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CRA Cosmic Coffee: Danielle Skinner
April 10, 2019 @ 3:00 pm - 4:00 pm
Title: Where Do Population III Stars Form?
Abstract: We perform a cosmological simulation with a comoving volume of 1 Mpc^3 to study the birth-places of Population III stars, using the adaptive mesh refinement code Enzo. We investigate the distribution of host halo masses and its relationship to the Lyman-Werner background intensity. In our sample of 688 host halos, we find that 84% of them have masses below the Machacek et al. (2001) relation because of the inclusion of H2 self-shielding. In our simulation above a redshift of 11.5, the mean halo mass is time-independent and 10^5.9 M⊙. Afterwards, it steadily rises above the Machacek et al. relation to a mean value of 10^6.6 M⊙. Most of these halos form multiple Population III stars, with a median number of four, up to a maximum of 16. We also find that a few halos do form stars below the Machacek et al. relation but in a high Lyman-Werner radiation field with values up to 50 J21. Our results suggest that Population III star formation may be less affected by Lyman-Werner radiation feedback than previously thought and that Population III multiple systems are common.