An Effective Bias Expansion for 21 cm Cosmology in Redshift Space

Qin, Wenzer; Schutz, Katelin; Smith, Aaron; Garaldi, Enrico; Kannan, Rahul; Slatyer, Tracy R.; Vogelsberger, Mark

doi:10.48550/arxiv.2205.06270

Cited by 4 publications

(12 citation statements)

References 93 publications

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“…These biases are consistent with those measured by ref. [20], however other theoretical calculations have found different values [50]. The effective bubble radius 9 is defined such that δ 21 ⊃ b(1 − R 2 eff k 2 /3)δ, so that the power spectrum P 21 ⊃ −2b 2 R 2 eff k 2 P/3 + • • • , and so we identify α 0 = −2b 2 R 2 eff /3.…”

Section: Model and Fiducial Scenariomentioning

confidence: 99%

“…For comparison the minimum µ kept in the current analysis of HERA data is 0.98 [20,57], which would render measurement of RSD ineffective. By contrast SKA predicts an observable window of µ > 0.67.…”

Section: More Realistic Scenariosmentioning

confidence: 99%

“…While this paper was being finalized, ref. [20] appeared which takes a highly related approach to modeling 21cm perturbations using a large-scale-structure-inspired bias modeling. Our Lagrangian formalism can be exactly mapped into their Eulerian one [42] so the approaches are highly synoptic.…”

Section: Acknowledgmentsmentioning

confidence: 99%

“…This approach is now quite commonplace in large-scale structure studies, but differs in some key respects from the standard approaches within the reionization field (see references above for examples of analytic or semi-numerical models and refs. [18][19][20] for notable examples similar in spirit to our approach). No matter how complex the physical processes leading to ionized regions, as long as they obey certain symmetries (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…rotational invariance and the equivalence principle) and are quasi-local we can write δ 21 as an expansion in powers of the density field, tidal field and low-order derivatives [21,22]. This expansion will be valid on large scales, in our case on scales larger than the typical size of an ionized bubble [19,20]. The impact of small-scale physics not explicitly included in the model is then handled by correction terms (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Optical depth to reionization from perturbative 21cm clustering

Sailer,

Chen,

White

2022

Preprint

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The optical depth τ is the least well determined parameter in the standard model of cosmology, and one whose precise value is important for both understanding reionization and for inferring fundamental physics from cosmological measurements. We forecast how well future epoch of reionization experiments could constraint τ using a symmetries-based bias expansion that highlights the special role played by anisotropies in the power spectrum on large scales. Given a parametric model for the ionization evolution inspired by the physical behavior of more detailed reionization simulations, we find that future 21cm experiments could place tight constraints on the timing and duration of reionization and hence constraints on τ that are competitive with proposed, space-based CMB missions provided they can measure k ≈ 0.1 h Mpc −1 with a clean foreground wedge across redshifts spanning the most active periods of reionization, corresponding to ionization fractions 0.2 x 0.8. Precise measurements of smaller scales will not improve constraints on τ until a better understanding of the astrophysics of reionization is achieved. In the presence of noise and foregrounds even future 21cm experiments will struggle to constrain τ if the ionization evolution deviates significantly from simple parametric forms.

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Section: Model and Fiducial Scenariomentioning

confidence: 99%

Section: More Realistic Scenariosmentioning

confidence: 99%

Section: Acknowledgmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optical depth to reionization from perturbative 21cm clustering

Sailer,

Chen,

White

2022

Preprint

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Optical depth to reionization from perturbative 21 cm clustering

Sailer

Chen

White

2022

J. Cosmol. Astropart. Phys.

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The optical depth τ is the least well determined parameter in the standard model of cosmology, and one whose precise value is important for both understanding reionization and for inferring fundamental physics from cosmological measurements. We forecast how well future epoch of reionization experiments could constraint τ using a symmetries-based bias expansion that highlights the special role played by anisotropies in the power spectrum on large scales. Given a parametric model for the ionization evolution inspired by the physical behavior of more detailed reionization simulations, we find that future 21 cm experiments could place tight constraints on the timing and duration of reionization and hence constraints on τ that are competitive with proposed, space-based CMB missions provided they can measure k ≈ 0.1 h Mpc-1 with a clean foreground wedge across redshifts spanning the most active periods of reionization, corresponding to ionization fractions 0.2 ≲ x ≲ 0.8. Significantly improving upon existing CMB-based measurements with next-generation 21 cm surveys would require substantially longer observations (∼ 5 years) than standard 𝒪(1000 hour) integration times. Precise measurements of smaller scales will not improve constraints on τ until a better understanding of the astrophysics of reionization is achieved. In the presence of noise and foregrounds even future 21 cm experiments will struggle to constrain τ if the ionization evolution deviates significantly from simple parametric forms.

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Cosmology before noon with multiple galaxy populations

Ebina,

White

2024

J. Cosmol. Astropart. Phys.

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Near-future facilities observing the high-redshift universe (2 < z < 5) will have an opportunity to take advantage of “multi-tracer” cosmology by observing multiple tracers of the matter density field: Lyman alpha emitters (LAE), Lyman break galaxies (LBG), and CMB lensing κ. In this work we use Fisher forecasts to investigate the effect of multi-tracers on next-generation facilities. In agreement with previous work, we show that multiple tracers improve constraints primarily from degeneracy breaking, instead of the traditional intuition of sample variance cancellation. Then, we forecast that for both BBN and CMB primary priors, the addition of lensing and LAEs onto a LBG-only sample will gain 25% or more in many parameters, with the largest gains being factor of ∼ 10 improvement for f EDE. We include a preliminary approach towards modelling the impact of radiative transfer (RT) on forecasts involving LAEs by introducing a simplified model at linear theory level. Our results, albeit preliminary, show that while RT influences LAE-only forecasts strongly, its effect on composite multi-tracer forecasts is limited.

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An Effective Bias Expansion for 21 cm Cosmology in Redshift Space

Cited by 4 publications

References 93 publications

Optical depth to reionization from perturbative 21cm clustering

Optical depth to reionization from perturbative 21cm clustering

Optical depth to reionization from perturbative 21 cm clustering

Cosmology before noon with multiple galaxy populations

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