Cosmological constraints from the angular power spectrum and bispectrum of luminous red galaxies and CMB lensing
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arXiv
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| Natura: | Preprint |
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2025
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| author | Verdiani, Francesco Harscouet, Lea Zennaro, Matteo Alonso, David Hadzhiyska, Boryana |
| author_facet | Verdiani, Francesco Harscouet, Lea Zennaro, Matteo Alonso, David Hadzhiyska, Boryana |
| contents | 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 $k_{\rm max}^P\simeq 0.2\,h{\rm Mpc}^{-1}$ and $k_{\rm max}^B\simeq 0.08\,h{\rm Mpc}^{-1}$, saturating the information recovered from the data. We obtain constraints on the amplitude of matter fluctuations $σ_8=0.761\pm 0.020$ and the non-relativistic matter fraction $Ω_m=0.307\pm 0.015$, as well as the combination $S_8\equivσ_8\sqrt{Ω_m/0.3}=0.769 \pm 0.020$. 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 $\sim2.5σ$ level. This tension is largely present in the standard two-point function dataset, and the addition of the bispectrum increases it slightly, marginally shifting $σ_8$ downwards and $Ω_m$ 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_17796 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Cosmological constraints from the angular power spectrum and bispectrum of luminous red galaxies and CMB lensing Verdiani, Francesco Harscouet, Lea Zennaro, Matteo Alonso, David Hadzhiyska, Boryana Cosmology and Nongalactic Astrophysics 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 $k_{\rm max}^P\simeq 0.2\,h{\rm Mpc}^{-1}$ and $k_{\rm max}^B\simeq 0.08\,h{\rm Mpc}^{-1}$, saturating the information recovered from the data. We obtain constraints on the amplitude of matter fluctuations $σ_8=0.761\pm 0.020$ and the non-relativistic matter fraction $Ω_m=0.307\pm 0.015$, as well as the combination $S_8\equivσ_8\sqrt{Ω_m/0.3}=0.769 \pm 0.020$. 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 $\sim2.5σ$ level. This tension is largely present in the standard two-point function dataset, and the addition of the bispectrum increases it slightly, marginally shifting $σ_8$ downwards and $Ω_m$ 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. |
| title | Cosmological constraints from the angular power spectrum and bispectrum of luminous red galaxies and CMB lensing |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2510.17796 |