| Autor: |
KLEIN, CHRISTOPHER R., RICHARDS, JOSEPH W., BUTLER, NATHANIEL R., BLOOM, JOSHUA S. |
| Předmět: |
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| Zdroj: |
Astrophysical Journal; Sep2011, Vol. 738 Issue 2, Special section p1-13, 13p |
| Abstrakt: |
Interstellar dust presents a significant challenge to extending parallax-determined distances of optically observed pulsational variables to larger volumes. Distance ladder work at mid-infrared wavebands, where dust effects are negligible and metallicity correlations are minimized, has been largely focused on few-epoch Cepheid studies. Here we present the first determination of mid-infrared period-luminosity (PL) relations of RR Lyrae stars from phase-resolved imaging using the preliminary data release of the Wide-field Infrared Survey Explorer (WISE). We present a novel statistical framework to predict posterior distances of 76 well observed RR Lyrae that uses the optically constructed prior distance moduli while simultaneously imposing a power-law PL relation to WAS/s-determined mean magnitudes. We find that the absolute magnitude in the bluest WISE filter is MW1 = (-0.421 ± 0.014) - (1.681 ± 0.147)log10(P/0.50118day), with no evidence for a correlation with metallicity. Combining the results from the three bluest WISE filters, we find that a typical star in our sample has a distance measurement uncertainty of 0.97% (statistical) plus 1.17% (systematic). We do not fundamentalize the periods of RRc stars to improve their fit to the relations. Taking the Hipparcos-derived mean V-band magnitudes, we use the distance posteriors to determine a new optical metallicity-luminosity relation. The results of this analysis will soon be tested by Hubble Space Telescope parallax measurements and, eventually, with the GAIA astrometric mission. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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