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Related papers: How early is early dark energy?

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We study a class of early dark energy (EDE) models, in which, unlike in standard dark energy models, a substantial amount of dark energy exists in the matter-dominated era. We self-consistently include dark energy perturbations, and show…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Ujjaini Alam , Zarija Lukić , Suman Bhattacharya

In this paper we fit two models of Early Dark Energy (EDE) (an increase in the expansion rate before recombination) to the combination of Atacama Cosmology Telescope (ACT) measurements of the Cosmic Microwave Background (CMB) with data from…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-05 Vivian Poulin , Tristan L. Smith , Alexa Bartlett

We investigate the possibility of using cosmological observations to probe and constrain an imperfect dark energy fluid. We consider a general parameterization of the dark energy component accounting for an equation of state, speed of sound…

Astrophysics · Physics 2008-12-18 D. F. Mota , J. R. Kristiansen , T. Koivisto , N. E. Groeneboom

We use the latest cosmic microwave background (CMB) observations to provide updated constraints on the dark matter lifetime as well as on p-wave suppressed annihilation cross sections in the 1 MeV to 1 TeV mass range. In contrast to…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-17 Roberta Diamanti , Laura Lopez-Honorez , Olga Mena , Sergio Palomares-Ruiz , Aaron C. Vincent

We investigate early dark energy models in the context of the lensing anomaly by considering two different Cosmic Microwave Background (CMB) datasets: a complete Planck, and a second one primarily based on SPTPol and Planck temperature…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-20 Balakrishna S. Haridasu , Hasti Khoraminezhad , Matteo Viel

A phenomenological model of dark energy that tracks the baryonic and cold dark matter at early times but resembles a cosmological constant at late times is explored. In the transition between these two regimes, the dark energy density drops…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-13 Jannis Bielefeld , W. L. Kimmy Wu , Robert R. Caldwell , Olivier Dore

Current cosmological data exhibit discordance between indirect and some direct inferences of the present-day expansion rate, $H_0$. Early dark energy (EDE), which briefly increases the cosmic expansion rate prior to recombination, is a…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-19 Samuel Goldstein , J. Colin Hill , Vid Iršič , Blake D. Sherwin

In this paper we study the sound speed - $c_s^2$, which is directly related to the classical perturbations - of the dynamical dark energy (DE), especially with an equation of state crossing the cosmological constant boundary in details and…

Astrophysics · Physics 2008-11-26 Jun-Qing Xia , Yi-Fu Cai , Tao-Tao Qiu , Gong-Bo Zhao , Xinmin Zhang

It has been noted that with the pre-recombination early dark energy (EDE) resolution of Hubble tension, the preference of recent datasets for the evolving dark energy (DE) can be suppressed significantly. In this work, we clarify and…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-21 Hao Wang , Yun-Song Piao

We forecast the expected cosmological constraints from a combination of probes of both the universal expansion rate and matter perturbation growth, in the form of weak lensing tomography, galaxy tomography, supernovae, and the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-10 Shahab Joudaki , Manoj Kaplinghat

Current observational bounds on dark energy depend on assumptions about the curvature of the universe. We present a simple and efficient method for incorporating constraints from CMB anisotropy data, and use it to derive constraints on…

Astrophysics · Physics 2010-04-06 Yun Wang , Pia Mukherjee

Recent cosmological data reveal tension between parameters inferred from measurements of the cosmic microwave background (CMB), baryon acoustic oscillations (BAO), and supernovae (SN) under $\Lambda$CDM. Typical dynamical dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-10 Tanisha Jhaveri , Tanvi Karwal , Thomas Crawford , Wayne Hu , Ali Rida Khalife , Lennart Balkenhol , Fei Ge

Early-matter-like dark energy is defined as a dark energy component whose equation of state approaches that of cold dark matter (CDM) at early times. Such a component is an ingredient of unified dark matter (UDM) models, which unify the…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-19 Ralf Aurich , Sven Lustig

Cosmic microwave background polarization encodes information not only on the early universe but also dark energy, neutrino mass, and gravity in the late universe through CMB lensing. Ground based surveys such as ACTpol, PolarBear, SPTpol…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-02 Sudeep Das , Eric V. Linder

Early dark energy (EDE) is one of the most promising possibilities in order to resolve the Hubble tension: the discrepancy between early and late-Universe measurements of the Hubble constant. In this paper we propose a model of a scalar…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-12 Lucy Brissenden , Konstantinos Dimopoulos , Samuel Sánchez López

We revisit cosmic microwave background (CMB) constraints on primordial black hole dark matter. Spectral distortion limits from COBE/FIRAS do not impose a relevant constraint. Planck CMB anisotropy power spectra imply that primordial black…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-17 Daniel Aloni , Kfir Blum , Raphael Flauger

We study a class of early dark energy models which has substantial amount of dark energy in the early epoch of the universe. We examine the impact of the early dark energy fluctuations on the growth of structure and the CMB power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-31 Bo-Yu Pu , Xiao-Dong Xu , Bin Wang , Elcio Abdalla

We study the constraints on dark energy equation of state $\omega^{X}$ and the deceleration parameter $q$ from the recent observational data including Hubble data and the cosmic microwave background (CMB) radiation by using a…

General Relativity and Quantum Cosmology · Physics 2015-03-26 Hassan Amirhashchi

Current observational data favor cosmological models which differ from the standard model due to the presence of some form of dark energy and, perhaps, by additional contributions to the more familiar dark matter. Primordial nucleosynthesis…

Astrophysics · Physics 2009-11-07 James P. Kneller , Gary Steigman

We constrain the evolution of the dark energy density from Cosmic Microwave Background, Large Scale Structure and Supernovae Ia measurements. While Supernovae Ia are most sensitive to the equation of state $w_0$ of dark energy today, the…

Astrophysics · Physics 2009-11-13 Michael Doran , Khamphee Karwan , Christof Wetterich