1998/09/21 by D. Thomas, L. Greggio, R. Bender · 4 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Galaxy merger #Gamma-ray bursts and supernovae #Initial mass function #Metallicity #Nucleosynthesis #Physics #Protogalaxy #Star formation #Stars #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.1999.02138.x
published as Mon.Not.Roy.Astron.Soc.302:537,1999 · Accepted for publication in MNRAS, LaTex 2.09 with mn.sty, 13 pages, 5 figures
arxiv created 1998/09/21 · openalex publication_date 1999/01/21 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We explore the formation of α-enhanced and metal-rich stellar populations in the nuclei of luminous ellipticals under the assumption of two extreme galaxy formation scenarios based on hierarchical clustering, namely a fast clumpy collapse and the merger of two spirals. We investigate the parameter space of the star formation time-scale, the slope of the initial mass function (IMF) and stellar yields. In particular, the latter add a huge uncertainty in constraining time-scales and IMF slopes. We find that—for Thielemann, Nomoto & Hashimoto nucleosynthesis—in a fast clumpy collapse scenario an [α/Fe] overabundance of ∼ 0.2 dex in the high-metallicity stars can be achieved with a Salpeter IMF and star formation time-scales of the order 109 yr. The scenario of two merging spirals that are similar to our Galaxy, instead, fails to reproduce the α-enhanced abundance ratios in the metal-rich stars, unless the IMF is flattened during the burst ignited by the merger. This result is independent of the burst time-scale. We suggest that abundance gradients give hints to distinguish between the two extreme formation scenarios considered in this paper.