The Past 15 Years of RVSAO

Jessica Mink
Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138


Since the last paper describing the IRAF RVSAO radial velocity package was published almost 15 years ago, this collection of tasks dealing with wavelength-shifted spectra has continued to grow and evolve. Many changes have been made to improve robustness and accuracy in the XCSAO cross-correlation and EMSAO emission line fitting tasks. Two new tasks, PXCSAO and PEMSAO, find radial velocities using the same methods, but save the results as task parameters, making them easier to use in CL scripts. Spectra can now be cross-correlated in pixel or wavelenth space as well as velocity space. A major task, EQWIDTH, based on the IRAF BANDS task, computes equivalent widths in redshifted spectra. SUMSPEC, which rebins, normalizes, re-redshifts, sums, and/or stacks spectra, has proven to be useful in multi-fiber spectrograph reduction pipelines. LISTSPEC lists spectra in a variety of user-selected formats, and several CL scripts plot spectra with labelled emission and absorption lines. Full documentation of this software is on-line at

Presented at the Twenty-Second Annual Conference on Astronomical Data Analysis Software and Systems in Champaign, Illinois, November 4-8, 2012

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