Marginal evidence for cosmic acceleration from Type Ia supernovae

Nielsen, Jeppe Trøst; Guffanti, A.; Sarkar, S.

doi:10.1038/srep35596

Cited by 196 publications

(232 citation statements)

References 33 publications

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“…These authors marginalized latent variables out of their effective likelihood, in an approach similar to our own, although with a number of detailed differences. 12 In particular, the s 1 (marginal posterior) contour obtained with BAHAMAS overlaps closely with the s 1 (profile likelihood) contour in Nielsen et al (2015), while the s 2 contour from BAHAMAS shows a degree of asymmetry that is not present in Nielsen et al (2015). (Recall that the analysis of Nielsen et al (2015) relies on approximating the confidence regions using Gaussians, while the numerical sampling of BAHAMAS does not.…”

Section: Ess( )mentioning

confidence: 99%

“…Nielsen et al (2015). These authors marginalized latent variables out of their effective likelihood, in an approach similar to our own, although with a number of detailed differences.…”

Section: Ess( )mentioning

confidence: 99%

“…More recently, Rubin et al (2015) applied a similar method to analyze Union 2.1 data on SNe Ia, extending it to deal with the selection effect and non-Gaussian distribution. Nielsen et al (2015) adopted the effective likelihood introduced in March et al (2011) but interpreted the results in terms of profile likelihood (rather than posterior distributions), showing that the profile likelihood in the W W L , m plane obtained from JLA data is much wider than what is recovered with the usual c 2 approach. This paper re-evaluates the JLA data in the light of the principled statistical analysis made possible by BAHAMAS.…”

Section: Introductionmentioning

confidence: 99%

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BAHAMAS: NEW ANALYSIS OF TYPE Ia SUPERNOVAE REVEALS INCONSISTENCIES WITH STANDARD COSMOLOGY

Shariff

Jiao

Trotta

et al. 2016

ApJ

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We present results obtained by applying our BAyesian HierArchical Modeling for the Analysis of Supernova cosmology (BAHAMAS) software package to the 740 spectroscopically confirmed supernovae of type Ia (SNe Ia) from the "Joint Light-curve Analysis" (JLA) data set. We simultaneously determine cosmological parameters and standardization parameters, including corrections for host galaxy mass, residual scatter, and object-by-object intrinsic magnitudes. Combining JLA and Planck data on the cosmic microwave background, we find significant discrepancies in cosmological parameter constraints with respect to the standard analysis: we find W =  0.399 0.027 m , s 2.8 higher than previously reported, and = - w 0.910 0.045, s 1.6 higher than the standard analysis. We determine the residual scatter to be s =  0.104 0.005 res . We confirm (at the 95% probability level) the existence of two subpopulations segregated by host galaxy mass, separated at, differing in mean intrinsic magnitude by 0.055 ± 0.022 mag, lower than previously reported. Cosmological parameter constraints, however, are unaffected by the inclusion of corrections for host galaxy mass. We find s4 evidence for a sharp drop in the value of the color correction parameter, ( ) b z , at a redshift =  z 0.662 0.055 t . We rule out some possible explanations for this behavior, which remains unexplained.

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Section: Ess( )mentioning

confidence: 99%

“…Nielsen et al (2015). These authors marginalized latent variables out of their effective likelihood, in an approach similar to our own, although with a number of detailed differences.…”

Section: Ess( )mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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BAHAMAS: NEW ANALYSIS OF TYPE Ia SUPERNOVAE REVEALS INCONSISTENCIES WITH STANDARD COSMOLOGY

Shariff

Jiao

Trotta

et al. 2016

ApJ

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“…A similar study [37] using the JLA dataset also showed that by ignoring the velocity covariance may produce a hint of anisotropy from the data. In this context, it is interesting to notice here the result of the work [49] where the authors studied the JLA set, considering all the information from possible systematics (encoded in the covariance) in the analysis, finding a marginal (less than 3σ) evidence for the accepted cosmic acceleration. …”

Section: Analysis Using the Loss Samplementioning

confidence: 99%

Asymmetry and dark energy evolution

Cárdenas

2018

J. Phys.: Conf. Ser.

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Abstract. The well known asymmetry of type Ia supernova data is used to infer general features of an alternative model for dark energy. Using a model that allows DE to vary with redshift as a probe, the results indicate the low redshift transition of the deceleration parameter q(z) is evident only taken data points from one hemisphere of the sky. A related effect is a reconstructed DE density X(z) that shows evolution (it decreases as redshift increases) only towards the hemisphere where q(z) manifest the transition. We discuss on possible theoretical frameworks where these effects can be explained.

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“…The ΛCDM model has become the standard cosmological model with the evidence for an accelerated expansion provided by the type Ia supernovae (SNIa) Hubble diagram (Riess et al 1998;Perlmutter et al 1999). However, there has recently been an important discussion in the literature concerning the ability of SNIa data alone to prove the accelerated expansion of the Universe (Nielsen et al 2016;Shariff et al 2016;Rubin & Hayden 2016;Ringermacher & Mead 2016).…”

Section: Introductionmentioning

confidence: 99%

Is cosmic acceleration proven by local cosmological probes?

Tutusaus

Lamine

Dupays

et al. 2017

A&A

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Context. The cosmological concordance model (ΛCDM) matches the cosmological observations exceedingly well. This model has become the standard cosmological model with the evidence for an accelerated expansion provided by the type Ia supernovae (SNIa) Hubble diagram. However, the robustness of this evidence has been addressed recently with somewhat diverging conclusions. Aims. The purpose of this paper is to assess the robustness of the conclusion that the Universe is indeed accelerating if we rely only on low-redshift (z 2) observations, that is to say with SNIa, baryonic acoustic oscillations, measurements of the Hubble parameter at different redshifts, and measurements of the growth of matter perturbations. Methods. We used the standard statistical procedure of minimizing the χ 2 function for the different probes to quantify the goodness of fit of a model for both ΛCDM and a simple nonaccelerated low-redshift power law model. In this analysis, we do not assume that supernovae intrinsic luminosity is independent of the redshift, which has been a fundamental assumption in most previous studies that cannot be tested. Results. We have found that, when SNIa intrinsic luminosity is not assumed to be redshift independent, a nonaccelerated low-redshift power law model is able to fit the low-redshift background data as well as, or even slightly better, than ΛCDM. When measurements of the growth of structures are added, a nonaccelerated low-redshift power law model still provides an excellent fit to the data for all the luminosity evolution models considered. Conclusions. Without the standard assumption that supernovae intrinsic luminosity is independent of the redshift, low-redshift probes are consistent with a nonaccelerated universe.

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Marginal evidence for cosmic acceleration from Type Ia supernovae

Cited by 196 publications

References 33 publications

BAHAMAS: NEW ANALYSIS OF TYPE Ia SUPERNOVAE REVEALS INCONSISTENCIES WITH STANDARD COSMOLOGY

BAHAMAS: NEW ANALYSIS OF TYPE Ia SUPERNOVAE REVEALS INCONSISTENCIES WITH STANDARD COSMOLOGY

Asymmetry and dark energy evolution

Is cosmic acceleration proven by local cosmological probes?

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