2000/08/24 by Masahiro Takada, Toshifumi Futamase · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1086/318305
published as Astrophys.J. 546 (2001) 620-634 · Accepted by ApJ. Received June 14, Accepted August 24. 24 pages including 9 figures
arxiv created 2000/08/24 · openalex publication_date 2001/01/10 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/30
We present quantitative investigations of the weak-lensing effect on the two-point correlation functions of local maxima (hot spots), ξ pk-pk (θ), in cosmic microwave background (CMB) maps. The lensing effect depends on the projected mass fluctuations between today and redshift z rec ≈ 1100. If we adopt the Gaussian assumption for the primordial temperature fluctuations field, the peak statistics can provide additional information about the intrinsic distribution of hot spots: that those pairs have some characteristic separation angles. The weak lensing then redistributes hot spots in the observed CMB maps from the intrinsic distribution and consequently imprints non-Gaussian signatures onto ξ pk-pk (θ). In particular, since the intrinsic ξ pk-pk (θ) has a pronounced depression feature around the angular scale of θ ≈ 70' for a flat universe, the weak lensing induces a large smoothing at that scale. We show that the lensing signature therefore has an advantage for effectively probing mass fluctuations with large wavelength modes around λ ≈ 50 h -1 Mpc. To reveal the detectability, we performed numerical experiments with specifications of the Microwave Anisotropy Probe ( MAP ) and Planck Surveyor , including the instrumental effects of beam smoothing and detector noise. We find that our method can successfully provide constraints on the amplitude of the mass fluctuations and cosmological parameters in a flat universe with and without the cosmological constant, provided that we use maps with the 65% sky coverage expected from Planck .