Extreme Primordial Star Formation Enabled by High-redshift Quasars

Abstract

Abstract High-redshift quasars emit copious X-ray photons that heat the intergalactic medium to temperatures up to ∼106 K. At such high temperatures the primordial gas will not form stars until it is assembled into dark matter halos with masses of up to ∼1011 M ⊙, at which point the hot gas collapses and cools under the influence of gravity. Once this occurs, there is a massive reservoir of primordial gas from which stars can form, potentially setting the stage for the brightest Population (Pop) III starbursts in the early universe. Supporting this scenario, recent observations of quasars at z ∼ 6 have revealed a lack of accompanying Lyα emitting galaxies, consistent with suppression of primordial star formation in halos with masses below ∼1010 M ⊙. Here we model the chemical and thermal evolution of the primordial gas as it collapses into such a massive halo irradiated by a nearby quasar in the run-up to a massive Pop III starburst. We find that, within ∼100 kpc of the highest-redshift quasars discovered to date, the Lyman–Werner flux produced in the quasar host galaxy may be high enough to stimulate the formation of a direct collapse black hole (DCBH). A survey with single pointings of the NIRCam instrument at individually known high-z quasars may be a promising strategy for finding Pop III stars and DCBHs with the James Webb Space Telescope.