Extremely alpha-Enriched Globular Clusters in Early-Type Galaxies: A Step towards the Dawn of Stellar Populations?

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dc.creatorPuzia, Thomas H.
dc.creatorKissler-Patig, Markus
dc.creatorGoudfrooij, Paul
dc.date2006-05-09
dc.date.accessioned2026-07-07T10:38:58Z
dc.date.available2026-07-07T10:38:58Z
dc.descriptionWe compare [alpha/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 [alpha/Fe] values (>0.5) than any clusters in lenticular and spiral galaxies. Most of these extremely alpha-enriched globular clusters are old (t > 8 Gyr) and cover the metallicity range -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_sol) with little contribution from lower-mass stars. The measured [alpha/Fe] ratios are also consistent with yields of very massive pair-instability supernovae (~130-190 M_sol). 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 [alpha/Fe] average ratios of the diffuse stellar population in early-type galaxies, our results suggest that these extremely alpha-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.
dc.description6 pages, 3 figures, accepted for publication in the Astrophysical Journal
dc.identifierhttps://arxiv.org/abs/astro-ph/0605210
dc.identifierhttp://arxiv.org/abs/astro-ph/0605210
dc.identifierAstrophys.J.648:383-388,2006
dc.identifierdoi:10.1086/505679
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/180870
dc.subjectAstrophysics
dc.titleExtremely alpha-Enriched Globular Clusters in Early-Type Galaxies: A Step towards the Dawn of Stellar Populations?
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