Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The evolution of the number density of large disk galaxies in COSMOS   We study a sample of approximately 16,500 galaxies with I_AB <= 22.5 in the
COSMOS field. Structural information on the galaxies is derived by fitting
single Sersic models to their two-dimensional surface brightness distributions.
We investigate the evolution of the number density of disk galaxies larger than
5 kpc between redshift z~1 and the present epoch. To this end, we use the
measurements of the half-light radii to construct, as a function of redshift,
the size function of both the total disk galaxy population and of disk galaxies
split in four bins of bulge-to-disk ratio. Furthermore, we use a selected
sample of roughly 1800 SDSS galaxies to calibrate our results with respect to
the local universe. We find that: (i) The number density of disk galaxies with
intermediate sizes (r_{1/2}~5-7 kpc) remains nearly constant from z~1 to today.
(ii) The number density of the largest disks (r_{1/2}>7 kpc) decreases by a
factor of about two out to z~1. (iii) There is a constancy in the number
density of large bulgeless disks out to z~1; the deficit of large disks at
early epochs seems to arise from a smaller number of bulged disks. Our results
indicate that the bulk of the large disk galaxy population has completed its
growth by z~1, and support the hypothesis that secular evolution processes
produce - or at least add stellar mass to - the bulge components of disk
galaxies.

29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
18
The categories of this paper are: econ