Multiphase probes of the baryon cycle from big data quasar spectroscopy

Fresco Arrom, Alejandra Yrupe (2023): Multiphase probes of the baryon cycle from big data quasar spectroscopy. Dissertation, LMU München: Fakultät für Physik

Abstract

Simulations of the large scale structure of the Universe show the filamentary cosmic web of gas connecting galaxies and groups of galaxies with each other, with substructures that involve complex physical processes that drive the evolution of galaxies. Examples of these substructures are filaments from intergalactic medium (IGM) or the circumgalactic medium (CGM) surrounding the galaxies. These are too diffuse to be observed in emission yet, thus using luminous background sources to detect this faint gas in absorption becomes the most powerful technique available to study these structures. The use of quasar spectra as a background source can be a useful tool in a variety of contexts, including the study of the large scale structure and investigations of the environments of the quasars themselves. The aim of this thesis was to make use of large sets of data to increase the signal to noise ratio in order to identify elusive components of baryonic matter that do not necessarily emit light, but can be revealed via absorption lines in the electromagnetic spectrum of a background source. Using different ground based telescopes from optical and near UV wavelengths, we use the technique of stacking, which takes advantage of the statistically significant large amounts of data being produced. The first chapter presents an introduction to the large scale structure and other objects that were targeted throughout each project of this thesis, while presenting an overall look of the methods and instruments used. The second chapter presents a search for the IGM using FeXXI λ 1354˚A tracing 107K gas at UV wavelengths. Using more than one hundred high-spectral resolution (R∼ 49, 000) and very high signal to noise quasar spectra from the Very Large Telescope (VLT) and the Ultraviolet Echelle Spectrograph (UVES), we stacked at the redshift of known Damped Lyman-alpha (DLA) absorbers which are tracers of overdensities. We present the results of the findings and provide an outlook for the possibility of performing a similar study with future instruments. The third chapter presents a study of the Intracluster Medium using quasar spectra from the Sloan Digital Sky Survey from Data Release 16 as background sources for X-ray selected clusters from the ROSAT All Sky Survey, with spectroscopic redshift from the SPectroscopic IDentifcation of ERosita Sources (SPIDERS) program. We present the final results and compare them with simulations. Using the MgII doublet as a tracer of this 104K gas, we stack spectra at th redhift of the foreground clusters and we also compare to a known MgII absorbers sample from SDSS DR16. We find tentative evidence of MgII absorption in the whole sample. In chapter four we study outflows from Active Galactic Nuclei (AGN) by using SDSS quasar spectra and looking for MgII intrinsic absorption lines by stacking a sample of 7100 spectra from Data Release 18 (DR18). We present our results and outlook for future work. We present summary and conclusions in chapter 5, with an outlook of possibilities to continue the research in different areas that were studied during the course of this thesis.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: Intergalactic medium, quasars, absorption lines, galaxy evolution, galaxy formation, galaxy clusters, Intracluster medium, galaxies abundance, galaxies haloes, quasars absorption lines, active galactic nuclei, AGN outflows, AGN Broad Line Region
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 530 Physik
• Fakultäten: Fakultät für Physik
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 20. Juni 2023
• 1. Bericht­erstatter:in: Nandra, Kirpal