{
  "id": "2208.04546",
  "version": "v1",
  "published": "2022-08-09T05:21:44.000Z",
  "updated": "2022-08-09T05:21:44.000Z",
  "title": "Analytic models of dust temperature in high-redshift galaxies",
  "authors": [
    "Hiroyuki Hirashita",
    "I-Da Chiang"
  ],
  "comment": "12 pages, 5 figures, Accepted for publication in MNRAS",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We investigate physical reasons for high dust temperatures ($T_\\mathrm{dust}\\gtrsim 40$ K) observed in some high-redshift ($z>5$) galaxies using analytic models. We consider two models that can be treated analytically: the radiative transfer (RT) model, {where a broad distribution of values for $T_\\mathrm{dust}$ is considered}, and the one-tempearture (one-$T$) model, which assumes {uniform $T_\\mathrm{dust}$}. These two extremes {serve to bracket the most realistic scenario}. We adopt the Kennicutt--Schmidt (KS) law to relate stellar radiation field to gas surface density, and vary the dust-to-gas ratio. As a consequence, our model is capable of predicting the relation between the surface density of star formation rate ($\\Sigma_\\mathrm{SFR}$) or dust mass ($\\Sigma_\\mathrm{dust}$) and $T_\\mathrm{dust}$. We show that the high $T_\\mathrm{dust}$ observed at $z\\gtrsim 5$ favour low dust-to-gas ratios ($\\lesssim 10^{-3}$). An enhanced star formation compared with the KS law gives an alternative explanation for the high $T_\\mathrm{dust}$. The dust temperatures are similar between the two (RT and one-$T$) models as long as we use ALMA Bands 6--8. We also examine the relation among $\\Sigma_\\mathrm{SFR}$, $\\Sigma_\\mathrm{dust}$ and $T_\\mathrm{dust}$ without assuming the KS law, and confirm the consistency with the actual observational data at $z>5$. In the one-$T$ model, we also examine a clumpy dust distribution, which predicts lower $T_\\mathrm{dust}$ because of the leakage of stellar radiation. This enhances the requirement of low dust abundance or high star formation efficiency to explain the observed high $T_\\mathrm{dust}$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-08-09T05:21:44.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "dust temperature",
      "analytic models",
      "high-redshift galaxies",
      "relate stellar radiation field",
      "ks law"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}