Speaker
Description
Understanding the accelerated expansion of the Universe remains one of the key challenges in cosmology. Leading explanations which do not rely on a cosmological constant are dark energy and modifications of General Relativity, both of which require robust tests on large scales. The Dark Energy Spectroscopic Instrument (DESI) provides unprecedented precision in measuring galaxy clustering from spectroscopic data, enabling the detection of relativistic effects beyond the standard redshift-space distortions. In particular, relativistic effects generate a dipole in the cross-power spectrum of two galaxy populations. We analyse the detectability of this dipole using mock galaxy catalogues produced from post-processed Newtonian simulations that mimic the DESI Bright Galaxy Survey, splitting galaxies into bright and faint populations, while validating the modelling against a relativistic simulation mock. Our results show that the detection significance improves with less bright sources and that the measured distortions are well described by linear theory predictions.