Effects of Supernova Redshift Uncertainties on the Determination of Cosmological Parameters

Abstract

Redshifts used in current cosmological supernova samples are measured using two primary techniques, one based on well-measured host galaxy spectral lines and the other based on supernova-dominated spectra. Here, we construct an updated Pantheon catalog with revised redshifts, redshift sources and estimated uncertainties for the entire sample to investigate whether these two techniques yield consistent results. The best-fit cosmological parameters using these two measurement techniques disagree, with a supernova-only sample producing ${\Omega }_m$ 3.2$\sigma$ higher and $H_0$ 2.5$\sigma$ lower than a hostz-only sample, and we explore several possible sources of bias which could result from using the lower-precision supernova-dominated redshifts. In a pilot study, we show that using a host redshift-only subsample will generically produce lower ${\Omega }_m$ and matter density ${\Omega }_m{h}^2$ and slightly higher $H_0$ than previous analysis which, for the Pantheon dataset, could result in supernova and CMB measurements agreeing on ${\Omega }_m{h}^2$ despite tension in $H_0$. To obtain rigorous results, though, the Pantheon catalog should be improved by obtaining host spectra for supernova that have faded and future surveys should be designed to use host galaxy redshifts rather than lower-precision methods.

arXiv comment13 pages

References in corpus (43)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Astropy: A Community Python Package for Astronomy
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The Complete Light-curve Sample of Spectroscopically Confirmed Type Ia Supernovae from Pan-STARRS1 and Cosmological Constraints from The Combined Pantheon Sample
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples
• New Hubble Space Telescope Discoveries of Type Ia Supernovae at z > 1: Narrowing Constraints on the Early Behavior of Dark Energy
• UniverseMachine: The Correlation between Galaxy Growth and Dark Matter Halo Assembly from z=0-10
• H0LiCOW XIII. A 2.4% measurement of $H_0$ from lensed quasars: $5.3\sigma$ tension between early and late-Universe probes
• Early Dark Energy Can Resolve The Hubble Tension
• BVRI Light Curves for 22 Type Ia Supernovae
• Milky Way Cepheid Standards for Measuring Cosmic Distances and Application to Gaia DR2: Implications for the Hubble Constant
• The Supernova Legacy Survey 3-year sample: Type Ia Supernovae photometric distances and cosmological constraints
• CfA3: 185 Type Ia Supernova Light Curves from the CfA
• Determining the Type, Redshift, and Age of a Supernova Spectrum
• The Dependence of Type Ia Supernova Luminosities on their Host Galaxies
• UBVRI Light Curves of 44 Type Ia Supernovae
• The Carnegie Supernova Project: First Photometry Data Release of Low-Redshift Type Ia Supernovae
• Cosmological Constraints from Measurements of Type Ia Supernovae discovered during the first 1.5 years of the Pan-STARRS1 Survey
• SNANA: A Public Software Package for Supernova Analysis
• The Effect of Host Galaxies on Type Ia Supernovae in the SDSS-II Supernova Survey
• Cosmological parameters from the comparison of peculiar velocities with predictions from the 2M++ density field
• Correcting Type Ia Supernova Distances for Selection Biases and Contamination in Photometrically Identified Samples
• Type Ia Supernova Distances at z > 1.5 from the Hubble Space Telescope Multi-Cycle Treasury Programs: The Early Expansion Rate
• ETHOS - An Effective Theory of Structure Formation: From dark particle physics to the matter distribution of the Universe
• STRIDES: a 3.9 per cent measurement of the Hubble constant from the strong lens system DES J0408-5354
• CfA4: Light Curves for 94 Type Ia Supernovae
• The Data Release of the Sloan Digital Sky Survey-II Supernova Survey
• Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe
• Type Ia Supernova Rate Measurements to Redshift 2.5 from CANDELS : Searching for Prompt Explosions in the Early Universe
• Systematic Uncertainties Associated with the Cosmological Analysis of the First Pan-STARRS1 Type Ia Supernova Sample
• Type-Ia Supernova Rates to Redshift 2.4 from CLASH: the Cluster Lensing And Supernova survey with Hubble
• Measuring Dark Energy Properties with Photometrically Classified Pan-STARRS Supernovae. II. Cosmological Parameters
• Cepheid calibration of type Ia Supernovae and the Hubble constant
• The SDSS-II Supernova Survey: Parameterizing the Type Ia Supernova Rate as a Function of Host Galaxy Properties
• The Impossibly Early Galaxy Problem
• Velocity Evolution and the Intrinsic Color of Type Ia Supernovae
• Improved constraints on cosmological parameters from SNIa data
• Can redshift errors bias measurements of the Hubble Constant?
• Leveraging 3D-HST Grism Redshifts to Quantify Photometric Redshift Performance
• Subaru FOCAS Spectroscopic Observations of High-Redshift Supernovae
• Nonparametric Methods in Astronomy: Think, Regress, Observe -- Pick Any Three

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• Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies
• Constraining the curvature density parameter in cosmology
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• Rapidly Descending Dark Energy and the End of Cosmic Expansion
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• Consistent extinction model for type Ia supernovae in Cepheid-based calibration galaxies and its impact on $H_0$
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• Hubble distancing: Focusing on distance measurements in cosmology
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