Issue |
A&A
Volume 495, Number 2, February IV 2009
|
|
---|---|---|
Page(s) | 491 - 504 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:200810931 | |
Published online | 14 January 2009 |
The population of barred galaxies in the local universe
I. Detection and characterisation of bars
1
Instituto de Astrofísica de Canarias, C/ Vía Láctea s/n, 38200 La Laguna, Spain e-mail: jalfonso@iac.es
2
INAF-Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, 35122 Padova, Italy e-mail: jairo.mendez@oapd.inaf.it
3
Universidad de La Laguna, Av. Astrofísico Francisco Sánchez s/n, 38206 La Laguna, Spain
4
Dipartimento di Astronomia, Università di Padova, vicolo dell'Osservatorio 3, 35122 Padova, Italy e-mail: enricomaria.corsini@unipd.it
Received:
8
September
2008
Accepted:
16
December
2008
Context. Bars are very common in the centre of the disc galaxies, and they drive the evolution of their structure. The state-of-the-art imaging and redshift surveys of galaxies allow us to study the relationships between the properties of the bars and those of their hosts in statistically significant samples.
Aims. A volume-limited sample of 2106 disc galaxies 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 sample galaxies were selected to not be strongly disturbed/interacting.
Methods. The bar and galaxy properties were obtained by analysing the r-band images of the sample galaxies available in the Sloan Digital Sky Survey Data Release 5.
Results. The bars were detected using the ellipse fitting method and Fourier
analysis method. They were tested and calibrated with extensive
simulations on artificial images. 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 . A bar was found
in
of the lenticular galaxies, in
and
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.
Conclusions. 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.
Key words: galaxies: elliptical and lenticular, cD / galaxies: evolution / galaxies: fundamental parameters / galaxies: kinematics and dynamics / galaxies: structure / galaxies: spiral
© ESO, 2009
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