Distances to Local Group Galaxies via Population II, Stellar Distance Indicators I: The Sculptor Dwarf Spheroidal

Abstract

We determine the distance to the Sculptor Dwarf Spheroidal via three Population II stellar distance indicators: (a) the Tip of the Red Giant Branch (TRGB), (b) RR Lyrae variables (RRLs), and (c) the ridgeline of the blue horizontal branch (HB). High signal-to-noise, wide-field $VI$ imaging that covers an area $48^{\prime }\times 48^{\prime }$ and reaches a photometric depth approximately 2 mag fainter than the HB was acquired with the Magellan-Baade 6.5m telescope. The true modulus derived from Sculptor's TRGB is found to be ${\mu }_o^{\mathrm{TRGB}}=19.59\pm 0.07_{\mathrm{stat}}\pm 0.05_{\mathrm{sys}}$ mag. Along with periods adopted from the literature, newly acquired RRL phase points are fit with template light curves to determine ${\mu }_{W_{I,V-I}}^{\mathrm{RRL}}=19.60\pm 0.01_{\mathrm{stat}}\pm 0.05_{\mathrm{sys}}$ mag. Finally, the HB distance is found to be ${\mu }_o^{\mathrm{HB}}=19.54\pm 0.03_{\mathrm{stat}}\pm 0.09_{\mathrm{sys}}$ mag. Absolute calibrations of each method are anchored by independent geometric zero-points, utilizes a different class of stars, and are determined from the same photometric calibration.

16 pages, 14 figures

References in corpus (23)

• The Gaia mission
• Gaia Early Data Release 3: The astrometric solution
• Measurements of the Hubble Constant: Tensions in Perspective
• Gaia EDR3 view on Galactic globular clusters
• Gaia Early Data Release 3 -- Catalogue validation
• Calibration of the Tip of the Red Giant Branch (TRGB)
• The Gas Content and Stripping of Local Group Dwarf Galaxies
• Homogeneous photometry VII. Globular clusters in the Gaia era
• The RR Lyrae Period - K Luminosity relation for Globular Clusters: an observational approach
• The Araucaria Project. The Distance to the Sculptor dwarf spheroidal galaxy from infrared photometry of RR Lyrae stars
• The brightness of the Red Giant Branch tip: Theoretical framework, a set of reference models, and predicted observables
• 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
• The Tip of the Red Giant Branch Distances to Type Ia Supernova Host Galaxies. IV. Color Dependence and Zero-Point Calibration
• Sharpening the Tip of the Red Giant Branch
• Gaia Early Data Release 3. Building the Gaia DR3 source list -- Cross-match of Gaia observations
• Standard Galactic Field RR Lyrae. I. Optical to Mid-infrared Phased Photometry
• Validation of the accuracy and precision of Gaia EDR3 parallaxes with globular clusters
• Fiducial Stellar Population Sequences for the u'g'r'i'z' System
• Standard Galactic Field RR Lyrae II: A Gaia DR2 calibration of the period-Wesenheit-metallicity relation
• The star formation history of the Sculptor dwarf spheroidal galaxy
• The proper motion of Andromeda from Gaia eDR3: confirming a nearly radial orbit
• Distances to Local Group Galaxies via Population II, Stellar Distance Indicators. II. The Fornax Dwarf Spheroidal
• Multi-Wavelength, Optical (VI) and Near-Infrared (JHK) Calibration of the Tip of the Red Giant Branch Method based on Milky Way Globular Clusters

Cited by in corpus (4)

• RR Lyrae mid-infrared Period-Luminosity-Metallicity and Period-Wesenheit-Metallicity relations based on Gaia DR3 parallaxes
• Tip of the Red Giant Branch Distances with JWST. II. I-band Measurements in a Sample of Hosts of 10 SN Ia Match HST Cepheids
• The use of double-mode RR Lyrae stars as robust distance and metallicity indicators
• Decoding RR Lyrae light curves with deep learning for accurate absolute magnitude estimation