A correction for GALEX spectral fluxes
to make them consistent with the HST UV calibration

Reference: Bohlin, R., and Bianchi, L. 2018, A.J., in press ; to be linked here soon

Abstract from paper Bohlin and Bianchi 2018, AJ
The CALSPEC database of absolute spectral energy distributions (SEDs) from the Hubble Space Telescope (HST), based on pure hydrogen model atmosphere calculations for three unreddened white dwarf (WD) stars, represents the current UV flux calibration standard, with a precision of about 3percent. Following our previous work to correct IUE fluxes, we provide in this work an average flux correction for the GALEX spectral database, that places GALEX spectroscopic fluxes on the current CALSPEC scale. Such correction is derived by comparing GALEX spectroscopic flux distributions with CALSPEC and IUE data. This re-calibration is relevant for any project based on GALEX archival spectroscopic data, including UV or multi-wavelength analyses correlating GALEX spectra with other existing databases or future missions, and planning of new observations. The re-calibration will be applied to our planned catalog of corrected GALEX SEDs.

Table 3: flux correction coefficients to bring GALEX spectra on the HST UV scale ( in 50 Å bins from 1300 - 3000 Å ). GALEX spectrophotometry is repeatable to only 10-20% in regions of good sensitivity, the average flux correction presented by Bohlin \& Bianchi 2018 has a precision of about3%.
Table 3 of Bohlin & Bianchi 2018b. The corrections for GALEX spectra fluxes

Combined IUE spectra for the 18 GALEX matched stars used for re-calibration (in addition to CALSPEC standard stars): (these merged spectra can be referred as DOI http://dx.doi.org/10.17909/T9FQ2N , and are also available in MAST High-Level-Science-Products at galex-fluxcal )

File columns are:
WAVELENGTH - Wavelength in vacuum in Angstroms.
NET - The averaged net signal in linearized IUE Flux Number (FN) units per second.
FLUX - The average flux in ergs cm-2 s-1 Angstrom-1.
BKG - The background signal (same units as NET column).
UNCERTAINTY - The formal, propagated uncertainty as the "error-in-the-mean" (same units as FLUX column).
NPTS - The number of observations averaged.
TIME - The total exposure time in seconds.
RMS - The RMS scatter among the observations as a percent.

Download merged spectra:
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