Predicting the Observability of Population III Stars with ELT-HARMONI via the Helium $1640\mathring{\mathrm{A}}$ emission line

Abstract

Population III (Pop. III) stars, as of yet, have not been detected, however as we move into the era of extremely large telescopes this is likely to change. One likely tracer for Pop. III stars is the HeII$\lambda 1640$ emission line, which will be detectable by the HARMONI spectrograph on the European Extremely Large Telescope (ELT) over a broad range of redshifts ($2\le z\le 14$). By post-processing galaxies from the cosmological, AMR-hydrodynamical simulation NewHorizon with theoretical spectral energy distributions (SED) for Pop. III stars and radiative transfer (i.e. the Yggdrasil Models and CLOUDY look-up tables respectively) we are able to compute the flux of HeII$\lambda 1640$ for individual galaxies. From mock 10 hour observations of these galaxies we show that HARMONI will be able to detect Pop. III stars in galaxies up to $z\sim 10$ provided Pop. III stars have a top heavy Initial Mass Function (IMF). Furthermore, we find that should Pop. III stars instead have an IMF similar to those of the Pop. I stars, the HeII$\lambda 1640$ line would only be observable for galaxies with Pop. III stellar masses in excess of $10^7{M}_{\odot }{\mathrm{yr}}^{-1}$, average stellar age $<1\mathrm{Myr}$ at $z=4$. Finally, we are able to determine the minimal intrinsic flux required for HARMONI to detect Pop. III stars in a galaxy up to $z=10$.

23 Pages, 17 Figures, Accepted for publication in Monthly Notices of the Royal Astronomical Society

References in corpus (20)

• The MAPPINGS III Library of Fast Radiative Shock Models
• Formation of Supermassive Black Holes by Direct Collapse in Pregalactic Halos
• Lyman Alpha Emitting Galaxies as a Probe of Reionization
• Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionisation
• Star formation at very low metallicity. I: Chemistry and cooling at low densities
• An Optical Catalog of Galaxy Clusters Obtained from an Adaptive Matched Filter Finder Applied to SDSS DR6
• VLA and ALMA Imaging of Intense, Galaxy-Wide Star Formation in z ~ 2 Galaxies
• Lyman alpha Resonant Scattering in Young Galaxies - Predictions from Cosmological Simulations
• Luminosity Functions of Lyman Alpha Emitting Galaxies and Cosmic Reionization of Hydrogen
• Significant primordial star formation at redshifts z ~ 3-4
• Secondary Star Formation in a Population III Object
• A photometric survey for Lyalpha-HeII dual emitters: Searching for Population III stars in high-redshift galaxies
• Black hole evolution: II. Spinning black holes in a supernova-driven turbulent interstellar medium
• Metal enriched gaseous halos around distant radio galaxies: Clues to feedback in galaxy formation
• Very Massive Stars in High-Redshift Galaxies
• On the Observed Diversity of Star Formation Efficiencies in Giant Molecular Clouds
• Constraining Lyman-alpha spatial offsets at $3<z<5.5$ from VANDELS slit spectroscopy
• Radiative Regulation of Population III Star Formation
• Boosting Lya and HeII 1640A Line Fluxes from Pop III Galaxies: Stochastic IMF Sampling and Departures from Case-B
• Simulating gas kinematic studies of high-redshift galaxies with the HARMONI Integral Field Spectrograph

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• Effects of chemically homogeneous evolution of the first stars on the 21-cm signal and reionization
• On the Viability of Determining Galaxy Properties from Observations I: Star Formation Rates and Kinematics
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