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Title: Structural evolution of massive galaxies in the last 11 Gyr
Author: Buitrago Alonso, Fernando
ISNI:       0000 0004 2727 1396
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2012
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This thesis describes the properties and evolution of massive (Mstellar ≥ 1011h−2 70 M⊙) galaxies at 0 < z < 3, including their relationship to lower mass systems. Present-day massive galaxies are composed mostly of early-type objects, although it is unknown whether this was also the case at higher redshifts. In a hierarchical assembling scenario the morphological content of the massive population is expected to change with time from disk-like objects in the early Universe to spheroid-like galaxies at present. We first probe this theoretical expectation by compiling a large sample of massive galaxies in the redshift interval 0 15°A Abstract 5 to secure their kinematical measurements. Through a 3D kinematical spectroscopy analysis we conclude that half (i.e. 50±7%) of our galaxies are compatible with being rotationally supported disks in agreement with our previous photometric expectations. This is around a factor of two higher than what is observed in the present Universe for objects of the same stellar mass. Strikingly, the majority of these massive galaxies show clear and fairly large rotational velocity maps, implying that massive galaxies acquire rapidly rotational support and hence gravitational equilibrium. In addition, we have evidence, based on our measured velocity dispersions and imaging, to favour a picture in which minor (and major) mergers are the main driving force behind the evolution of this massive galaxy population. There is also cumulative evidence showing that the formation process for a number of these massive galaxies occur at even higher redshifts (z > 5) and that their morphological features are preserved when observing them in the UV restframe. Hence, we made use of the excellent capabilities of GNS to locate and study massive galaxies beyond z = 3 within our imaging and secondly determining whether the strong masssize relation found for the most massive objects holds as well for lower mass objects. Our findings show the extreme compactness of massive objects at z > 3 and only a moderate evolution in size below our 1011M⊙ mass limit.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QB Astronomy