{
  "id": "2010.05510",
  "version": "v1",
  "published": "2020-10-12T08:05:14.000Z",
  "updated": "2020-10-12T08:05:14.000Z",
  "title": "The infrared-radio correlation of star-forming galaxies is strongly M$_{\\star}$-dependent but nearly redshift-invariant since z$\\sim$4",
  "authors": [
    "I. Delvecchio",
    "E. Daddi",
    "M. T. Sargent",
    "M. J. Jarvis",
    "D. Elbaz",
    "S. Jin",
    "D. Liu",
    "I. H. Whittam",
    "H. Algera",
    "R. Carraro",
    "C. D'Eugenio",
    "J. Delhaize",
    "B. Kalita",
    "S. Leslie",
    "D. Cs. Molnar",
    "M. Novak",
    "I. Prandoni",
    "V. Smolcic",
    "Y. Ao",
    "M. Aravena",
    "F. Bournaud",
    "J. D. Collier",
    "S. M. Randriamampandry",
    "Z. Randriamanakoto",
    "G. Rodighiero",
    "J. Schober",
    "S. V. White",
    "G. Zamorani"
  ],
  "comment": "Submitted to A&A. 30 pages, 26 figures, 3 tables. Comments are welcome",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "Several works in the past decade have used the ratio between total (rest 8-1000$\\mu$m) infrared and radio (rest 1.4 GHz) luminosity in star-forming galaxies (q$_{TIR}$), often referred to as the \"infrared-radio correlation\" (IRRC), to calibrate radio emission as a star formation rate (SFR) indicator. Previous studies constrained the evolution of q$_{TIR}$ with redshift, finding a mild but significant decline, that is yet to be understood. For the first time, we re-calibrate q$_{TIR}$ as a function of both stellar mass (M$_{*}$) and redshift, starting from an M$_{*}$-selected sample of >400,000 star-forming galaxies in the COSMOS field, identified via (NUV-r)/(r-J) colours, at redshifts 0.1<z<4.5. Within each (M$_{*}$,z) bin, we stack the deepest available infrared/sub-mm and radio images. We fit the stacked IR spectral energy distributions with typical star-forming galaxy and IR-AGN templates, and carefully remove radio AGN candidates via a recursive approach. We find that the IRRC evolves primarily with M$_{*}$, with more massive galaxies displaying systematically lower q$_{TIR}$. A secondary, weaker dependence on redshift is also observed. The best-fit analytical expression is the following: q$_{TIR}$(M$_{*}$,z)=(2.646$\\pm$0.024)$\\times$(1+z)$^{(-0.023\\pm0.008)}$-(0.148$\\pm$0.013)$\\times$($\\log~M_{*}$/M$_{\\odot}$-10). Adding the UV dust-uncorrected contribution to the IR as a proxy for the total SFR, would further steepen the q$_{TIR}$ dependence on M$_{*}$. The lower IR/radio ratio in more massive galaxies could be possibly linked to higher SFR surface density, which induces larger cosmic-ray scale heights. Our findings highlight that using radio emission as a proxy for SFR requires novel M$_{*}$-dependent recipes, that will enable us to convert detections from future ultra deep radio surveys into accurate SFR measurements down to low-SFR, low-M$_{*}$ galaxies.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-10-12T08:05:14.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "star-forming galaxy",
      "infrared-radio correlation",
      "ir spectral energy distributions",
      "galaxies displaying systematically lower",
      "induces larger cosmic-ray scale heights"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 30,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}