| Full text | |
| Author(s): |
Total Authors: 2
|
| Affiliation: | [1] Univ Cruzeiro Sul, Nucleo Astrofis Teor, BR-01506000 Sao Paulo - Brazil
[2] European So Observ, Santiago 19 - Chile
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | Astrophysical Journal Letters; v. 743, n. 1 DEC 10 2011. |
| Web of Science Citations: | 56 |
| Abstract | |
We obtained stellar ages and metallicities via spectrum fitting for a sample of 575 bulges with spectra available from the Sloan Digital Sky Survey. The structural properties of the galaxies have been studied in detail in 2009 by Gadotti and the sample contains 251 bulges in galaxies with bars. Using the whole sample, where galaxy stellar mass distributions for barred and unbarred galaxies are similar, we find that bulges in barred and unbarred galaxies occupy similar loci in the age versus metallicity plane. However, the distribution of bulge ages in barred galaxies shows an excess of populations younger than similar to 4 Gyr, when compared to bulges in unbarred galaxies. Kolmogorov-Smirnov statistics confirm that the age distributions are different with a significance of 99.94%. If we select sub-samples for which the bulge stellar mass distributions are similar for barred and unbarred galaxies, this excess vanishes for galaxies with bulge mass logM < 10.1 M(circle dot), while for more massive galaxies we find a bimodal bulge age distribution for barred galaxies only, corresponding to two normal distributions with mean ages of 10.4 and 4.7 Gyr. We also find twice as much active galactic nuclei among barred galaxies, as compared to unbarred galaxies, for low-mass bulges. By combining a large sample of high-quality data with sophisticated image and spectral analysis, we are able to find evidence that the presence of bars affects the mean stellar ages of bulges. This lends strong support to models in which bars trigger star formation activity in the centers of galaxies. (AU) | |
| FAPESP's process: | 08/58406-4 - The modeling of stellar populations and detailed abundance patterns |
| Grantee: | Paula Rodrigues Teixeira Coelho |
| Support Opportunities: | Research Grants - Young Investigators Grants |
| FAPESP's process: | 09/09465-0 - The modeling of stellar populations and detailed abundance pattern |
| Grantee: | Paula Rodrigues Teixeira Coelho |
| Support Opportunities: | Scholarships in Brazil - Young Researchers |