2007/07/18 by Carlos Allende Prieto · 1 citation
Chemistry · Physics and Astronomy · #Astronomy and Astrophysical Research #Spectroscopy and Chemometric Analyses #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/522051
published as Astron.J.134:1843-1848,2007 · 7 pages, 3 figures, uses emulateapj.cls; to appear in the Astronomical Journal; see http://hebe.as.utexas.edu/stools/ to obtain the companion software
arxiv created 2007/07/18 · openalex publication_date 2007/09/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
The measurement of Doppler velocity shifts in spectra is a ubiquitous theme in astronomy, usually handled by computing the cross-correlation of the signals and finding the location of its maximum. This paper addresses the problem of the determination of wavelength or velocity shifts among multiple spectra of the same, or very similar, objects. We implement the classical cross-correlation method and experiment with several simple models to determine the location of the maximum of the cross-correlation function. We propose a new technique, self-improvement , to refine the derived solutions by requiring that the relative velocity for any given pair of spectra be consistent with all others. By exploiting all available information, spectroscopic surveys involving large numbers of similar objects may improve their precision significantly. As an example, we simulate the analysis of a survey of G-type stars with the SDSS instrumentation. Applying self-improvement refines relative radial velocities by more than 50% at low signal-to-noise ratios. The concept is equally applicable to the problem of combining a series of spectroscopic observations of the same object, each with a different Doppler velocity or instrument-related offset, into a single spectrum with an enhanced signal-to-noise ratio.