Detection of Prominent Stellar Disks in the Progenitors of Present-day Massive Elliptical Galaxies

Massive galaxies at high redshifts (z > 2) show different characteristics from their local counterparts: they are compact and most likely have a disk. In this study, we trace the evolution of local massive galaxies by performing a detailed morphological analysis, namely, fitting single Sérsic pro...

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Bibliographic Details
Published in:The Astrophysical journal 2017-02, Vol.836 (1), p.75
Main Authors: Davari, Roozbeh H., Ho, Luis C., Mobasher, Bahram, Canalizo, Gabriela
Format: Article
Language:English
Subjects:
Astrophysics
Decomposition
Elliptical galaxies
Galactic bulge
Galactic evolution
Galaxies
galaxies: bulges
galaxies: elliptical and lenticular, cD
galaxies: evolution
galaxies: formation
galaxies: high-redshift
galaxies: photometry
galaxies: spiral
galaxies: structure
Inspection
Morphology
Red shift
Space telescopes
Star formation
Stars
Stars & galaxies
Stellar evolution
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Summary:Massive galaxies at high redshifts (z > 2) show different characteristics from their local counterparts: they are compact and most likely have a disk. In this study, we trace the evolution of local massive galaxies by performing a detailed morphological analysis, namely, fitting single Sérsic profiles and performing bulge+disk decompositions. We analyze ∼250 massive galaxies selected from all CANDELS fields (COSMOS, UDS, EGS, GOODS-South, and GOODS-North). We confirm that both star-forming and quiescent galaxies increase their sizes significantly from z 2.5 to the present day. The global Sérsic index of quiescent galaxies increases over time (from n 2.5 to n > 4), while that of star-forming galaxies remains roughly constant (n 2.5). By decomposing galaxy profiles into bulge+disk components, we find that massive galaxies at high redshift have prominent stellar disks, which are also evident from visual inspection of the images. By z 0.5, the majority of the disks disappear and massive quiescent galaxies begin to resemble the local elliptical galaxies. Star-forming galaxies have lower bulge-to-total ratios (B/T) than their quiescent counterparts in each redshift bin. The bulges of star-forming and quiescent galaxies follow different evolutionary histories, while their disks evolve similarly. Based on our morphological analysis and previous cosmological simulations, we argue that major mergers, along with minor mergers, have played a crucial role in the significant increase in size of high-z galaxies and the destruction of their massive and large-scale disks.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/836/1/75