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Paper: A Guide for Primordial Star Hunters
Volume: 379, Cosmic Frontiers
Page: 314
Authors: Martel, H.; Brook, C.; Kawata, D.; Gibson, B.; Scannapieco, E.
Abstract: We use cosmological, chemodynamical, SPH simulations of Milky-Way-analogue galaxies to find the expected present-day distributions of both the metal-free stars that formed from primordial gas and the oldest stars. We find that metal-free stars continue to form until z ∼ 3 in halos that are chemically isolated and located far away from the biggest progenitor of the final system. As a result, at z = 0 they are distributed throughout the Galactic halo. On the other hand, the oldest stars form in halos that collapsed close to the highest density peak of the final system, and at z = 0 they are located preferentially in the central region of the Galaxy, i.e., in the bulge. We conclude that surveys of low-metallicity stars in the Galactic halo can be used to directly constrain the properties of primordial stars. In particular, we suggest that the current lack of detections of metal-free stars implies that their lifetimes were shorter than a Hubble time, placing constraints on the metal-free initial mass function.
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