RR Lyrae Las Campanas spectra

This directory contains spectra that were used in the paper,

"The Axial Rotation and Variable Macroturbulence of RR Lyrae Stars",
2019, Astronomical J., by G. W. Preston, C. Sneden, M. Chadid,
I. B. Thompson, and S. A. Shectman.

The spectra of RR Lyrae variables were obtained with the Las Campanas
Observatory Du Pont Telescope and its echelle spectrograph.  This
instrument has a spectral resolving power R ~= 27,000.  Integration
times were almost always < 900 sec in order to avoid velocity phase
smearing of the absorption features.  Therefore the typical S/N
values are < 30 in the individial spectra.  The Du Pont reduced spectra are
gathered here in subdirectoris aas-rrab for the RRab stars, aas-rrc for the
RRc stars, and aas-thar for the thorium-argon calibrations.  The
spectral range is 4000-4600A, the region used to derive the macroturbulent
and rotational velocities of the RR Lyrae stars.

Spectra for RHB stars discussed in this paper are in subdirectory aas-rhb.
They were originally employed in the paper " Atmospheres, Chemical
Compositions, and Evolutionary Histories of Very Metal-Poor Red
Horizontal-Branch Stars in the Galactic Field and in NGC 7078 (M15)", 2006,
Astronomical J., 132, 85.  These spectra were obtained with the Las Campanas
Magellan MIKE spectrsgraph, with R ~= 40,000.  These non-variable stars
were obtained with longer integration times, resulting in higher S/N.

Guides to the individual spectra are contained in EXCEL documents in
each subfolder.