RT info:eu-repo/semantics/doctoralThesis
T1 Morphology and metallicities of OTELO galaxies.
A1 Nadolny, Jakub
A2 Programa de Doctorado en Astrofísica
K1 Galaxias
K1 Astrofísica
AB In this thesis we explore the OTELO (OSIRIS Tunable Filter Emission Line Object) survey. OTELO is a very deep, pencil beam survey for the search of emission line sources by means of the tunable filters of the OSIRIS instrument, installed at the Gran Telescopio Canarias. A tomography scan method results in 2D, low-resolution pseudo-spectra for all the sources in the observed field. The reached line flux of 4:6   10^19 erg s^-1 cm^2 makes it the deepest survey in terms of the line flux.In particular, we present the morphological catalogue of the OTELO sources detected in high-resolution images from the ACS instrument of the Hubble Space Telescope. We have employed a parametric method to fit 2D model composed of single-Sérsic profile using a multi-wavelength version of GALFIT software. This software fits simultaneously selected model to all given images using Chebyshev polynomial functions. We show that this multi-wavelength method provides better results in the low signal-to-noise, recovering a substantial fraction of sources in this regime, as compared to a standard version of the same software. We also provide a preliminary visual morphology of the selected sample (up to magnitude I=24.5 mag). The results of this analysis are consistent with the obtained from the parametric method. We have tested various methods for separation of early-type galaxies from late-type galaxies, as well as the mass-size relation. We also found a median stellar mass evolution up to z = 2 finding good agreement with previous works.From the morphological catalogue we selected a population of early-type emission line galaxies (ET-ELG). Even if under investigation for many decades, there is lack of the clear consensus on the nature and origin of the emission lines found in the ET-ELG. We study a sample of 14 such objects at intermediate redshift. Due to the limited spectral information available, we compared the number densities of our sample with a carefully selected sample of local counterparts from SDSS. We found that OTELO detects a considerably higher ET-ELG density than it would be expected from the local SDSS sample. This result holds even considering a cosmic variance – the most important source of uncertainties for a pencil beam survey ( 56 arcmin^2) as OTELO.Finally, we studied a stellar-mass–metallicity relation (MZR) of selected Ha emission line sources at z~0.4. Particularly, and taking advantage of the depth reached by the OTELO survey, we focus on the very low-mass end of this relation, with the low-mass limit (10^7Msun ). Most of the galaxies in the Ha sample are morphologically classified as disk-like sources with low Sérsic index, as expected for the star-forming galaxies. We have found no evidence for the evolution of the MZR since z = 0.4.
YR 2021
FD 2021
LK http://riull.ull.es/xmlui/handle/915/25756
UL http://riull.ull.es/xmlui/handle/915/25756
LA en
DS Repositorio institucional de la Universidad de La Laguna
RD 27-dic-2024