{
  "abstract": "We investigate the dwarf spheroidal (dSph) satellites and stellar halo of M31 using near-infrared imaging from the Wide-Field Camera on the UKIRT 3.8 m telescope. Our homogeneous analysis covers the stellar extents of 12 dSphs, as well as their surrounding halo field populations. We identify carbon-rich (C) and oxygen-rich (M) thermally-pulsing AGB stars (TP-AGBs) using colour-magnitude and colour-colour diagrams, which also allows for effective contaminant rejection. TP-AGB stars are detected in eight of the 12 dSphs, indicating small intermediate-age populations in a substantial fraction of the sample; they are also found in considerable numbers throughout most of M31's stellar halo. By combining 316 new detections with a revised classification of objects previously reported in the literature, we increase the TP-AGB candidate population in the dSphs from 82 to 359. We use the resulting dSph and halo AGB samples to compute C/M ratios and infer metallicities in the dSphs and adjacent halo fields with non-zero AGB counts. A clear metallicity gradient is observed in the M31 stellar halo out to ~150 kpc, consistent with that found using other tracers. Using literature star formation histories from main-sequence turn-off photometry, we find a tight correlation between the number of C stars in the dSphs and the stellar mass formed in the last 0.5--3 Gyr. This study underscores the promise of AGB stars as quantitative tracers of intermediate-age star formation, particularly in intrinsically faint systems, and provides a catalogue of candidate TP-AGB stars for follow-up.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.20810",
  "author_total": 8,
  "authors": [
    {
      "name": "Jess M. Howell"
    },
    {
      "name": "Annette M. N. Ferguson"
    },
    {
      "name": "Olivia C. Jones"
    },
    {
      "name": "Mike. J. Irwin"
    },
    {
      "name": "Maria-Rosa L. Cioni"
    },
    {
      "name": "Geraint F. Lewis"
    },
    {
      "name": "Nicolas. F. Martin"
    },
    {
      "name": "Alan. W. McConnachie"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/b71ejzcxn680s.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.20810",
  "fulltext_url": null,
  "id": "b71ejzcxn680s",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.20810",
  "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/2609.20810",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-17",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/b71ejzcxn680s.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:19Z",
      "native_id": "2609.20810",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.20810"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "A near-IR survey of luminous asymptotic giant branch stars in the satellites and stellar halo of M31",
  "title_text": "A near-IR survey of luminous asymptotic giant branch stars in the satellites and stellar halo of M31",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:19Z",
  "url": "https://research.draconitic.com/paper/b71ejzcxn680s",
  "venue": "arXiv",
  "versions": []
}