English

Full-sky maps for gravitational lensing of the CMB

Astrophysics 2008-11-26 v2

Abstract

We use the large cosmological Millennium Simulation (MS) to construct the first all-sky maps of the lensing potential and the deflection angle, aiming at gravitational lensing of the CMB, with the goal of properly including small-scale non-linearities and non-Gaussianity. Exploiting the Born approximation, we implement a map-making procedure based on direct ray-tracing through the gravitational potential of the MS. We stack the simulation box in redshift shells up to z11z\sim 11, producing continuous all-sky maps with arcminute angular resolution. A randomization scheme avoids repetition of structures along the line of sight and structures larger than the MS box size are added to supply the missing contribution of large-scale (LS) structures to the lensing signal. The angular power spectra of the projected lensing potential and the deflection-angle modulus agree quite well with semi-analytic estimates on scales down to a few arcminutes, while we find a slight excess of power on small scales, which we interpret as being due to non-linear clustering in the MS. Our map-making procedure, combined with the LS adding technique, is ideally suited for studying lensing of CMB anisotropies, for analyzing cross-correlations with foreground structures, or other secondary CMB anisotropies such as the Rees-Sciama effect.

Keywords

Cite

@article{arxiv.0711.2655,
  title  = {Full-sky maps for gravitational lensing of the CMB},
  author = {Carmelita Carbone and Volker Springel and Carlo Baccigalupi and Matthias Bartelmann and Sabino Matarrese},
  journal= {arXiv preprint arXiv:0711.2655},
  year   = {2008}
}

Comments

LaTeX file, 10 pages, MNRAS in press, scales larger than the Millennium Simulation box size semi-analytically added, maps changed, references added, typos corrected

R2 v1 2026-06-21T09:44:17.015Z