Open AccessSignificant effects of weak gravitational lensing on determinations of the cosmology from Type Ia supernovae
Author(s) -
Barber Andrew J.
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03728.x
Subject(s) - physics , astrophysics , redshift , cosmology , supernova , weak gravitational lensing , gravitational lens , deceleration parameter , strong gravitational lensing , dark energy , galaxy , astronomy
Significant adjustments to the values of the cosmological parameters estimated from high‐redshift Type Ia supernovae data are reported, almost an order of magnitude greater than previously found. They arise from the effects of weak gravitational lensing on observations of high‐redshift sources. The lensing statistics used have been obtained from computations of the three‐dimensional shear in a range of cosmological N ‐body simulations, from which it is estimated that cosmologies with an underlying deceleration parameter may be interpreted as having q 0 =−0.55 (appropriate to the currently popular cosmology with density parameter Ω M =0.3 and vacuum energy density parameter Ω Λ =0.7). In addition, the standard deviation expected from weak lensing for the peak magnitudes of Type Ia supernovae at redshifts of z =1 is expected to be approximately 0.078 mag, and 0.185 mag at redshift z =2. This latter value is greater than the accepted intrinsic dispersion of 0.17 mag. Consequently, the effects of weak lensing in observations of high‐redshift sources must be taken properly into account.