Free Access
Astron. Astrophys. Suppl. Ser.
Volume 136, Number 3, May I 1999
Page(s) 591 - 601
Published online 15 May 1999
DOI: 10.1051/aas:1999236

Astron. Astrophys. Suppl. Ser. 136, 591-601

Random-error minimization during cross-correlation of early-type spectra

W. Verschueren[*] - M. David

Send offprint request: W. Verschueren,

Astrophysics Research Group, University of Antwerp (RUCA), Groenenborgerlaan 171, B-2020 Antwerpen, Belgium

Received October 16, 1998; accepted February 18, 1999


Owing to the typical morphology of spectra of early-type stars, random errors play a much more important role in the derivation of their radial velocities than in the case of late-type spectra. We derive a generalised lower bound of the random error on a cross-correlation derived radial velocity shift in the presence of random noise on both object and template spectrum, and discuss its dependence on spectral parameters and noise. In order to limit in practice the random error to this lower bound for early-type spectra, we show that a number of specific cross-correlation peak centering techniques are required. The influence of rotational mismatch between object and template on the random error is examined. Finally, the widely used error estimate based on the so-called r-statistic is critically evaluated in the context of early-type spectra.

Key words: methods: numerical -- techniques: radial velocities -- techniques: spectroscopic -- stars: early-type

Copyright The European Southern Observatory (ESO)

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.