THE DOMINANT EPOCH OF STAR FORMATION IN THE MILKY WAY FORMED THE THICK DISK
- Observatoire de Paris, GEPI, CNRS, Université Paris Diderot, 5 Place Jules Janssen, F-92190 Meudon (France)
- Institut d'Astrophysique de Paris, UMR 7095, CNRS, Université Pierre et Marie Curie, 98 bis Bd Arago, F-75005 Paris (France)
- Observatoire de Paris, LERMA, CNRS, 61 Avenue de l'Observatoire, F-75014 Paris (France)
We report the first robust measurement of the Milky Way star formation history using the imprint left on chemical abundances of long-lived stars. The formation of the Galactic thick disk occurs during an intense star formation phase between 9.0 (z ∼ 1.5) and 12.5 Gyr (z ∼ 4.5) ago and is followed by a dip (at z ∼ 1.1) lasting about 1 Gyr. Our results imply that the thick disk is as massive as the Milky Way's thin disk, suggesting a fundamental role of this component in the genesis of our Galaxy, something that had been largely unrecognized. This new picture implies that huge quantities of gas necessary to feed the building of the thick disk must have been present at these epochs, in contradiction with the long-term infall assumed by chemical evolution models in the last two decades. These results allow us to fit the Milky Way within the emerging features of the evolution of disk galaxies in the early universe.
- OSTI ID:
- 22364015
- Journal Information:
- Astrophysical Journal Letters, Vol. 781, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
DISSIPATIONLESS FORMATION AND EVOLUTION OF THE MILKY WAY NUCLEAR STAR CLUSTER
A spectroscopic study of the ancient milky way: f- and g-type stars in the third data release of the sloan digital sky survey