Absolute flux calibration of the IRAC instrument on the spitzer space telescope using hubble space telescope flux standards

R. C. Bohlin, K. D. Gordon, George H. Rieke, D. Ardila, S. Carey, S. Deustua, C. Engelbracht, H. C. Ferguson, K. Flanagan, J. Kalirai, M. Meixner, A. Noriega-Crespo, K. Y L Su, P. E. Tremblay

Research output: Contribution to journalArticle

14 Scopus citations


The absolute flux calibration of the James Webb Space Telescope (JWST) will be based on a set of stars observed by the Hubble and Spitzer Space Telescopes. In order to cross-calibrate the two facilities, several A, G, and white dwarf stars are observed with both Spitzer and Hubble and are the prototypes for a set of JWST calibration standards. The flux calibration constants for the four Spitzer IRAC bands 1-4 are derived from these stars and are 2.3%, 1.9%, 2.0%, and 0.5% lower than the official cold-mission IRAC calibration of Reach et al., i.e., in agreement within their estimated errors of 2%. The causes of these differences lie primarily in the IRAC data reduction and secondarily in the spectral energy distributions of our standard stars. The independent IRAC 8 μm band-4 fluxes of Rieke et al. are about 1.5% 2% higher than those of Reach et al. and are also in agreement with our 8 μm result.

Original languageEnglish (US)
Article number173
JournalAstronomical Journal
Issue number5
Publication statusPublished - May 2011
Externally publishedYes



  • stars: atmospheres
  • stars: fundamental parameters
  • techniques: spectroscopic

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

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