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|Title: ||A multiwavelength study of near-and mid-infrared selected galaxies at high redshift : ERGs, AGN-identification and the contribution from dust|
|Authors: ||Messias, Hugo G., 1972-|
|Advisor: ||Afonso, José Manuel, 1974-|
Teses de doutoramento - 2011
|Issue Date: ||2011|
|Abstract: ||The main focus of this thesis is the IR spectral regime, which since the 70's and 80's has
revolucionised our understanding of the Universe.
A multi-wavelength analysis on Extremely Red Galaxy populations is rst presented
in one of the most intensively observed patch of the sky, the Chandra Deep Field South.
By adopting a purely statistical methodology, we consider all the photometric and spectroscopic
information available on large samples of Extremely Red Objects (EROs, 553
sources), IRAC EROs (IEROs, 259 sources), and Distant Red Galaxies (DRGs, 289 sources).
We derive general properties: redshift distributions, AGN host fraction, star-formation rate
densities, dust content, morphology, mass funtions and mass densities. The results point
to the fact that EROs, IEROs, and DRGs all belong to the same population, yet seen at
di erent phases of galaxy evolution.
The second part of this thesis is dedicated to the AGN selection in the IR, with particular
relevance to the soon to be launched James Webb Space Telescope in 2014. We develop
an improved IR criterion (using K and IRAC bands) as an alternative to existing IR AGN
criteria for the z . 2:5 regime, and develop another IR criterion which reliably selects
AGN hosts at 0 < z < 7 (using K, Spitzer-IRAC, and Spitzer-MIPS24 m bands, KIM).
The ability to track AGN activity since the end of reionization holds great advantages for
the study of galaxy evolution.
The last chapter of this thesis focus on the importance of dust. Based on deep IR data
on the Cosmological Survey, we derive rest-frame 1.6, 3.3, and 6.2 m luminosity functions
and their dependency on redshift. We estimate the dust contribution to those wavelengths
and show that the hot dust luminosity density evolves since z = 12 with a much steeper
drop than the star-formation history of the Universe.|
|Description: ||Tese de doutoramento, Astronomia e Astrofísica, Universidade de Lisboa, Faculdade de Ciências, 2011|
|Appears in Collections:||FC - Teses de Doutoramento|
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