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Related papers: Isocurvature modes in the CMB bispectrum

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We investigate new shapes of local primordial non-Gaussianities in the CMB. Allowing for a primordial isocurvature mode along with the main adiabatic one, the angular bispectrum is in general a superposition of six distinct shapes: the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 David Langlois , Bartjan van Tent

This contribution discusses isocurvature modes, in particular the non-Gaussianities of local type generated by these modes. Since the isocurvature transfer functions differ from the adiabatic one, the coexistence of a primordial…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 David Langlois

Simple curvaton models can generate a mixture of of correlated primordial adiabatic and isocurvature perturbations. The baryon and cold dark matter isocurvature modes differ only by an observationally null mode in which the two…

Astrophysics · Physics 2009-11-07 Christopher Gordon , Antony Lewis

We constrain cosmological models where the primordial perturbations have both an adiabatic and a (possibly correlated) cold dark matter (CDM) or baryon isocurvature component. We use both a phenomenological approach, where the primordial…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-09 Jussi Valiviita , Matti Savelainen , Marianne Talvitie , Hannu Kurki-Suonio , Stanislav Rusak

The damping of primordial perturbations at small scales gives rise to distortions of the cosmic microwave background (CMB). Here, the dependence of the distortion on the different types of cosmological initial conditions is explored,…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-18 Jens Chluba , Daniel Grin

We perform a joint analysis of the power spectrum and the bispectrum of the CMB temperature and polarization anisotropies to improve the constraints on isocurvature modes. We construct joint likelihoods, both for the existing Planck data,…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-19 Thomas Montandon , Guillaume Patanchon , Bartjan van Tent

We use CMB (WMAP and ACBAR), large scale structure (SDSS luminous red galaxies) and supernova (SNLS) data to constrain the possible contribution of CDM isocurvature modes to the primordial perturbation spectrum. We consider three different…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-09 Ian Sollom , Anthony Challinor , Michael P. Hobson

Non-linear effects in the early Universe generate non-zero bispectra of the cosmic microwave background (CMB) temperature and polarization, even in the absence of primordial non-Gaussianity. In this paper, we compute the contributions from…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-09 Pedro Carrilho , Karim A. Malik

Prospects for testing the adiabaticity of the primordial cosmological perturbations using MAP and PLANCK are evaluated. The most general cosmological perturbation in a universe with just baryons, photons, neutrinos, and a cold dark matter…

Astrophysics · Physics 2009-10-31 Martin Bucher , Kavilan Moodley , Neil Turok

We examine bounds on adiabatic and isocurvature density fluctuations from $\mu$-type spectral distortions of the cosmic microwave background (CMB). Studies of such distortion are complementary to CMB measurements of the spectral index and…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 James B. Dent , Damien A. Easson , Hiroyuki Tashiro

We use cosmic microwave background (CMB) and large-scale structure data to constrain cosmological models where the primordial perturbations have both an adiabatic and a cold dark matter (CDM) isocurvature component. We allow for a possible…

Astrophysics · Physics 2008-06-23 Hannu Kurki-Suonio , Vesa Muhonen , Jussi Valiviita

We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear $\delta…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Hooshyar Assadullahi , Hassan Firouzjahi , Mohammad Hossein Namjoo , David Wands

There exist several models of inflation that produce primordial bispectra that contain a large number of oscillations. In this paper we discuss these models, and aim at finding a method of detecting such bispectra in the data. We explain…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 P. Daniel Meerburg

We develop the formalism necessary to study four-point functions of the cosmic microwave background (CMB) temperature and polarization fields. We determine the general form of CMB trispectra, with the constraints imposed by the assumption…

Astrophysics · Physics 2011-05-12 Takemi Okamoto , Wayne Hu

We forecast how current ({\planck}) and future ({\prism}) cosmic microwave background (CMB) experiments constrain the adiabatic mode and its admixtures with primordial isocurvature modes, using measurements of the reconstructed CMB lensing…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Simon Muya Kasanda , Kavilan Moodley

We use a separable mode expansion estimator with WMAP data to estimate the bispectrum for all the primary families of non-Gaussian models. We review the late-time mode expansion estimator methodology which can be applied to any…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 J. R. Fergusson , M. Liguori , E. P. S. Shellard

Current cosmological data are well-described by the Lambda-Cold Dark Matter ($\Lambda$CDM) model, which assumes adiabatic initial conditions for the primordial density perturbations. This agreement between data and theory enables strong…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-02 Matthew R. Buckley , Peizhi Du , Nicolas Fernandez , Mitchell J. Weikert

If time-dependent disruptions from slow-roll occur during inflation, the correlation functions of the primordial curvature perturbation should have scale-dependent features, a case which is marginally supported from the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-04 Jinn-Ouk Gong , Gonzalo A. Palma , Spyros Sypsas

The temperature perturbations of the cosmic microwave background radiation (CMB) appear systematically suppressed, at large angular scales, with respect to the prediction of the LambdaCDM concordance model. This behavior might be a glimpse…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Noriaki Kitazawa

It is shown that double inflation (two minimally coupled massive scalar fields) can produce correlated adiabatic and isocurvature primordial perturbations. Depending on the two relevant parameters of the model, the contributions to the…

Astrophysics · Physics 2016-08-30 David Langlois
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