Here we present a re-calibrated version of the UVES-POP stellar spectral library. The original library was released in 2003 (Bagnulo et al., 2003) and contained optical spectra of about 400 stars with the resolving power of R=80,000 collected with the UVES spectrograph at ESO VLT. The new release consists of spectra of 406 stars, has the wavelength coverage 3200 Å < λ < 10250 Å and is available at two resolving powers of R=80,000 and R=20,000. All stars were observed with UVES using a 0.5"-wide slit.

We re-reduced raw UVES-POP spectra from the ESO data archive with the 2018 version of the UVES pipeline and some additional algorithms that we developed to correct artifacts, which were present in the original UVES-POP release. The most significant improvements in comparison with the original UVES-POP library are: (i) the improved merging of Echelle orders which eliminates “ripples” present in the original spectra by correctly accounting for scattered light and blaze shift between flat field and science exposures; (ii) full telluric absorption correction; (iii) merging of non-overlapping UVES spectral setups which preserves the global continuum shape; (iv) spectrophotometric correction and absolute flux calibration with use of 33 middle- and broad-band photometry including several ground-based datasets plus Gaia and Tycho data. We also estimated the E(B-V) values for all stars from the library. The overall final absolute flux uncertainty is better than 1.5-2% for over half of the sample, 2-3% for about a quarter, and better than 4% for the remaining 100 stars.