A correction for GALEX spectral fluxes
to make them consistent with the HST UV calibration
Reference: Bohlin, R., and Bianchi, L. 2019, AJ, 157, 107 (DOI: 10.3847/1538-3881/aafdb8 , doi:10.17909/T9H59D, doi:10.17909/T9DX2D) ,
( arXiv:1901.06410 )
A Correction for GALEX UV Flux Distributions from Comparisons with
CALSPEC and IUE
Abstract from paper : |
The CALSPEC database of absolute spectral energy distributions (SEDs) from the Hubble Space Telescope (HST) is based on pure hydrogen model atmosphere calculations for three unreddened white dwarf (WD) stars and represents the current UV flux calibration standard with a precision approaching 1% for well observed stars. Following our previous work to correct IUE fluxes, this paper provides an average correction for the GALEX spectral database that places GALEX fluxes on the current CALSPEC scale. Our correction is derived by comparing GALEX spectroscopic flux distributions with CALSPEC and corrected IUE SEDs. 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 or future databases, and planning of new observations. The re-calibration will be applied to our planned catalog of corrected GALEX SEDs.
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: