Issue |
A&A
Volume 414, Number 3, February II 2004
|
|
---|---|---|
Page(s) | 905 - 918 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20031679 | |
Published online | 27 January 2004 |
Near-infrared observations of galaxies in Pisces-Perseus *,**
V. On the origin of bulges
1
Istituto di Radioastronomia-Firenze/CNR, Largo E. Fermi 5, 50125 Firenze, Italy e-mail: hunt@arcetri.astro.it
2
Max-Planck-Institut für extraterrestrische Physik (MPE), Giessenbachstrasse, 85748 Garching, Germany e-mail: dpierini@mpe.mpg.de
3
INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy e-mail: giova@arcetri.astro.it
Corresponding author: L. K. Hunt, hunt@arcetri.astro.it
Received:
7
July
2003
Accepted:
30
October
2003
We investigate the scaling relations of bulge and disk
structural parameters for a sample of 108 disk galaxies.
Structural parameters of individual galaxies are obtained from
two-dimensional bulge/disk decomposition of their H-band surface brightness
distributions.
Bulges are modelled with a generalized exponential (Sérsic) with variable
integer shape index n.
We find that bulge effective scalelengths and luminosity MB
increase with increasing n, but disk properties are independent of bulge shape.
As Hubble type T increases,
bulges become less luminous and their mean effective surface brightness
gets fainter;
disk
shows a similar, but much weaker, trend.
When bulge parameters (
,
, MB) are
compared with disk ones (
,
, MD),
they are tightly correlated for
bulges.
The correlations gradually worsen with increasing n such that
bulges appear virtually independent of their disks.
The Kormendy relation,
vs.
, is shown to depend on bulge shape n;
the two parameters are tightly correlated in
bulges (
),
and increasingly less so as n decreases;
disk
and
are well correlated (
).
Bulge-to-disk size ratios
are independent of Hubble type,
but smaller for exponential bulges;
the mean
for
bulges is 4 times smaller than
that for
, with a spread which is 9 times smaller.
Strongly barred SB galaxies with exponential bulges are more luminous than their
unbarred counterparts.
Exponential bulges appear to be closely related to their underlying
disks, while bulges with higher n values are less so;
bulges and their disks apparently have no relation.
We interpret our results as being most consistent with a secular evolutionary scenario,
in which dissipative processes in the disk are responsible for building up the bulges
in most spirals.
Key words: galaxies: evolution / galaxies: formation / galaxies: fundamental parameters / galaxies: spiral / galaxies: structure / infrared: galaxies
Full Table 1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/414/905
Based on observations at the TIRGO, NOT, and VATT telescopes. TIRGO (Gornergrat, CH) is operated by IRA-CNR, Arcetri, Firenze. NOT (La Palma, Canary Islands) is operated by NOTSA, the Nordic Observatory Scientific Association. VATT (Mt. Graham, AZ) is operated by VORG, the Vatican Observatory Research Group.
© ESO, 2004
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