Lensing and Supernovae: Quantifying The Bias on the Dark Energy Equation of State

Abstract

The gravitational magnification and demagnification of Type Ia supernovae (SNe) modify their positions on the Hubble diagram, shifting the distance estimates from the underlying luminosity-distance relation. This can introduce a systematic uncertainty in the dark energy equation of state (EOS) estimated from SNe, although this systematic is expected to average away for sufficiently large data sets. Using mock SN samples over the redshift range $0<z\le 1.7$ we quantify the lensing bias. We find that the bias on the dark energy EOS is less than half a percent for large datasets ($\gtrsim$ 2,000 SNe). However, if highly magnified events (SNe deviating by more than 2.5$\sigma$) are systematically removed from the analysis, the bias increases to $\sim$ 0.8%. Given that the EOS parameters measured from such a sample have a 1$\sigma$ uncertainty of 10%, the systematic bias related to lensing in SN data out to $z\sim 1.7$ can be safely ignored in future cosmological measurements.

5 pages, 4 figures; one figure and references added; minor modifications to text; reflects version accepted for publication in ApJ

References in corpus (4)

• Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
• Report of the Dark Energy Task Force
• Narrowing Constraints with Type Ia Supernovae: Converging on a Cosmological Constant
• Light Propagation in Inhomogeneous Universes. V. Gravitational Lensing of Distant Supernovae

Cited by in corpus (11)

• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• Cosmography of f(R) gravity
• Hot Jupiters from Coplanar High-eccentricity Migration
• Do stochastic inhomogeneities affect dark-energy precision measurements?
• Luminosity distance in "Swiss cheese" cosmology with randomized voids: I. Single void size
• Beyond Two Dark Energy Parameters
• Magnification Probability Distribution Functions of Standard Candles in a Clumpy Universe
• Modification to the Luminosity Distance Redshift Relation in Modified Gravity Theories
• Impact of weak lensing on bright standard siren analyses
• The impact of weak lensing on Type Ia supernovae luminosity distances
• Effect of lensing magnification on type Ia supernova cosmology