A flux-calibrated, high-resolution atlas of optical sky emission from UVES

Abstract

This paper presents a flux-calibrated, high-resolution, high-SNR atlas of optical and near-IR sky emission. It provides a complete template of the high-resolution night-sky emission spectrum with the deepest exposures ever obtained from the ground. The data have been acquired by UVES, ESO's echelle spectrograph at the 8.2-m UT2 telescope of the Very Large Telescope (VLT). Raw data stacks with up to 16 hours of integration time have been combined. The spectrum covers the range 3140-10 430 A at a resolving power of about 45 000. A total of 2810 sky emission lines have been measured. This high-resolution spectrum is intended to be used for the identification of previously unknown faint sky lines, for simulations of ground based observations where the sky background is important, as a template for checks on the accuracy and stability of the wavelength scale, and as a reference for the reduction of spectra of faint objects.