Stress Testing $Λ$CDM with High-redshift Galaxy Candidates

Boylan-Kolchin, Michael

doi:10.48550/arxiv.2208.01611

Cited by 27 publications

(26 citation statements)

References 17 publications

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“…Recently, Boylan-Kolchin (2022) pointed out tension between the estimated galaxy stellar masses (Labbé et al 2022) and those expected in ΛCDM-like models (see also Behroozi & Silk 2018). Our concept in this paper basically follows what they discussed, but in comparison with theoretical models, we adopt UV luminosities, which are more reliable than the stellar-mass estimates.…”

Section: Introductionmentioning

confidence: 91%

A Lower Bound of Star Formation Activity in Ultra-high-redshift Galaxies Detected with JWST: Implications for Stellar Populations and Radiation Sources

Inayoshi

Harikane

Inoue

et al. 2022

ApJL

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Early results of James Webb Space Telescope observations have delivered bright z ≳ 10 galaxy candidates in greater numbers than expected, enabling construction of rest-frame UV luminosity functions (LFs). The LFs contain key information on the galaxy assembly history, star formation activity, and stellar population of the distant universe. Given an upper bound of the total baryonic mass inflow rate to galaxies from their parent halos estimated from abundance matching, we derive a lower bound on the product of the star formation and UV photon production efficiency in galaxies at each redshift. This stringent constraint requires a high efficiency (≳10%–30%) converting gas into stars, assuming a normal stellar population with a Salpeter-like mass distribution. The efficiency is substantially higher than those of typical nearby galaxies, but is consistent with those seen in starburst galaxies and super-star clusters observed in the nearby universe. Alternatively, the star formation efficiency may be as low as a few percent, which is the average value for the entire galaxy population at z ≃ 6, if the stellar population is metal-free and drawn from a top-heavy mass distribution that produces more intense UV radiation. We discuss several other possible scenarios to achieve the constraint, for instance, energetic radiation produced from compact stellar remnants and quasars, and propose ways to distinguish the scenarios by forthcoming observations.

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Section: Introductionmentioning

confidence: 91%

A Lower Bound of Star Formation Activity in Ultra-high-redshift Galaxies Detected with JWST: Implications for Stellar Populations and Radiation Sources

Inayoshi

Harikane

Inoue

et al. 2022

ApJL

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“…DISCUSSION 4.1. Implications of the z ≈ 17 scenario If CEERS-1749 is confirmed to lie at z ≈ 17, it would force a major revision of early galaxy evolution models, and potentially even our underlying cosmological framework (see, e.g., Steinhardt et al 2016;Mason et al 2022;Boylan-Kolchin 2022). It is very challenging to produce such extraordinarily luminous and massive galaxies only ∼200 Myrs after the Big Bang under standard assumptions in the framework of ΛCDM cosmology (see also the candidates reported in Atek et al 2022;Yan et al 2022).…”

Section: Clues From Morphologymentioning

confidence: 99%

Schrodinger's Galaxy Candidate: Puzzlingly Luminous at $z\approx17$, or Dusty/Quenched at $z\approx5$?

Naidu¹,

Oesch²,

Setton³

et al. 2022

Preprint

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JWST 's first glimpse of the z > 10 Universe has yielded a surprising abundance of luminous galaxy candidates. Here we present the most extreme of these systems: CEERS-1749. Based on 0.6 − 5µm photometry, this strikingly luminous (≈26 mag) galaxy appears to lie at z ≈ 17. This would make it an M UV ≈ −22, M ≈ 5 × 10 9 M system that formed a mere ∼ 220 Myrs after the Big Bang. The implied number density of this galaxy and its analogues challenges virtually every early galaxy evolution model that assumes ΛCDM cosmology. However, there is strong environmental evidence supporting a secondary redshift solution of z ≈ 5: all three of the galaxy's nearest neighbors at < 2.5 have photometric redshifts of z ≈ 5. Further, we show that CEERS-1749 may lie in a z ≈ 5 protocluster that is 5× overdense compared to the field. Intense line emission at z ≈ 5 from a quiescent galaxy harboring ionized gas, or from a dusty starburst, may provide satisfactory explanations for CEERS-1749's photometry. The emission lines at z ≈ 5 conspire to boost the > 2µm photometry, producing an apparent blue slope as well as a strong break in the SED. Such a perfectly disguised contaminant is possible only in a narrow redshift window (∆z 0.1), implying that the permitted volume for such interlopers may not be a major concern for z > 10 searches, particularly when medium-bands are deployed. If CEERS-1749 is confirmed to lie at z ≈ 5, it will be the highest-redshift quiescent galaxy, or one of the lowest mass dusty galaxies of the early Universe detected to-date (A 5500 ≈ 1.2 mag, M ≈ 5 × 10 8 M ). Both redshift solutions of this intriguing galaxy hold the potential to challenge existing models of early galaxy evolution, making spectroscopic follow-up of this source critical.

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“…larger than that obtained byBoylan-Kolchin (2022) due to our consideration of measurement uncertainties in the observed value of M * and to our conservative choice of adopting f b = 0.18, while the latter author adopts f b = 0.158, derived from the best-fit values of the Plank cosmological parameters. The tension is larger for increasing values of w a , thus showing that…”

mentioning

confidence: 69%

High-redshift Galaxies from Early JWST Observations: Constraints on Dark Energy Models

Menci

Castellano

Santini

et al. 2022

ApJL

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Early observations with JWST have led to the discovery of an unexpectedly large density (stellar-mass density ρ * ≈ 106 M ⊙ Mpc−3) of massive galaxies (stellar masses M * ≥ 1010.5 M ⊙) at extremely high redshifts z ≈ 10. While such a result is based on early measurements that are still affected by uncertainties currently under consideration by several observational groups, its confirmation would have a strong impact on cosmology. Here we show that—under the most conservative assumptions and independently of the baryon physics involved in galaxy formation—such galaxy abundance is not only in tension with the standard ΛCDM cosmology but provides extremely tight constraints on the expansion history of the universe and on the growth factors corresponding to a wide class of Dynamical Dark Energy (DDE) models. Adopting a parameterization w = w 0 + w a (1 − a) for the evolution of the DDE equation of the state parameter w with the expansion factor a, we derive constraints on combinations of (w 0, w a ) that rule out with confidence level >2σ a major portion of the parameter space (w 0, w a ) allowed (or even favored) by existing cosmological probes.

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Stress Testing $Λ$CDM with High-redshift Galaxy Candidates

Cited by 27 publications

References 17 publications

A Lower Bound of Star Formation Activity in Ultra-high-redshift Galaxies Detected with JWST: Implications for Stellar Populations and Radiation Sources

A Lower Bound of Star Formation Activity in Ultra-high-redshift Galaxies Detected with JWST: Implications for Stellar Populations and Radiation Sources

Schrodinger's Galaxy Candidate: Puzzlingly Luminous at $z\approx17$, or Dusty/Quenched at $z\approx5$?

High-redshift Galaxies from Early JWST Observations: Constraints on Dark Energy Models

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