RT info:eu-repo/semantics/doctoralThesis
T1 Cold-flows in the local Universe
A1 Olmo García, Amanda María del
AB One of the main mechanisms of disk formation is accretion of gas from the intergalactic medium (the so-called cold-flow accretion). The accreted gas fuels and is responsible for the star formation in galaxies. The need for this external gas supply is clear in numerical simulations, however it has been difficult to confirm observationally. This thesis is focused on the study of Extremely Metal-Poor (XMP) galaxies, where the star-forming gas has a metallicity smaller than a tenth of the solar metallicity. They are relevant in this context because XMPs seem to be undergoing a gas accretion event at present. The aim of this thesis is to investigate objects that could shed light into the process of cold-flow accretion in the local Universe, and to explore various possibilities to constrain it observationally.To this end, several studies were carried out. First, an analysis of the kinematics of nine XMP galaxies was made. The XMPs were found to have low rotation and large turbulent motions. Expanding shell-like structures with mass loading factors greater than 10 were also found. Second, deep H-alpha images were taken around an XMP galaxy using the GTC telescope (10 m). In these images, a low surface brightness halo and 63 objects dominated by emission lines were detected around the XMP galaxy, arranged along certain directions. Third, the connection between the ultra-diffuse galaxies and XMPs was explored. The metallicity of the galaxy UGC2162 was measured. From this analysis it was obtained that this galaxy shares the properties of an XMP host galaxy without the low metallicity stellar burst. It is therefore concluded that they are the type of galaxy expected before or after a gas accretion event.
YR 2019
FD 2019
LK http://riull.ull.es/xmlui/handle/915/17639
UL http://riull.ull.es/xmlui/handle/915/17639
LA en
DS Repositorio institucional de la Universidad de La Laguna
RD 18-may-2024