{
  "abstract": "Whether the unusually strong nitrogen emission in nitrogen-loud (N-loud) quasars reflects high overall metallicity, enhanced nitrogen abundance relative to other elements, or both has long been debated. We analyze the broad-line region (BLR) abundances of 121 N-loud quasars at $2.13 \\leq z \\leq 3.90$ selected from the Dark Energy Spectroscopic Instrument Data Release 1 and construct a control sample of normal quasars matched in redshift, continuum luminosity, and virial black hole mass. Within the N-loud sample, metallicities inferred from N V/C IV span $\\sim 3$-$50\\,Z_\\odot$ and are systematically higher than those inferred from the nitrogen-independent (Si IV+O IV])/C IV and Al III/C IV diagnostics, which agree closely and mainly span $\\sim 1$-$20\\,Z_\\odot$. Compared with the matched controls, the N-loud quasars show systematically higher metallicities in both N V/C IV and (Si IV+O IV])/C IV, with median values approximately three times those of the controls. Notably, the discrepancy between the metallicities inferred from N V/C IV and (Si IV+O IV])/C IV becomes more pronounced toward the high-metallicity end of the N-loud sample, suggesting additional nitrogen enrichment beyond the overall metal enrichment. Together, these results indicate that N-loud quasars have both high overall BLR metallicity and enhanced relative nitrogen abundance, suggesting that relative nitrogen abundance is at least partially decoupled from overall metallicity. N-loud quasars therefore provide a high-metallicity laboratory for understanding how nuclear environments can produce unusual abundance patterns and offer a complementary view of how nitrogen enrichment arises across cosmic time.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.14460",
  "author_total": 6,
  "authors": [
    {
      "name": "Shuo Zhai"
    },
    {
      "name": "Wei-jian Guo"
    },
    {
      "name": "Yong-Jie Chen"
    },
    {
      "name": "Haining Li"
    },
    {
      "name": "Jian-Min Wang"
    },
    {
      "name": "Gang Zhao"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3njme0kxd22s0.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.14460",
  "fulltext_url": null,
  "id": "3njme0kxd22s0",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.14460",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.14460",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-13",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3njme0kxd22s0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:25Z",
      "native_id": "2609.14460",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.14460"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Nitrogen-Loud Quasars from the Dark Energy Spectroscopic Instrument. II. Broad-Line Region Metallicity and Relative Nitrogen Enrichment",
  "title_text": "Nitrogen-Loud Quasars from the Dark Energy Spectroscopic Instrument. II. Broad-Line Region Metallicity and Relative Nitrogen Enrichment",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:25Z",
  "url": "https://research.draconitic.com/paper/3njme0kxd22s0",
  "venue": "arXiv",
  "versions": []
}