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arXiv · 1902.06581

The linear bias of radio galaxies at z~0.3 via cosmic microwave background lensing

C. Devereux·J. E. Geach·M. J. Hardcastle
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Abstract

We present a new measurement of the linear bias of radio loud active galactic nuclei (RLAGN) at $z\approx0.3$ and $L_{\rm 1.4GHz}>10^{23}\,{\rm W\,Hz^{-1}}$ selected from the Best & Heckman (2012) sample, made by cross-correlating the RLAGN surface density with a map of the convergence of the weak lensing field of the cosmic microwave background from Planck. We detect the cross-power signal at a significance of $3\sigma$ and use the amplitude of the cross-power spectrum to estimate the linear bias of RLAGN, $b=2.5 \pm 0.8$, corresponding to a typical dark matter halo mass of $\log_{10}(M_{\rm h} /h^{-1} M_\odot)=14.0^{+0.3}_{-0.5}$. When RLAGN associated with optically-selected clusters are removed we measure a lower bias corresponding to $\log_{10}(M_{\rm h} /h^{-1} M_\odot)=13.7^{+0.4}_{-1.0}$. These observations support the view that powerful RLAGN typically inhabit rich group and cluster environments.

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C. Devereux, J. E. Geach, M. J. Hardcastle. 2019-02-18. The linear bias of radio galaxies at z~0.3 via cosmic microwave background lensing. https://doi.org/10.1093/mnrasl%2Fslz024

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