Bispectrum of the sunyaev-zel'dovich effect

Suman Bhattacharya, Daisuke Nagai, Laurie Shaw, Tom Crawford, Gilbert P. Holder

Research output: Contribution to journalArticlepeer-review


We perform a detailed study of the bispectrum of the Sunyaev-Zel'dovich (SZ) effect. Using an analytical model for the pressure profiles of the intracluster medium, we demonstrate the SZ bispectrum to be a sensitive probe of the amplitude of the matter power spectrum parameter σ8. We find that the bispectrum amplitude scales as B tSZσ11-12 8, compared to that of the power spectrum, which scales as A tSZσ7-9 8. We show that the SZ bispectrum is principally sourced by massive clusters at redshifts around z ∼ 0.4, which have been well studied observationally. This is in contrast to the SZ power spectrum, which receives a significant contribution from less well understood low-mass and high-redshift groups and clusters. Therefore, the amplitude of the bispectrum at ℓ ∼ 3000 is less sensitive to astrophysical uncertainties than the SZ power spectrum. We show that current high-resolution cosmic microwave background (CMB) experiments should be able to detect the SZ bispectrum amplitude with high significance, in part due to the low contamination from extragalactic foregrounds. A combination of the SZ bispectrum and the power spectrum can sharpen the measurements of thermal and kinetic SZ components and help distinguish cosmological and astrophysical information from high-resolution CMB maps.

Original languageEnglish (US)
Article number5
JournalAstrophysical Journal
Issue number1
StatePublished - Nov 20 2012
Externally publishedYes


  • cosmic background radiation
  • cosmology: theory
  • galaxies: clusters: intracluster medium
  • large-scale structure of universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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