Fables of reconstruction: controlling bias in the dark energy equation of state

Crittenden, Robert; Zhao, Gong-Bo; Pogosian, Levon; Samushia, Lado; Zhang, Xinmin

doi:10.1088/1475-7516/2012/02/048

Cited by 100 publications

(137 citation statements)

References 67 publications

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“…Any representation of a function with a finite number of parameters is necessarily inaccurate and, in the absence of additional priors, the outcome of the fit would directly depend on N . As shown by Crittenden et al [27], it is possible to eliminate the dependence on N and explicitly control the reconstruction bias by adding a prior that correlates the nearby bins.…”

Section: The Reconstruction Methodsmentioning

confidence: 99%

Reconstruction of the dark matter–vacuum energy interaction

Wang

Zhao

Wands³

et al. 2015

Phys. Rev. D

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An interaction between the vacuum energy and dark matter is an intriguing possibility which may offer a way of solving the cosmological constant problem. Adopting a general prescription for momentum exchange between the two dark components, we reconstruct α(a), the temporal evolution of the coupling strength between dark matter and vacuum energy, in a nonparametric Bayesian approach using combined observational data sets from the cosmic microwave background, supernovae and large scale structure. An evolving interaction between the vacuum energy and dark matter removes some of the tensions between different data sets. However, it is not preferred over ΛCDM in the Bayesian sense, as improvement in the fit is not sufficient to compensate for the increase in the volume of the parameter space.PACS numbers: 98.80. -k, 98.80.Es

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Section: The Reconstruction Methodsmentioning

confidence: 99%

Reconstruction of the dark matter–vacuum energy interaction

Wang

Zhao

Wands³

et al. 2015

Phys. Rev. D

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“…Here we follow Crittenden et al (2009), but we modify their method to use scale factor rather than redshift as the independent variable (see also Crittenden et al 2012), adopting a correlation function…”

Section: Constraints On W(z) In the General Modelmentioning

confidence: 99%

Observational probes of cosmic acceleration

et al. 2013

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The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious efforts to understand its origin, with experiments that aim to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and the abundance of galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski effect, and direct measurements of the Hubble constant H 0 . We present extensive forecasts for constraints on the dark energy equation of state and parameterized deviations from General Relativity, achievable with Stage III and Stage IV experimental programs that incorporate supernovae, BAO, weak lensing, and cosmic microwave background data. We also show the level of precision required for clusters or other methods to provide constraints competitive with those of these fiducial programs. We emphasize the value of a balanced program that employs several of the most powerful methods in combination, both to cross-check systematic uncertainties and to take advantage of complementary information. Surveys to probe cosmic acceleration produce data sets that support a wide range of scientific investigations, and they continue the longstanding astronomical tradition of mapping the universe in ever greater detail over ever larger scales.

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“…To address these issues, we recently introduced a new reconstruction method which imposes an explicit prior directly on the space of w(z) functions, which is combined with observations in a straightforward Bayesian framework and is simple to implement [4,6]. (The Gaussian Process method [7][8][9] is close in spirit to our approach, but the methods and interpretation of the results differ significantly.)…”

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confidence: 99%

“…In [6] we have considered other choices of correlation functions and found that changing the shape of the correlation function does not significantly impact the reconstruction results.…”

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confidence: 99%

Examining the Evidence for Dynamical Dark Energy

et al. 2012

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We apply a new non-parametric Bayesian method for reconstructing the evolution history of the equation-of-state w of dark energy, based on applying a correlated prior for w(z), to a collection of cosmological data. We combine the latest supernova (SNLS 3-year or Union2.1), cosmic microwave background, redshift space distortion and the baryonic acoustic oscillation measurements (including BOSS, WiggleZ and 6dF) and find that the cosmological constant appears consistent with current data, but that a dynamical dark energy model which evolves from w < −1 at z ∼ 0.25 to w > −1 at higher redshift is mildly favored. Estimates of the Bayesian evidences show little preference between the cosmological constant model and the dynamical model for a range of correlated prior choices. Looking towards future data, we find that the best fit models for current data could be well distinguished from the ΛCDM model by observations such as Planck and Euclid-like surveys. Dark energy (DE), the source driving the acceleration of the universe in the framework of general relatively (GR), has remained an enigma since its discovery [1]. The accumulating observational data, including supernovae (SN), cosmic microwave background radiation (CMB) and large scale structure (LSS), constrains its equation-of-state w(z), which can be a general function of redshift z. An accurate reconstruction of w(z) can help us understand DE and gravity: a w = −1 would indicate a dynamical DE, while a w(z) evolving across −1 would imply an additional intrinsic degree of freedom of DE and could be a smoking gun of the breakdown of Einstein's theory of general relativity on cosmological scales.

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Fables of reconstruction: controlling bias in the dark energy equation of state

Cited by 100 publications

References 67 publications

Reconstruction of the dark matter–vacuum energy interaction

Reconstruction of the dark matter–vacuum energy interaction

Observational probes of cosmic acceleration

Examining the Evidence for Dynamical Dark Energy

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