Observed galaxy power spectrum in cubic Galileon model

In this paper, we study the effects of general relativistic corrections on the observed galaxy power spectrum in thawing class of cubic Galileon model with linear potential that preserves the shift symmetry. In this scenario, the observed galaxy power spectrum differs from the standard matter power spectrum mainly due to redshift space distortion (RSD) factor and relativistic effects. The RSD term enhances the matter power spectrum both at larger and smaller scales whereas the relativistic terms further enhance the matter power spectrum only at larger scales. In comparison with ΛCDM, the observed galaxy power spectrum is always suppressed at large scales in this scenario although this suppression is always small compared to the canonical quintessence scenario. We also study the small scale non linear power spectrum for Galileon model using the publicly available HMcode. Our study shows that at the nonlinear regime, the small scale power is enhanced in Galileon model compared to the ΛCDM . But this enhancement in Galileon model is lower than the quintessence case.