Bibcode
Kim, T.; Sheth, Kartik; Gadotti, Dimitri A.; Lee, Myung Gyoon; Zaritsky, Dennis; Elmegreen, Bruce G.; Athanassoula, E.; Bosma, Albert; Holwerda, Benne; Ho, Luis C.; Comerón, Sébastien; Knapen, J. H.; Hinz, Joannah L.; Muñoz-Mateos, Juan-Carlos; Erroz-Ferrer, S.; Buta, Ronald J.; Kim, Minjin; Laurikainen, Eija; Salo, Heikki; Madore, Barry F.; Laine, Jarkko; Menéndez-Delmestre, Karín; Regan, Michael W.; de Swardt, Bonita; Gil de Paz, Armando; Seibert, Mark; Mizusawa, Trisha
Bibliographical reference
The Astrophysical Journal, Volume 799, Issue 1, article id. 99, 10 pp. (2015).
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1
2015
Journal
Citations
35
Refereed citations
34
Description
We have measured the radial light profiles and global shapes of bars
using two-dimensional 3.6 μm image decompositions for 144 face-on
barred galaxies from the Spitzer Survey of Stellar Structure in
Galaxies. The bar surface brightness profile is correlated with the
stellar mass and bulge-to-total (B/T) ratio of their host galaxies. Bars
in massive and bulge-dominated galaxies (B/T > 0.2) show a flat
profile, while bars in less massive, disk-dominated galaxies (B/T ~ 0)
show an exponential, disk-like profile with a wider spread in the radial
profile than in the bulge-dominated galaxies. The global two-dimensional
shapes of bars, however, are rectangular/boxy, independent of the bulge
or disk properties. We speculate that because bars are formed out of
disks, bars initially have an exponential (disk-like) profile that
evolves over time, trapping more disk stars to boxy bar orbits. This
leads bars to become stronger and have flatter profiles. The narrow
spread of bar radial profiles in more massive disks suggests that these
bars formed earlier (z > 1), while the disk-like profiles and a
larger spread in the radial profile in less massive systems imply a
later and more gradual evolution, consistent with the cosmological
evolution of bars inferred from observational studies. Therefore, we
expect that the flatness of the bar profile can be used as a dynamical
age indicator of the bar to measure the time elapsed since the bar
formation. We argue that cosmic gas accretion is required to explain our
results on bar profile and the presence of gas within the bar region.
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