http://arxiv.org/abs/2205.08548
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 $48′ \times 48’$ 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 $\mu^\mathrm{TRGB}o = 19.59 \pm 0.07\mathrm{stat} \pm 0.05_\mathrm{sys}$ 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 $\mu^\mathrm{HB}o = 19.54 \pm 0.03\mathrm{stat} \pm 0.09_\mathrm{sys}$ 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.
Q. Tran, T. Hoyt, W. Freedman, et. al.
Thu, 19 May 22
54/61
Comments: 16 pages, 14 figures