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Caught Napping by JWST UNCOVER+MegaScience: Constraining bursty star formation histories and number densities of mini-quenched galaxies at redshifts 4-7 — arXiv:2608.30011

Source: arXiv (en)
Original: https://arxiv.org/abs/2608.30011
License (as archived): CC0-1.0
Archived: 2026-10-17T10:32:24.746Z
SHA-256 of the archived text: 7163645758ca2ed2154ca5d404750e5681f1ceab6a62ac277d9b254a2361e81b
Stable URL of this page: https://metraipolis.com/documento/dc_4635c9faeff6

How to cite

Caught Napping by JWST UNCOVER+MegaScience: Constraining bursty star formation histories and number densities of mini-quenched galaxies at redshifts 4-7 — arXiv:2608.30011 — arXiv (en), https://arxiv.org/abs/2608.30011 (CC0-1.0); archived copy: https://metraipolis.com/documento/dc_4635c9faeff6 (Metraipolis archive dc_4635c9faeff6, sha256 7163645758ca2ed2154ca5d404750e5681f1ceab6a62ac277d9b254a2361e81b)

BibTeX

@misc{dc4635c9faeff6,
  title = {Caught Napping by JWST UNCOVER+MegaScience: Constraining bursty star formation histories and number densities of mini-quenched galaxies at redshifts 4-7 — arXiv:2608.30011},
  howpublished = {arXiv (en)},
  url = {https://arxiv.org/abs/2608.30011},
  note = {License CC0-1.0; archived copy https://metraipolis.com/documento/dc_4635c9faeff6; sha256 7163645758ca2ed2154ca5d404750e5681f1ceab6a62ac277d9b254a2361e81b},
  year = {2026}
}

Archived text

Reproduced under CC0-1.0. Attribution: arXiv (en), https://arxiv.org/abs/2608.30011. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

We explore the prevalence of mini-quenched or ``napping'' galaxies selected from spectroscopic and photometric samples in the UNCOVER/MegaScience survey. These galaxies are empirically identified by the presence of moderate Balmer breaks, weak emission lines ($EW(H\alpha) < 100$A) and relatively blue UV continua. We infer the star formation histories (SFHs) of our sample using flexible non-parametric models with Prospector optimized to capture recent episodes of bursty star formation and quenching, and find that they are uniquely identifiable in the SFR$_{10}$/SFR$_{100}$ parameter space moving towards (temporary) quiescence. We demonstrate that although spectroscopy is best able to identify rapidly declining SFRs, densely sampled medium-band photometry recover these key spectral features and thus robustly identify pure samples of this transient phase -- with imaging alone. We quantify the number density of napping galaxies at $z=4-7$ in the Abell 2744 lensing field, finding 8 spectroscopically confirmed nappers and 60 photometric candidates spanning log$_{10}$(M$_*$/M$_\odot$) $= 7.5-10$. We verify that the photometry alone can identify a pure sample of nappers, leveraging a smaller high signal-to-noise ratio spectroscopic sample. Consistent with previous studies, we find that nappers are most common at low stellar mass (log$_{10}$(M$_*$/M$_\odot$) $\sim9$). We see a hint that the number densities increase from $z\sim6$ to $z\sim4$, though our small sample is likely affected by cosmic variance. Our study demonstrates the increasing importance of stochastic star formation as a regulator of low-mass galaxy growth in the several hundred Myr after reionization, and offers a direct observational testbed for the strength and duty cycle of stellar feedback in cosmological simulations.

Tema degli esploratori: fisica e astronomia (retro-catalogo arXiv: annunci del 2026-09-01 in astro-ph.IM).
Categorie arXiv: Astrophysics of Galaxies (astro-ph.GA) ; Instrumentation and Methods for Astrophysics (astro-ph.IM).
Pagina del lavoro: https://arxiv.org/abs/2608.30011 — autori e testo completo sono lì (qui omessi i nomi: nessun dato personale nel deposito).
Licenza: titolo e abstract sono metadati arXiv distribuiti in CC0 1.0; il testo completo ha la licenza scelta dagli autori, indicata sulla pagina.
Letto il 2026-10-17T10:18:17.141Z dalla pagina https://arxiv.org/catchup/astro-ph.IM/2026-09-01?abs=True (consentita dal robots.txt di arxiv.org, con il suo crawl-delay).