The population of barred galaxies in the local universe I. Detection and
  characterisation of bars
  (Abridge) Bars are very common in the centre of the disc galaxies, and they
drive the evolution of their structure. A volume-limited sample of 2106 disc
galaxies extracted from the Sloan Digital Sky Survey Data Release 5 was studied
to derive the bar fraction, length, and strength as a function of the
morphology, size, local galaxy density, light concentration, and colour of the
host galaxy. The bars were detected using the ellipse fitting method and
Fourier analysis method. The ellipse fitting method was found to be more
efficient in detecting bars in spiral galaxies. The fraction of barred galaxies
turned out to be 45%. A bar was found in 29% of the lenticular galaxies, in 55%
and 54% of the early- and late-type spirals, respectively. The bar length
(normalised by the galaxy size) of late-type spirals is shorter than in
early-type or lenticular ones. A correlation between the bar length and galaxy
size was found with longer bars hosted by larger galaxies. The bars of the
lenticular galaxies are weaker than those in spirals. Moreover, the unimodal
distribution of the bar strength found for all the galaxy types argues against
a quick transition between the barred and unbarred statues. There is no
difference between the local galaxy density of barred and unbarred galaxies.
Besides, neither the length nor strength of the bars are correlated with the
local density of the galaxy neighbourhoods. In contrast, a statistical
significant difference between the central light concentration and colour of
barred and unbarred galaxies was found. Bars are mostly located in less
concentrated and bluer galaxies. These results indicate that the properties of
bars are strongly related to those of their host galaxies, but do not depend on
the local environment.
