Is there any scaling in the cluster distribution? (original) (raw)

Fractal analysis of the galaxy distribution in the redshift range 0.45 < z < 5.0

Evidence is presented that the galaxy distribution can be described as a fractal system in the redshift range of the FDF galaxy survey. The fractal dimension D was derived using the FDF galaxy volume number densities in the spatially homogeneous standard cosmological model with Ωm0=0.3, ΩΛ0=0.7 and H0=70kms−1Mpc−1. The ratio between the differential and integral number densities γ and γ∗ obtained from the red and blue FDF galaxies provides a direct method to estimate D, implying that γ and γ∗ vary as power-laws with the cosmological distances. The luminosity distance dL, galaxy area distance dG and redshift distance dz were plotted against their respective number densities to calculate D by linear fitting. It was found that the FDF galaxy distribution is characterized by two single fractal dimensions at successive distance ranges. Two straight lines were fitted to the data, whose slopes change at z≈1.3 or z≈1.9 depending on the chosen cosmological distance. The average fractal dimension calculated using γ∗ changes from ⟨D⟩=1.4+0.7−0.6 to ⟨D⟩=0.5+1.2−0.4 for all galaxies, and D decreases as z increases. Small values of D at high z mean that in the past galaxies were distributed much more sparsely and the large-scale galaxy structure was then possibly dominated by voids. Results of Iribarrem et al. (2014, arXiv:1401.6572) indicating similar fractal features with ⟨D⟩=0.6±0.1 in the far-infrared sources of the Herschel/PACS evolutionary probe (PEP) at 1.5≲z≲3.2 are also mentioned.

Galaxy distributions as fractal systems

The European Physical Journal C

This paper discusses if large scale galaxy distribution samples containing almost one million objects can be characterized as fractal systems. The analysis performed by Teles et al. (Phys Lett B 813:136034, 2021) on the UltraVISTA DR1 survey is extended here to the SPLASH and COSMOS2015 catalogs, hence adding 750k new galaxies with measured redshifts to the studied samples. The standard \Lambda ΛCDMcosmologyhavingΛ CDM cosmology havingΛCDMcosmologyhavingH_0=(70\pm 5)H0=(70±5)km/s/MpcandnumberdensitytoolsrequiredfordescribingthesegalaxydistributionsassinglefractalsystemswithdimensionDareadopted.WeusetheluminositydistanceH 0 = ( 70 ± 5 ) km/s/Mpc and number density tools required for describing these galaxy distributions as single fractal systems with dimension D are adopted. We use the luminosity distanceH0=(70±5)km/s/MpcandnumberdensitytoolsrequiredfordescribingthesegalaxydistributionsassinglefractalsystemswithdimensionDareadopted.Weusetheluminositydistanced_{\scriptscriptstyle L}dL,redshiftdistanced L , redshift distancedL,redshiftdistanced_zdzandgalaxyareadistance(transversecomovingdistance)d z and galaxy area distance (transverse comoving distance)dzandgalaxyareadistance(transversecomovingdistance)d_{\scriptscriptstyle G}dGasrelativisticdistancedefinitionstoderivegalaxynumberdensitiesintheredshiftintervald G as relativistic distance definitions to derive galaxy number densities in the redshift intervaldGasrelativisticdistancedefinitionstoderivegalaxynumberdensitiesintheredshiftinterval0.1\le z\le 4$$ 0.1 ≤ z ≤ 4 at volume limited subsamples defined by absolute magnitudes in the K-band. Similar t...

On the fractal structure of the visible universe

Arxiv preprint astro-ph/9611197, 1996

Abstract: Some years ago we proposed a new approach for the analysis of galaxy and cluster correlations based on the concepts and methods of modern statistical physics. This led to the surprising result that galaxy correlations are fractal and not homogeneous up to the limits of the available catalogues. In the meantime many more redshifts have been measured and we have extended our methods also to the analysis of number counts and angular catalogues. This has led to a complete analysis of all the available data that we ...