CORRELATION AND CLUSTERING Statistical properties of galaxy large scale structures
نویسندگان
چکیده
In this lecture we clarify the basic difference between the correlation properties for systems characterized by small or large fluctuations. The concepts of correlation length, homogeneity scale, scale invariance and criticality are discussed as well. We relate these concepts to the interpretation of galaxy clsutering.
منابع مشابه
Faint Galaxy Redshift Survey XII : Clustering of Galaxies
A clustering analysis is performed on two samples of ∼ 600 faint galaxies each, in two widely separated regions of the sky, including the Hubble Deep Field. One of the survey regions is configured so that some galaxy pairs span angular separations of up to 1 deg. The median redshift is zmed ≈ 0.55. Strong clustering is obvious, with every pencil-beam field containing a handful of narrow redshif...
متن کاملThe Durham / UKST Galaxy Redshift Survey - III . Large Scale Structure via the 2 - Point Correlation Function
We have investigated the statistical clustering properties of galaxies by calculating the 2-point galaxy correlation function from the Durham/UKST Galaxy Redshift Survey. This survey is magnitude limited to bJ ∼ 17, contains∼2500 galaxies sampled at a rate of one on three and surveys a ∼4×10(hMpc) volume of space. We have empirically determined the optimal method of estimating the 2-point corre...
متن کاملQuasar-Galaxy and Galaxy-Galaxy Cross-Correlations: Model Predictions with Realistic Galaxies
Several measurements of QSO-galaxy correlations have reported signals much larger than predictions of magnification by large-scale structure. We find that changes by a factor of 2-10 in the expected signal arise naturally on arcminute scales if the galaxy distribution is modeled realistically, as opposed to a linearly biased version of the mass distribution. Thus the resolution of the measured ...
متن کاملThe environmental dependence of clustering in hierarchical models
In hierarchical models, density fluctuations on different scales are correlated. This induces correlations between dark halo masses, their formation histories, and their larger-scale environments. In turn, this produces a correlation between galaxy properties and environment. This correlation is entirely statistical in nature. We show how the observed clustering of galaxies can be used to quant...
متن کاملAngular Cross-Correlation of Galaxies: A Probe of Gravitational Lensing by Large-Scale Structure
The angular cross-correlation between two galaxy samples separated in redshift is shown to be a useful measure of weak lensing by large-scale structure. Angular correlations in faint galaxies arise due to spatial clustering of the galaxies as well as gravitational lensing by dark matter along the line-of-sight. The lensing contribution to the 2-point auto-correlation function is typically small...
متن کامل