2026/01/31 by A Ferrara, Stefano Carniani, Takahiro Morishita +1 · 1 voice
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae
paper · doi:10.33232/001c.162107
openalex publication_date 2026/05/13 · openalex created_date 2026/05/14 · openalex updated_date 2026/07/28
Recent JWST observations have revealed a population of unexpectedly bright sources at ultra-high redshift ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>></mml:mo> <mml:mn>15</mml:mn> </mml:mrow> </mml:math> ), challenging current models of early galaxy formation. One extreme example is , an F356W-dropout identified in the CEERS survey and initially interpreted as a luminous galaxy at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>∼</mml:mo> <mml:mn>30</mml:mn> </mml:mrow> </mml:math> , but subsequently found to be variable over an <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mo>∼</mml:mo> <mml:mn>800</mml:mn> </mml:mrow> </mml:math> day baseline. Motivated by this variability, we explore the alternative hypothesis that is a pair-instability supernova (PISN) originating from a massive ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mo>∼</mml:mo> <mml:mn>250</mml:mn> </mml:mrow> </mml:math> – <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mn>260</mml:mn> <mml:mspace width="0.167em"/> <mml:msub> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:msub> </mml:mrow> </mml:math> ), metal-free star. Using state-of-the-art PISN light curves, spectral energy distributions, and synthetic spectra, we show that a PISN at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>≃</mml:mo> <mml:mn>15</mml:mn> </mml:mrow> </mml:math> can plausibly reproduce the observed brightness, temporal evolution, photometry, and NIRSpec spectrum. We compare this scenario with alternative interpretations, including a local Y0 brown dwarf, and discuss observational tests to discriminate among them. If confirmed, this event would provide a rare window onto Population~III stars, and highlights the importance of transient contamination in ultra-high redshift galaxy samples.