► Neutrinos leave a distinct imprint on the large scale structure of the Universe. ► Large surveys are sensitive to the sum of the neutrino masses. ► We collect and explain current and future ...constraints from different probes of the structure of the Universe.
Cosmological and astrophysical measurements provide powerful constraints on neutrino masses complementary to those from accelerators and reactors. Here we provide a guide to these different probes, for each explaining its physical basis, underlying assumptions, current and future reach.
The simplest model that can accommodate a viable nonbaryonic dark matter candidate is the standard electroweak theory with the addition of right-handed (sterile) neutrinos. We consider a single ...generation of neutrinos with a Dirac mass mu and a Majorana mass ital M for the right-handed component. If ital Mmuch gtmu (standard hot dark matter corresponds to ital M=0), then sterile neutrinos are produced via oscillations in the early Universe with energy density independent of ital M. However, ital M is crucial in determining the large scale structure of the Universe; for ital Msimilar to100 eV, sterile neutrinos make an excellent warm dark matter candidate.
We find that current cosmic microwave background anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near ...critical-as predicted by inflation. This result is robust to editing of data sets, and variation of other cosmological parameters (totaling seven, including a cosmological constant). Other lines of argument indicate that the energy density of nonrelativistic matter is much less than critical. Together, these results are evidence, independent of supernovae data, for dark energy in the Universe.
CosmoSIS is a modular system for cosmological parameter estimation, based on Markov Chain Monte Carlo and related techniques. It provides a series of samplers, which drive the exploration of the ...parameter space, and a series of modules, which calculate the likelihood of the observed data for a given physical model, determined by the location of a sample in the parameter space. While CosmoSIS ships with a set of modules that calculate quantities of interest to cosmologists, there is nothing about the framework itself, nor in the Markov Chain Monte Carlo technique, that is specific to cosmology. Thus CosmoSIS could be used for parameter estimation problems in other fields, including HEP. This paper describes the features of CosmoSIS and show an example of its use outside of cosmology. It also discusses how collaborative development strategies differ between two different communities: that of HEP physicists, accustomed to working in large collaborations, and that of cosmologists, who have traditionally not worked in large groups.
Cosmological parameter estimation is entering a new era. Large collaborations need to coordinate high-stakes analyses using multiple methods; furthermore such analyses have grown in complexity due to ...sophisticated models of cosmology and systematic uncertainties. In this paper we argue that modularity is the key to addressing these challenges: calculations should be broken up into interchangeable modular units with inputs and outputs clearly defined. We present a new framework for cosmological parameter estimation, CosmoSIS, designed to connect together, share, and advance development of inference tools across the community. We describe the modules already available in CosmoSIS, including camb, Planck, cosmic shear calculations, and a suite of samplers. We illustrate it using demonstration code that you can run out-of-the-box with the installer available at http://bitbucket.org/joezuntz/cosmosis.
Cosmic microwave background (CMB) temperature anisotropies have and will
continue to revolutionize our understanding of cosmology. The recent discovery
of the previously predicted acoustic peaks in ...the power spectrum has
established a working cosmological model: a critical density universe
consisting of mainly dark matter and dark energy, which formed its structure
through gravitational instability from quantum fluctuations during an
inflationary epoch. Future observations should test this model and measure its
key cosmological parameters with unprecedented precision. The phenomenology and
cosmological implications of the acoustic peaks are developed in detail. Beyond
the peaks, the yet to be detected secondary anisotropies and polarization
present opportunities to study the physics of inflation and the dark energy.
The analysis techniques devised to extract cosmological information from
voluminous CMB data sets are outlined, given their increasing importance in
experimental cosmology as a whole.
Mapping the integrated Sachs-Wolfe effect Manzotti, A.; Dodelson, S.
Physical review. D, Particles, fields, gravitation, and cosmology,
12/2014, Volume:
90, Issue:
12
Journal Article
Open access
On large scales, the anisotropies in the cosmic microwave background (CMB) reflect not only the primordial density field but also the energy gain when photons traverse decaying gravitational ...potentials of large scale structure, what is called the integrated Sachs-Wolfe (ISW) effect. Decomposing the anisotropy signal into a primordial piece and an ISW component, the main secondary effect on large scales, is more urgent than ever as cosmologists strive to understand the Universe on those scales. We present a likelihood technique for extracting the ISW signal combining measurements of the CMB, the distribution of galaxies, and maps of gravitational lensing. We test this technique with simulated data showing that we can successfully reconstruct the ISW map using all the data sets together. Then we present the ISW map obtained from a combination of real data: the NRAO VLA sky survey (NVSS) galaxy survey, temperature anisotropies, and lensing maps made by the Planck satellite. This map shows that, with the data sets used and assuming linear physics, there is no evidence, from the reconstructed ISW signal in the Cold Spot region, for an entirely ISW origin of this large scale anomaly in the CMB. However a large scale structure origin from low redshift voids outside the NVSS redshift range is still possible. Finally we show that future surveys, thanks to a better large scale lensing reconstruction will be able to improve the reconstruction signal to noise which is now mainly coming from galaxy surveys.
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