scholarly journals Revisiting the statistical isotropy of GRB sky distribution

2019 ◽  
Vol 490 (4) ◽  
pp. 4481-4488 ◽  
Author(s):  
Uendert Andrade ◽  
Carlos A P Bengaly ◽  
Jailson S Alcaniz ◽  
Salvatore Capozziello
Keyword(s):  
Correlation Function ◽  
Angular Correlation ◽  
Large Scale ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Significant Evidence ◽  
Standard Cosmology ◽  
Angular Correlation Function ◽  
Statistical Isotropy

ABSTRACT The assumption of homogeneity and isotropy on large scales is one of the main hypotheses of the standard cosmology. In this paper, we test the hypothesis of isotropy from the two-point angular correlation function of 2626 gamma-ray bursts (GRB) of the FERMI GRB catalogue. We show that the uncertainties in the GRB positions induce spurious anisotropic signals in their sky distribution. However, when such uncertainties are taken into account no significant evidence against the large-scale statistical isotropy is found. This result remains valid even for the sky distribution of short-lived GRB, contrarily to previous reports.

scholarly journals Measuring the Angular Correlation Function for Faint Galaxies at High Galactic Latitudes

1996 ◽  
Vol 171 ◽  
pp. 470-470
Author(s):  
D. Woods ◽  
G.G. Fahlman ◽  
H.B. Richer
Keyword(s):  
Correlation Function ◽  
Galaxy Evolution ◽  
Angular Correlation ◽  
Correlation Functions ◽  
Surface Brightness ◽  
Large Scale ◽  
Angular Correlation Function ◽  
Number Counts ◽  
Large Scale Structure Formation ◽  
Important Test

The angular correlation function (ω(θ)) for faint, magnitude-limited samples is an important test of large scale structure formation scenarios, as well as being a valuable probe of galaxy evolution. By measuring ω(θ) one hopes to better understand the mechanism or galaxy species responsible for the number counts excess (relative to “no-evolution” models of galaxies) typically observed at blue wavelengths. Images of three ‘blank’ fields were obtained at the prime focus of the CFHT with sub-arcsecond seeing in V, R and I, to magnitude limits of 25, 24.5 and 24, respectively. The angular correlation functions calculated for one field, NF1, in V is shown in Figure 1. Clearly the amplitude of ω(θ) is decreasing at fainter magnitude limits. Note the number of objects detected are not sufficient to accurately measure ω(θ) for an individual field, in a given colour, to significantly small angular separations. In order to do this we must combine the data from our three fields and perform a multi-field fit. A full summary of this analysis will be presented in Woods et al. (1995, in prep.) including determinations of ω(θ) using galaxy samples culled from all our fields and selected by magnitude, colour and surface brightness.

scholarly journals Large-scale analysis of the SDSS-III DR8 photometric luminous galaxies angular correlation function

2013 ◽  
Vol 435 (4) ◽  
pp. 3017-3027 ◽  
Author(s):  
Fernando de Simoni ◽  
Flávia Sobreira ◽  
Aurelio Carnero ◽  
Ashley J. Ross ◽  
Hugo O. Camacho ◽  
...  
Keyword(s):  
Correlation Function ◽  
Angular Correlation ◽  
Large Scale ◽  
Scale Analysis ◽  
Large Scale Analysis ◽  
Luminous Galaxies ◽  
Angular Correlation Function
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