2006/05/09 by Thomas H. Puzia, M. Kissler‐Patig, Markus Kissler-Patig +1 · 2 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/505679
published as Astrophys.J.648:383-388,2006 · 6 pages, 3 figures, accepted for publication in the Astrophysical Journal
arxiv created 2006/05/09 · openalex publication_date 2006/08/31 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We compare [α/Fe], metallicity, and age distributions of globular clusters in elliptical, lenticular, and spiral galaxies, which we derive from Lick line index measurements. We find a large number of globular clusters in elliptical galaxies that reach significantly higher [α/Fe] values ([α/Fe] > 0.5) than any clusters in lenticular and spiral galaxies. Most of these extremely α-enriched globular clusters are old ( t > 8 Gyr), and cover the metallicity range Pub Lcl changemark =" ins ">-1 ≲ [ Z /H] ≲ 0. A comparison with supernova yield models suggests that the progenitor gas clouds of these globular clusters must have been predominantly enriched by massive stars (≳20 M ☉ ), with little contribution from lower mass stars. The measured [α/Fe] ratios are also consistent with yields of very massive pair-instability supernovae (~130-190 M ☉ ). Both scenarios imply that the chemical enrichment of the progenitor gas was completed on extremely short timescales of the order of a few Myr. Given the lower [α/Fe] average ratios of the diffuse stellar population in early-type galaxies, our results suggest that these extremely α-enhanced globular clusters could be members of the very first generation of star clusters formed, and that their formation epochs would predate the formation of the majority of stars in giant early-type galaxies.