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| Author(s): |
Natália Crepaldi Del Coco
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto Astronômico e Geofísico (IAG/SBD) |
| Defense date: | 2019-12-16 |
| Examining board members: |
Gastao Cesar Bierrenbach Lima Neto;
Tatiana Ferraz Laganá;
André Luís Batista Ribeiro;
Laerte Sodre Junior
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| Advisor: | Gastao Cesar Bierrenbach Lima Neto |
| Abstract | |
At large scales, matter in the Universe is organized in a web-like structure, with clusters of galaxies connected by filaments, enclosing nearly empty regions. The relation of these environments and their effect on smaller-scale objects has been vastly discussed in the last years, leading to diverging scenarios. The main goal of this project is to search for correlations between the components of the matter distribution at scales of tens of Mpc. Specifically, we study whether the properties of galaxy clusters and filamentary structures in its surroundings are linked or not. The cluster properties were obtained from the intra-cluster plasma emission in X-rays. With public data from the XMM-Newton satellite, we derived physical parameters such as temperature, mass and dynamical state of 14 clusters in redshift range 0.14<z<0.35. The filamentary structure around each cluster was studied from the galaxy distribution in cylindrical regions of radius r=35 h^-1 Mpc and thickness Delta_z = 0.16. We applied the Cosmic Web Reconstruction algorithm to determine the web skeleton in each field. The Principal Filament (PF) was identified as the one crossing any of our central clusters, and all galaxies closer than 1.5 Mpc from these filamentary axes were considered as members of the structure. We analyzed PFs properties such as average and gradient colors, length, and relative density. The results show that filaments have similar (g-i) color index, with no gradient in direction to the filamentary axis, although it becomes denser when closer to the structure center. This is in agreement with Darvish et al. (2015), which argues that the color-density relation is not fundamental in these environments. On the other hand, there is a trend of reddening in direction to the closest cluster without expressive change in the relative density. Also, we observe that more massive non cool-core clusters are redder if compared to its filament color. Both results point out to red galaxies falling faster into the cluster than the star forming ones, as proposed by Sarron et. al (2019). Furthermore, we observed that more massive clusters reside in smaller and less dense PF, suggesting a co-evolving system in which smaller filaments are more collapsed towards the cluster, growing the cluster mass through higher matter inflow and reducing the filament density. Further progress may be gained by observing the filamentary gas content, providing more clues as how the largest structures in the Universe evolve. (AU) | |
| FAPESP's process: | 17/14601-7 - The relation between the physical properties of the intracluster plasma and the large scale structure of the Universe |
| Grantee: | Natália Crepaldi Del Coco |
| Support Opportunities: | Scholarships in Brazil - Master |