Bibcode
James, P. A.; Bretherton, C. F.; Knapen, J. H.
Bibliographical reference
Astronomy and Astrophysics, Volume 501, Issue 1, 2009, pp.207-220
Advertised on:
7
2009
Journal
Citations
61
Refereed citations
57
Description
Aims: We analyse the current build-up of stellar mass within the disks
and bulges of nearby galaxies through a comparison of the spatial
distributions of forming and old stellar populations. Methods:
Hα and R-band imaging are used to determine the distributions of
young and old stellar populations in 313 S0a-Im field galaxies out to
~40 Mpc. Concentration indices and mean normalised light profiles are
calculated as a function of galaxy type and bar classification. Results: The mean profiles and concentration indices show a strong and
smooth dependence on galaxy type. Apart from a central deficit due to
bulge/bar light in some galaxy types, mean Hα and R-band profiles
are very similar. Mean profiles within a given type are remarkably
constant even given wide ranges in galaxy luminosity and size. SBc,
SBbc, and particularly SBb galaxies have profiles that are markedly
different from those of unbarred galaxies. The Hα emission from
individual SBb galaxies is studied in detail; virtually all show
resolved central components and concentrations of star formation at or
just outside the bar-end radius. Conclusions: Galaxy type is an
excellent predictor of R-band light profile. In field galaxies, star
formation has the same radial distribution as R-band light, i.e. stellar
mass is building at approximately constant morphology, with no strong
evidence for outer truncation or inside-out disk formation. Bars have a
strong impact on the radial distribution of star formation, particularly
in SBb galaxies.
Based on observations made with the Jacobus Kapteyn Telescope operated
on the island of La Palma by the Isaac Newton Group in the Spanish
Observatorio del Roque de los Muchachos of the Instituto de Astrofisica
de Canarias.
Related projects
![The moderately-inclined spiral galaxy NGC 4536 features two very-well defined arms, sparsely populated by star forming regions. Right above its yellow core, made up mostly of old stars, two dust lanes appear to intersect forming an 'X' shape. Project Image](/sites/default/files/styles/crop_square_2_2_to_320px/public/images/project/imagen-jhk.jpg?itok=fuDqntc5)
Spiral Galaxies: Evolution and Consequences
Our small group is well known and respected internationally for our innovative and important work on various aspects of the structure and evolution of nearby spiral galaxies. We primarily use observations at various wavelengths, exploiting synergies that allow us to answer the most pertinent questions relating to what the main properties of
Johan Hendrik
Knapen Koelstra