Potential signature of Population III pair-instability supernova ejecta in the BLR gas of the most distant quasar at z = 7.54

Abstract

The search for Population III (Pop III) stars has fascinated and eluded astrophysicists for decades. One promising place for capturing evidence of their presence must be high-redshift objects; signatures should be recorded in their characteristic chemical abundances. We deduce the Fe and Mg abundances of the broad-line region (BLR) from the intensities of ultraviolet Mg II and Fe II emission lines in the near-infrared spectrum of UKIDSS Large Area Survey (ULAS) J1342+0928 at $z=7.54$, by advancing our novel flux-to-abundance conversion method developed for $z\sim 1$ quasars. We find that the BLR of this quasar is extremely enriched, by a factor of 20 relative to the solar Fe abundance, together with a very low Mg/Fe abundance ratio: $[Fe/H]=+1.36\pm 0.19$ and $[Mg/Fe]=-1.11\pm 0.12$, only 700 million years after the Big Bang. We conclude that such an unusual abundance feature cannot be explained by the standard view of chemical evolution that considers only the contributions from canonical supernovae. While there remains uncertainty in the high-mass end of the Pop III IMF, here we propose that the larger amount of iron in ULAS J1342+0928 was supplied by a pair-instability supernova (PISN) caused by the explosion of a massive Pop III star in the high-mass end of the possible range of 150-300 $M_{\odot }$. Chemical-evolution models based on initial PISN enrichment well explain the trend in [Fe/Mg]-$z$ all the way from $z<3$ to $z=7.54$. We predict that stars with very low [Mg/Fe] at all metallicities are hidden in the Galaxy, and they will be efficiently discovered by ongoing new-generation photometric surveys.

17 pages, 4 figures, 3 tables. Accepted for publication in ApJ

References in corpus (22)

• A Catalog of Quasar Properties from SDSS DR7
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• Nucleosynthetic signatures of the first stars
• A Luminous Quasar at Redshift 7.642
• Primordial Star Formation under the Influence of Far Ultraviolet Radiation: 1540 Cosmological Halos and the Stellar Mass Distribution
• Physical properties of 15 quasars at $z\gtrsim 6.5$
• The Mass Spectrum of the First Stars
• The Landscape of the Neutrino Mechanism of Core-Collapse Supernovae: Neutron Star and Black Hole Mass Functions, Explosion Energies and Nickel Yields
• Fe II Emission in 14 Low-Redshift Quasars: I - Observations
• Ionized outflows from active galactic nuclei as the essential elements of feedback
• How the First Stars Regulated Local Star Formation I: Radiative Feedback
• Explosion and nucleosynthesis of low redshift pair instability supernovae
• No Redshift Evolution in the Broad Line Region Metallicity up to z=7.54: Deep NIR Spectroscopy of ULAS J1342+0928
• Delay Time Distributions of Type Ia Supernovae From Galaxy and Cosmic Star Formation Histories
• Following the Cosmic Evolution of Pristine Gas III: The Observational Consequences of the Unknown Properties of Population III Stars
• The FeII/MgII flux ratio of low-luminosity quasars at z~3
• The Origin and Evolution of \civ Baldwin Effect in QSOs from the Sloan Digital Sky Survey
• Chemical evolution of the Universe at 0.7 < z < 1.6 derived from abundance diagnostics of the broad-line region of quasars
• Origin of metals in old Milky Way halo stars based on GALAH and Gaia
• Mg II and Fe II fluxes of luminous quasars at z ~ 2.7 and evaluation of the Baldwin effect in the flux-to-abundance conversion method for quasars
• The full evolution of supernova remnants in low and high density ambient media
• Effect of interstellar objects on metallicity of low-mass first stars formed in a cosmological model

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• A needle in a haystack? Catching Pop III stars in the Epoch of Reionization: I. Pop III star forming environments
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• Evolution and explosions of metal enriched supermassive stars: proton rich general relativistic instability supernovae
• On the Contribution of Very Massive Stars to the Sulfur Abundance in Star-Forming Galaxies: the Role of PISN
• Ultraviolet photon production rates of the first stars: Impact on the He II $\lambda$ 1640 Å emission line from primordial star clusters and the 21-cm signal from cosmic dawn
• Studying The Effect of Radiation Pressure on Evolution of a Population III Stellar Cluster
• Radiative feedback on supermassive star formation: the massive end of the Population III initial mass function