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Symposium 241

Abstract details

Studying stellar populations at high spectral resolution
Gustavo Bruzual

The use of high signal-to-noise ratio stellar spectral libraries of intermediate and high spectral resolution in population synthesis models is now possible. Several libraries of empirical spectra of stars covering wide ranges of values of the atmospheric parameters Teff, log g, [Fe/H], as well as spectral type, have become available in the last few years. The Hubble's New Generation Spectral Library (HNGSL, Heap & Lanz 2003) contains spectra for over 200 stars covering the wavelength range from 1700 A to 10,200 A, providing excellent coverage of the near-UV and the range from 9000 A to 10,200 A, which is generally noisy or absent in other data sets. The Medium resolution INT Library of Empirical Spectra (MILES, Sánchez-Blázquez et al. 2006) contains carefully calibrated and homogeneous quality spectra for 1003 stars in the wavelength range 3500 A to 7500 A with 2 A spectral resolution and dispersion 0.9 A/pixel. The stars included in this library were chosen aiming at sampling stellar atmospheric parameters as completely as possible. The UVES Paranal Observatory Project (UVES POP Library, Bagnulo et al. 2004) has produced a library of very-high resolution and high signal-to-noise ratio spectra for over 400 stars distributed throughout the HRD. For most of the spectra, the typical final SNR obtained in the V band is between 300 and 500. The UVES POP library is the richest available database of observed optical spectral lines. The Indo-US library (Valdes et al. 2004) contains complete spectra over the entire 3460 A to 9464 A wavelength region for 885 stars obtained with the 0.9m Coudé Feed telescope at KPNO. The spectral resolution is ~ 1 A and the dispersion 0.44 A/pixel. The library includes data for an additional 388 stars, but only with partial spectral coverage. I show the results of using the HNGSL and the IndoUS libraries to build population synthesis models. These libraries are complementary in spectral resolution and wavelength coverage, and will prove extremely useful to describe spectral features expected in galaxy spectra from the NUV to the NIR. Applications of these models to study galaxy populations will be discussed.

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