Genus statistics using the Delaunay tessellation field estimation method: I tests with the Millennium Simulation and the SDSS DR7 - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




Genus statistics using the Delaunay tessellation field estimation method: I tests with the Millennium Simulation and the SDSS DR7 - Astrophysics > Cosmology and Nongalactic Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We study the topology of cosmic large-scale structure through the genusstatistics, using galaxy catalogues generated from the Millennium Simulationand observational data from the latest Sloan Digital Sky Survey Data ReleaseSDSS DR7. We introduce a new method for constructing galaxy density fieldsand for measuring the genus statistics of its isodensity surfaces. It is basedon a Delaunay tessellation field estimation DTFE technique that allows thedefinition of a piece-wise continuous density field and the exact computationof the topology of its polygonal isodensity contours, without introducing anyfree numerical parameter. Besides this new approach, we also employ thetraditional approaches of smoothing the galaxy distribution with a Gaussian offixed width, or by adaptively smoothing with a kernel that encloses a constantnumber of neighboring galaxies. Our results show that the Delaunay-based methodextracts the largest amount of topological information. Unlike the traditionalapproach for genus statistics, it is able to discriminate between the differenttheoretical galaxy catalogues analyzed here, both in real space and in redshiftspace, even though they are based on the same underlying simulation model. Inparticular, the DTFE approach detects with high confidence a discrepancy of oneof the semi-analytic models studied here compared with the SDSS data, while theother models are found to be consistent.



Autor: Youcai Zhang, Volker Springel, Xiaohu Yang

Fuente: https://arxiv.org/







Documentos relacionados