The effect of finite halo size on the clustering of neutral hydrogen

Umeh, Obinna; Maartens, Roy; Padmanabhan, Hamsa; Camera, Stefano

doi:10.48550/arxiv.2102.06116

Cited by 4 publications

(4 citation statements)

References 67 publications

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“…In IM surveys, there is shot noise, but also thermal (or instrumental) noise. The Poissonian shot noise (see [77] for non-Poissonian corrections) is derived in a halo-model framework and given by [74,78],…”

Section: Noisementioning

confidence: 99%

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

2023

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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 $$f_{\textrm{NL}}$$ 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 $$\sigma (f_{\textrm{NL}}) \sim 4$$ σ ( f NL ) ∼ 4 .

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Section: Noisementioning

confidence: 99%

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

2023

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“…In IM surveys, there is shot noise, but also thermal (or instrumental) noise. The Poissonian shot noise (see [75] for non-Poissonian corrections) is derived in a halo-model framework and given by [72,76],…”

Section: Noisementioning

confidence: 99%

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.

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“…Recent studies have shown that r ∆c does not correspond to the physical boundary of a gravitationally bound astrophysical system. The reason is that the mass contained within r ∆c is subject to pseudo-evolution [91,92]. And there are physical processes that are known to redistribute sub-structures formed during collapse from small to large radii greater than r ∆c [93][94][95].…”

Section: Iv1 Causal Horizon and The Expanding Regions Of Spacetimementioning

confidence: 99%

Consequences of using a smooth cosmic distance in a lumpy universe: I

Umeh¹

2022

Preprint

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How do we appropriately fit a model based on an idealised Friedmann-Lemaıtre Robertson-Walker (FLRW) spacetime to observations made from a single location in a lumpy Universe? We address this question for surveys that measure the imprints of the Baryon Acoustic Oscillation (BAO) in galaxy distribution and the peak apparent magnitude of the type 1A supernova (SN1A). These observables are related to the cosmological model through the Alcock-Paczynski parameters and the distance-redshift relation. Using the corresponding inhomogeneous spacetime expressions of these as observed data, we perform a parameter inference assuming that the background FLRW model is the correct model of the universe. This process allows us to estimate the best fit Hubble rate and the deceleration parameter. We find that the inferred Hubble rate from the monopole of the Alcock-Paczynski parameters is in tension with the Hubble rate determined using the distance-redshift relation. The latter gives the best fit Hubble rate for the cosmological expansion. The constraint on the Hubble rate from the Alcock-Paczynski parameters is contaminated by the environment. When the environmental contribution is restricted to modes in the Hubble flow, we find about (9-12)% discrepancy in the Hubble rate. Finally, we comment on the insufficiency of the method of cosmography in constraining the deceleration parameter. CONTENTS

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The effect of finite halo size on the clustering of neutral hydrogen

Cited by 4 publications

References 67 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

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

Consequences of using a smooth cosmic distance in a lumpy universe: I

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