Looking for Population III stars with He II line intensity mapping

Abstract

Constraining the properties of Population III (Pop III) stars will be very challenging because they reside in small galaxies at high redshift which will be difficult to directly detect. In this paper, we suggest that intensity mapping may be a promising method to study Pop III stars. Intensity mapping is a technique proposed to measure large-scale fluctuations of galaxy line emission in three dimensions without resolving individual sources. This technique is well suited for observing many faint galaxies because it can measure their cumulative emission even if they cannot be directly detected. We focus on intensity mapping of He II recombination lines. These lines are much stronger in Pop III stars than Pop II stars because the harder spectra of Pop III stars are expected to produce many He II ionizing photons. Measuring the He II 1640 Å intensity mapping signal, along with the signals from other lines such as Ly$\alpha$, H$\alpha$, and metal lines, could give constraints on the initial mass function (IMF) and star formation rate density (SFRD) of Pop III stars as a function of redshift. To demonstrate the feasibility of these observations, we estimate the strength of the Pop III He II 1640 Å intensity mapping signal from $z=10-20$. We show that at $z\approx 10$, the signal could be measured accurately by two different hypothetical future instruments, one which cross-correlates He II 1640 Å with CO(1-0) line emission from galaxies and the other with 21 cm emission from the intergalactic medium (IGM).

8 pages, 5 figures, replaced with version accepted by MNRAS

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Cited by in corpus (18)

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• LIMFAST. II. Line Intensity Mapping as a Probe of High-Redshift Galaxy Formation
• LIMFAST. I. A Semi-Numerical Tool for Line Intensity Mapping
• Probing Population III Initial Mass Functions with He II/H$\alpha$ Intensity Mapping
• A Global Semi-Analytic Model of the First Stars and Galaxies Including Dark Matter Halo Merger Histories
• Exploring the Correlation between $\mathrm{H}\alpha$-to-UV Ratio and Burstiness for Typical Star-forming Galaxies at $z\sim 2$
• Strong nebular HeII emission induced by He${}^{+}$ ionizing photons escaping through the clumpy winds of massive stars
• Signatures of reionization feedback in the near-infrared background
• The Hydrogen Mixing Portal, Its Origins, and Its Cosmological Effects
• oLIMpus: An Effective Model for Line Intensity Mapping Auto- and Cross- Power Spectra in Cosmic Dawn and Reionization
• Revealing the formation histories of the first stars with the cosmic near-infrared background
• Constraining the [CII] luminosity function from the power spectrum of line-intensity maps at redshift 3.6
• From Dark Matter Minihalos to Large-Scale Radiative Feedback: A Self-Consistent 3D Simulation of the First Stars and Galaxies using Neural Networks
• Probing the warm dark matter mass with [C II] intensity mapping