Multi-Band Galaxy surveys
Metadatos
Mostrar el registro completo del ítemAutor
Schoenell, WilliamEditorial
Universidad de Granada
Director
Benítez Lozano, NarcisoDepartamento
Universidad de Granada. Programa Oficial de Doctorado en Física y MatemáticasMateria
Cosmografía Geografía matemática Estadística Galaxias Cartografía Astronomía
Materia UDC
53 51 2200 220410
Fecha
2017Fecha lectura
2017-09-28Referencia bibliográfica
Schoenell, W. Multi-Band Galaxy surveys. Granada: Universidad de Granada, 2017. [http://hdl.handle.net/10481/48451]
Patrocinador
Tesis Univ. Granada. Programa Oficial de Doctorado en Física y MatemáticasResumen
This doctorate thesis covers the use of recent astronomical surveys
and statistical techniques to answer questions about the composition
of galaxies, by following two different perspectives: the instruments
needed to gather the data and the development of a statistical
tool to turn the observed data into physical properties of galaxies.
We start by giving some background contextualization about the
largest extragalactic surveys to date, and how they influenced the
three surveys studied in this thesis: the S-PLUS survey, the ALHAMBRA
survey, and the J-PAS survey.
The first half of this work is dedicated to the S-PLUS survey, a
Local Universe survey that started at the beginning of 2017 and is
designed to study nearby galaxies in 12 bands with a 80 cm telescope.
Its design, installation, and commissioning occurred in the
course of this thesis and both hard and software components of the
observatory are described as well how they are projected to map the
sky autonomously every night.
In the second half of this work, we turn our attention into the data
generated by other two multi-band surveys: the ALHAMBRA and JPAS
surveys. The ALHAMBRA survey, which completed the map of
3 deg2 in 20 medium band optical filters on 2014, provided the photometric
data and redshifts (photo-zs) used in this work. The studies
performed here with the ALHAMBRA data will provide guidelines
to explore the data of its successor, the J-PAS survey, which starts
next year building a map of the whole northern sky in 56 narrow
band filters.
We show how the problem of the estimation of the photo-z in the
Universe is unfolded by the use of Bayesian statistics, where galaxies
positions are described not by a single point estimator, but by a
probability distribution function (PDF). Within the Bayesian photo-z
framework, we develop a method for estimation of galaxy properties
using the template-redshift PDFs given by photometric redshift
codes as, for example, the BPZ code. We propose a concrete implementation
of this method by fitting the photo-z templates with
composite stellar populations models, or -models. The output of
the proposed implementation is used to, in combination to the ALHAMBRA
photo-z PDFs, estimate galaxies stellar properties like the
mean ages, extinctions, and stellar masses. The derived stellar mass
PDFs were used to estimate the stellar mass function in different
redshift bins.
The resulting ages, stellar masses, and the stellar mass functions
are shown to be systematically inclined to make galaxies bluer and,
hence, less massive than the expected. This deficit of massive galaxies
in the application of the method is discussed, and the solution
proposed relies on changing the photo-z templates to more physical
realistic ones while maintaining the so-pursued photo-z precision.