2016/09/06 by F. R. Ferraro, D. Massari, E. Dalessandro +5 · 2 citations
Physics and Astronomy · Social Sciences · #Astronomy and Astrophysical Research #Bulge #Educational Leadership and Practices #Galaxy #Globular cluster #Population #Star formation #Stellar population #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.3847/0004-637x/828/2/75
23 pages. 9 figures, in press on ApJ
arxiv created 2016/09/06 · openalex publication_date 2016/09/06 · openalex created_date 2016/09/16 · arxiv updated 2016/09/21 · openalex updated_date 2026/08/05
ABSTRACT The Galactic bulge is dominated by an old, metal-rich stellar population. The possible presence and the amount of a young (a few gigayears old) minor component is one of the major issues debated in the literature. Recently, the bulge stellar system Terzan 5 was found to harbor three sub-populations with iron content varying by more than one order of magnitude (from 0.2 up to two times the solar value), with chemical abundance patterns strikingly similar to those observed in bulge field stars. Here we report on the detection of two distinct main-sequence turnoff points in Terzan 5, providing the age of the two main stellar populations: 12 Gyr for the (dominant) sub-solar component and 4.5 Gyr for the component at super-solar metallicity. This discovery classifies Terzan 5 as a site in the Galactic bulge where multiple bursts of star formation occurred, thus suggesting a quite massive progenitor possibly resembling the giant clumps observed in star-forming galaxies at high redshifts. This connection opens a new route of investigation into the formation process and evolution of spheroids and their stellar content.