Is lensing of point sources a problem for future CMB experiments?
Abstract
Weak gravitational lensing from large-scale structure enhances and reduces the fluxes from extragalactic point sources with an rms amplitude of order 15 per cent. In cosmic microwave background (CMB) experiments, sources exceeding some flux threshold phi_c are removed, which means that lensing will modulate the brightness map of the remaining unresolved sources. Because this mean brightness is of order 100 muK at 30 GHz for a reasonable flux cut, one might be concerned that this modulation could cause substantial problems for future CMB experiments. We present a detailed calculation of this effect and, fortunately, find that its power spectrum is always smaller than the normal point source power spectrum. Thus although this effect should be taken into account when analysing future high-precision CMB measurements, it will not substantially reduce the accuracy with which cosmological parameters can be measured.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 1997
- DOI:
- 10.1093/mnras/289.1.169
- arXiv:
- arXiv:astro-ph/9608173
- Bibcode:
- 1997MNRAS.289..169T
- Keywords:
-
- COSMIC MICROWAVE BACKGROUND;
- COSMOLOGY: THEORY;
- GRAVITATIONAL LENSING;
- LARGE-SCALE STRUCTURE OF UNIVERSE;
- Astrophysics
- E-Print:
- Expanded to match published version. 14 pages, with 3 figures included. Color figures at http://www.sns.ias.edu/~max/lensing.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/lensing.html (faster from Europe) or from max@ias.edu