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Primordial non-Gaussianity of local type is known to produce a scale-dependent contribution to the galaxy bias. Several classes of multi-field inflationary models predict non-Gaussian bias which is stochastic, in the sense that dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-05 Simone Ferraro , Kendrick M. Smith

Primordial non-Gaussianity (PNG) is a signature of fundamental physics in the early universe that is probed by cosmological observations. It is well known that the local type of PNG generates a strong signal in the two-point function of…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-28 James M. Sullivan , Uros Seljak

We present the strongest robust constraints on primordial non-Gaussianity (PNG) from currently available galaxy surveys, combining large-scale clustering measurements and their cross-correlations with the cosmic microwave background. We…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-22 Tommaso Giannantonio , Ashley J. Ross , Will J. Percival , Robert Crittenden , David Bacher , Martin Kilbinger , Robert Nichol , Jochen Weller

We explore the use of different radio galaxy populations as tracers of different mass halos and therefore, with different bias properties, to constrain primordial non-Gaussianity of the local type. We perform a Fisher matrix analysis based…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Luis D. Ferramacho , Mario G. Santos , Matt J. Jarvis , Stefano Camera

The proper general relativistic description of the observed galaxy power spectrum is substantially different from the standard Newtonian description on large scales, providing a unique opportunity to test general relativity on horizon…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-17 Jaiyul Yoo , Nico Hamaus , Uros Seljak , Matias Zaldarriaga

The identification and extraction of non-Gaussian signals is one of the main cosmological challenges facing future experimental measurements of the cosmic microwave background temperature pattern. We present a generalized statistical…

Astrophysics · Physics 2009-11-07 Lung-Yih Chiang , Pavel Naselsky , Peter Coles

Constraining primordial non-Gaussianities (PNG) is one of the main goals of new-generation large-scale galaxy surveys. It had been proposed that unclustered tracers (with bias $b_1=0$) could be optimal for PNG studies, and that these could…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-18 Celia Merino , Santiago Avila , A. G. Adame , A. Anguren , V. Gonzalez-Perez , J. Meneses-Rizo

The simplest models of inflation predict small non-gaussianities and a featureless power spectrum. However, there exist a large number of well-motivated theoretical scenarios in which large non-gaussianties could be generated. In general,…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-11 Stefano Gariazzo , Laura Lopez-Honorez , Olga Mena

Primordial non-Gaussianity (PNG) is one of the most powerful probes of the early Universe and measurements of the large scale structure of the Universe have the potential to transform our understanding of this area. However relating…

The brightness temperature fluctuations in the 21 cm background related to neutral Hydrogen distribution provide a probe of physics related to the era of reionization when the intergalactic medium changed from a completely neutral to a…

Astrophysics · Physics 2009-06-15 Asantha Cooray

Multiple pulsar-timing-array collaborations have reported strong evidence for the existence of a gravitational-wave background. We study physical implications of this signal for cosmology, assuming that it is attributed to scalar-induced…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-25 Sai Wang , Zhi-Chao Zhao , Jun-Peng Li , Qing-Hua Zhu

The next generation of spectroscopic surveys is expected to achieve an unprecedented level of accuracy in the measurement of cosmological parameters. To avoid confirmation bias and thereby improve the reliability of these results, blinding…

The NRAO VLA Sky Survey (NVSS) is the only dataset that allows an accurate determination of the auto-correlation function (ACF) on angular scales of several degrees for Active Galactic Nuclei (AGNs) at typical redshifts $z \simeq 1$.…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-11 Jun-Qing Xia , Matteo Viel , Carlo Baccigalupi , Gianfranco De Zotti , Sabino Matarrese , Licia Verde

We introduce an exact Bayesian approach to search for non-Gaussianity of local type in Cosmic Microwave Background (CMB) radiation data. Using simulated CMB temperature maps, the newly developed technique is compared against the…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-15 Franz Elsner , Benjamin D. Wandelt

We present forecasts for constraints on deviations from Gaussian distribution of primordial density perturbations from future X-ray surveys of galaxy clusters. Our analysis is based on computing the Fisher-Matrix for number counts and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 B. Sartoris , S. Borgani , C. Fedeli , S. Matarrese , L. Moscardini , P. Rosati , J. Weller

We propose a method to estimate non-Gaussian error bars on the matter power spectrum from galaxy surveys in the presence of non-trivial survey selection functions. The estimators are often obtained from formalisms like FKP and PKL, which…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Joachim Harnois-Deraps , Ue-Li Pen

Local non-Gaussianity, parametrized by $f_{\rm NL}$, introduces a scale-dependent bias that is strongest at large scales, precisely where General Relativistic (GR) effects also become significant. With future data, it should be possible to…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Marco Bruni , Robert Crittenden , Kazuya Koyama , Roy Maartens , Cyril Pitrou , David Wands

We present the clustering of galaxy clusters as a useful addition to the common set of cosmological observables. The clustering of clusters probes the large-scale structure of the Universe, extending galaxy clustering analysis to the…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-03 Annalisa Mana , Tommaso Giannantonio , Jochen Weller , Ben Hoyle , Gert Huetsi , Barbara Sartoris

We investigate expected constraints on equilateral-type primordial non-Gaussianities from future/ongoing imaging surveys, making use of the fact that they enhance the halo/galaxy bispectrum on large scales. As model parameters to be…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-31 Ichihiko Hashimoto , Shuntaro Mizuno , Shuichiro Yokoyama