JADES Possible Population III signatures at z = 10.6 in the halo of GN-z11

Roberto Maiolino, Hannah Übler, Michele Perna, Jan Scholtz, Francesco D’Eugenio, Callum Witten, Nicolas Laporte, Joris Witstok, Stefano Carniani, Sandro Tacchella, William M. Baker, Santiago Arribas, Kimihiko Nakajima, Daniel J. Eisenstein, Andrew J. Bunker, Stéphane Charlot, Giovanni Cresci, Mirko Curti, Emma Curtis-Lake, Anna de GraaffEiichi Egami, Zhiyuan Ji, Benjamin D. Johnson, Nimisha Kumari, Tobias J. Looser, Michael Maseda, Erica Nelson, Brant Robertson, Bruno Rodríguez Del Pino, Lester Sandles, Charlotte Simmonds, Renske Smit, Fengwu Sun, Giacomo Venturi, Christina C. Williams, Christopher N.A. Willmer

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Finding the first generation of stars formed out of pristine gas in the early Universe, known as Population III (PopIII) stars, is one of the most important goals of modern astrophysics. Recent models have suggested that PopIII stars may form in pockets of pristine gas in the halo of more evolved galaxies. We present NIRSpec integral field spectroscopy and micro-shutter array spectroscopic observations of the region around GNz11, an exceptionally luminous galaxy at z = 10.6, that reveal a greater than 5σ detection of a feature consistent with being HeIIλ1640 emission at the redshift of GN-z11. The very high equivalent width of the putative HeII emission in this clump (log (EWrest(HeII)/Å) = 1.79+001525) and a lack of metal lines can be explained in terms of photoionisation by PopIII stars, while photoionisation by PopII stars is inconsistent with the data. The high equivalent width would also indicate that the putative PopIII stars likely have an initial mass function with an upper cutoff reaching at least 500 M . The PopIII bolometric luminosity inferred from the HeII line would be ∼7 × 109 L , which would imply a total stellar mass formed in the burst of ∼2 × 105 M . We find that photoionisation by the active galactic nucleus (AGN) in GN-z11 cannot account for the HeII luminosity observed in the clump but can potentially be responsible for an additional HeII emission observed closer to GN-z11. We also consider the possibility of in situ photoionisation by an accreting direct collapse black hole hosted by the HeII clump. We find that this scenario is less favoured, but it remains a possible alternative interpretation. We also report the detection of a Lyα halo stemming out of GN-z11 and extending out to ∼2 kpc as well as resolved funnel-shaped CIII emission likely tracing the ionisation cone of the AGN.

Original languageEnglish (US)
Article numberA67
JournalAstronomy and astrophysics
Volume687
DOIs
StatePublished - Jul 1 2024

Keywords

  • dark ages, reionization, first stars
  • galaxies: active
  • galaxies: high-redshift
  • galaxies: individual: GN-z11
  • stars: Population II
  • stars: Population III

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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