Probing primordial nonGaussianity via iSW measurements with SKA continuum surveys
Abstract
The Planck CMB experiment has delivered the best constraints so far on primordial nonGaussianity, ruling out earlyUniverse models of inflation that generate large nonGaussianity. Although small improvements in the CMB constraints are expected, the next frontier of precision will come from future largescale surveys of the galaxy distribution. The advantage of such surveys is that they can measure many more modes than the CMB—in particular, forthcoming radio surveys with the Square Kilometre Array will cover huge volumes. Radio continuum surveys deliver the largest volumes, but with the disadvantage of no redshift information. In order to mitigate this, we use two additional observables. First, the integrated SachsWolfe effect—the crosscorrelation of the radio number counts with the CMB temperature anisotropies—helps to reduce systematics on the large scales that are sensitive to nonGaussianity. Second, optical data allows for crossidentification in order to gain some redshift information. We show that, while the single redshift bin case can provide a σ(f{sub NL}) ∼ 20, and is therefore not competitive with current and future constraints on nonGaussianity, a tomographic analysis could improve the constraints by an order of magnitude, even with only two redshift bins. A huge improvement is provided by the addition of highredshift sources, so havingmore »
 Authors:
 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)
 Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth P01 3FX (United Kingdom)
 Publication Date:
 OSTI Identifier:
 22382006
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 01; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; CORRELATIONS; COSMOLOGICAL INFLATION; GALAXIES; LIMITING VALUES; MATRICES; POTENTIALS; RED SHIFT; UNIVERSE
Citation Formats
Raccanelli, Alvise, Doré, Olivier, Email: alvise@jhu.edu, Email: olivier.dore@caltech.edu, Bacon, David J., Maartens, Roy, Email: David.Bacon@port.ac.uk, Email: roy.maartens@gmail.com, and and others. Probing primordial nonGaussianity via iSW measurements with SKA continuum surveys. United States: N. p., 2015.
Web. doi:10.1088/14757516/2015/01/042.
Raccanelli, Alvise, Doré, Olivier, Email: alvise@jhu.edu, Email: olivier.dore@caltech.edu, Bacon, David J., Maartens, Roy, Email: David.Bacon@port.ac.uk, Email: roy.maartens@gmail.com, & and others. Probing primordial nonGaussianity via iSW measurements with SKA continuum surveys. United States. doi:10.1088/14757516/2015/01/042.
Raccanelli, Alvise, Doré, Olivier, Email: alvise@jhu.edu, Email: olivier.dore@caltech.edu, Bacon, David J., Maartens, Roy, Email: David.Bacon@port.ac.uk, Email: roy.maartens@gmail.com, and and others. 2015.
"Probing primordial nonGaussianity via iSW measurements with SKA continuum surveys". United States.
doi:10.1088/14757516/2015/01/042.
@article{osti_22382006,
title = {Probing primordial nonGaussianity via iSW measurements with SKA continuum surveys},
author = {Raccanelli, Alvise and Doré, Olivier, Email: alvise@jhu.edu, Email: olivier.dore@caltech.edu and Bacon, David J. and Maartens, Roy, Email: David.Bacon@port.ac.uk, Email: roy.maartens@gmail.com and and others},
abstractNote = {The Planck CMB experiment has delivered the best constraints so far on primordial nonGaussianity, ruling out earlyUniverse models of inflation that generate large nonGaussianity. Although small improvements in the CMB constraints are expected, the next frontier of precision will come from future largescale surveys of the galaxy distribution. The advantage of such surveys is that they can measure many more modes than the CMB—in particular, forthcoming radio surveys with the Square Kilometre Array will cover huge volumes. Radio continuum surveys deliver the largest volumes, but with the disadvantage of no redshift information. In order to mitigate this, we use two additional observables. First, the integrated SachsWolfe effect—the crosscorrelation of the radio number counts with the CMB temperature anisotropies—helps to reduce systematics on the large scales that are sensitive to nonGaussianity. Second, optical data allows for crossidentification in order to gain some redshift information. We show that, while the single redshift bin case can provide a σ(f{sub NL}) ∼ 20, and is therefore not competitive with current and future constraints on nonGaussianity, a tomographic analysis could improve the constraints by an order of magnitude, even with only two redshift bins. A huge improvement is provided by the addition of highredshift sources, so having crossID for highz galaxies and an even higherz radio tail is key to enabling very precise measurements of f{sub NL}. We use Fisher matrix forecasts to predict the constraining power in the case of no redshift information and the case where crossID allows a tomographic analysis, and we show that the constraints do not improve much with 3 or more bins. Our results show that SKA continuum surveys could provide constraints competitive with CMB and forthcoming optical surveys, potentially allowing a measurement of σ(f{sub NL}) ∼ 1 to be made. Moreover, these measurements would act as a useful check of results obtained with other probes at other redshift ranges with other methods.},
doi = {10.1088/14757516/2015/01/042},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 01,
volume = 2015,
place = {United States},
year = 2015,
month = 1
}

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