{
  "abstract": "Dark matter sets the gravitational environment in which galaxies form and evolve, but cannot be observed directly. We present a conditional diffusion model that reconstructs the projected dark matter density field from the galaxy stellar-mass density field for direct application to galaxy surveys. The model is trained on CAMELS and validated on the independent IllustrisTNG300-1 simulation. Halo masses inferred from the reconstructed projected-aperture measurements agree well with the corresponding true values, with a scatter below 0.2 dex. On 100 kpc scales, reconstructed surface densities show a typical scatter of ~0.3 dex in the regime most relevant for observations. We apply the model to SDSS galaxies with $M_\\star\\ge10^9\\,M_\\odot$ in a contiguous low-redshift region. Averaging over 100 stochastic realizations, we reconstruct and publicly release a projected dark matter field covering $90\\times90\\,(h^{-1}\\mathrm{Mpc})^2$ with a pixel size of $0.097\\,h^{-1}\\mathrm{Mpc}$. This pixel area corresponds to the characteristic projected area of halos with masses of ~$10^{10.6}\\,h^{-1}\\,M_\\odot$. The map reveals the multiscale projected cosmic web, including cluster-scale overdensities, filaments and voids. Projected-aperture masses are statistically consistent with SDSS group-catalog masses, while the derived halo mass function broadly matches mock-catalog expectations. The reconstructed projected potential places Coma in one of the deepest wells and near a convergence region of the inferred projected acceleration field, suggesting that the reconstruction retains both local overdensities and coherent large-scale projected gravitational structure. This work shows that diffusion-based dark matter reconstruction can be applied to real galaxy surveys, enabling halo-mass- and spatially resolved dark-matter-environment-based studies of galaxy evolution in SDSS and future wide-area surveys.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.19295",
  "author_total": 19,
  "authors": [
    {
      "name": "Kunyao Zhao"
    },
    {
      "name": "Yingjie Peng"
    },
    {
      "name": "Dingyi Zhao"
    },
    {
      "name": "Xiaohu Yang"
    },
    {
      "name": "Luis C. Ho"
    },
    {
      "name": "Kai Wang"
    },
    {
      "name": "Jing Dou"
    },
    {
      "name": "Zeyu Gao"
    },
    {
      "name": "Qiusheng Gu"
    },
    {
      "name": "Yukun Liu"
    },
    {
      "name": "Roberto Maiolino"
    },
    {
      "name": "Houjun Mo"
    },
    {
      "name": "Alvio Renzini"
    },
    {
      "name": "Canpo Su"
    },
    {
      "name": "Bitao Wang"
    },
    {
      "name": "Yu-Chen Wang"
    },
    {
      "name": "Bingxiao Xu"
    },
    {
      "name": "Feng Yuan"
    },
    {
      "name": "Xingye Zhu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9qm7d6rn4q1t9.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.19295",
  "fulltext_url": null,
  "id": "9qm7d6rn4q1t9",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.19295",
  "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": "W7213613135",
  "pdf_url": "https://arxiv.org/pdf/2609.19295",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-16",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9qm7d6rn4q1t9.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:19Z",
      "native_id": "2609.19295",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.19295"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Reconstructing the Projected Dark Matter Field across 0.1-100 Mpc Scales from the SDSS Survey",
  "title_text": "Reconstructing the Projected Dark Matter Field across 0.1-100 Mpc Scales from the SDSS Survey",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:19Z",
  "url": "https://research.draconitic.com/paper/9qm7d6rn4q1t9",
  "venue": "arXiv",
  "versions": []
}