{
  "abstract": "Some high-redshift overdensities show an enhanced incidence of AGNs, suggesting that large-scale environment may influence supermassive black hole fuelling and triggering. Whether environment also affects AGN variability remains unclear. Using the Cosmic Himalayas (CH), an extreme concentration of 11 type 1 quasars at z=2.16-2.20, we investigate possible offsets in rest-frame ultraviolet variability relative to quasars with comparable redshifts, black hole masses, and Eddington ratios. We construct a parent sample of 1,138 Stripe 82 quasars at 2.11<=z<=2.25 and combine photometry from the SDSS, the PS1, and the ZTF to build observer-frame g- and r-band light curves spanning up to 27~yr. We compare DRW parameters and ensemble structure functions (SFs) with control pseudo-samples matched in black hole mass and Eddington ratio, and use injection--recovery simulations to forecast the detectability of a CH-like offset. The CH quasars show a tendency toward shorter DRW damping timescales (median offsets of -0.32 and -0.13 dex in g and r) and slightly higher asymptotic amplitudes. None of the four DRW comparisons is statistically significant, including the largest offset in the g-band damping timescale (p=0.16). Ensemble SFs generally exceed matched-control medians, although 18 of 19 lag bins per band remain within the 95% pointwise envelopes. Assuming a true uniform -0.32 dex g-band timescale offset, injection--recovery simulations predict an 80% probability of nominal 3sigma detection with approximately 60 quasars of comparable variability scatter and data quality. If confirmed, the tentative variability offsets may suggest that large-scale environment influences accretion-flow variability beyond its potential role in quasar triggering. Larger samples with higher-precision light curves, such as those expected from the LSST, are required to test this possibility.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.30570",
  "author_total": 5,
  "authors": [
    {
      "name": "Jiaqi Lin"
    },
    {
      "name": "Zhenya Zheng"
    },
    {
      "name": "Bin Ma"
    },
    {
      "name": "Yongming Liang"
    },
    {
      "name": "Lin Long"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5ecv68cgqp07m.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.30570",
  "fulltext_url": null,
  "id": "5ecv68cgqp07m",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.30570",
  "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",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7223367636",
  "pdf_url": "https://arxiv.org/pdf/2610.30570",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5ecv68cgqp07m.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:35Z",
      "native_id": "2610.30570",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.30570"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Rest-frame Ultraviolet Variability of Quasars in the Cosmic Himalayas Overdensity",
  "title_text": "Rest-frame Ultraviolet Variability of Quasars in the Cosmic Himalayas Overdensity",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:35Z",
  "url": "https://research.draconitic.com/paper/5ecv68cgqp07m",
  "venue": "arXiv",
  "versions": []
}