Journal article
The Mira-based Distance to the Galactic Center
The Astrophysical journal, Vol.865(1), p.47
09/20/2018
DOI: 10.3847/1538-4357/aad7fb
Abstract
Mira variables are useful distance indicators, due to their high luminosities and well-defined period-luminosity relation. We select 1863 Miras from SAAO and MACHO observations to examine their use as distance estimators in the Milky Way. We measure a distance to the Galactic center of R-0 = 7.9 +/- 0.3 kpc, which is in good agreement with other literature values. The uncertainty has two components of similar to 0.2 kpc each: the first is from our analysis and predominantly due to interstellar extinction, the second is due to zero-point uncertainties extrinsic to our investigation, such as the distance to the Large Magellanic Cloud (LMC). In an attempt to improve existing period-luminosity calibrations, we use theoretical models of Miras to determine the dependence of the period-luminosity relation on age, metallicity, and helium abundance, under the assumption that Miras trace the bulk stellar population. We find that at a fixed period of log P = 2.4, changes in the predicted K-s magnitudes can be approximated by Delta M-Ks approximate to -0.109(Delta[Fe/H]) + 0.033(Delta t/Gyr) + 0.021(Delta Y/0.01), and these coefficients are nearly independent of period. The expected overestimate in the Galactic center distance from using an LMC-calibrated relation is similar to 0.3 kpc. This prediction is not validated by our analysis; a few possible reasons are discussed. We separately show that while the predicted color-color diagrams of solar-neighborhood Miras work well in the near-infrared; though, there are offsets from the model predictions in the optical and mid-infrared.
Details
- Title: Subtitle
- The Mira-based Distance to the Galactic Center
- Creators
- Wenzer Qin - Johns Hopkins UniversityDavid M. Nataf - Johns Hopkins UniversityNadia Zakamska - Johns Hopkins UniversityPeter R. Wood - Australian National UniversityLuca Casagrande - Australian National University
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.865(1), p.47
- Publisher
- Iop Publishing Ltd
- DOI
- 10.3847/1538-4357/aad7fb
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Number of pages
- 13
- Grant note
- Mount Stromlo and Siding Spring Observatory, part of the Australian National University; Australian National University NASA's Maryland Space Grant Consortium Allan C. and Dorothy H. Davis Fellowship ohns Hopkins University Catalyst Award National Science Foundation; National Science Foundation (NSF) MAESTRO 2014/14/A/S3T9/00121 / National Science Centre, Poland National Aeronautics and Space Administration; National Aeronautics & Space Administration (NASA) DP150100250; FT160100402 / Australian Research Council AST-8809616 / National Science Foundation through the Center for Particle Astrophysics of the University of California; National Science Foundation (NSF) W-7405-Eng-48 / US Department of Energy through the University of California, Lawrence Livermore National Laboratory; United States Department of Energy (DOE)
- Language
- English
- Date published
- 09/20/2018
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984701734202771
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