EMSAO: Radial Velocities from Emission Lines in Spectra
Douglas J. Mink and William F. Wyatt
Harvard-Smithsonian Center for Astrophysics
Many extragalactic objects for which radial velocities are desired
display strong emission lines. For large surveys, the interactive
determination of line centers and calculation of redshifts is too slow.
The EMSAO task of the RVSAO IRAF package automatically finds emission
lines, fits them with single or multiple Gaussians, and combines the
determined redshifts weighting them by the uncertainty in the line
centers. In addition to being used in the CfA and other redshift
surveys, EMSAO has been used to study sky line shifts in 15 years of
observations to characterize the uncertainty in instrumental
measurements. RVSAO can be obtained via anonymous FTP from
cfa-ftp.harvard.edu in the pub/iraf directory or through the World Wide
Presented at the Fourth Annual Conference on Astronomical Data Analysis
Software and Systems (ADASS 94) in Baltimore, Maryland September 1994.
Published in Astronomical Data Analysis Software and Systems IV,
ASP Conf. Ser., Vol. 77, eds. R.A> Shaw, H.E. Payne, and J.J.E. Hayes,
p. 496-499 (1995).