Massive Population III Galaxies Near a GN-z11 Analog: The Role of the Baryon-Dark Matter Streaming Velocity
Abstract
Recently the James Webb Space Telescope (JWST) detected Hebe, a Population III (Pop III) candidate located ∼3 kpc in projection from the massive z=10.6 galaxy GN-z11. This raises the question of whether Pop III star formation is expected in the vicinity of massive high-redshift galaxies or whether it would be prevented by early metal enrichment. We address this with a semi-analytic model of Pop III and metal-enriched star formation applied to a zoom-in N-body simulation of a highly overdense region surrounding a GN-z11 analog. The zoom-in region resolves the minihalos where the first stars form. We find that Pop III and metal-enriched star formation both occur earlier, and with a higher star formation rate density, than in a typical mean-density environment. The majority of Pop III star formation in minihalos ends by z∼15; however, we identify a distinct population of late-forming Pop III galaxies that form near the central galaxy. These systems have their star formation delayed due to ionizing feedback from the central GN-z11 analog and experience a Lyman-Werner (LW) intensity of ∼10 - 100 J21, potentially leading to massive Pop III starbursts similar to Hebe. Interestingly, the abundance of these Pop III galaxies depends strongly on the baryon-dark matter streaming velocity, vbc, because a higher streaming velocity allows halos to remain chemically pristine for longer. None of these late-forming Pop III sources occur for vbc=0, while many form at high vbc. Averaging over the expected distribution of streaming velocities, we predict that of order four GN-z11-like galaxies would need to be surveyed at z∼11 to expect to find one such source. We also note these environments may provide a natural formation site for heavy black hole seeds.
Related
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BibTeX
@misc{visbal2026massive,
title = {{Massive Population III Galaxies Near a GN-z11 Analog: The Role of the Baryon-Dark Matter Streaming Velocity}},
author = {Eli Visbal and Greg L. Bryan and Ryan Hazlett},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.35941},
eprint = {2609.35941},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.35941},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Massive Population III Galaxies Near a GN-z11 Analog: The Role of the Baryon-Dark Matter Streaming Velocity
AU - Eli Visbal
AU - Greg L. Bryan
AU - Ryan Hazlett
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.35941
UR - https://arxiv.org/abs/2609.35941
AB - Recently the James Webb Space Telescope (JWST) detected Hebe, a Population III (Pop III) candidate located ∼3 kpc in projection from the massive z=10.6 galaxy GN-z11. This raises the question of whether Pop III star formation is expected in the vicinity of massive high-redshift galaxies or whether it would be prevented by early metal enrichment. We address this with a semi-analytic model of Pop III and metal-enriched star formation applied to a zoom-in N-body simulation of a highly overdense region surrounding a GN-z11 analog. The zoom-in region resolves the minihalos where the first stars form. We find that Pop III and metal-enriched star formation both occur earlier, and with a higher star formation rate density, than in a typical mean-density environment. The majority of Pop III star formation in minihalos ends by z∼15; however, we identify a distinct population of late-forming Pop III galaxies that form near the central galaxy. These systems have their star formation delayed due to ionizing feedback from the central GN-z11 analog and experience a Lyman-Werner (LW) intensity of ∼10 - 100 J_21, potentially leading to massive Pop III starbursts similar to Hebe. Interestingly, the abundance of these Pop III galaxies depends strongly on the baryon-dark matter streaming velocity, v_bc, because a higher streaming velocity allows halos to remain chemically pristine for longer. None of these late-forming Pop III sources occur for v_bc=0, while many form at high v_bc. Averaging over the expected distribution of streaming velocities, we predict that of order four GN-z11-like galaxies would need to be surveyed at z∼11 to expect to find one such source. We also note these environments may provide a natural formation site for heavy black hole seeds.
ER -