Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The evolution of the morphological scale of early-type galaxies since
  z=2   We present the morphological analysis based on HST-NICMOS observations in the
F160W filter of a sample of 30 early-type galaxies spectroscopically confirmed
at 1.2<z<2. We derive the effective radius R_e and the mean surface brightness
mu_e of galaxies in the rest-frame R-band. We find that early-types at z~1.5
are characterized by a surface brightness (SB) much higher then their local
counterparts with comparable R_e. In particular, we find that the mean SB of
these early-types should get fainter by ~2.5 mag from z~1.5 to z=0 to match the
SB of the local early-types with comparable R_e. This evolution exceeds by a
factor two the luminosity evolution expected for early-types in this redshift
range and more than a factor three the one derived from the observed luminosity
function of galaxies. Consequently, an evolution of the effective radius R_e
from the epoch of their formation towards z=0 has to be invoked and the
hypothesis of fixed size rejected.

14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat