H <scp>i</scp> IM correlation function from UNIT simulations: BAO and observationally induced anisotropy

Ávila, S.; Vos-Ginés, Bernhard; Cunnington, Steven; Stevens, Adam; Yepes, Gustavo; Knebe, Alexander; Chuang, Chia-Hsun

doi:10.1093/mnras/stab3406

Cited by 9 publications

(4 citation statements)

References 79 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The relation between H I mass and dark matter halo mass has been explored in many previous works (Padmanabhan et al 2017;Castorina & Villaescusa-Navarro 2017;Villaescusa-Navarro et al 2018;Obuljen et al 2019;Guo et al 2020;Chauhan et al 2020;Avila et al 2022). For example, Obuljen et al (2019) and Guo et al (2020) constrain the parameters in the H I halo mass relation using the ALFALFA survey (Giovanelli et al 2005).…”

Section: Introductionmentioning

confidence: 99%

H i HOD. I. The Halo Occupation Distribution of H i Galaxies

Qin

Howlett

Stevens

et al. 2022

ApJ

Self Cite

View full text Add to dashboard Cite

The next generation of galaxy surveys will provide more precise measurements of galaxy clustering than have previously been possible. The 21 cm radio signals that are emitted from neutral atomic hydrogen (H i) gas will be detected by large-area radio surveys such as the Widefield Australian Square Kilometre Array (SKA) Pathfinder L-band Legacy All-sky Blind Survey and SKA, and deliver galaxy positions and velocities that can be used to measure galaxy clustering statistics. However, to harness this information to improve our cosmological understanding and learn about the physics of dark matter and dark energy, we need to accurately model the manner in which galaxies detected in H i trace the underlying matter distribution of the universe. For this purpose, we develop a new H i-based halo occupation distribution (HOD) model, which makes predictions for the number of galaxies present in dark matter halos conditional on their H i mass. The parameterized HOD model is fit and validated using the Dark Sage semi-analytic model, where we show that the HOD parameters can be modeled by simple linear and quadratic functions of the H i mass. However, we also find that the clustering predicted by the HOD depends sensitively on the radial distributions of the H i galaxies within their host dark matter halos, which does not follow the Navarro–Frenk–White profile in the Dark Sage simulation. As such, this work enables—for the first time—a simple prescription for placing galaxies of different H i masses within dark matter halos in a way that is able to reproduce the H i mass-dependent galaxy clustering and H i mass function simultaneously and without requiring knowledge of the optical properties of the galaxies. Further efforts are required to demonstrate that this model can be used to produce large ensembles of mock galaxy catalogs for upcoming surveys.

show abstract

Section: Introductionmentioning

confidence: 99%

H i HOD. I. The Halo Occupation Distribution of H i Galaxies

Qin

Howlett

Stevens

et al. 2022

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…They can be used to help developing analysis methodology (e.g. Ross et al 2017;Chan et al 2022;Avila et al 2022), validate and compare the performance of different tools (e.g. Avila et al 2020;Alam et al 2021;Rossi et al 2021), understand the impact of observational systematic effects (e.g.…”

Section: Introductionmentioning

confidence: 99%

Validating galaxy clustering models with Fixed & Paired and Matched-ICs simulations: application to Primordial Non-Gaussianities

Ávila¹,

Adame²

2022

Preprint

Self Cite

View full text Add to dashboard Cite

The Fix and Pair techniques were designed to generate simulations with reduced variance in the 2-point statistics by modifying the Initial Conditions (ICs). In this paper we show that this technique is also valid when the initial conditions have local non-Gaussianities (PNG), parametrised by 𝑓 NL , without biasing the 2-point statistics but reducing significantly their variance. We show how to quantitatively use these techniques to test the accuracy of galaxy/halo clustering models down to a much reduced uncertainty and we apply them to test the standard model for halo clustering in the presence of PNG. Additionally, we show that by Matching the stochastic part of the ICs for two different cosmologies (Gaussian and non-Gaussian) we obtain a large correlation between the (2-point) statistics that can explicitly be used to further reduce the uncertainty of the model testing. For our reference analysis (we obtain an uncertainty of 𝜎( 𝑓 NL ) = 60 with a standard simulation, whereas using Fixed [Fixed-Paired] initial conditions it reduces to 𝜎( 𝑓 NL ) = 12 [𝜎( 𝑓 NL ) = 12]. When also Matching the ICs we obtain 𝜎( 𝑓 NL ) = 18 for the standard case, and 𝜎( 𝑓 NL ) = 8 [𝜎( 𝑓 NL ) = 7] for Fixed [Fixed-Paired]. The combination of the Fix, Pair and Match techniques can be used in the context of PNG to create simulations with an effective volume incremented by a factor ∼ 70 at given computational resources.

show abstract

“…This means the density field will be mapped with low angular resolution ( 1 deg) due to the large beam associated with the relatively small 15 m SKAO dishes. This poor angular resolution has been shown to pose challenges for SKAO-related H IM experiments aiming to detect BAO (Villaescusa-Navarro et al 2017;Kennedy & Bull 2021;Avila et al 2021;Rubiola et al 2021). A power spectrum feature on larger scales than the BAO would be better suited for detection by H IM if a sufficiently wide survey is commissioned, as planned with MeerKLASS (Santos et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Detecting the power spectrum turnover with HI intensity mapping

Cunnington

2022

Preprint

Self Cite

View full text Add to dashboard Cite

A goal for pathfinder intensity mapping (IM) surveys will be detecting features in the neutral hydrogen (H ) power spectrum, which serve as conclusive evidence of cosmological signals. Observing such features at the expected scales in H IM auto-correlations, where contribution from systematics is uncertain, will provide a more convincing cosmological detection. We demonstrate how the turnover, i.e. the peak of the power spectrum at ultra-large scales, can be detected with H IM. We find that a MeerKAT 4,000 deg 2 survey using the UHF-band is capable of a 3.1𝜎 detection of the turnover, relative to a null model power spectrum with no turnover. This should exceed that capable from current galaxy surveys in optical and near-infrared. The detection significance falls to ∼1𝜎 in MeerKAT's L-band but can reach ∼13𝜎 with the SKAO, which should easily surpass the constraint capable from future Stage-IV-like spectroscopic galaxy surveys. We also propose a new model-independent methodology for constraining the precise turnover scale (𝑘 0 ) and our tests on UHF-band simulated data achieved a precision of 10%. This improved to 2.4% when using the full SKAO. We demonstrate how the results are robust to foreground contamination by using transfer functions, even when an incorrect cosmology has been assumed in their construction. Given that the turnover is related to the horizon scale at matter-radiation equality, a sufficiently precise constraint of 𝑘 0 presents the possibility for a novel probe of cosmology. We therefore present a potential methodology for constructing a standard-ruler-based distance measurement, independent of the sound horizon, using the turnover location in the H power spectrum.

show abstract

H i IM correlation function from UNIT simulations: BAO and observationally induced anisotropy

Cited by 9 publications

References 79 publications

H i HOD. I. The Halo Occupation Distribution of H i Galaxies

H i HOD. I. The Halo Occupation Distribution of H i Galaxies

Validating galaxy clustering models with Fixed & Paired and Matched-ICs simulations: application to Primordial Non-Gaussianities

Detecting the power spectrum turnover with HI intensity mapping

Contact Info

Product

Resources

About