We correlate the positions of radio galaxies in the FIRST survey with the cosmic microwave background lensing convergence estimated from the Atacama Cosmology Telescope over 470 deg2 to determine the bias of these galaxies. We remove optically cross-matched sources below redshift z = 0.2 to preferentially select active galactic nuclei (AGN). We measure the angular cross-power spectrum Clkg at 4.4σ significance in the multipole range 100 < l < 3000, corresponding to physical scales within ≈2-60 Mpc at an effective redshift zeff = 1.5. Modelling the AGN population with a redshift-dependent bias, the cross-spectrum is well fitted by the Planck best-fitting Λ cold dark matter cosmological model. Fixing the cosmology and assumed redshift distribution of sources, we fit for the overall bias model normalization, finding b(zeff) = 3.5 ± 0.8 for the full galaxy sample and b(zeff) = 4.0 ± 1.1(3.0 ± 1.1) for sources brighter (fainter) than 2.5 mJy. This measurement characterizes the typical halo mass of radio-loud AGN: we find log(Mhalo/M⊙) = 13.6-0.4+0.3.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
- Large-scale structure of Universe
- Radio continuum: galaxies