| Full text | |
| Author(s): |
Trevisan, M.
[1, 2]
;
Ferreras, I.
[3]
;
de La Rosa, I. G.
[4, 5, 6]
;
La Barbera, F.
[7]
;
de Carvalho, R. R.
[2]
Total Authors: 5
|
| Affiliation: | [1] Univ Sao Paulo IAG, Dept Astron Geofis & Ciencias Atmosfer, Sao Paulo - Brazil
[2] Inst Nacl Pesquisas Espaciais MCT, Sao Jose Dos Campos - Brazil
[3] Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey - England
[4] Univ La Laguna, Dept Astrofis, E-38205 Tenerife - Spain
[5] Univ London Univ Coll, Dept Phys & Astron, London WC1E 6BT - England
[6] Inst Astrofis Canarias IAC, E-38200 Tenerife - Spain
[7] INAF Osservatorio Astron Capodimonte, Naples - Italy
Total Affiliations: 7
|
| Document type: | Journal article |
| Source: | Astrophysical Journal Letters; v. 752, n. 2 JUN 20 2012. |
| Web of Science Citations: | 5 |
| Abstract | |
Galaxies are found to obey scaling relations between a number of observables. These relations follow different trends at the low- and high-mass ends. The processes driving the curvature of scaling relations remain uncertain. In this Letter, we focus on the specific family of early-type galaxies, deriving the star formation histories of a complete sample of visually classified galaxies from Sloan Digital Sky Survey DR7 over the redshift range 0.01 < z < 0.025, covering a stellar mass interval from 10(9) to 3 x 10(11) M-circle dot. Our sample features the characteristic ``knee{''} in the surface brightness versus mass distribution at M-star similar to 3 x 10(10)M(circle dot). We find a clear difference between the age and metallicity distributions of the stellar populations above and beyond this knee, which suggests a sudden transition from a constant, highly efficient mode of star formation in high-mass galaxies, gradually decreasing toward the low-mass end of the sample. At fixed mass, our early-type sample is more efficient in building up the stellar content at early times in comparison to the general population of galaxies, with half of the stars already in place by redshift z similar to 2 for all masses. The metallicity-age trend in low-mass galaxies is not compatible with infall of metal-poor gas, suggesting instead an outflow-driven relation. (AU) | |