{
  "abstract": "We present a near-infrared spectroscopic follow-up study of seven H$α$ emitter candidates at $z\\sim2$ in the ZFOURGE-COSMOS field, selected via the $K_{\\rm s}$-band flux excess method. Spectra obtained with Subaru/SWIMS confirm strong H$α$ emission line at $z=2.06-2.49$ for all the targets. Three galaxies are low-mass systems ($\\log(M_\\star/M_\\odot) < 9$) with high specific SFRs, while four are high-mass systems ($\\log(M_\\star/M_\\odot) > 10$) on the star-forming main sequence. The low-mass galaxies show consistent H$α$ flux measurements between the $K_{\\rm s}$-band flux excess method and the spectroscopy, whereas the high-mass galaxies show higher H$α$ flux inferred from the $K_{\\rm s}$-band flux excess than the spectroscopic measurement which may be attributed to their extended star formation distributions. The low-mass galaxies exhibit extreme [O III] $\\lambda5007$ emission with high rest-frame equivalent widths ($\\mathrm{EW}_{\\mathrm{rest}}$) ranging from 480 to 1064 $\\mathring{\\mathrm{A}}$. They are characterized by high [O III]/H$β$ ratios ($>4$) and weak [O II] and [N II] emission lines, indicating high ionization parameters and low metallicity. The line ratios are comparable to those of star-forming galaxies at $z \\gtrsim 6$ and their local analogs. JWST/NIRCam imaging reveals a clear mass-dependent color gradient: the low-mass galaxies present positive F115W-F277W radial gradients with blue cores, while the high-mass galaxies exhibit negative gradients with red cores. These results suggest distinct assembly pathways for low- and high-mass galaxies during the cosmic noon epoch.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.26788",
  "author_total": 12,
  "authors": [
    {
      "name": "Jeung Yun"
    },
    {
      "name": "Kentaro Motohara"
    },
    {
      "name": "Kosuke Kushibiki"
    },
    {
      "name": "Nuo Chen"
    },
    {
      "name": "Masahiro Konishi"
    },
    {
      "name": "Hidenori Takahashi"
    },
    {
      "name": "Tomoya Yukino"
    },
    {
      "name": "Shuhei Koyama"
    },
    {
      "name": "Akiyoshi Tsujita"
    },
    {
      "name": "Ichi Tanaka"
    },
    {
      "name": "Hirofumi Okita"
    },
    {
      "name": "Tsuyoshi Terai"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/40jt295xd0415.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.26788",
  "fulltext_url": null,
  "id": "40jt295xd0415",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.26788",
  "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": "W7223043142",
  "pdf_url": "https://arxiv.org/pdf/2610.26788",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-19",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/40jt295xd0415.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:52Z",
      "native_id": "2610.26788",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.26788"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Low-mass and High-sSFR H$α$ Emitters at $z \\sim 2$ in the ZFOURGE-COSMOS Field",
  "title_text": "Low-mass and High-sSFR Hα Emitters at z ∼ 2 in the ZFOURGE-COSMOS Field",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:41Z",
  "url": "https://research.draconitic.com/paper/40jt295xd0415",
  "venue": "arXiv",
  "versions": []
}