{
  "id": "1910.10735",
  "version": "v1",
  "published": "2019-10-23T18:00:09.000Z",
  "updated": "2019-10-23T18:00:09.000Z",
  "title": "Metal Abundances across Cosmic Time ($\\mathcal{MACT}$) Survey. III. The Relationship between Stellar Mass and Star Formation Rate in Extremely Low-Mass Galaxies",
  "authors": [
    "Kaitlyn Shin",
    "Chun Ly",
    "Matthew A. Malkan",
    "Sangeeta Malhotra",
    "Mithi de los Reyes",
    "James E. Rhoads"
  ],
  "comment": "19 pages, 14 figures, 6 tables. Key results, as described in the abstract, are in (1) Fig. 5, (2) Fig. 6, (3) Fig. 10, (4) Fig. 11. Submitted to MNRAS",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "Extragalactic studies have demonstrated that there is a moderately tight ($\\approx$ 0.3 dex) relationship between galaxy stellar mass ($M_{\\star}$) and star formation rate (SFR) that holds for star-forming galaxies at $M_{\\star} \\sim 3 \\times 10^8$-10$^{11}~M_{\\odot}$. This relationship has often been referred to as the \"star formation main sequence.\" However, it has yet to be determined whether such a relationship extends to even lower mass galaxies. Here, we present new results using observations for 777 narrowband H$\\alpha$-selected galaxies with stellar masses between $10^6$ and $10^{10}~M_{\\odot}$ (average of $10^{8.2}~M_{\\odot}$) at $z \\approx$ 0.07--0.5. These galaxies have sensitive UV to near-infrared photometric measurements and optical spectroscopy. The latter allows us to correct our H$\\alpha$\\ SFRs for dust attenuation using Balmer decrements. Our study reveals: (1) for low-SFR galaxies, our H$\\alpha$ SFRs systematically underpredicts compared to FUV measurements; (2) on average, sSFR increases with decreasing stellar mass, but at a slower rate compared to more massive galaxies; (3) the SFR--$M_{\\star}$ relation holds for galaxies down to $\\sim$10$^6~M_{\\odot}$ ($\\sim$1.5 dex below previous studies), and follows a redshift-dependent main-sequence relation of $\\log{({\\rm SFR})} \\propto \\alpha \\log{M_{\\star}} + \\beta z$ with $\\alpha=0.58 \\pm 0.01$ and $\\beta=2.08 \\pm 0.07$, over lookback times of up to 5 Gyr; (4) the intrinsic dispersion in the SFR--$M_{\\star}$ relation at low stellar masses is $\\approx0.3$ dex with no strong evidence that lower mass galaxies display a larger dispersion, consistent with results obtained at similar or higher stellar masses.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-10-23T18:00:09.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "stellar mass",
      "star formation rate",
      "extremely low-mass galaxies",
      "metal abundances",
      "cosmic time"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 19,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}