D. Burgarella et al., The ultraviolet visibility and quantitative morphology of galactic disks at low and high redshift, ASTRON ASTR, 369(2), 2001, pp. 421-431
We have used ultraviolet (200 nm) images of the local spiral galaxies M33:
M51, M81, M100, M101 to compute morphological parameters of galactic disks
a this wavelength: half-light radius ri,l, surface brightness distributions
, asymmetries (A) and concentrations (C-A). The visibility and the evolutio
n of the morphological parameters are studied as a function of the redshift
. The main results are: local spiral galaxies would he hardly observed and
classified if projected at high redshifts (z greater than or equal to 1) un
less a strong luminosity evolution is assumed. Consequently, the non-detect
ion of large galactic disks cannot be used without caution as a constraint
on the evolution of galatic disks. Spiral galaxies observed in ultraviolet
appear more irregular since the contribution from the young stellar populat
ion becomes predominent. When these galaxies are put in a (log A vs. log CI
A) diagram, they move to the irregular sector defined at visible wavelength
s. Moreover, the log A parameter is degenerate and cannot be used for an ef
ficient classification of morphological ultraviolet types. The analysis of
high redshift galaxies cannot be carried out in a reliable way so far and a
multi-wavelength approach is required if one does not want to misinterpret
the data.