013, Eqn. 8) — with assumed intrinsic thickness (q0) of the disk. For all q0 values and near face-on systems, a steeper increase in observed inclination angl… view at source ↗
Figure 5
Figure 5. Figure 5: , we show an example of HerBS-51 (z = 2.183) with an SED fit and the corresponding corner plot of the posterior distributions of the derived parameters [PITH_FULL_IMAGE:figures/full_fig_p011_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: (Left panel) Comparison of the ALMA-observed dust sizes to the characteristic radius inferred from the TUNER LVG modeling. As expected due to radiative transfer effects (G. Calistro Rivera et al. 2018; L. A. Boogaard et al. 2026a), the LVG-derived radii are systematically larger than the observed dust sizes in most targets. (Right panel) Observed CO(1–0) line luminosities compared with those fitted by TUNE… view at source ↗
Figure 7
Figure 7. Figure 7: HerBS-51 (z = 2.183) is shown as a representative example of the TUNER LVG modeling results. Upper panel: The black dashed curve represents the median best-fit model to the combined dust and CO SEDs, while the gray shaded region indicates the 1σ confidence interval. Black points show the observed fluxes, and the colored dotted curves correspond to individual density components, scaled up for clarity. Compa… view at source ↗
Figure 8
Figure 8. Figure 8: Comparison between dynamical masses and gas masses for the explored 12 sources. The upper panel and lower panel are for Group-1 and Group-2 targets, respectively. We explore three different radii to derive dynamical masses, namely dust size (Rdust, panels-(a,b)), LVG radius (RLVG, panels-(c,d)), and a fiducial cold gas disk of 2.5× the dust size (panels-(e,f)). Different colored symbols represent various g… view at source ↗
Figure 9
Figure 9. Figure 9: Same as [PITH_FULL_IMAGE:figures/full_fig_p022_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: GN20 as an example to show collective effects of various contributors, uncertainties/assumptions that contribute to plausible changes in the dynamical upper limits of αCO. We note that CO excitation correction also contributes to the αCO discrepancy in the absence of integrated CO(1–0) measurements. of F. Rizzo et al. (2024). While isotropic virial estimators yield gas masses consistent with dynamical con… view at source ↗
Figure 11
Figure 11. Figure 11: Dynamical mass as a function of dust size for 21 Vz -GAL unlensed DSFGs. All the data points are colored using their dust-inferred inclination angles (i; [PITH_FULL_IMAGE:figures/full_fig_p024_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: Comparison of the TUNER LVG-derived CO excitation budget with the star formation rate surface density (ΣSFR). The CO excitation budget (y-axis) is defined as the ratio of the integrated CO line flux in the high-J transitions (J = 7 − 15) to that in the low-/mid-J transitions (J = 1 − 6). Left: ΣSFR computed using the observed SFRs (8–1000 µm; S. Berta et al. 2023) and ALMA dust continuum sizes ( [PITH_FU… view at source ↗
Figure 13
Figure 13. Figure 13: shows the remaining unlensed Vz -GAL fields that exhibit multiple dust continuum components in the ALMA 1 mm imaging. Since the corresponding CO(1–0) emission remains unresolved within the VLA beam, the molecular gas cannot be reliably associated with individual dust components. These systems are therefore excluded from the present analysis. Details on the nature of these objects will be discussed by Bakx… view at source ↗
Figure 14
Figure 14. Figure 14: Vz -GAL CO(1–0) spectra (yellow) of Group-2 targets that show complex CO(1–0) line profiles (see § 2.3 for more details). In gray are the higher-J CO line profiles for each source to compare line shapes. The upper panel is adopted from P. Prajapati et al. (2026), and the pilot sources in the lower panel are from F. Stanley et al. (2023) [PITH_FULL_IMAGE:figures/full_fig_p035_14.png] view at source ↗
Figure 15
Figure 15. Figure 15: Kolmogorov-Smirnov-Test or KS-test showing the cumulative distribution of dust inclination angles in blue. The shaded area in gray presents the expected spread for a sample of 21 randomly oriented inclinations, which ideally follows 1−cos(i) for a sufficiently large sample size. To give proper historical credit, we note that Equations 16 and 17 are specific examples of a more general result derived by S. … view at source ↗
Figure 16
Figure 16. Figure 16: HerBS-51 as an example to show TUNER-derived corner plots (D. Foreman-Mackey 2016) of the posterior for the model ( [PITH_FULL_IMAGE:figures/full_fig_p041_16.png] view at source ↗
Figure 17
Figure 17. Figure 17: Similar to [PITH_FULL_IMAGE:figures/full_fig_p042_17.png] view at source ↗
Figure 17
Figure 17. Figure 17: (continued) TUNER fits for HerBS-165 and HerBS-169 from Group-1, and HeLMS-50 and HerBS-43a from Group-2 [PITH_FULL_IMAGE:figures/full_fig_p043_17.png] view at source ↗
Figure 17
Figure 17. Figure 17: (continued) TUNER fits for Group-2 sources, namely HerBS-43b, HerBS-188, and HerBS-191 [PITH_FULL_IMAGE:figures/full_fig_p044_17.png] view at source ↗
Figure 18
Figure 18. Figure 18: Similar to [PITH_FULL_IMAGE:figures/full_fig_p045_18.png] view at source ↗
Figure 18
Figure 18. Figure 18: (continued) TUNER fits for HerBS-165 and HerBS-169 from Group-1, and HeLMS-50 and HerBS-43a from Group-2 [PITH_FULL_IMAGE:figures/full_fig_p046_18.png] view at source ↗
Figure 18
Figure 18. Figure 18: (continued) TUNER fits for Group-2 sources, namely HerBS-43b, HerBS-188, and HerBS-191 [PITH_FULL_IMAGE:figures/full_fig_p047_18.png] view at source ↗
Figure 19
Figure 19. Figure 19: Similar to [PITH_FULL_IMAGE:figures/full_fig_p048_19.png] view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

288 extracted references · 15 canonical work pages · 5 internal anchors

  1. [1]

    , keywords =

    Vz-GAL: Probing Cold Molecular Gas in Dusty Star-forming Galaxies at z = 1─6. , keywords =. doi:10.3847/1538-4365/ae27d4 , archivePrefix =. 2509.25167 , primaryClass =

  2. [2]

    Monthly Notices of the Royal Astronomical Society , volume =

    Behroozi, Peter and Wechsler, Risa H and Hearin, Andrew P and Conroy, Charlie , title =. Monthly Notices of the Royal Astronomical Society , volume =. 2019 , month =. doi:10.1093/mnras/stz1182 , url =

  3. [3]

    , keywords =

    The ALMA-CRISTAL Survey: Spatial extent of [CII] line emission in star-forming galaxies at z = 4 - 6. , keywords =. doi:10.1051/0004-6361/202451811 , archivePrefix =. 2408.03374 , primaryClass =

  4. [4]

    CO(7-6) and [C I](2-1) survey in z > 6 quasars

    CO(7-6) and [C I](2-1) survey in z > 6 quasars. arXiv e-prints , keywords =. doi:10.48550/arXiv.2605.20698 , archivePrefix =. 2605.20698 , primaryClass =

  5. [5]

    , keywords =

    HerS-3: An Exceptional Einstein Cross Reveals a Massive Dark Matter Halo. , keywords =. doi:10.3847/1538-4357/adf204 , archivePrefix =. 2509.14983 , primaryClass =

  6. [6]

    , keywords =

    The Kiloparsec-scale Star Formation Law at Redshift 4: Widespread, Highly Efficient Star Formation in the Dust-obscured Starburst Galaxy GN20. , keywords =. doi:10.1088/2041-8205/798/1/L18 , archivePrefix =. 1412.2132 , primaryClass =

  7. [7]

    , keywords =

    GalPak ^ 3D : A Bayesian Parametric Tool for Extracting Morphokinematics of Galaxies from 3D Data. , keywords =. doi:10.1088/0004-6256/150/3/92 , archivePrefix =. 1501.06586 , primaryClass =

  8. [8]

    , keywords =

    The ALMA-CRISTAL survey: Resolved kinematic studies of main sequence star-forming galaxies at 4 < z < 6. , keywords =. doi:10.1051/0004-6361/202555362 , archivePrefix =. 2507.11600 , primaryClass =

  9. [9]

    , keywords =

    CASA, the Common Astronomy Software Applications for Radio Astronomy. , keywords =. doi:10.1088/1538-3873/ac9642 , archivePrefix =. 2210.02276 , primaryClass =

  10. [10]

    , keywords =

    Predicting the resolved CO emission of z = 1 - 3 star-forming galaxies. , keywords =. doi:10.1051/0004-6361/202453057 , archivePrefix =. 2506.13899 , primaryClass =

  11. [11]

    arXiv e-prints , keywords =

    A stellar bar hidden in an extreme gas-rich disk galaxy at z=4.055. arXiv e-prints , keywords =. doi:10.48550/arXiv.2605.15273 , archivePrefix =. 2605.15273 , primaryClass =

  12. [12]

    , keywords =

    GA-NIFS: NIRSpec reveals evidence for non-circular motions and AGN feedback in GN20. , keywords =. doi:10.1093/mnras/stae1993 , archivePrefix =. 2403.03192 , primaryClass =

  13. [13]

    , keywords =

    Uncovering the stellar structure of the dusty star-forming galaxy GN20 at z = 4.055 with MIRI/JWST. , keywords =. doi:10.1051/0004-6361/202346535 , archivePrefix =. 2304.13529 , primaryClass =

  14. [14]

    , keywords =

    Resolving the ISM at the Peak of Cosmic Star Formation with ALMA: The Distribution of CO and Dust Continuum in z 2.5 Submillimeter Galaxies. , keywords =. doi:10.3847/1538-4357/aacffa , archivePrefix =. 1804.06852 , primaryClass =

  15. [15]

    , keywords =

    Metal factories in the early Universe. , keywords =. doi:10.1093/mnras/stae1564 , archivePrefix =. 2303.07376 , primaryClass =

  16. [16]

    , keywords =

    A high-resolution investigation of the multiphase ISM in a galaxy during the first two billion years. , keywords =. doi:10.1093/mnras/stab3569 , archivePrefix =. 2112.03936 , primaryClass =

  17. [17]

    , keywords =

    ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm. , keywords =. doi:10.1093/mnras/sty138 , archivePrefix =. 1801.07282 , primaryClass =

  18. [18]

    , keywords =

    Characterization of Herschel-selected strong lens candidates through HST and sub-mm/mm observations. , keywords =. doi:10.1093/mnras/stad3381 , archivePrefix =. 2311.01158 , primaryClass =

  19. [19]

    Physics and Chemistry of Star Formation: The Dynamical ISM Across Time and Spatial Scales , year = 2023, editor =

    The ALMA Wideband Sensitivity Upgrade. Physics and Chemistry of Star Formation: The Dynamical ISM Across Time and Spatial Scales , year = 2023, editor =. doi:10.48550/arXiv.2211.00195 , archivePrefix =. 2211.00195 , primaryClass =

  20. [20]

    , keywords =

    Molecular Gas and the Star-Formation Process on Cloud Scales in Nearby Galaxies. , keywords =. doi:10.1146/annurev-astro-071221-052651 , archivePrefix =. 2403.19843 , primaryClass =

  21. [21]

    , keywords =

    A dusty protocluster surrounding the binary galaxy HerBS-70 at z = 2.3. , keywords =. doi:10.1093/mnras/stae1155 , archivePrefix =. 2404.18991 , primaryClass =

  22. [22]

    Planck's dusty GEMS. VI. Multi-J CO excitation and interstellar medium conditions in dusty starburst galaxies at z = 2-4. , keywords =. doi:10.1051/0004-6361/201833625 , archivePrefix =. 1811.11215 , primaryClass =

  23. [23]

    , keywords =

    ALMA Imaging and Gravitational Lens Models of South Pole Telescope Selected Dusty, Star-Forming Galaxies at High Redshifts. , keywords =. doi:10.3847/0004-637X/826/2/112 , archivePrefix =. 1604.05723 , primaryClass =

  24. [24]

    arXiv e-prints , keywords =

    Bright [CII]158 μ m Streamers as a Beacon for Giant Galaxy Formation in SPT2349 - 56 at z=4.3. arXiv e-prints , keywords =. doi:10.48550/arXiv.2509.08035 , archivePrefix =. 2509.08035 , primaryClass =

  25. [25]

    , keywords =

    PACS Evolutionary Probe (PEP) - A Herschel key program. , keywords =. doi:10.1051/0004-6361/201117107 , archivePrefix =. 1106.3285 , primaryClass =

  26. [26]

    , keywords =

    Herschel-ATLAS Data Release III: near-infrared counterparts in the South Galactic Pole field - another 100 000 submillimetre galaxies. , keywords =. doi:10.1093/mnras/stab3300 , archivePrefix =. 2202.07687 , primaryClass =

  27. [27]

    , keywords =

    The deepest Herschel-PACS far-infrared survey: number counts and infrared luminosity functions from combined PEP/GOODS-H observations. , keywords =. doi:10.1051/0004-6361/201321371 , archivePrefix =. 1303.4436 , primaryClass =

  28. [28]

    , keywords =

    Erratum: Evolution of cosmic star formation in the SCUBA-2 Cosmology Legacy Survey. , keywords =. doi:10.1093/mnras/stx1497 , adsurl =

  29. [29]

    , keywords =

    ALMA twenty-six arcmin ^ 2 survey of GOODS-S at one millimeter (ASAGAO): Source catalog and number counts. , keywords =. doi:10.1093/pasj/psy104 , archivePrefix =. 1808.04502 , primaryClass =

  30. [30]

    , keywords =

    The Evolution of the IR Luminosity Function and Dust-obscured Star Formation over the Past 13 Billion Years. , keywords =. doi:10.3847/1538-4357/abdb27 , archivePrefix =. 2101.04734 , primaryClass =

  31. [31]

    , keywords =

    Submillimeter galaxies. , keywords =. doi:10.1016/S0370-1573(02)00134-5 , archivePrefix =. astro-ph/0202228 , primaryClass =

  32. [32]

    , keywords =

    Dusty star-forming galaxies at high redshift. , keywords =. doi:10.1016/j.physrep.2014.02.009 , archivePrefix =. 1402.1456 , primaryClass =

  33. [33]

    Royal Society Open Science , keywords =

    High-redshift star formation in the Atacama large millimetre/submillimetre array era. Royal Society Open Science , keywords =. doi:10.1098/rsos.200556 , archivePrefix =. 2004.00934 , primaryClass =

  34. [34]

    An ESA facility for far-infrared and submillimetre astronomy

    Herschel Space Observatory. An ESA facility for far-infrared and submillimetre astronomy. , keywords =. doi:10.1051/0004-6361/201014759 , archivePrefix =. 1005.5331 , primaryClass =

  35. [35]

    , keywords =

    Planck's dusty GEMS: The brightest gravitationally lensed galaxies discovered with the Planck all-sky survey. , keywords =. doi:10.1051/0004-6361/201425128 , archivePrefix =. 1506.01962 , primaryClass =

  36. [36]

    Planck intermediate results. XXVII. High-redshift infrared galaxy overdensity candidates and lensed sources discovered by Planck and confirmed by Herschel-SPIRE. , keywords =. doi:10.1051/0004-6361/201424790 , archivePrefix =. 1503.08773 , primaryClass =

  37. [37]

    , keywords =

    The 10 Meter South Pole Telescope. , keywords =. doi:10.1086/659879 , archivePrefix =. 0907.4445 , primaryClass =

  38. [38]

    , keywords =

    Extragalactic Millimeter-wave Sources in South Pole Telescope Survey Data: Source Counts, Catalog, and Statistics for an 87 Square-degree Field. , keywords =. doi:10.1088/0004-637X/719/1/763 , archivePrefix =. 0912.2338 , primaryClass =

  39. [39]

    High-Redshift Starburst Galaxies Under the Cosmic Microscope: Unveiling the stellar histories of strongly lensed starburst galaxies with ALMA and Spitzer

  40. [40]

    , keywords =

    Submillimeter Galaxies at z -0.5ex 2: Evidence for Major Mergers and Constraints on Lifetimes, IMF, and CO-H _ 2 Conversion Factor. , keywords =. doi:10.1086/587168 , archivePrefix =. 0801.3650 , primaryClass =

  41. [41]

    American Astronomical Society Meeting Abstracts \#229 , year = 2017, series =

    The Cold Gas History of the Universe as seen by the ngVLA. American Astronomical Society Meeting Abstracts \#229 , year = 2017, series =

  42. [42]

    , keywords =

    Rise of the Titans: A Dusty, Hyper-luminous 870 m Riser Galaxy at z 6. , keywords =. doi:10.3847/1538-4357/aa8ccf , archivePrefix =. 1705.09660 , primaryClass =

  43. [43]

    Multiwavelength Study of Massive Galaxies at z -0.5ex 2. I. Star Formation and Galaxy Growth. , keywords =. doi:10.1086/521818 , archivePrefix =. 0705.2831 , primaryClass =

  44. [44]

    American Astronomical Society Meeting Abstracts \#227 , year = 2016, series =

    Herschel+Hubble Observations of a Multiply-Lensed Sub-millimeter Galaxy at z -0.5ex 3. American Astronomical Society Meeting Abstracts \#227 , year = 2016, series =

  45. [45]

    , keywords =

    The Herschel ATLAS. , keywords =. doi:10.1086/653086 , archivePrefix =. 0910.4279 , primaryClass =

  46. [47]

    , keywords =

    The Herschel Bright Sources (HerBS): sample definition and SCUBA-2 observations. , keywords =. doi:10.1093/mnras/stx2267 , archivePrefix =. 1709.01514 , primaryClass =

  47. [48]

    doi:10.26093/cds/vizier.22100022 , adsurl =

    VizieR Online Data Catalog: Herschel Stripe 82 survey (HerS) first catalog (Viero+, 2014). doi:10.26093/cds/vizier.22100022 , adsurl =

  48. [49]

    z-GAL: A NOEMA spectroscopic redshift survey of bright Herschel galaxies. I. Overview. , keywords =. doi:10.1051/0004-6361/202346801 , archivePrefix =. 2307.15732 , primaryClass =

  49. [50]

    Science , keywords =

    The Detection of a Population of Submillimeter-Bright, Strongly Lensed Galaxies. Science , keywords =. doi:10.1126/science.1193420 , archivePrefix =. 1011.1255 , primaryClass =

  50. [51]

    , keywords =

    The Herschel-ATLAS: a sample of 500 m-selected lensed galaxies over 600 deg ^ 2. , keywords =. doi:10.1093/mnras/stw2911 , archivePrefix =. 1611.03922 , primaryClass =

  51. [52]

    , keywords =

    Discovery of a Multiply Lensed Submillimeter Galaxy in Early HerMES Herschel/SPIRE Data. , keywords =. doi:10.1088/2041-8205/732/2/L35 , archivePrefix =. 1104.4113 , primaryClass =

  52. [53]

    , keywords =

    Dynamical Structure of the Molecular Interstellar Medium in an Extremely Bright, Multiply Lensed z -0.5ex = 3 Submillimeter Galaxy Discovered with Herschel. , keywords =. doi:10.1088/2041-8205/733/1/L12 , archivePrefix =. 1104.4116 , primaryClass =

  53. [54]

    , keywords =

    Gravitational Lens Models Based on Submillimeter Array Imaging of Herschel-selected Strongly Lensed Sub-millimeter Galaxies at z > 1.5. , keywords =. doi:10.1088/0004-637X/779/1/25 , archivePrefix =. 1309.0836 , primaryClass =

  54. [55]

    , keywords =

    The ISM Properties and Gas Kinematics of a Redshift 3 Massive Dusty Star-forming Galaxy. , keywords =. doi:10.3847/1538-4357/aaf860 , archivePrefix =. 1812.06095 , primaryClass =

  55. [56]

    , keywords =

    ^ 3D BAROLO: a new 3D algorithm to derive rotation curves of galaxies. , keywords =. doi:10.1093/mnras/stv1213 , archivePrefix =. 1505.07834 , primaryClass =

  56. [57]

    Galactic Dynamics: Second Edition

  57. [58]

    The ALMA-ALPAKA survey. I. High-resolution CO and [CI] kinematics of star-forming galaxies at z = 0.5-3.5. , keywords =. doi:10.1051/0004-6361/202346444 , archivePrefix =. 2303.16227 , primaryClass =

  58. [59]

    , keywords =

    Clumpy star formation and an obscured nuclear starburst in the luminous dusty z = 4 galaxy GN20 seen by MIRI/JWST. , keywords =. doi:10.1051/0004-6361/202348845 , archivePrefix =. 2312.03074 , primaryClass =

  59. [60]

    , keywords =

    Direct detection of cool molecular gas in a star-forming galaxy at z=7.31. , keywords =. doi:10.1093/mnras/stag924 , archivePrefix =. 2606.13393 , primaryClass =

  60. [61]

    , keywords =

    HerMES: Candidate Gravitationally Lensed Galaxies and Lensing Statistics at Submillimeter Wavelengths. , keywords =. doi:10.1088/0004-637X/762/1/59 , archivePrefix =. 1205.3778 , primaryClass =

  61. [62]

    , keywords =

    Candidate Gravitationally Lensed Dusty Star-forming Galaxies in the Herschel Wide Area Surveys. , keywords =. doi:10.3847/0004-637X/823/1/17 , archivePrefix =. 1601.03401 , primaryClass =

  62. [63]

    , keywords =

    A search for the lenses in the Herschel Bright Sources (HerBS) sample. , keywords =. doi:10.1093/mnras/staa506 , archivePrefix =. 2002.08373 , primaryClass =

  63. [64]

    , keywords =

    IRAM 30-m-EMIR redshift search of z = 3-4 lensed dusty starbursts selected from the HerBS sample. , keywords =. doi:10.1093/mnras/staa1664 , archivePrefix =. 2006.05992 , primaryClass =

  64. [65]

    , keywords =

    Resolved CO(1-0) Emission and Gas Properties in Luminous Dusty Star-forming Galaxies at z = 2-4. , keywords =. doi:10.3847/1538-4357/acb6f7 , archivePrefix =. 2301.12976 , primaryClass =

  65. [66]

    , keywords =

    The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3. , keywords =. doi:10.1038/nature12184 , archivePrefix =. 1305.4930 , primaryClass =

  66. [67]

    , keywords =

    Herschel-ATLAS: A Binary HyLIRG Pinpointing a Cluster of Starbursting Protoellipticals. , keywords =. doi:10.1088/0004-637X/772/2/137 , archivePrefix =. 1302.4436 , primaryClass =

  67. [68]

    , keywords =

    Hyperluminous starburst gives up its secrets. , keywords =. doi:10.1093/mnras/stz2180 , archivePrefix =. 1908.03199 , primaryClass =

  68. [69]

    , keywords =

    Witnessing the Birth of the Red Sequence: ALMA High-resolution Imaging of [C II] and Dust in Two Interacting Ultra-red Starbursts at z = 4.425. , keywords =. doi:10.3847/0004-637X/827/1/34 , archivePrefix =. 1601.07549 , primaryClass =

  69. [70]

    , keywords =

    A dust-obscured massive maximum-starburst galaxy at a redshift of 6.34. , keywords =. doi:10.1038/nature12050 , archivePrefix =. 1304.4256 , primaryClass =

  70. [71]

    , keywords =

    HerMES: ALMA Imaging of Herschel-selected Dusty Star-forming Galaxies. , keywords =. doi:10.1088/0004-637X/812/1/43 , archivePrefix =. 1504.05256 , primaryClass =

  71. [72]

    , keywords =

    An Extreme Protocluster of Luminous Dusty Starbursts in the Early Universe. , keywords =. doi:10.3847/1538-4357/aaa1f1 , archivePrefix =. 1709.02809 , primaryClass =

  72. [73]

    , keywords =

    Confirming Herschel Candidate Protoclusters from ALMA/VLA CO Observations. , keywords =. doi:10.3847/1538-4357/ab002a , archivePrefix =. 1905.08813 , primaryClass =

  73. [74]

    , keywords =

    The Evolution of the Baryons Associated with Galaxies Averaged over Cosmic Time and Space. , keywords =. doi:10.3847/1538-4357/abb82e , archivePrefix =. 2009.11126 , primaryClass =

  74. [76]

    , keywords =

    Imaging the Molecular Gas Properties of a Major Merger Driving the Evolution of a z = 2.5 Submillimeter Galaxy. , keywords =. doi:10.1088/2041-8205/733/1/L11 , archivePrefix =. 1104.4348 , primaryClass =

  75. [77]

    , keywords =

    Extended Cold Molecular Gas Reservoirs in z -0.5ex = 3.4 Submillimeter Galaxies. , keywords =. doi:10.1088/2041-8205/739/1/L31 , archivePrefix =. 1105.4177 , primaryClass =

  76. [78]

    , keywords =

    Blind Detections of CO J = 1-0 in 11 H-ATLAS Galaxies at z = 2.1-3.5 with the GBT/Zpectrometer. , keywords =. doi:10.1088/0004-637X/752/2/152 , archivePrefix =. 1204.4706 , primaryClass =

  77. [79]

    , keywords =

    A survey of the cold molecular gas in gravitationally lensed star-forming galaxies at z > 2. , keywords =. doi:10.1093/mnras/stw275 , archivePrefix =. 1602.00652 , primaryClass =

  78. [80]

    , keywords =

    Cool Gas in High-Redshift Galaxies. , keywords =. doi:10.1146/annurev-astro-082812-140953 , archivePrefix =. 1301.0371 , primaryClass =

  79. [81]

    , keywords =

    A Total Molecular Gas Mass Census in Z 2-3 Star-forming Galaxies: Low-J CO Excitation Probes of Galaxies Evolutionary States. , keywords =. doi:10.3847/0004-637X/827/1/18 , archivePrefix =. 1606.02309 , primaryClass =

  80. [82]

    , keywords =

    First Redshift Determination of an Optically/Ultraviolet Faint Submillimeter Galaxy Using CO Emission Lines. , keywords =. doi:10.1088/0004-637X/705/1/L45 , archivePrefix =. 0909.3177 , primaryClass =

Showing first 80 references.