Sub-percent photometry: Faint da white dwarf spectrophotometric standards for astrophysical observatories

Gautham Narayan, Thomas Matheson, Abhijit Saha, Tim Axelrod, Annalisa Calamida, Edward Olszewski, Jenna Claver, Kaisey S. Mandel, Ralph C. Bohlin, Jay B. Holberg, Susana Deustua, Armin Rest, Christopher W. Stubbs, Clare E. Shanahan, Amali L. Vaz, Alfredo Zenteno, Giovanni Strampelli, Ivan - Hubeny, Sean Points, Elena SabbiJohn Mackenty

Research output: Contribution to journalArticlepeer-review


We have established a network of 19 faint (16.5 mag < V <19 mag) northern and equatorial DA white dwarfs as spectrophotometric standards for present and future wide-field observatories. Our analysis infers SED models for the stars that are tied to the three CALSPEC primary standards. Our SED models are consistent with panchromatic Hubble Space Telescope (HST) photometry to better than 1%. The excellent agreement between observations and models validates the use of non-local-thermodynamic-equilibrium (NLTE) DA white dwarf atmospheres extinguished by interstellar dust as accurate spectrophotometric references. Our standards are accessible from both hemispheres and suitable for ground and space-based observatories covering the ultraviolet to the near infrared. The high-precision of these faint sources make our network of standards ideally suited for any experiment that has very stringent requirements on flux calibration, such as studies of dark energy using the Large Synoptic Survey Telescope (LSST) and the Wide-Field Infrared Survey Telescope (WFIRST).

Original languageEnglish (US)
JournalUnknown Journal
StatePublished - Nov 29 2018


  • Cosmology: Observations
  • Methods: Data Analysis
  • Standards
  • Stars: White Dwarfs
  • Surveys

ASJC Scopus subject areas

  • General

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