Reducing the gravitational lensing scatter of Type Ia supernovae without introducing any extra bias

Abstract

Magnification and de-magnification due to gravitational lensing will contribute to the brightness scatter of Type Ia supernovae (SNe Ia). The purpose of this paper is to investigate the possibility to decrease this scatter by correcting individual SNe Ia using observations of galaxies in the foreground, without introducing any extra bias. We simulate a large number of SN Ia lines of sight populated by galaxies. For each line of sight the true magnification factor and an estimate thereof are calculated. The estimated magnification factor corresponds to what an observer would infer from a survey like SNLS. Using the simulated data we investigate the possibility to estimate the magnification of individual supernovae with enough precision to be able to correct their brightness for gravitational lensing with negligible bias. Our simulations show that the bias arising from gravitational lensing corrections of individual SNe Ia is negligible for current and next generation surveys and that the scatter from lensing can be reduced by approximately a factor 2. The total scatter in the SN Ia magnitudes could be reduced by 4% for an intrinsic dispersion of 0.13 mag. For an intrinsic dispersion of 0.09 mag, which might not be to unrealistic for future surveys, the total scatter could be reduced by 6%. This will reduce the errors on cosmological parameters derived from supernova data by 4-8%. The prospect of correcting for lensing is thus very good.

7 pages, 7 figures, accepted by A&A

References in corpus (7)

• Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
• The Sloan Digital Sky Survey-II Supernova Survey: Technical Summary
• The ESSENCE Supernova Survey: Survey Optimization, Observations, and Supernova Photometry
• Lensing and Supernovae: Quantifying The Bias on the Dark Energy Equation of State
• Supernovae and Cosmology
• Tuning Gravitationally Lensed Standard Sirens
• Prospects and pitfalls of gravitational lensing in large supernova surveys

Cited by in corpus (9)

• Reducing the weak lensing noise for the gravitational wave Hubble diagram using the non-Gaussianity of the magnification distribution
• Constraining dark matter halo properties using lensed SNLS supernovae
• Delensing Gravitational Wave Standard Sirens with Shear and Flexion Maps
• Reducing distance errors for standard candles and standard sirens with weak-lensing shear and flexion maps
• Lens modelling of the strongly lensed Type Ia supernova iPTF16geu
• Gravitational Lensing with Three-Dimensional Ray Tracing
• Constraints on Cosmological Parameters with a Sample of Type Ia Supernovae from JWST
• The $m$-$z$ relation for type Ia supernovae, locally inhomogeneous cosmological models, and the nature of dark matter
• Effect of lensing magnification on type Ia supernova cosmology