Precise Empirical Determination of Metallicity Dependence of Near-infrared Period-Luminosity Relations for RR Lyrae Variables

Anupam Bhardwaj, Marcella Marconi, Marina Rejkuba, Richard de Grijs, Harinder P. Singh, Vittorio F. Braga, Shashi Kanbur, Chow Choong Ngeow, Vincenzo Ripepi, Giuseppe Bono, Giulia De Somma, Massimo Dall’Ora

研究成果: 雜誌貢獻期刊論文同行評審

6 引文 斯高帕斯(Scopus)

摘要

RR Lyrae variables are excellent Population II distance indicators thanks to their well-defined period-luminosity relations (PLRs) at infrared wavelengths. We present results of near-infrared (NIR) monitoring of Galactic globular clusters to empirically quantify the metallicity dependence of NIR PLRs for RR Lyrae variables. Our sample includes homogeneous, accurate, and precise photometric data for 964 RR Lyrae variables in 11 globular clusters covering a large metallicity range (Δ[Fe/H] ∼ 2 dex). We derive JHK s -band period-luminosity-metallicity (PLZ) and period-Wesenheit-metallicity (PWZ) relations anchored using 346 Milky Way field RR Lyrae stars with Gaia parallaxes, and simultaneously solved for independent distances to globular clusters. We find a significant metallicity dependence of ∼0.2 mag dex−1 in the JHK s -band PLZ and PWZ relations for RR Lyrae stars independent of the adopted metallicity scale. The metallicity coefficients and the zero-points of the empirical PLZ and PWZ relations are in excellent agreement with the predictions from the horizontal branch evolution and pulsation models. Furthermore, RR Lyrae-based distances to our sample of globular clusters are also statistically consistent with other independent measurements in the literature.

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文章編號L51
期刊Astrophysical Journal Letters
944
發行號2
DOIs
出版狀態已出版 - 1 2月 2023

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