Can we actually constrain $f_{\rm NL}$ using the scale-dependent bias effect? An illustration of the impact of galaxy bias uncertainties using the BOSS DR12 galaxy power spectrum

Barreira, Alexandre

doi:10.48550/arxiv.2205.05673

Cited by 3 publications

(5 citation statements)

References 81 publications

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“…In the simplest (universal) halo model, p A = 1 for all tracers A. But this model is not consistent with simulations [20,69,70]. An improved (but still over-simplified) model allows the constant p A to vary with tracer.…”

Section: Multi-tracer Power Spectramentioning

confidence: 89%

“…The non-Gaussian bias factor b Aφ is halo-dependent and should be determined with the aid of simulations [20,69,70]…”

Section: Multi-tracer Power Spectramentioning

confidence: 99%

“…• Astrophysical complications entailed in the modelling of tracer clustering, in particular, the uncertainties in modelling the scale-dependent bias [20,21]. We use a simplified model since a full treatment requires simulations, beyond the scope of this paper.…”

Section: Introductionmentioning

confidence: 99%

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Constraining primordial non-Gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys

Jolicoeur¹,

Maartens²,

Dlamini³

2023

Preprint

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Surveys of the matter distribution contain 'fossil' information on possible non-Gaussianity that is generated in the primordial Universe. This primordial signal survives only on the largest scales where cosmic variance is strongest. By combining different surveys in a multi-tracer approach, we can suppress the cosmic variance and significantly improve the precision on the level of primordial non-Gaussianity. We consider a combination of an optical galaxy survey, like the recently initiated DESI survey, together with a new and very different type of survey, a 21 cm intensity mapping survey, like the upcoming SKAO survey. A Fisher forecast of the precision on the local primordial non-Gaussianity parameter f NL , shows that this multi-tracer combination, together with non-overlap single-tracer information, can deliver precision comparable to that from the CMB. Taking account of the largest systematic, i.e. foreground contamination in intensity mapping, we find that σ(f NL ) ∼ 3.

show abstract

Section: Multi-tracer Power Spectramentioning

confidence: 89%

“…The non-Gaussian bias factor b Aφ is halo-dependent and should be determined with the aid of simulations [20,69,70]…”

Section: Multi-tracer Power Spectramentioning

confidence: 99%

See 1 more Smart Citation

Constraining primordial non-Gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys

Jolicoeur¹,

Maartens²,

Dlamini³

2023

Preprint

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show abstract

“…However, the dependence of β f on b h may require further simulation-based analysis for a non-Gaussian universe (see Ref. [70]). Although there are other modelling assumptions intrinsic to our calculation of velocity reconstruction noise, such as the assumed distribution of electron gas within halos, we expect a marginalisation over these model parameters to have a minimal impact on our sensitivity to f NL and τ NL .…”

Section: Discussionmentioning

confidence: 99%

Primordial trispectrum from kinetic Sunyaev-Zel’dovich tomography

et al. 2022

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The kinetic Sunyaev Zel'dovich effect is a secondary CMB temperature anisotropy that provides a powerful probe of the radial-velocity field of matter distributed across the Universe. This velocity field is reconstructed by combining high-resolution CMB measurements with galaxy survey data, and it provides an unbiased tracer of matter perturbations in the linear regime. In this paper, we show how this measurement can be used to probe primordial non-Gaussianity of the local type, particularly focusing on the trispectrum amplitude τNL, as may arise in a simple two-field inflation model that we provide by way of illustration. Cross-correlating the velocity-field-derived matter distribution with the biased large-scale galaxy density field allows one to measure the scale-dependent bias factor with sample variance cancellation. We forecast that a configuration corresponding to CMB-S4 and VRO results in a sensitivity of σ f NL ≈ 0.59 and στ NL ≈ 1.5. These forecasts predict improvement factors of 10 and 195 for σ f NL and στ NL , respectively, over the sensitivity using VRO data alone, without internal sample variance cancellation. Similarly, for a configuration corresponding to DESI and SO, we forecast a sensitivity of σ f NL ≈ 3.1 and στ NL ≈ 69, with improvement factors of 2 and 5, respectively, over the use of the DESI data-set in isolation. We find that a high galaxy number density and large survey volume considerably improve our ability to probe the amplitude of the primordial trispectrum for the multi-field model considered.

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“…Note that constraints on f local NL from large-scale structure probes are weaker by at least an order of magnitude, see for instance refs [252][253][254][255][256]…”

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confidence: 99%

Testing scale-invariant inflation against cosmological data

Cecchini,

De Angelis,

Giarè

et al. 2024

J. Cosmol. Astropart. Phys.

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There is solid theoretical and observational motivation behind the idea of scale-invariance as a fundamental symmetry of Nature. We consider a recently proposed classically scale-invariant inflationary model, quadratic in curvature and featuring a scalar field non-minimally coupled to gravity. We go beyond earlier analytical studies, which showed that the model predicts inflationary observables in qualitative agreement with data, by solving the full two-field dynamics of the system — this allows us to corroborate previous analytical findings and set robust constraints on the model's parameters using the latest Cosmic Microwave Background (CMB) data from Planck and BICEP/Keck. We demonstrate that scale-invariance constrains the two-field trajectory such that the effective dynamics are that of a single field, resulting in vanishing entropy perturbations and protecting the model from destabilization effects. We derive tight upper limits on the non-minimal coupling strength, excluding conformal coupling at high significance. By explicitly sampling over them, we demonstrate an overall insensitivity to initial conditions. We argue that the model predicts a minimal level of primordial tensor modes set by r ≳ 0.003, well within the reach of next-generation CMB experiments. These will therefore provide a litmus test of scale-invariant inflation, and we comment on the possibility of distinguishing the model from Starobinsky and α-attractor inflation. Overall, we argue that scale-invariant inflation is in excellent health, and possesses features which make it an interesting benchmark for tests of inflation from future CMB data.

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Can we actually constrain $f_{\rm NL}$ using the scale-dependent bias effect? An illustration of the impact of galaxy bias uncertainties using the BOSS DR12 galaxy power spectrum

Cited by 3 publications

References 81 publications

Constraining primordial non-Gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys

Constraining primordial non-Gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys

Primordial trispectrum from kinetic Sunyaev-Zel’dovich tomography

Testing scale-invariant inflation against cosmological data

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