Specific Effect of Peculiar Velocities on Dark-Energy Constraints from Type Ia Supernovae

Abstract

Peculiar velocities of type Ia supernova (SNIa) host galaxies affect the dark-energy parameter constraints in a small but very specific way: the parameters are biased in a single direction in parameter space that is a-priori knowable for a given SNIa dataset. We demonstrate the latter fact with a combination of inference from a cosmological N-body simulation with overwhelming statistics applied to the Pantheon SNIa data set, then confirm it by simple quantitative arguments. We quantify small modifications to the current analyses that would ensure that the effect of cosmological parameters is essentially guaranteed to be negligible.

arXiv comment5 pages, 1 figure; v2: ApJL version

References in corpus (33)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Planck 2015 results. XIII. Cosmological parameters
• Type Ia Supernova Discoveries at z>1 From the Hubble Space Telescope: Evidence for Past Deceleration and Constraints on Dark Energy Evolution
• Cosmological parameters from CMB and other data: a Monte-Carlo approach
• The Complete Light-curve Sample of Spectroscopically Confirmed Type Ia Supernovae from Pan-STARRS1 and Cosmological Constraints from The Combined Pantheon Sample
• The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda and w from the First Year Data Set
• Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples
• Improved Cosmological Constraints from New, Old and Combined Supernova Datasets
• The Rockstar Phase-Space Temporal Halo Finder and the Velocity Offsets of Cluster Cores
• Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
• Supernova Constraints and Systematic Uncertainties from the First 3 Years of the Supernova Legacy Survey
• First-year Sloan Digital Sky Survey-II (SDSS-II) Supernova Results: Hubble Diagram and Cosmological Parameters
• SNLS3: Constraints on Dark Energy Combining the Supernova Legacy Survey Three Year Data with Other Probes
• Correlated Fluctuations in Luminosity Distance and the (Surprising) Importance of Peculiar Motion in Supernova Surveys
• Weak Lensing and Dark Energy
• The 2M++ galaxy redshift catalogue
• Fluctuations of the luminosity distance
• Systematic Uncertainties Associated with the Cosmological Analysis of the First Pan-STARRS1 Type Ia Supernova Sample
• The Impact of Inhomogeneous Reionization on Cosmic Microwave Background Anisotropy
• Streaming motions of galaxy clusters within 12000 km/s - V. The peculiar velocity field
• Testing $\Lambda$CDM at the lowest redshifts with SN Ia and galaxy velocities
• Measuring Dark Energy Properties with Photometrically Classified Pan-STARRS Supernovae. II. Cosmological Parameters
• The effect of peculiar velocities on supernova cosmology
• First Cosmology Results Using Type Ia Supernovae From the Dark Energy Survey: Analysis, Systematic Uncertainties, and Validation
• Sample variance in the local measurements of the Hubble constant
• Measuring cosmic bulk flows with Type Ia Supernovae from the Nearby Supernova Factory
• Is the expansion of the universe accelerating? All signs point to yes
• Large-Scale Bulk Motions Complicate the Hubble Diagram
• Virial scaling of galaxies in clusters: bright to faint is cool to hot
• Is the expansion of the universe accelerating? All signs still point to yes a local dipole anisotropy cannot explain dark energy
• The Cluster-EAGLE project: velocity bias and the velocity dispersion - mass relation of cluster galaxies
• No evidence for bulk velocity from type Ia supernovae

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