Alternative Data Reduction Procedures for UVES: Wavelength Calibration and Spectrum Addition

Abstract

This paper addresses alternative procedures to the ESO supplied pipeline procedures for the reduction of UVES spectra of two quasar spectra to determine the value of the fundamental constant mu = Mp/Me at early times in the universe. The procedures utilize intermediate product images and spectra produced by the pipeline with alternative wavelength calibration and spectrum addition methods. Spectroscopic studies that require extreme wavelength precision need customized wavelength calibration procedures beyond that usually supplied by the standard data reduction pipelines. An example of such studies is the measurement of the values of the fundamental constants at early times in the universe. This article describes a wavelength calibration procedure for the UV-Visual Echelle Spectrometer on the Very Large Telescope, however, it can be extended to other spectrometers as well. The procedure described here provides relative wavelength precision of better than 3E-7 for the long-slit Thorium-Argon calibration lamp exposures. The gain in precision over the pipeline wavelength calibration is almost entirely due to a more exclusive selection of Th/Ar calibration lines.

Accepted for publication in New Astronomy

References in corpus (3)

• A new list of thorium and argon spectral lines in the visible
• A new constraint on the time dependence of the proton-to-electron mass ratio. Analysis of the Q 0347-383 and Q 0405-443 spectra
• Selection of ThAr lines for wavelength calibration of echelle spectra and implications for variations in the fine-structure constant

Cited by in corpus (10)

• The UVES Large Program for Testing Fundamental Physics II: Constraints on a Change in μ Towards Quasar HE 0027-1836
• An Observational Determination of the Proton to Electron Mass Ratio in the Early Universe
• Search for a drifting proton--electron mass ratio from H${}_2$
• Constraining the Variation of the Fine Structure Constant with Observations of Narrow Quasar Absorption Lines
• QSO 0347-383 and the invariance of m_p/m_e in the course of cosmic time
• Spatially resolved spectroscopy across stellar surfaces. II. High-resolution spectra across HD209458 (G0V)
• Constraining fundamental constants of physics with quasar absorption line systems
• Robust limit on a varying proton-to-electron mass ratio from a single H2 system
• Constraints on variations of m${}_{\mathrm{p}}$/m${}_{\mathrm{e}}$ based on UVES observations of H${}_2$
• Astrophysical Probes of Fundamental Physics