2007/10/05 by Sugata Kaviraj, S. Kaviraj · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1142/s021773230802608x
published as Mod.Phys.Lett.A23:153-167,2008 · Brief Review, Mod. Phys. Lett. A
arxiv created 2007/10/05 · openalex publication_date 2008/01/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Our current understanding of the star formation histories of early-type galaxies is reviewed, in the context of recent observational studies of their ultraviolet (UV) properties. Combination of UV and optical spectro-photometric data indicates that the bulk of the stellar mass in the early-type population forms at high redshift (z>2), possibly over short timescales (<1 Gyr). Nevertheless, early-types of all luminosities form stars over the lifetime of the Universe, with most luminous (-23<M(V)<-21) systems forming 10–15% of their stellar mass after z = 1 (with a scatter to higher value), while their less luminous (M(V)>-21) counterparts form 30–60% of their mass in the same redshift range. The large scatter in the (rest-frame) UV colours in the redshift range 0<z<0.7 indicates widespread low-level star formation in the early-type population over the last 8 billion years. The mass fraction of young (<1 Gyr old) stars in luminous early-type galaxies varies between 1% and 6% at z ~ 0 and is in the range 5–13% at z ~ 0.7. The intensity of recent star formation and the bulk of the UV colour distribution is consistent with what might be expected from minor mergers (mass ratios ≲ 1:6) in a ΛCDM cosmology.