Principal components of dark energy with SNLS supernovae: the effects of systematic errors

Alexander Conley (Colorado); Daniel L. Shafer (Michigan); Dragan Huterer (Michigan); Eduardo J. Ruiz (Michigan)

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Principal components of dark energy with SNLS supernovae: the effects of systematic errors

Eduardo J. Ruiz (Michigan), Daniel L. Shafer (Michigan), Dragan Huterer (Michigan), Alexander Conley (Colorado)

Cosmology and Nongalactic Astrophysics · Submitted 19 Jul 2012

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The authors' main claim We find that the SN Ia systematics degrade the total generalized figure of merit (FoM), which characterizes constraints in multi-dimensional DE parameter space, by a factor of two to three.

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arXiv ID1207.4781 (version 2)

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CitationAlexander Conley (Colorado), Daniel L. Shafer (Michigan), Dragan Huterer (Michigan), Eduardo J. Ruiz (Michigan). "Principal components of dark energy with SNLS supernovae: the effects of systematic errors." arXiv:1207.4781 (2012). https://pith.science/paper/K3OUAGVD

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What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.70 · human participants 0.02 · controlled comparison 0.12 · randomized assignment 0.01 · states quantitative result 0.97 · compares with prior results 0.40 · mentions code or data availability 0.02.

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We study the effects of current systematic errors in Type Ia supernova (SN Ia) measurements on dark energy (DE) constraints using current data from the Supernova Legacy Survey (SNLS). We consider how SN systematic errors affect constraints from combined SN Ia, baryon acoustic oscillations (BAO), and cosmic microwave background (CMB) data, given that SNe Ia still provide the strongest constraints on DE but are arguably subject to more significant systematics than the latter two probes. We focus our attention on the temporal evolution of DE described in terms of principal components (PCs) of the equation of state, though we examine a few of the more common, simpler parametrizations as well. We find that the SN Ia systematics degrade the total generalized figure of merit (FoM), which characterizes constraints in multi-dimensional DE parameter space, by a factor of two to three. Nevertheless, overall constraints obtained on more than five PCs are very good even with current data and systematics. We further show that current constraints are robust to allowing for the finite detection significance of the BAO feature in galaxy surveys.

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What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	We study the effects of current systematic errors in Type Ia supernova (SN Ia) measurements on dark energy (DE) constraints using current data from the Supernova Legacy Survey (SNLS).	contribution 0.99	0.88	0.04	asserted 0.84
s1	We consider how SN systematic errors affect constraints from combined SN Ia, baryon acoustic oscillations (BAO), and cosmic microwave background (CMB) data, given that SNe Ia still provide the strongest constraints on DE but are arguably subject to more significant systematics than the latter two probes.	background 0.57	0.34	0.04	asserted 0.65
s2	We focus our attention on the temporal evolution of DE described in terms of principal components (PCs) of the equation of state, though we examine a few of the more common, simpler parametrizations as well.	method 0.77	0.62	0.03	asserted 0.86
s3	We find that the SN Ia systematics degrade the total generalized figure of merit (FoM), which characterizes constraints in multi-dimensional DE parameter space, by a factor of two to three.	result 1.00	0.96	0.48	asserted 1.00
s4	Nevertheless, overall constraints obtained on more than five PCs are very good even with current data and systematics.	result 0.99	0.93	0.24	asserted 1.00
s5	We further show that current constraints are robust to allowing for the finite detection significance of the BAO feature in galaxy surveys.	result 0.99	0.91	0.06	asserted 1.00

What kind of paper the classifier reports this is: simulation study 0.70 · evidence from analysis of existing data 1.00.

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The paper

Original abstract

We study the effects of current systematic errors in Type Ia supernova (SN Ia) measurements on dark energy (DE) constraints using current data from the Supernova Legacy Survey (SNLS). We consider how SN systematic errors affect constraints from combined SN Ia, baryon acoustic oscillations (BAO), and cosmic microwave background (CMB) data, given that SNe Ia still provide the strongest constraints on DE but are arguably subject to more significant systematics than the latter two probes. We focus our attention on the temporal evolution of DE described in terms of principal components (PCs) of the equation of state, though we examine a few of the more common, simpler parametrizations as well. We find that the SN Ia systematics degrade the total generalized figure of merit (FoM), which characterizes constraints in multi-dimensional DE parameter space, by a factor of two to three. Nevertheless, overall constraints obtained on more than five PCs are very good even with current data and systematics. We further show that current constraints are robust to allowing for the finite detection significance of the BAO feature in galaxy surveys.

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References

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Cited by 3 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: weighing the neutrino mass using the galaxy power spectrum of the CMASS sample
astro-ph.CO 2012-11 conditional novelty 6.0 of 10

The summed neutrino mass is bounded at Sigma m_nu < 0.340 eV (95 percent CL) in flat Lambda CDM and < 0.821 eV when dark energy, curvature, running and tensors are all freed, using the BOSS CMASS DR9 galaxy power spectrum.
A model with interaction of dark components and recent observational data
gr-qc 2016-09 conditional novelty 4.0 of 10

A linear dark-sector interaction with constant or variable dark-energy equation of state fits current cosmological data no better than ΛCDM once parameter counts are penalized.
Dark energy two decades after: Observables, probes, consistency tests
astro-ph.CO 2017-09 accept novelty 2.0 of 10

Two decades of supernova, baryon-acoustic-oscillation, cosmic-microwave-background, lensing and cluster measurements converge on a dark energy component with equation of state w close to -1, and the review maps which ...

How the literature uses it

12 arXiv papers cite this in 19 sentences

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Papers citing it · 12 sentences without a confident label

Uses its method or tool 1 paper

We correct for these effects by writing the magnitude as [ref] [equation] where $s$ is the stretch and $𝒞$ the color of each SNIa, and $α_s$ and $β_𝒞$ are additional, global nuisance parameters.

Banana Split: Testing the Dark Energy Consistency with Geometry and Growth · Type Ia Supernovae · 0.94

Compares with it 1 paper

We verify that our SN-only constraints match those in [ref] , where $α$ and $β$ are varied.

Chasing the phantom: A closer look at Type Ia supernovae and the dark energy equation of state · SNLS3 · 0.95

Cites it as support 1 paper

This is evinced by the results obtained so far in the literature [ref] .

A general reconstruction of the recent expansion history of the universe · Introduction · 0.99

Cites it as background 4 papers

For further explanation of this effect and how it relates to BAO measurements, see [ref] .

Robust model comparison disfavors power law cosmology · BAO data · 0.80
Let us now switch gears and discuss conceptual questions associated with inflation, and with the late-time accelerating universe [ref] [ref] .

TASI lectures on cosmological observables and string theory · What is the framework? · 0.97
Let us now switch gears and discuss conceptual questions associated with inflation, and with the late-time accelerating universe [ref] [ref] .

Les Houches lectures on inflationary observables and string theory · What is the framework? · 1.00

What it cites · 47 sentences without a confident label

Builds on 1 paper

We extended the similar analysis from [ref] by constraining the temporal evolution of the equation of state of DE described by the pair of parameters $(w_0, w_a)$ as well as a much richer description in terms of 10 PCs of the equation of state (shown in Fig. [ref]).

Supernova Constraints and Systematic Uncertainties from the First 3 Years of the Supernova Legacy Survey · Conclusions · 0.86

Uses the method or tool of 8 papers

While we closely follow the accounting for the SN Ia systematics from [ref] , we note that several other analyses have considered the effect of SN systematics.

Supernova Constraints and Systematic Uncertainties from the First 3 Years of the Supernova Legacy Survey · Introduction · 0.96
We therefore model the apparent magnitude of a SN Ia with the equation [ref] [equation] where $d_L$ is the luminosity distance, $α_s$ is a nuisance parameter associated with the measured stretch $s$ of a SN Ia light curve, and $β_c$ is a nuisance parameter associated with the measured color $𝒞$ of the light curve.

SALT2: using distant supernovae to improve the use of Type Ia supernovae as distance indicators · SN Ia Data and Covariance · 0.93
The equation of state can be described as [ref] [equation] where $α_i$ are amplitudes for each PC $e_i(z)$.

Falsifying Paradigms for Cosmic Acceleration · Principal Components · 0.86

Uses data or values from 6 papers

The complete covariance matrix from [ref] can be written most usefully as the sum of two separate parts, a diagonal part consisting of typical statistical errors and an off-diagonal systematic part.

Supernova Constraints and Systematic Uncertainties from the First 3 Years of the Supernova Legacy Survey · SN Ia Data and Covariance · 0.87
We take the measured value of $R$ to be the value determined by WMAP7, $R_0 = 1.725 ± 0.0184$ [ref] .

Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation · BAO and CMB data · 1.00
The significances of the detection of the BAO feature are 2.4$σ$ (corresponding to $S/N = 2.4$) for 6dF [ref] , 2.8$σ$ for WiggleZ [ref] (combined for three redshift bins), 3.6$σ$ for SDSS [ref] (combined for two redshift bins), and 5.0$σ$ for BOSS [ref] .

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the Data Release 9 Spectroscopic Galaxy Sample · Effect of Finite Detection Significance of BAO · 1.00

Compares with 1 paper

We are extremely encouraged by the fact that constraints on more than five of the lowest PCs are very good even with current data, a result incidentally also found by [ref] using a slightly different combined “current” data set that, most notably, did not include the BOSS and WiggleZ BAO measurements.

Testable dark energy predictions from current data · Principal Components · 0.96

Cites as background 4 papers

Since the discovery of the accelerating universe in the late 1990s [ref] , a tremendous amount of effort has been devoted to improving measurements of dark energy (DE) parameters.

Measurements of Omega and Lambda from 42 High-Redshift Supernovae · Introduction · 1.00
Since the discovery of the accelerating universe in the late 1990s [ref] , a tremendous amount of effort has been devoted to improving measurements of dark energy (DE) parameters.

Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant · Introduction · 1.00
For recent comprehensive reviews of DE probes, see [ref] .

Dark Energy and the Accelerating Universe · Introduction · 1.00

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