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Paper: The Galactic Leavitt Law from Gaia DR2 Visual Binaries: Implications on the Distance Scale
Volume: 529, RR Lyrae/Cepheid 2019: Frontiers of Classical Pulsators
Page: 279
Authors: Breuval, L.; Kervella, P.
Abstract: The Cepheid Leavitt law or Period-Luminosity (PL) relation is an essential tool in the understanding of the distance scale of the universe. However, the precision of its calibration is still unsatisfactory and constitutes the main limit in the determination of the Hubble constant H0. In this study, we present an original calibration of the Cepheid Leavitt law in the Milky Way. We use the Gaia DR2 parallaxes of Cepheids resolved companions, in order to avoid the astrometric bias that affects variable stars. This new PL relation is directly compared with a similar calibration based on HST/FGS parallaxes. We translate our results in terms of the Hubble constant by rescaling the value determined by the SH0ES team, and we derive a new value of H0 = 71 ± 2.5 km/s/Mpc for a Gaia DR2 parallax zero-point between -0.029 mas and -0.046 mas.
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