{
  "id": "1903.03126",
  "version": "v1",
  "published": "2019-03-07T19:04:56.000Z",
  "updated": "2019-03-07T19:04:56.000Z",
  "title": "A GeV-TeV Measurement of the Extragalactic Background Light",
  "authors": [
    "Abhishek Desai",
    "Kári Helgason",
    "Marco Ajello",
    "Vaidehi Paliya",
    "Alberto Domínguez",
    "Justin Finke",
    "Dieter H. Hartmann"
  ],
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "The Extragalactic Background Light (EBL) can be probed via the absorption imprint it leaves in the spectra of gamma-ray sources ($\\gamma\\gamma \\rightarrow e^-e^+$). We recently developed a dedicated technique to reconstruct the EBL, and its evolution with redshift, from $\\gamma$ ray optical depth data using a large sample of blazars detected by the {\\it Fermi} Large Area Telescope. Here, we extend this dataset to the TeV regime using ground-based Cherenkov observations of 38 blazars and report the first homogeneous measurement of the EBL spectral intensity covering the ultraviolet to infrared wavelengths ($\\sim$0.1-100$\\mathrm{\\mu m}$). A minimal EBL throughout the wavelength range with respect to integrated galaxy light is found, allowing little additional unresolved emission from faint or truly diffuse populations setting an upper limit of $\\lesssim 4~{\\rm nW\\cdot m^{-2}sr^{-1}}$ at 1.4\\,${\\rm \\mu m}$. In particular, the cosmic optical background (COB) at $z=0$ is found to be $27.8_{-2.0}^{+2.1}~{\\rm nW\\cdot m^{-2}sr^{-1}}$. This work lays the foundation for accurate gamma-ray measurements of the EBL across its whole spectral range using a combination of GeV and TeV data.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-03-07T19:04:56.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "extragalactic background light",
      "gev-tev measurement",
      "accurate gamma-ray measurements",
      "little additional unresolved emission",
      "ray optical depth data"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}