Primordial non-Gaussianity with angular correlation function: integral constraint and validation for DES

Riquelme, Walter; Ávila, S.; García-Bellido, J.; Porredon, A.; Ferrero, I.; Chan, Kwan Chuen; Rosenfeld, R.; Chavez, Hugo Orlando Camacho; Adame, Adrian Gutierrez; Rosell, A. Carnero; Crocce, M.; Vicente, J. De; Eifler, T. F.; Elvin-Poole, J.; Fang, X.; Krause, E.; Rodriguez, Monroy, Martin; Ross, Ashley J.; Sánchez, E.; Sevilla-Noarbe, I.

doi:10.1093/mnras/stad1429

Cited by 3 publications

(1 citation statement)

References 65 publications

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“…One example is the study of Primordial Non-Gaussianities, a probe forecasted to beat CMB and spectroscopic constraints [144] if different sources of systematic errors are kept under control. Preparations from DES in this direction are presented in [145].…”

Section: B Outlookmentioning

confidence: 99%

Dark Energy Survey Year 3 results: A 2.7% measurement of baryon acoustic oscillation distance scale at redshift 0.835

Abbott¹,

Aguena²,

Allam³

et al. 2022

Phys. Rev. D

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We present angular diameter measurements obtained by measuring the position of baryon acoustic oscillations (BAO) in an optimized sample of galaxies from the first three years of Dark Energy Survey data (DES Y3). The sample consists of 7 million galaxies distributed over a footprint of 4100 deg 2 with 0.6 < z photo < 1.1 and a typical redshift uncertainty of 0.03ð1 þ zÞ. The sample selection is the same as in the BAO measurement with the first year of DES data, but the analysis presented here uses three times the area, extends to higher redshift, and makes a number of improvements, including a fully analytical BAO template, the use of covariances from both theory and simulations, and an extensive preunblinding protocol. We used two different statistics; angular correlation function and power spectrum, and validate our pipeline with an ensemble of over 1500 realistic simulations. Both statistics yield compatible results. We combine the likelihoods derived from angular correlations and spherical harmonics to constrain the ratio of comoving angular diameter distance D M at the effective redshift of our sample to the sound horizon scale at the drag epoch. We obtain D M ðz eff ¼ 0.835Þ=r d ¼ 18.92 AE 0.51, which is consistent with, but smaller than, the Planck prediction assuming flat ΛCDM, at the level of 2.3σ. The analysis was performed blind and is robust to changes in a number of analysis choices. It represents the most precise BAO distance measurement from imaging data to date, and is competitive with the latest transverse ones from spectroscopic samples at z > 0.75. When combined with DES 3x2pt þ SNIa, they lead to improvements in H 0 and Ω m constraints by ∼20%.

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Section: B Outlookmentioning

confidence: 99%

Dark Energy Survey Year 3 results: A 2.7% measurement of baryon acoustic oscillation distance scale at redshift 0.835

Abbott¹,

Aguena²,

Allam³

et al. 2022

Phys. Rev. D

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Local primordial non-Gaussianity from the large-scale clustering of photometric DESI luminous red galaxies

Rezaie,

Ross,

Seo

et al. 2024

Monthly Notices of the Royal Astronomical Society

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We use angular clustering of luminous red galaxies from the Dark Energy Spectroscopic Instrument (DESI) imaging surveys to constrain the local primordial non-Gaussianity parameter fNL. Our sample comprises over 12 million targets, covering 14,000 square degrees of the sky, with redshifts in the range 0.2 < z < 1.35. We identify Galactic extinction, survey depth, and astronomical seeing as the primary sources of systematic error, and employ linear regression and artificial neural networks to alleviate non-cosmological excess clustering on large scales. Our methods are tested against simulations with and without fNL and systematics, showing superior performance of the neural network treatment. The neural network with a set of nine imaging property maps passes our systematic null test criteria, and is chosen as the fiducial treatment. Assuming the universality relation, we find $f_{\rm NL} = 34^{+24(+50)}_{-44(-73)}$ at 68 per cent(95 per cent) confidence. We apply a series of robustness tests (e.g. cuts on imaging, declination, or scales used) that show consistency in the obtained constraints. We study how the regression method biases the measured angular power-spectrum and degrades the fNL constraining power. The use of the nine maps more than doubles the uncertainty compared to using only the three primary maps in the regression. Our results thus motivate the development of more efficient methods that avoid over-correction, protect large-scale clustering information, and preserve constraining power. Additionally, our results encourage further studies of fNL with DESI spectroscopic samples, where the inclusion of 3D clustering modes should help separate imaging systematics and lessen the degradation in the fNL uncertainty.

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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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Primordial non-Gaussianity with angular correlation function: integral constraint and validation for DES

Cited by 3 publications

References 65 publications

Dark Energy Survey Year 3 results: A 2.7% measurement of baryon acoustic oscillation distance scale at redshift 0.835

Dark Energy Survey Year 3 results: A 2.7% measurement of baryon acoustic oscillation distance scale at redshift 0.835

Local primordial non-Gaussianity from the large-scale clustering of photometric DESI luminous red galaxies

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

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