Morphostatistical characterization of the spatial galaxy distribution through Gibbs point processes (original) (raw)

2021, Monthly Notices of the Royal Astronomical Society

This paper proposes a morphostatistical characterization of the galaxy distribution through spatial statistical modelling based on inhomogeneous Gibbs point processes. The galaxy distribution is supposed to exhibit two components. The first one is related to the major geometrical features exhibited by the observed galaxy field, here, its corresponding filamentary pattern. The second one is related to the interactions exhibited by the galaxies. Gibbs point processes are statistical models able to integrate these two aspects in a probability density, controlled by some parameters. Several such models are fitted to real observational data via the ABC shadow algorithm. This algorithm provides simultaneous parameter estimation and posterior-based inference, hence allowing the derivation of the statistical significance of the obtained results.

Bayesian galaxy shape estimation

2002

The accurate measurement of galaxy ellipticities is vital for weak lensing studies, in particular cosmic shear. We describe a Bayesian approach to this problem in which galaxies are parameterized as sums of Gaussians, convolved with a PSF which is also a sum of Gaussians, following Kuijken (1999). We calculate the uncertainties in the output parameters using a Markov Chain Monte Carlo approach. We show that for a simple simulation, the ellipticity estimates do not give a biased result when averaged by statistical weight.

A non-parametric method for galaxy morphology (Grootes+, 2014)

Tables listing full discretization of the parameter space spanned by the parameter combinations (log(n),log(re),Mi), (log(n),log(re),log(mu*)), and (log(n),log(M*),log(mu*)). The tables provide the resolution level, the front left corner of each cell in a mathematically right-handed cartesian coordinate system, the size of the cell in each parameter direction, the spiral fraction of the cell's population, the relative error on the spiral fraction, the elliptical fraction of the cell's population, and the relative error on the elliptical fraction. Galaxies with a Galaxy Zoo DR1 (Lintott et al., 2008MNRAS.389.1179L, 2011, Cat. J/MNRAS/410/166) debiased probability (Bamford et al., 2009MNRAS.393.1324B) of >=0.7 of being a spiral are considered to be spirals, for the definition of spiral fractions. The elliptical fraction is defined analogously.(3 data files).

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