TY - JOUR
T1 - Mid-infrared period-luminosity relations of RR Lyrae stars derived from the wise preliminary data release
AU - Klein, Christopher R.
AU - Richards, Joseph W.
AU - Butler, Nathaniel R.
AU - Bloom, Joshua S.
PY - 2011/9/10
Y1 - 2011/9/10
N2 - 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 WISE-determined mean magnitudes. We find that the absolute magnitude in the bluest WISE filter is M W1 = (- 0.421 0.014) - (1.681 0.147)log10(P/0.50118 day), 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.
AB - 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 WISE-determined mean magnitudes. We find that the absolute magnitude in the bluest WISE filter is M W1 = (- 0.421 0.014) - (1.681 0.147)log10(P/0.50118 day), 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.
KW - infrared: stars
KW - methods: statistical
KW - stars: distances
KW - stars: variables: RR Lyrae
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U2 - 10.1088/0004-637X/738/2/185
DO - 10.1088/0004-637X/738/2/185
M3 - Article
AN - SCOPUS:80052786968
SN - 0004-637X
VL - 738
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 185
ER -