Luminosity distance dispersion in Swiss-cheese cosmology as a function of the hole size distribution

Fuente: arXiv
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Autori principali: Cheunchitra, Thippayawis, Melatos, Andrew, Webster, Rachel
Natura: Preprint
Pubblicazione: 2025
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author Cheunchitra, Thippayawis
Melatos, Andrew
Webster, Rachel
author_facet Cheunchitra, Thippayawis
Melatos, Andrew
Webster, Rachel
contents The luminosity distance-redshift ($D_{\rm L}$--$z$) relation derived from Type Ia supernovae (SNe Ia) yields evidence for a nonzero cosmological constant. SNe Ia analyses typically fit to the functional form $D_{\rm L}(z)$ derived theoretically from the homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) metric. Yet, the metric in the epoch relevant to SNe Ia measurements deviates slightly from FLRW due to gravitational clumping of mass into large-scale structures like filaments and voids, whose sizes span many orders of magnitude. The small deviation is modeled typically by scalar perturbations to the FLRW metric. Each line of sight to a SNe Ia passes through a random sequence of structures, so $D_{\rm L}$ differs stochastically from one line of sight to the next. Here, we calculate the $D_{\rm L}$ dispersion in an exact Lemaitre-Tolman-Bondi Swiss-cheese universe with a power-law hole size distribution, as a function of the lower cut-off $R_{\rm min}$ and logarithmic slope $γ$. We find that the standard deviation of $D_{\rm L}$ scales as $σ_{D_{\rm L}} \propto z^{2.25\pm0.01} (R_{\rm min}/24\pm1\,{\rm Mpc})^{(0.157\pm0.003)\left[γ- (1.16\pm0.02)\right]}$ for redshifts in the range $0.5 \lesssim z \lesssim 2.1$. The scaling shows that the $D_{\rm L}$ dispersion is dominated by a few large voids rather than the many small voids.
format Preprint
id arxiv_https___arxiv_org_abs_2510_05579
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Luminosity distance dispersion in Swiss-cheese cosmology as a function of the hole size distribution
Cheunchitra, Thippayawis
Melatos, Andrew
Webster, Rachel
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
The luminosity distance-redshift ($D_{\rm L}$--$z$) relation derived from Type Ia supernovae (SNe Ia) yields evidence for a nonzero cosmological constant. SNe Ia analyses typically fit to the functional form $D_{\rm L}(z)$ derived theoretically from the homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) metric. Yet, the metric in the epoch relevant to SNe Ia measurements deviates slightly from FLRW due to gravitational clumping of mass into large-scale structures like filaments and voids, whose sizes span many orders of magnitude. The small deviation is modeled typically by scalar perturbations to the FLRW metric. Each line of sight to a SNe Ia passes through a random sequence of structures, so $D_{\rm L}$ differs stochastically from one line of sight to the next. Here, we calculate the $D_{\rm L}$ dispersion in an exact Lemaitre-Tolman-Bondi Swiss-cheese universe with a power-law hole size distribution, as a function of the lower cut-off $R_{\rm min}$ and logarithmic slope $γ$. We find that the standard deviation of $D_{\rm L}$ scales as $σ_{D_{\rm L}} \propto z^{2.25\pm0.01} (R_{\rm min}/24\pm1\,{\rm Mpc})^{(0.157\pm0.003)\left[γ- (1.16\pm0.02)\right]}$ for redshifts in the range $0.5 \lesssim z \lesssim 2.1$. The scaling shows that the $D_{\rm L}$ dispersion is dominated by a few large voids rather than the many small voids.
title Luminosity distance dispersion in Swiss-cheese cosmology as a function of the hole size distribution
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2510.05579