2025/10/20 by Verdiani, Francesco, Harscouet, Lea, Zennaro, Matteo +2 · 2 citations
#Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2510.17796
We study the projected clustering of photometric luminous red galaxies from the DESI Legacy Survey, combining their angular power spectrum, bispectrum, and cross-correlation with maps of the CMB lensing convergence from the Planck satellite. We employ a perturbative bias expansion in Eulerian space to describe the clustering of galaxies, modelling the power spectrum and bispectrum at one-loop and tree level, respectively. This allows us to use the power spectrum to self-consistently calibrate the perturbative bias parameters. We validate this model against an N-body simulation, and show that it can be used up to scales of at least k\rm maxP≃ 0.2 h\rm Mpc-1 and k\rm maxB≃ 0.08 h\rm Mpc-1, saturating the information recovered from the data. We obtain constraints on the amplitude of matter fluctuations σ8=0.761± 0.020 and the non-relativistic matter fraction Ωm=0.307± 0.015, as well as the combination S8≡σ8√(Ωm/0.3)=0.769 ± 0.020. Including the galaxy bispectrum leads to a 10-20% improvement on the cosmological constraints, which are also in good agreement with previous analyses of the same data, and in mild tension with Planck at the ∼2.5σ level. This tension is largely present in the standard two-point function dataset, and the addition of the bispectrum increases it slightly, marginally shifting σ8 downwards and Ωm upwards. Finally, using the bispectrum allows for a substantially more precise measurement of the bias parameters of this sample, which are in reasonable agreement with existing coevolution relations.