Topological Bias

Bermejo, Raul (2019) Topological Bias. Bachelor's Thesis, Astronomy.

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Abstract

The Cosmic Web features a highly interconnected network where different morphological elements meet at multiple scales. To understand the conjuction of overdense voids, elongated filaments, compact clusters of galaxies and walls, we study the connectivity of dark halos and the dark matter distribution in a $\Lambda$CDM simulation. This leads us to adapt the mathematical formalism that studies connectivity, Topology and Persistent Homology. By means of Betti numbers and persistence diagrams, we are able to trace the topology signatures of dark halos and the underlying dark matter distribution in the Cosmic Web. Combining the abstract formalism of Topology and Persistent Homology with the first-order probe of clustering, the two-point correlation function, we test the existence of a topological bias between the dark matter distribution and dark halos of different mass ranges. We discover compelling evidence of the topological signature probing higher level clustering than that probed by the two-point correlation function. In particular, we find that lighter halos form most of their filamentary structure at lower length scales than heavy halos, even when the first level two-point correlation function is taken into account. Some preliminary results from a larger halo catalogue show that this difference in structure formation occurs in the case of voids as well.

Item Type:	Thesis (Bachelor's Thesis)
Supervisor name:	Wilding, G. and Weijgaert, M.A.M. van de
Degree programme:	Astronomy
Thesis type:	Bachelor's Thesis
Language:	English
Date Deposited:	15 Jul 2019
Last Modified:	16 Jul 2019 12:11
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/20225

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