Morphology of the local volume

Abstract

To study the global morphology of the galaxy distribution in our local neighbourhood we calculate the Minkowski functionals for a sequence of volume limited samples within a sphere of 8 Mpc centred on our galaxy. The well known strong clustering of the galaxies and the dominance of voids and coherent structures on larger scales is clearly visible in the Minkowski functionals. The morphology of the galaxy distribution changes with the limiting absolute magnitude. The samples, encompassing the more luminous galaxies, show emptier voids and more pronounced coherent structures. Indeed there is a prominent peak in the luminosity function of isolated galaxies for M B ≈ −14, which at least partly explains these morphological changes. We compare our date with halo samples from a ΛCDM simulation. Special care was taken to reproduce the observed local neighbourhood as well as the observed luminosity function in these mock samples. All in all the mock samples render the global morphology of the galaxy distribution quite well. However, the detailed morphological analysis reveals that real galaxies cluster stronger, the observed voids are emptier and the structures are more pronounced compared to the mock samples from the ΛCDM simulation.

Tomographic local 2D analyses of the WISExSuperCOSMOS all-sky galaxy catalogue

“…Accordingly, our analyses intend to reveal regions with unexpected excess-of or lack-of luminous matter, suggestive of the presence of superclusters of galaxies or giant voids, respectively. For these analyses we shall use the MF, successfully employed in recent morphological analyses of the large-scale galaxy distribution, where they capture the imprints left by the clustering of galaxies and the presence of voids [Kerscher & Tikhonov (2010); see, e.g., Novaes et al (2016) for the application of MF to the inspection of the CMB temperature fluctuations field].…”

“…The capability of the MF in probing it has also been applied to differentiate between cosmological models, constraining cosmological parameters (Shirasaki & Yoshida 2014;Pratten & Munshi 2012;Petri et al 2015;Kratochvil et al 2017) and probing modifications of the gravity (Fang & Zhao 2017;Shirasaki et al 2017). In this sense, several authors have also used these morphological tools to analyse volume distributed samples, as, for example, in Schmalzing & Diaferio (2000); Hikage et al (2003); Saar et al (2007); Kerscher & Tikhonov (2010); Challinor & Lewis (2013), in general comparing the results to the expected in the ΛCDM cosmology.…”

A Study on the Baryon Acoustic Oscillation with Topological Data Analysis

“…Since basically the smoothed random field contains the whole information on the infinitely high-order moments of the field, in principle the Minkowski Functionals can specify the galaxy density field completely. Indeed this method has been applied very extensively to the analysis of the cosmic density field [e.g., 9,12,13,14,15,16,17], as well as redshift distortion [e.g., 18], weak lensing cosmology [e.g., 19,20,21], cosmic reionization [22,23,24,25], test of cosmological/gravity theories [26,27,28,29], and the cosmic microwave background (CMB: e.g., [30,31,32,33,34,35]).…”

Automatic sorting of point pattern sets using Minkowski functionals

“…This makes them a more complete "fingerprint" for pattern comparison [19,20]. These functionals have enjoyed marked success in astrophysics [21], soft matter [22], and fluid turbulence [23].…”