Gaia Parallax Zero Point From RR Lyrae Stars

Abstract

Like Hipparcos, Gaia is designed to give absolute parallaxes, independent of any astrophysical reference system. And indeed, Gaia's internal zero-point error for parallaxes is likely to be smaller than any individual parallax error. Nevertheless, due in part to mechanical issues of unknown origin, there are many astrophysical questions for which the parallax zero-point error $\sigma ({\pi }_0)$ will be the fundamentally limiting constraint. These include the distance to the Large Magellanic Cloud and the Galactic Center. We show that by using the photometric parallax estimates for RR Lyrae stars (RRL) within 8kpc, via the ultra-precise infrared period-luminosity relation, one can independently determine a hyper-precise value for ${\pi }_0$. Despite their paucity relative to bright quasars, we show that RRL are competitive due to their order-of-magnitude improved parallax precision for each individual object relative to bright quasars. We show that this method is mathematically robust and well-approximated by analytic formulae over a wide range of relevant distances.

arXiv comment5 pages, 1 Figure, submitted to JKAS

References in corpus (6)

• Clustering of Local Group distances: publication bias or correlated measurements? I. The Large Magellanic Cloud
• The Absolute Magnitude and Kinematics of RR Lyrae Stars via Statistical Parallax
• On the distance of the globular cluster M4 (NGC 6121) using RR Lyrae stars: I. optical and near-infrared Period-Luminosity and Period-Wesenheit relations
• Theoretical insights into the RR Lyrae K-band Period-Luminosity relation
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Cited by in corpus (5)

• Impact of basic angle variations on the parallax zero point for a scanning astrometric satellite
• The Araucaria Project: The distance to the Fornax Dwarf Galaxy from near-infrared photometry of RR Lyrae stars
• TGAS Error Renormalization from the RR Lyrae Period-Luminosity Relation
• The Carnegie-Chicago Hubble Program: Calibration of the Near-Infrared RR Lyrae Period-Luminosity Relation With HST
• Predicted Information Content of Gaia-Hipparcos