Robustness of the pairwise kinematic Sunyaev-Zeldovich power spectrum shape as a cosmological gravity probe
Abstract
We prove from the modified gravity (MG) galaxy/halo mock catalogs that the shape of the pairwise kinematic Sunyaev-Zeldovich (kSZ) power spectrum P kSZ has constraining power on discriminating different gravity theories on cosmological scales. By varying the effective optical depth τ T as a free parameter, we verify that the τ T-f (the linear growth rate) degeneracy in the linear theory of P kSZ is broken down by the non-linear structure growth and the scale-dependence of f in some MG theories. Equivalently speaking, the shape of P kSZ alone could be used to constrain the MG theories on cosmological scales. With a good knowledge of galaxy density biases, we verify that, a combination of the next generation of CMB and galaxy spectroscopic redshift surveys, e.g. BOSS+CMB-S4 or DESI+CMB-S4, could potentially discriminate f(R) models from the general relativity at 5σ level using the shape of the galaxy pairwise kSZ dipole P kSZ,=1 alone, when fR0=10-4.