On the Color-Metallicity Relation of the Red Clump and the Reddening Toward the Magellanic Clouds

Abstract

The zero point of the reddening toward the Large Magellanic Cloud (LMC) has been the subject of some dispute. Its uncertainty propagates as a systematic error for methods which measure the extragalactic distance scale through knowledge of the absolute extinction of LMC stars. In an effort to resolve this issue, we used three different methods to calibrate the most widely-used metric to predict LMC extinction, the intrinsic color of the red clump, $(V-I{)}_{RC,0}$, for the inner $\sim$3 degrees of that galaxy. The first approach was to empirically calibrate the color zeropoints of the BaSTI isochrones over a wide metallicity range of $\Delta [Fe/H]\approx 1.10$ using measurements of red clump stars in 47 Tuc, the Solar Neighborhood, and NGC 6791. From these efforts we also measure these properties of the Solar Neighborhood red clump, ($V-I$, $G_{BP}-K_s$, $G-K_s$, $G_{RP}-K_s$, $J-K_s$, $H-K_s$, $M_I$, $M_{Ks}$)${}_{RC,0}=$ (1.02, 2.75, 2.18, 1.52, 0.64, 0.15, $-$0.23, $-$1.63). The second and third methods were to compare the observed colors of the red clump to those of Cepheids and RR Lyrae in the LMC. With these three methods, we estimated the intrinsic color of the red clump of the LMC to be $(V-I{)}_{RC,0,\mathrm{LMC}}=\{\approx 0.93,0.91\pm 0.02,0.89\pm 0.02\}$ respectively, and similarly using the first and third method we estimated $(V-I{)}_{RC,0,\mathrm{SMC}}=\{\approx 0.85,0.84\pm 0.02\}$ respectively for the Small Magellanic Cloud. We estimate the luminosities to be $M_{I,RC,\mathrm{LMC}}=-0.26$ and $M_{I,RC,\mathrm{SMC}}=-0.37$. We show that this has important implications for recent calibrations of the tip of the red giant branch in the Magellanic Clouds used to measure $H_0$.

20 pages, 5 figures, 4 tables. Accepted for Publication in The Astrophysical Journal as of February 9th, 2021

References in corpus (38)

• The Gaia mission
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• The GALAH Survey: Scientific Motivation
• A distance to the Large Magellanic Cloud that is precise to one per cent
• Improving PARSEC models for very low mass stars
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters Without Previous HST Photometry
• New PARSEC evolutionary tracks of massive stars at low metallicity: testing canonical stellar evolution in nearby star forming dwarf galaxies
• Updated Electron-Conduction Opacities: The Impact on Low-Mass Stellar Models
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• Calibration of the Tip of the Red Giant Branch (TRGB)
• The Structure of the Milky Way's Bar Outside the Bulge
• Synthetic Stellar Photometry - I. General considerations and new transformations for broad-band systems
• A new Cepheid distance to the maser-host galaxy NGC 4258 and its implications for the Hubble Constant
• The APOGEE red-clump catalog: Precise distances, velocities, and high-resolution elemental abundances over a large area of the Milky Way's disk
• Tracing chemical evolution over the extent of the Milky Way's Disk with APOGEE Red Clump Stars
• New Optical Reddening Maps of the Large and Small Magellanic Clouds
• Interstellar Extinction Law toward the Galactic Center II: V, J, H, and Ks Bands
• Distances and parallax bias in Gaia DR2
• A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the full Asymptotic Giant Branch phase and Web tools for stellar population analyses
• OGLE-ing the Magellanic System: Optical Reddening Maps of the Large and Small Magellanic Cloud from Red Clump Stars
• The Chemical Enrichment History of the Large Magellanic Cloud
• The Peculiar Horizontal Branch Morphology of the Galactic Globular Clusters NGC 6388 and NGC 6441: new insights from UV observations
• The Tip of the Red Giant Branch Distances to Type Ia Supernova Host Galaxies. IV. Color Dependence and Zero-Point Calibration
• Standard Galactic Field RR Lyrae. I. Optical to Mid-infrared Phased Photometry
• Red clump stars and Gaia: Calibration of the standard candle using a hierarchical probabilistic model
• The panchromatic view of the Magellanic Clouds from Classical Cepheids. I. Distance, Reddening and Geometry of the Large Magellanic Cloud disk
• Standard Galactic Field RR Lyrae II: A Gaia DR2 calibration of the period-Wesenheit-metallicity relation
• Empirical calibration of the reddening maps in the Magellanic Clouds
• AGB Sodium Abundances in the Globular Cluster 47 Tucanae (NGC 104)
• The Relationship Between Globular Cluster Mass, Metallicity, and Light Element Abundance Variations
• The chemical composition of red giants in 47 Tucanae I: Fundamental parameters and chemical abundance patterns
• LMC Blue Supergiant Stars and the Calibration of the Flux-weighted Gravity--Luminosity Relationship
• vbyCaHbeta CCD Photometry of Clusters. VIII. The Super-Metal Rich, Old Open Cluster NGC 6791
• Optical Identification of Cepheids in 19 Host Galaxies of Type Ia Supernovae and NGC 4258 with the Hubble Space Telescope
• The Cluster Ages Experiment (CASE). VIII. Age and Distance of the Globular Cluster 47 Tuc from the Analysis of Two Detached Eclipsing Binaries
• The Helium Abundance of NGC 6791 from Modeling of Stellar Oscillations
• The Old, Super-Metal-Rich Open Cluster, NGC 6791 - Elemental Abundances in Turn-off Stars from Keck/HIRES Spectra
• On the Correlation Between Metallicity and the X-Shaped Morphology of the Milky Way Bulge

Cited by in corpus (10)

• The trouble beyond $H_0$ and the new cosmic triangles
• A sub-2% Distance to M31 from Photometrically Homogeneous Near-Infrared Cepheid Period-Luminosity Relations Measured with the Hubble Space Telescope
• Limits on planetary-mass primordial black holes from the OGLE high-cadence survey of the Magellanic Clouds
• Dust distributions in the Magellanic Clouds
• A census of new globular clusters in the Galactic bulge
• On Zero Point Calibration of the Red Giant Branch Tip in the Magellanic Clouds
• Relativistic corrections for measuring Hubble's constant to 1% using stellar standard candles
• 3D Parameter Maps of Red Clump Stars in the Milky Way -- Absolute Magnitudes and Intrinsic Colors
• A Near-Infrared Extinction and Reddening Map Towards the Galactic Bulge Using UKIRT
• Blanco DECam Bulge Survey (BDBS) IV: Metallicity Distributions and Bulge Structure from 2.6 Million Red Clump Stars