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Semi-empirical analysis of Sloan Digital Sky Survey galaxies : II . The bimodality of the galaxy population revisited
| Content Provider | Semantic Scholar |
|---|---|
| Author | Mateus, A. Sernadas C. Sernadas J. Rasga P. Sodŕe, Laerte Fernandes, Roberto Cid Stasínska, Grȧzyna Schoenell, William Gomes, J. L. M. A. |
| Copyright Year | 2005 |
| Abstract | We revisit the bimodal distribution of the galaxy populatio n commonly seen in the local universe. Here we address the bimodality observed in galaxy properties in terms of spectral synthesis products, such as mean stellar ages and stell ar masses, derived from the application of this powerful method to a volume-limited sampl e, with magnitude limit cutoff M(r) = −20.5, containing about 50 thousand luminous galaxies from the SD S ata Release 2. In addition, galaxies are classi£ed according to the ir emission line properties in three distinct spectral classes: star-forming galaxies, with yo ung stellar populations; passive galaxies, dominated by old stellar populations; and, hosts of act ive nuclei, which comprise a mix of young and old stellar populations. We show that the extrem es of the distribution of some galaxy properties, essentially galaxy colours, 4000 a A break index, and mean stellar ages, are associated to star-forming galaxies at one side, and passiv e galaxies at another. We £nd that the mean light-weighted stellar age of galaxies is the direc t responsible for the bimodality seen in the galaxy population. The stellar mass, in this view, has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results also give support to the existence of a ‘downsizing’ in galaxy for mation, where massive galaxies seen nowadays have stellar populations formed at early time s. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://cds.cern.ch/record/908718/files/0511578.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/astro-ph/0511578v1.pdf |
| Alternate Webpage(s) | http://arxiv.org/pdf/astro-ph/0511578v2.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Class Color GUCY2C protein, human Galaxy Iridium Luminous Studio Population Semiconductor industry Star Wars Galaxies Stellar (payment network) Stellar classification WeatherStar |
| Content Type | Text |
| Resource Type | Article |
