{
  "abstract": "The cosmic chronometer (CC) method provides a direct measurement of the expansion history of the universe, $H(z)$, from the differential ages of passively evolving galaxies. However, most CC analyses rely on high-quality spectroscopy to select passive galaxies, measure age-sensitive spectral features, and control stellar-population systematics. We build on existing works that use the D4000 spectral break as a proxy for measuring galaxy ages and apply it to a photometry-selected galaxy sample from VIPERS PDR2 in the range $0.5 \\le z \\le 0.8$. Our goal is to extend the scope of the standard CC framework to photometric surveys. To achieve this, we first selected a massive and passive galaxy sample using rest-frame colors and mass. Second, we designed a Bayesian framework to infer full galaxy age posteriors in fine redshift bins, using a D4000-age-metallicity grid from stellar population synthesis models. We marginalized over metallicity, using a Gaussian metallicity prior to break the D4000-age-metallicity degeneracy. Subsequently, we derived age-difference posteriors between redshift bins by convolving their age posteriors. Finally, using the median and errors extracted from the differential age posteriors, we calculated the weighted average $H(z)$ over our selected redshift range. We obtain $H(z=0.65)=93.68\\pm28.27\\,{\\rm (stat.)}\\pm10.67\\,{\\rm (syst.)}\\ {\\rm km\\,s^{-1}\\,Mpc^{-1}}$, which is consistent with existing spectroscopic CC measurements and with the $Λ$ cold dark matter ($Λ$CDM) model prediction from Planck at the same redshift. This result provides a proof of concept for extending direct $H(z)$ measurements from cosmic chronometers to photometric and spectro-photometric surveys, where larger samples can compensate for lower spectral resolution, provided that passive-galaxy selection, metallicity priors, and stellar-population systematics are carefully controlled.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.07298",
  "author_total": 5,
  "authors": [
    {
      "name": "Swaraj Pradhan"
    },
    {
      "name": "Pablo Renard"
    },
    {
      "name": "Enrique Gaztanaga"
    },
    {
      "name": "Malgorzata Siudek"
    },
    {
      "name": "Thibaud Moutard"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/93qw16zwfr081.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.07298",
  "fulltext_url": null,
  "id": "93qw16zwfr081",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.07298",
  "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.CO"
    ],
    [
      "arxiv",
      "astro-ph.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.07298",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/93qw16zwfr081.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:15Z",
      "native_id": "2606.07298",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.07298"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Toward Bayesian photometric cosmic chronometers: Application to VIPERS",
  "title_text": "Toward Bayesian photometric cosmic chronometers: Application to VIPERS",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:15Z",
  "url": "https://research.draconitic.com/paper/93qw16zwfr081",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1051/0004-6361/202661301",
      "pid": "7rr8kcde1a4kp",
      "relation": "published-as",
      "title": "Toward Bayesian photometric cosmic chronometers: Application to VIPERS",
      "venue": "Astronomy & Astrophysics"
    }
  ]
}