Metallicity of Galactic RR Lyrae from Optical and Infrared Light Curves: II. Period-Fourier-Metallicity Relations for First Overtone RR Lyrae

Abstract

We present new period-${\varphi }_{31}$-[Fe/H] relations for first overtone RRL stars (RRc), calibrated over a broad range of metallicities ($-2.5<\text{[Fe/H]}<0.0$) utilizing the largest currently available set of Galactic halo field RRL with homogeneous spectroscopic metallicities. Our relations are defined in the optical (ASAS-SN $V$-band) and, inaugurally, in the infrared (WISE $W1$ and $W2$ bands). Our $V$-band relation can reproduce individual RRc spectroscopic metallicities with a dispersion of 0.30 dex over the entire metallicity range of our calibrator sample (an RMS smaller than what we found for other relations in literature including non-linear terms). Our infrared relation has a similar dispersion in the low and intermediate metallicity range ($\text{[Fe/H]}<-0.5$) but tends to underestimate the [Fe/H] abundance around solar metallicity. We tested our relations by measuring both the metallicity of the Sculptor dSph and a sample of Galactic globular clusters, rich in both RRc and RRab stars. The average metallicity we obtain for the combined RRL sample in each cluster is within $\pm 0.08$ dex of their spectroscopic metallicities. The infrared and optical relations presented in this work will enable deriving reliable photometric RRL metallicities in conditions where spectroscopic measurements are not feasible; e.g., in distant galaxies or reddened regions (observed with upcoming Extremely Large Telescopes and the James Webb Space Telescope), or in the large sample of new RRL that will be discovered in large-area time-domain photometric surveys (such as LSST and the Roman space telescope).

arXiv commentAccepted by ApJ, 22 pages, 9 Figures, 3 Tables

References in corpus (51)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• Gaia Data Release 2. Summary of the contents and survey properties
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Transiting Exoplanet Survey Satellite
• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• The James Webb Space Telescope
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• First Results from the Catalina Real-time Transient Survey
• Kepler Mission Design, Realized Photometric Performance, and Early Science
• SEGUE: A Spectroscopic Survey of 240,000 stars with g=14-20
• Preliminary Results from NEOWISE: An Enhancement to the Wide-field Infrared Survey Explorer for Solar System Science
• Intrinsic iron spread and a new metallicity scale for Globular Clusters
• Abundances for Globular Cluster Giants: I. Homogeneous Metallicities for 24 Clusters
• LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) The survey science plan
• The ASAS-SN Catalog of Variable Stars I: The Serendipitous Survey
• On a new theoretical framework for RR Lyrae stars I: the metallicity dependence
• Comparing the properties of local globular cluster systems: implications for the formation of the Galactic halo
• RR Lyrae stars as standard candles in the Gaia Data Release 2 Era
• Metal Abundances, Radial Velocities and other Physical Characteristics for the RR Lyrae Stars in the Kepler Field
• Chemo-kinematics of the $Gaia$ RR Lyrae: the halo and the disc
• RR Lyrae variables: visual and infrared luminosities, intrinsic colours, and kinematics
• The ACS LCID Project. I. Short-Period Variables in the Isolated Dwarf Spheroidal Galaxies Cetus & Tucana
• Fourier analysis of non-Blazhko ab-type RR Lyrae stars observed with the Kepler space telescope
• The Cepheid period -- luminosity -- metallicity relation based on Gaia DR2 data
• Gaia Data Release 1 - The Cepheid & RR Lyrae star pipeline and its application to the south ecliptic pole region
• Light curve analysis of Variable stars using Fourier decomposition and Principal component analysis
• [Fe/H] relations for c-type RR Lyrae Variables based upon Fourier Coefficients
• Variable Stars in Local Group Galaxies. I: Tracing the Early Chemical Enrichment and Radial Gradients in the Sculptor dSph with RR Lyrae Stars
• The age of the Milky Way inner stellar spheroid from RR Lyrae population synthesis
• Variable stars in Local Group Galaxies - II. Sculptor dSph
• On a new theoretical framework for RR Lyrae stars II: Mid--Infrared Period--Luminosity--Metallicity Relations
• The ACS LCID Project. II. Faint Variable Stars in the Isolated Dwarf Irregular Galaxy IC1613
• Standard Galactic Field RR Lyrae II: A Gaia DR2 calibration of the period-Wesenheit-metallicity relation
• BVI time series data of the Galactic Globular Cluster NGC3201. I. RR Lyrae stars
• The influence of metallicity on the Leavitt Law from geometrical distances of Milky Way and Magellanic Clouds Cepheids
• On the Use of Field RR Lyrae as Galactic Probes. II. A new $\Delta$S calibration to estimate their metallicity
• LSS-GAC - A LAMOST Spectroscopic Survey of the Galactic Anti-center
• The ACS LCID Project. VIII. The short-period Cepheids of Leo A
• The metal abundance distribution of the oldest stellar component in the Sculptor dwarf spheroidal galaxy
• Probing the early chemical evolution of the Sculptor dSph with purely old stellar tracers
• Metallicity of Galactic RR Lyrae from Optical and Infrared Light Curves: I. Period-Fourier-Metallicity Relations for Fundamental Mode RR Lyrae
• The ISLAnds Project III: Variable Stars in Six Andromeda Dwarf Spheroidal Galaxies
• Metallicities for Double Mode RR Lyrae in the Large Magellanic Cloud
• On the distance of the globular cluster M4 (NGC 6121) using RR Lyrae stars: II. Mid-infrared period-luminosity relations
• On the Use of Field RR Lyrae as Galactic Probes. III. The $\alpha$-element abundances
• On the use of field RR Lyrae as Galactic probes: IV. New insights into and around the Oosterhoff dichotomy
• Metallicities from high resolution spectra of 49 RR Lyrae Variables
• Variable Stars in Large Magellanic Cloud Globular Clusters III: Reticulum
• Palomar Transient Factory and RR Lyrae: Metallicity-Light Curve Relation Based on ab-Type RR Lyrae in Kepler Field
• Modelling the chemical evolution of the Milky Way

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• Photometric metallicity and distance estimates for $\sim$ 136,000 RR Lyrae stars from Gaia DR3
• RR Lyrae From Binary Evolution: Abundant, Young and Metal-Rich
• The GALAH survey: Tracing the Milky Way's formation and evolution through RR Lyrae stars
• RR Lyrae mid-infrared Period-Luminosity-Metallicity and Period-Wesenheit-Metallicity relations based on Gaia DR3 parallaxes
• RR Lyrae stars as probes of the outer Galactic halo: Chemical and kinematic analysis of a pilot sample
• The Galactic Bulge exploration IV.: RR~Lyrae stars as traces of the Galactic bar -- 3D and 5D analysis, extinction variation
• Two Different Weak Modulations in ab-type RR Lyrae Variable V838 Cyg, and Potential Influence of Metal Abundance on Blazhko Modulation
• A Study of Pulsation properties of 57 Non-Blazhko effect ab-type RR Lyrae stars with homogeneous metallicities from the LAMOST-Kepler/K2 survey
• High-cadence stellar variability studies of RR Lyrae stars with DECam: New multi-band templates
• IY Lyr: A Thick-Disk first-overtone RR Lyrae Star with a Possible Neutron Star Companion