Conditions for detecting lensed Population III galaxies in blind surveys with the James Webb Space Telescope, the Roman Space Telescope and Euclid

Abstract

Dark matter halos that reach the HI-cooling mass without prior star formation or external metal pollution represent potential sites for the formation of small - extremely faint - Population III galaxies at high redshifts. Gravitational lensing may in rare cases boost their fluxes to detectable levels, but to find even a small number of such objects in randomly selected regions of the sky requires very large areas to be surveyed. Because of this, a small, wide-field telescope can in principle offer better detection prospects than a large telescope with a smaller field of view. Here, we derive the minimum comoving number density required to allow gravitational lensing to lift such objects at redshift $z=5-16$ above the detection thresholds of blind surveys carried out with the James Webb space telescope (JWST), the Roman space telescope (RST) and Euclid. We find that the prospects for photometric detections of Pop III galaxies is promising, and that they are better for RST than for JWST and Euclid. However, the Pop III galaxies favoured by current simulations have number densities too low to allow spectroscopic detections based on the strength of the HeII1640 emission line in any of the considered surveys unless very high star formation efficiencies ($\epsilon >0.1$) are envoked. We argue that targeting individual cluster lenses instead of the wide field surveys considered in this paper results in better spectroscopic detection prospects, while for photometric detection, the wide field surveys perform considerably better.

15 pages, 4 figures

References in corpus (19)

• The Wide Field Infrared Survey Telescope: 100 Hubbles for the 2020s
• The Evolution of Supermassive Population III Stars
• Occurrence of Metal-free Galaxies in the Early Universe
• Strong lensing optical depths in a LCDM universe II: the influence of the stellar mass in galaxies
• Metal-Free Gas Supply at the Edge of Reionization: Late-Epoch Population III Star Formation
• When did Population III star formation end?
• Cradles of the first stars: self-shielding, halo masses, and multiplicity
• Predicting the locations of possible long-lived low-mass first stars: Importance of satellite dwarf galaxies
• Exploring HeII$\lambda$1640 emission line properties at $z\sim 2-4$
• Primordial star clusters at extreme magnification
• The MUSE Hubble Ultra Deep Field Survey. XV. The mean rest-UV spectra of Ly-alpha emitters at z>3
• Following the Cosmic Evolution of Pristine Gas III: The Observational Consequences of the Unknown Properties of Population III Stars
• On the Detection of Supermassive Primordial Stars
• Finding Direct-Collapse Black Holes at Birth
• Boosting Lya and HeII 1640A Line Fluxes from Pop III Galaxies: Stochastic IMF Sampling and Departures from Case-B
• On the Detection of Supermassive Primordial Stars. II. Blue Supergiants
• Upper limits on the mass and luminosity of Population III-dominated galaxies
• Finding bright $z\ge 6.6$ Lyman-$\alpha$ emitters with lensing: prospects for Euclid
• Predicting the Observability of Population III Stars with ELT-HARMONI via the Helium $1640\mathring{\mathrm{A}}$ emission line

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• JWST-JADES. Possible Population III signatures at z=10.6 in the halo of GN-z11
• An extremely metal poor star complex in the reionization era: Approaching Population III stars with JWST
• On the single-event-based identification of primordial black hole mergers at cosmological distances
• The Challenges of Identifying Population III Stars in the Early Universe
• A strong He II $\lambda$1640 emitter with extremely blue UV spectral slope at $z=8.16$: presence of Pop III stars?
• Probing Population III Initial Mass Functions with He II/H$\alpha$ Intensity Mapping
• The most massive Population III stars
• A hide-and-seek game: Looking for Population III stars during the Epoch of Reionization through the HeII$\lambda$1640 line
• Dark Freeze-out Cogenesis
• A Global Semi-Analytic Model of the First Stars and Galaxies Including Dark Matter Halo Merger Histories
• Detecting Population III Stars through Tidal Disruption Events in the Era of JWST and Roman
• Detectability of Supermassive Dark Stars with the Roman Space Telescope
• Searching for globular clusters in the inner halo of the Circinus galaxy
• Effects of chemically homogeneous evolution of the first stars on the 21-cm signal and reionization
• Radiation magnetohydrodynamics simulations of Population III star formation during the Epoch of Reionization
• Constraining high-redshift stellar-mass primordial black holes with next-generation ground-based gravitational-wave detectors
• Finding lensed direct-collapse black holes and supermassive primordial stars
• Source Confusion of Massive Black Hole Binaries for the Taiji Mission