Constraints on modified gravity from the BOSS galaxy survey by Lorenzo Piga et al. on Thursday 24 November

We develop a pipeline to set new constraints on scale-independent modified

gravity, from the galaxy power spectrum in redshift space of BOSS DR12. The

latter is modelled using the effective field theory of large-scale structure up

to 1-loop order in perturbation theory. We test our pipeline on synthetic and

simulated data, to assess systematic biases on the inferred cosmological

parameters due to marginalization and theoretical errors, and we apply it to

the normal branch of the DGP model with a $\Lambda$CDM background. We observe

biased posteriors due to the strong degeneracy between the nDGP parameter

$\Omega_{\rm rc}$ and the primordial amplitude of fluctuations $A_s$. Fixing

the latter to the Planck central value, we obtain $\Omega_{\rm rc}\lesssim 0.2$

at 95$\%$ C.L. We also discuss a procedure to alleviate the prior dependence of

this bound.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12523v1