Open AccessThe giant arc statistics in the three‐year Wilkinson Microwave Anisotropy Probe cosmological model
Author(s) -
Li G. L.,
Mao S.,
Jing Y. P.,
Mo H. J.,
Gao L.,
Lin W. P.
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2006.00230.x
Subject(s) - physics , cmb cold spot , astrophysics , cold dark matter , dark matter , cosmic microwave background , baryon , population , weak gravitational lensing , anisotropy , astronomy , redshift , galaxy , quantum mechanics , demography , sociology
We use high‐resolution N ‐body simulations to investigate the optical depth of giant arcs with length‐to‐width ratios larger than 7.5 and 10 in the ‘standard’Λ cold dark matter (ΛCDM) model with σ 8 = 0.9 and Ω m,0 = 0.3 and a model based on three‐year Wilkinson Microwave Anisotropy Probe ( WMAP ) data. We find that, in dark‐matter‐only simulations, the lensing probability in the three‐year WMAP model (with σ 8 = 0.74 and Ω m,0 = 0.238) decreases by a factor of ∼6 compared with that in the ‘standard’Λ cold dark matter (ΛCDM) model. The effects of baryonic cooling, star formation and feedbacks are uncertain, but we argue that baryons will only increase the the lensing cross‐section by a moderate factor, ∼2. We conclude that the low central value of σ 8 and Ω m,0 preferred by the WMAP three‐year data may be too low to be compatible with observations if the conventional assumptions of the background source population are correct.