Journal article

THE RELATIVE AND ABSOLUTE AGES OF OLD GLOBULAR CLUSTERS IN THE LCDM FRAMEWORK

Michele Trenti, Paolo Padoan, Raul Jimenez

ASTROPHYSICAL JOURNAL LETTERS | IOP PUBLISHING LTD | Published : 2015

Abstract

Old globular clusters (GCs) in the Milky Way have ages of about 13 Gyr, placing their formation time in the reionization epoch. We propose a novel scenario for the formation of these systems based on the merger of two or more atomic cooling halos at high redshift (z > 6). First-generation stars are formed as an intense burst in the center of a minihalo that grows above the threshold for hydrogen cooling (halo mass ∼Mh 10 8M⊙ ) by undergoing a major merger within its cooling timescale (∼150 Myr). Subsequent minor mergers and sustained gas infall bring a new supply of pristine gas to the halo center, creating conditions that can trigger new episodes of star formation. The dark-matter halo arou..

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University of Melbourne Researchers