MEDUSA: Minkowski functionals estimated from Delaunay tessellations of the threedimensional largescale structure
Abstract
Minkowski functionals (MFs) are a set of statistics that characterize the geometry and topology of the cosmic density field and contain complementary information to the standard twopoint analyses. We present MEDUSA, an implementation of an accurate method for estimating the MFs of threedimensional point distributions. These estimates are inferred from triangulated isodensity surfaces that are constructed from the Delaunay tessellation of the input point sample. MEDUSA can account for periodic boundary conditions, which is crucial for the analysis of Nbody simulations. We validate our code against several test samples with known MFs, including Gaussian random fields with a ΛCDM power spectrum, and find excellent agreement with the theory predictions. We use MEDUSA to measure the MFs of synthetic galaxy catalogues constructed from Nbody simulations. Our results show clearly nonGaussian signatures that arise from the nonlinear gravitational evolution of the density field. We find that, although redshiftspace distortions change our MFs estimates, their impact is considerably reduced if these measurements are expressed as a function of the volumefilling fraction. We also show that the effect of AlcockPaczynski (AP) distortions on the MFs can be described by scaling them with different powers of the isotropic AP parameter q defined in terms of the volumeaveraged distance D_{V}(z). Thus the MFs estimates by MEDUSA are useful probes of nonlinearities in the density field, and the expansion and growth of structure histories of the Universe.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 December 2021
 DOI:
 10.1093/mnras/stab2820
 arXiv:
 arXiv:2012.08529
 Bibcode:
 2021MNRAS.508.3771L
 Keywords:

 methods: statistical;
 largescale structure of Universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 14 pages, 16 figures, submitted to MNRAS