Nonparametric reconstruction of the dark energy equation of state

Holsclaw, Tracy; Alam, Ujjaini; Sansó, Bruno; Lee, Herbert; Heitmann, Katrin; Habib, Salman; Higdon, David

doi:10.1103/physrevd.82.103502

Cited by 140 publications

(139 citation statements)

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“…While there are several methods such as principle component analysis [19][20][21], Gaussian smoothing [22,23] and Gaussian processes [24][25][26][27], in this paper we will reconstruct D(z) and its derivatives more precisely by using the GP method.…”

Section: Reconstruction Methodsmentioning

confidence: 99%

Reconstructing the interaction between dark energy and dark matter using Gaussian processes

2015

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We present a nonparametric approach to reconstruct the interaction between dark energy and dark matter directly from SNIa Union 2.1 data using Gaussian processes, which is a fully Bayesian approach for smoothing data. In this method, once the equation of state (w) of dark energy is specified, the interaction can be reconstructed as a function of redshift. For the decaying vacuum energy case with w = −1, the reconstructed interaction is consistent with the standard ΛCDM model, namely, there is no evidence for the interaction. This also holds for the constant w cases from −0.9 to −1.1 and for the Chevallier-Polarski-Linder (CPL) parametrization case. If the equation of state deviates obviously from −1, the reconstructed interaction exists at 95% confidence level. This shows the degeneracy between the interaction and the equation of state of dark energy when they get constraints from the observational data.PACS numbers: 95.36.+x, 98.80.Es

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Section: Reconstruction Methodsmentioning

confidence: 99%

Reconstructing the interaction between dark energy and dark matter using Gaussian processes

2015

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“…Based on the definition of a GP, one can assume that, for any collection z 1 , ..., z n , w(z 1 ), ..., w(z n ) follow a multivariate Gaussian distribution with a constant negative mean This new, nonparametric reconstruction method has the following advantages: it avoids artificial biases due to restricted parametric assumptions for w(z), it does not lose information about the data by smoothing it, and it does not introduce arbitrariness (and lack of error control) in reconstruction by representing the data using a certain number of bins, or cutting off information by using a restricted set of basis functions to represent the data [767,768]. In [767], using this reconstruction method, Holsclaw et al reconstructed w(z) utilizing the Constitution dataset [332].…”

Section: Gaussian Process Modelingmentioning

confidence: 99%

Dark Energy

Li¹,

Li²,

Wang³

et al. 2011

Commun. Theor. Phys.

772

560

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“…In practice, one must fit the distance data with a smooth function, and the fitting process introduces systematic biases. While a variety of methods have been pursued [Huterer and Turner (2001); Weller and Albrecht (2002)], it appears that direct reconstruction is too challenging and not robust even with SN Ia data of excellent quality (though see Holsclaw et al (2010)). And while the reconstruction of ρ DE (z) is easier since it involves only first derivatives of distance, w(z) is more useful a quantity since it contains more information about the nature of dark energy than ρ DE (z).…”

Section: Direct Reconstructionmentioning

confidence: 99%

The Accelerating Universe

Huterer

2011

Adventures in Cosmology

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In this article we review the discovery of the accelerating universe using type Ia supernovae. We then outline ways in which dark energy -component that causes the acceleration -is phenomenologically described. We finally describe principal cosmological techniques to measure large-scale properties of dark energy. This chapter therefore complements articles by Caldwell and Linder (2010) in this book who describe theoretical understanding (or lack thereof) of the cause for the accelerating universe.Evidence for the missing component. Inflationary theory [Guth (1981)] explains how tiny quantum-mechanical fluctuations in the early universe could grow to become structures we see on the sky today. One of the factors that motivated inflation is that it predicts that the total energy density relative to the critical value is unity, Ω ≡ ρ/ρ crit = 1. This inflationary prediction convinced many theorists that the universe is precisely flat.Around the same time that inflation was proposed, a variety of dynamical probes of the large-scale structure in the universe were starting to indicate that the matter energy density is much lower than the value needed to make the flat. Perhaps the most specific case was made by the measurements of the clustering of galaxies, which are sensitive to the parameter combination Γ ≡ Ω M h, where Ω M is the energy density in matter relative to critical, and h is the Hubble constant in units of 100 km/s/Mpc. The measured value at the time was Γ 0.25 (with rather large errors). One way to preserve a flat universe was to postulate that the Hubble constant itself was much lower than the measurements indicated (h ∼ 0.7), so that Ω M = 1 but h ∼ 0.3 [Bartlett et al. (1995)]. Another possibility was the presence of Einstein's cosmological constant (see the Caldwell article in this book), which was World Scientific Book -9.75in x 6.5in bookchapter 2 Book Title suggested as far back as 1984 as the possible missing ingredient that could alleviate tension between data and matter-only theoretical predictions [Peebles (1984); Turner et al. (1984)] by making the universe older, and allowing flatness with a low value of the matter density. Type Ia supernovae and cosmologyThe revolutionary discovery of the accelerating universe took place in the late 1990s, but to understand it and its implications, we have to step back a few decades.Type Ia supernovae. Type Ia supernovae (SN Ia) are explosions seen to distant corners of the universe, and are thought to be cases where a rotating carbonoxygen white dwarf accretes matter from a companion star, approaches the Chandrasekhar limit, starts thermonuclear burning, and then explodes. The Ia nomenclature refers to spectra of SN Ia, which have no hydrogen, but show a prominent Silicon (Si II) line at 6150Å. SN Ia had been studied extensively by Fritz Zwicky who also gave them their name [Baade and Zwicky (1934)], and by Walter Baade, who noted that SN Ia have very uniform luminosities [Baade (1938)]. Light from type Ia supernovae brightens and fades over a period of ab...

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Nonparametric reconstruction of the dark energy equation of state

Cited by 140 publications

References 72 publications

Reconstructing the interaction between dark energy and dark matter using Gaussian processes

Reconstructing the interaction between dark energy and dark matter using Gaussian processes

Dark Energy

The Accelerating Universe

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