scholarly journals Consistent scalar and tensor perturbation power spectra in single fluid matter bounce with dark energy era

2018 ◽  
Vol 97 (8) ◽  
Author(s):  
Anna Paula Bacalhau ◽  
Nelson Pinto-Neto ◽  
Sandro Dias Pinto Vitenti
Keyword(s):  
Dark Energy ◽  
Power Spectra ◽  
Tensor Perturbation ◽  
Fluid Matter

scholarly journals SPATIAL RICCI SCALAR DARK ENERGY MODEL

2011 ◽  
Vol 26 (02) ◽  
pp. 317-329 ◽  
Author(s):  
RONG-JIA YANG ◽  
ZONG-HONG ZHU ◽  
FENGQUAN WU
Keyword(s):  
Dark Energy ◽  
Power Spectra ◽  
Ricci Scalar ◽  
Temperature Anisotropy ◽  
Microwave Background ◽  
Cosmic Microwave Background Temperature ◽  
Acceleration Of The Universe ◽  
Background Temperature ◽  
Best Fit ◽  
The Universe

Inspired by the holographic principle, we suggest that the density of dark energy is proportional to the spatial Ricci scalar curvature (SRDE). Such a model is phenomenologically viable. The best fit values of its parameters at 68% confidence level are found to be Ωm 0= 0.259±0.016 and α = 0.261±0.0122, constrained from the Union+CFA3 sample of 397 SNIa and the BAO measurement. We find that the equation of state of SRDE crosses -1 at z ≃ -0.14. The present value of the deceleration parameter q(z) for SRDE is found to be qz = 0~-0.85. The phase transition from deceleration to acceleration of the Universe for SRDE occurs at the redshift zq = 0~0.4. After studying the perturbation of each component of the Universe, we show that the matter power spectra and cosmic microwave background temperature anisotropy are slightly affected by SRDE, compared with ΛCDM.

scholarly journals Gravitational waves × HI intensity mapping: cosmological and astrophysical applications

2022 ◽  
Vol 2022 (01) ◽  
pp. 004
Author(s):  
Giulio Scelfo ◽  
Marta Spinelli ◽  
Alvise Raccanelli ◽  
Lumen Boco ◽  
Andrea Lapi ◽  
...  
Keyword(s):  
Black Holes ◽  
Dark Energy ◽  
Gravitational Waves ◽  
Power Spectra ◽  
Neutral Hydrogen ◽  
Redshift Distribution ◽  
Binary Black Holes ◽  
Intensity Mapping ◽  
Einstein Telescope ◽  
Dynamical Dark Energy

Abstract Two of the most rapidly growing observables in cosmology and astrophysics are gravitational waves (GW) and the neutral hydrogen (HI) distribution. In this work, we investigate the cross-correlation between resolved gravitational wave detections and HI signal from intensity mapping (IM) experiments. By using a tomographic approach with angular power spectra, including all projection effects, we explore possible applications of the combination of the Einstein Telescope and the SKAO intensity mapping surveys. We focus on three main topics: (i) statistical inference of the observed redshift distribution of GWs; (ii) constraints on dynamical dark energy models as an example of cosmological studies; (iii) determination of the nature of the progenitors of merging binary black holes, distinguishing between primordial and astrophysical origin. Our results show that: (i) the GW redshift distribution can be calibrated with good accuracy at low redshifts, without any assumptions on cosmology or astrophysics, potentially providing a way to probe astrophysical and cosmological models; (ii) the constrains on the dynamical dark energy parameters are competitive with IM-only experiments, in a complementary way and potentially with less systematics; (iii) it will be possible to detect a relatively small abundance of primordial black holes within the gravitational waves from resolved mergers. Our results extend towards GW × IM the promising field of multi-tracing cosmology and astrophysics, which has the major advantage of allowing scientific investigations in ways that would not be possible by looking at single observables separately.

scholarly journals Clustering dark energy imprints on cosmological observables of the gravitational field

2020 ◽  
Vol 500 (4) ◽  
pp. 4514-4529
Author(s):  
Farbod Hassani ◽  
Julian Adamek ◽  
Martin Kunz
Keyword(s):  
Dark Energy ◽  
Gravitational Field ◽  
Time Delay ◽  
Gravitational Lensing ◽  
Power Spectra ◽  
Gravitational Redshift ◽  
Weak Gravitational Lensing ◽  
Angular Power Spectrum ◽  
Energy Field ◽  
High Degree

ABSTRACT We study cosmological observables on the past light-cone of a fixed observer in the context of clustering dark energy. We focus on observables that probe the gravitational field directly, namely the integrated Sachs–Wolfe and non-linear Rees–Sciama effect (ISW-RS), weak gravitational lensing, gravitational redshift, and Shapiro time delay. With our purpose-built N-body code ‘k-evolution’ that tracks the coupled evolution of dark matter particles and the dark energy field, we are able to study the regime of low speed of sound cs where dark energy perturbations can become quite large. Using ray tracing, we produce two-dimensional sky maps for each effect and we compute their angular power spectra. It turns out that the ISW-RS signal is the most promising probe to constrain clustering dark energy properties coded in $w-c_\mathrm{ s}^2$, as the linear clustering of dark energy would change the angular power spectrum by ${\sim}30{{\ \rm per\ cent}}$ at low ℓ when comparing two different speeds of sound for dark energy. Weak gravitational lensing, Shapiro time delay, and gravitational redshift are less sensitive probes of clustering dark energy, showing variations of only a few per cent. The effect of dark energy non-linearities in all the power spectra is negligible at low ℓ, but reaches about $2{{\ \rm per\ cent}}$ and $3{{\ \rm per\ cent}}$, respectively, in the convergence and ISW-RS angular power spectra at multipoles of a few hundred when observed at redshift ∼0.85. Future cosmological surveys achieving per cent precision measurements will allow us to probe the clustering of dark energy to a high degree of confidence.

scholarly journals Clustering and halo abundances in early dark energy cosmological models

2021 ◽  
Vol 504 (1) ◽  
pp. 769-781
Author(s):  
Anatoly Klypin ◽  
Vivian Poulin ◽  
Francisco Prada ◽  
Joel Primack ◽  
Marc Kamionkowski ◽  
...  
Keyword(s):  
Dark Energy ◽  
Cold Dark Matter ◽  
Power Spectra ◽  
Hubble Constant ◽  
Cosmological Models ◽  
Acoustic Oscillations ◽  
Microwave Background ◽  
Linear Evolution ◽  
James Webb Space Telescope ◽  
Non Linear

ABSTRACT Cold Dark Matter with cosmological constant (ΛCDM) cosmological models with early dark energy (EDE) have been proposed to resolve tensions between the Hubble constant $H_0=100\, h$ km ṡ−1Ṁpc−1 measured locally, giving h ≈ 0.73, and H0 deduced from Planck cosmic microwave background (CMB) and other early-Universe measurements plus ΛCDM, giving h ≈ 0.67. EDE models do this by adding a scalar field that temporarily adds dark energy equal to about 10 per cent of the cosmological energy density at the end of the radiation-dominated era at redshift z ∼ 3500. Here, we compare linear and non-linear predictions of a Planck-normalized ΛCDM model including EDE giving h = 0.728 with those of standard Planck-normalized ΛCDM with h = 0.678. We find that non-linear evolution reduces the differences between power spectra of fluctuations at low redshifts. As a result, at z = 0 the halo mass functions on galactic scales are nearly the same, with differences only 1–2 per cent. However, the differences dramatically increase at high redshifts. The EDE model predicts 50 per cent more massive clusters at z = 1 and twice more galaxy-mass haloes at z = 4. Even greater increases in abundances of galaxy-mass haloes at higher redshifts may make it easier to reionize the universe with EDE. Predicted galaxy abundances and clustering will soon be tested by the James Webb Space Telescope (JWST) observations. Positions of baryonic acoustic oscillations (BAOs) and correlation functions differ by about 2 per cent between the models – an effect that is not washed out by non-linearities. Both standard ΛCDM and the EDE model studied here agree well with presently available acoustic-scale observations, but the Dark Energy Spectroscopic Instrument and Euclid measurements will provide stringent new tests.

scholarly journals Cosmology with weak lensing surveys

2005 ◽  
Vol 363 (1837) ◽  
pp. 2675-2691 ◽  
Author(s):  
Dipak Munshi ◽  
Patrick Valageas
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Lensing ◽  
Large Scale ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Power Spectra ◽  
Weak Lensing ◽  
Satellite Mission ◽  
The Universe

Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening mass. Since the lensing effects arise from deflections of the light rays due to fluctuations of the gravitational potential, they can be directly related to the underlying density field of the large-scale structures. Weak gravitational surveys are complementary to both galaxy surveys and cosmic microwave background observations as they probe unbiased nonlinear matter power spectra at medium redshift. Ongoing CMBR experiments such as WMAP and a future Planck satellite mission will measure the standard cosmological parameters with unprecedented accuracy. The focus of attention will then shift to understanding the nature of dark matter and vacuum energy: several recent studies suggest that lensing is the best method for constraining the dark energy equation of state. During the next 5 year period, ongoing and future weak lensing surveys such as the Joint Dark Energy Mission (JDEM; e.g. SNAP) or the Large-aperture Synoptic Survey Telescope will play a major role in advancing our understanding of the universe in this direction. In this review article, we describe various aspects of probing the matter power spectrum and the bispectrum and other related statistics with weak lensing surveys. This can be used to probe the background dynamics of the universe as well as the nature of dark matter and dark energy.

scholarly journals Matter power spectra in dynamical dark energy cosmologies

2011 ◽  
Vol 419 (2) ◽  
pp. 1588-1602 ◽  
Author(s):  
C. Fedeli ◽  
K. Dolag ◽  
L. Moscardini
Keyword(s):  
Dark Energy ◽  
Power Spectra ◽  
Dynamical Dark Energy

scholarly journals Accurate halo-model matter power spectra with dark energy, massive neutrinos and modified gravitational forces

2016 ◽  
Vol 459 (2) ◽  
pp. 1468-1488 ◽  
Author(s):  
A. J. Mead ◽  
C. Heymans ◽  
L. Lombriser ◽  
J. A. Peacock ◽  
O. I. Steele ◽  
...  
Keyword(s):  
Dark Energy ◽  
Power Spectra ◽  
Gravitational Forces ◽  
Massive Neutrinos
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