Marked Correlation Functions Show Promise for Extracting Enhanced Cosmological Information from Galaxy Surveys
A new study using 129 cosmological simulations finds that neighbor-density-weighted marked correlation functions (MCFs) can extract significantly more cosmological information than the standard two-point correlation function (2PCF). The research, posted to arXiv, builds Gaussian-process emulators to test how well these statistics constrain key parameters like matter density and the amplitude of matter fluctuations. The findings suggest MCFs could be a powerful tool for upcoming large-scale galaxy surveys seeking tighter constraints on dark energy and neutrino mass.
Researchers have investigated whether neighbor-density-weighted marked correlation functions (MCFs) can go beyond the information captured by the standard redshift-space two-point correlation function, a workhorse statistic in observational cosmology. Using the Kun simulation suite — comprising 129 w0waCDM plus summed neutrino mass simulations in 1 Gpc/h boxes — the team constructed Gaussian-process emulators for two MCF statistics: a normalized scale statistic and an angular statistic. Joint analyses combining three mark parameters improved the figure of merit (FoM) in the Ω_m–σ_8 plane by factors of 1.7 to 2.5 relative to the 2PCF alone, while five-mark combinations yielded gains of 1.9 to 2.4. The study also compared density-based and normalized-gradient marks, finding them largely redundant for isotropic statistics but complementary for angular statistics, where combining them improved the FoM by up to 43%. Robustness tests across different scale ranges and halo selections confirmed that the marked statistics remain stable under varied analysis choices, with the angular statistic proving particularly resilient to tracer selection effects. The authors conclude that MCFs represent a robust and information-rich probe well suited to next-generation galaxy surveys such as DESI, Euclid, and the Rubin Observatory LSST.
What's missing
The study is a preprint and has not yet undergone formal peer review. The analysis is conducted on simulated halos rather than observed galaxies, so the impact of realistic observational systematics — such as fiber collisions, photometric redshift errors, and survey geometry — on MCF performance remains to be demonstrated. The computational cost of deploying these emulators on real survey data at scale is not discussed.
What different sources said
- arXiv astro-phCenter
Cosmological constraints from neighbor-density-weighted marked correlation functions
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