{
  "abstract": "We investigate the mass-metallicity relation (MZR) from z=1 to z=9 using electron-temperature-based gas-phase metallicities and examine how auroral-line selection, star-formation history, and secondary abundances affect its interpretation in the early Universe. We compile a homogeneous sample of 286 star-forming galaxies observed with JWST/NIRSpec medium resolution spectroscopy, selected through detections of the [O\\,III]\\,$λ$4363 auroral line from the public DAWN JWST Archive (DJA). We derive electron densities, temperatures, and oxygen abundances using the direct $T_e$ method, along with relative N/O and He/H abundances. Stellar masses are obtained via SED fitting and star-formation rates from reddening-corrected Balmer emission lines. To quantify auroral-line selection biases, we additionally stack galaxy spectra with and without auroral-line detections, extending the MZR into regimes inaccessible to individual measurements. The auroral-line-detected sample spans log(M*/Msun)=6.77-10.5 and 12+log(O/H)=6.9-8.4. A linear fit gives an MZR slope of $γ$=0.38 $\\pm$ 0.09. Stacked galaxies without individual $λ$4363 detections define a relation with a similar slope but metallicities higher by ~0.2-0.3 dex at fixed stellar mass. Auroral-line detections also show higher SFRs, larger equivalent widths, and larger offsets from the fundamental metallicity relation, whereas non-detections appear more chemically evolved and closer to it. Several stacked bins also show enhanced N/O and He/H ratios. These results indicate that the low-mass high-redshift MZR traced by JWST is shaped by both recent star-formation history and auroral-line selection effects. Auroral lines preferentially identify high-EW, high-sSFR galaxies in the low-metallicity envelope, whereas non-detections reveal a more enriched sequence closer to the metallicity expected from the FMR.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2605.05327",
  "author_total": 3,
  "authors": [
    {
      "name": "A. Giménez-Alcázar"
    },
    {
      "name": "R. Amorín"
    },
    {
      "name": "J. M. Vilchez"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2g217jshmkx10.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.05327",
  "fulltext_url": null,
  "id": "2g217jshmkx10",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.05327",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2605.05327",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2g217jshmkx10.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:53Z",
      "native_id": "2605.05327",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.05327"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Shape of the direct-method mass-metallicity relation with JWST: Fast-Track Nitrogen and Helium Enrichment",
  "title_text": "Shape of the direct-method mass-metallicity relation with JWST: Fast-Track Nitrogen and Helium Enrichment",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:53Z",
  "url": "https://research.draconitic.com/paper/2g217jshmkx10",
  "venue": "arXiv",
  "versions": []
}