The X-Shooter Spectral Library

Format of the spectra :

The spectra delivered in this release span the wavelengths 3000–10200 Å, observed at a resolving power R ≡ λ/∆λ ∼ 10000.

The spectra are flux-calibrated and telluric-corrected.

The output spectra are delivered in FITS files. There are two extensions: the first is the flux and the second is the error.

The wavelength scale of the spectra is in natural logarithmic spacing. To use these spectra in IRAF, which expects base-10 logarithmic wavelength spacing, please divide CRVAL1, CDELT1 and CD1_1 by ln(10)=2.302585092994046.

The fluxes are flux densities in F_lambda units, in erg s^-1 cm^-1 Å^-1.

PNG plots of each star are also available for a quick view.

Information about the objects can be found in the headers of the files.

Important notes:

(i) The spectral types listed in this release are taken from the literature, not derived from the spectra.

(ii) The errors related to the correction for telluric absorption are not included in the error spectrum, and about 10% of the error spectra are erroneous, in the sense that their level is obviously too high by a factor of 10 or more. This will be corrected as soon as possible.

(iii) For some stars, the absolute flux calibration was not performed, due to a missing wide-slit observation. Please read table B1 from Chen et al. (2014) for more details.

Policy :

A registration is required to download the spectra (FITS files).

If you use these spectra, please reference Chen et al. (2014) .

Warning :

Some users might experience issues while downloading the zip files. Some solutions are the following:

zip -FF --out



jar xvf