Detection of warm and diffuse baryons in large scale structure from the cross correlation of gravitational lensing and the thermal Sunyaev-Zeldovich effect

作者：Van Waerbeke Ludovic^*; Hinshaw Gary; Murray Norman

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2014, 89(2): 023508.

DOI：10.1103/PhysRevD.89.023508

We report the first detection of a correlation between gravitational lensing by large scale structure and the thermal Sunyaev-Zeldovich ( tSZ) effect. Using the mass map from the Canada France Hawaii Telescope Lensing Survey and a newly constructed tSZ map from Planck, we measure a nonzero correlation between the two maps out to one degree angular separation on the sky, with an overall significance of 6 sigma. The tSZ maps are formed in a manner that removes primary cosmic microwave background fluctuations and minimizes residual contamination by galactic and extragalactic dust emission, and by CO line emission. We perform numerous tests to show that our measurement is immune to these residual contaminants. The resulting correlation function is consistent with the existence of a warm baryonic gas tracing the large scale structure with a bias b(gas). Given the shape of the lensing kernel, our signal sensitivity peaks at a redshift z similar to 0.4, where half a degree separation on the sky corresponds to a physical scale of similar to 10 Mpc. The amplitude of the signal constrains the product (b(gas)/1)(T-e/0.1 keV)((n) over bar (e)/1 m(-3)) = 2.01 +/- 0.31 +/- 0.21, at redshift zero. Our study suggests that a substantial fraction of the "missing" baryons in the Universe may reside in a low-density warm plasma that traces dark matter.

• 出版日期2014-1-13