On the Lengths, Colours and Ages of Bars
Abstract
In an effort to obtain further observational evidences for secular evolution processes in galaxies, as well as observational constrains to current theoretical models of secular evolution, we have used BVRI and Ks images of a sample of 18 barred galaxies to measure the lengths and colours of bars, create colour maps and estimate global colour gradients. In addition, applying a method we developed in a previous contribution, we could distinguish for 7 galaxies in our sample those whose bars have been recently formed from the ones with already evolved bars. We estimated an average difference in the optical colours between young and evolved bars that may be translated to an age difference of the order of 10 Gyr, meaning that bars may be, at least in some cases, long standing structures. Moreover, our results show that, on average, evolved bars are longer than young bars. This seems to indicate that, during its evolution, a bar grows longer by capturing stars from the disk, in agreement with recent numerical and analytical results. Although the statistical significance of these results is low, and further studies are needed to confirm them, we discuss the implications from our results on the possibility of bars being a recurrent phenomenon.
- Publication:
-
Galaxy Evolution across the Hubble Time
- Pub Date:
- May 2007
- DOI:
- 10.1017/S1743921306005333
- arXiv:
- arXiv:astro-ph/0610780
- Bibcode:
- 2007IAUS..235...98G
- Keywords:
-
- Astrophysics
- E-Print:
- To appear in Galaxy Evolution Across the Hubble Time, proceedings of the IAU Symp. 235, F. Combes and J. Palous (eds.)