Speaker
Description
Our well-established gravity model, the theory of general relativity, has been extensively tested in strong-field regimes. However, no observational test has yet confirmed its validity on cosmological scales, where the universe’s dark components are necessary to fit LSS data. The detection of large-scale relativistic effects via galaxy power spectrum measurements would provide such an unprecedented confirmation. Amongst these relativistic contributions, the Doppler term acts as an imaginary correction in the relation between the galaxy density contrast and that of matter, and mostly affects the large scales usually plagued by cosmic variance. Also, it is sample-dependent, thus different galaxy populations display different contributions in their power spectra. In the search for the optimal galaxy samples to achieve a detection of the relativistic term, we can split a galaxy population according to luminosity, and then perform a multi-tracer analysis with auto-correlations of the sub-samples and their cross-power spectrum. While forecasts claim relativistic Doppler dipole as detectable with data from ongoing galaxy surveys, analysis pipelines able to extract the signal from source catalogues need to be set up. In fact, they cannot help considering wide-angle and survey window effects, as well as being carefully tested against simulations that include relativistic corrections. I will be talking about current efforts in this sense, showing ongoing tests of the faint-bright multi-tracer approach with mock catalogues, which are crucial to pave the way towards a measurement on real data.