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A correction for IUE UV fluxes
to make them consistent with the HST UV calibration
Reference: Bohlin, R., and Bianchi, L. 2018, A.J., 155, 162 ; arXiv : 1802.03419 (you may download pdf here)
A Correction for IUE UV Flux Distributions from Comparisons with CALSPEC
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Abstract:
A collection of spectral energy distributions (SEDs) is available in the Hubble Space
Telescope (HST) CALSPEC database that is based on calculated model atmospheres
for pure hydrogen white dwarfs (WDs). A much larger set (about 100,000) of UV SEDs
covering the range (1150-3350 Ang) with somewhat lower quality are available in the
IUE database. IUE low-dispersion flux distributions are compared with CALSPEC
to provide a correction that places IUE fluxes on the CALSPEC scale. While IUE
observations are repeatable to only 4–10% in regions of good sensitivity, the average
flux corrections have a precision of 2–3%. Our re-calibration places the IUE flux scale
on the current UV reference standard and is relevant for any project based on IUE
archival data, including our planned comparison of GALEX to the corrected IUE fluxes.
IUE SEDs may be used to plan observations and cross-calibrate data from
future missions, so the IUE flux calibration must be consistent with HST
instrumental calibrations to the best possible precision.
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