Non-Gaussianity from extragalactic point sources

7th International Conference on Gravitation and Cosmology

Lacasa, F.^1

Institut d'Astrophysique Spatiale (IAS), Orsay, France^1

关键词: Compact sources;    Extragalactic point sources;    Frequency dependence;    High frequency HF;    Orders of magnitude;    Parametrizations;    Primordial Non-Gaussianity;    Scale dependence;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/484/1/012037/pdf
DOI  :  10.1088/1742-6596/484/1/012037

来源: IOP

【 摘 要 】

We have described briefly the population of compact sources appearing at CMB frequencies, and studied their non-Gaussianity using publicly available full-sky simulations. Introducing a parametrization permitting to visualise efficiently the bispectrum, we have described the configuration and scale dependence of the bispectrum of radio and IR point sources, as well as its frequency dependence, and shown that it is well fitted by an analytical prescription. We have shown further that the clustering of IR sources increases their non-Gaussianity by several orders of magnitude, and that their bispectrum peaks in the squeezed triangles. Examining the impact of these sources on primordial non-Gaussianity estimation, we have found that the radio sources yield an important positive bias to local fNLestimation at low frequencies, but this bias is efficiently reduced by masking detectable sources. On the other hand, IR sources produce a negative bias at high frequencies, which is not dimmed by the masking, as their clustering is dominated by faint sources.