Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Patryk Iwanek
Radosław Poleski
Szymon Kozłowski
Igor Soszyński
Paweł Pietrukowicz
Makiko Ban
Jan Skowron
Przemysław Mróz
Marcin Wrona
Andrzej Udalski
Michał K. Szymański
Dorota M. Skowron
Krzysztof Ulaczyk
Mariusz Gromadzki
Krzysztof Rybicki
Milena Ratajczak
Abstract： We study the three-dimensional structure of the Milky Way using 65,981 Mira variable stars discovered by the Optical Gravitational Lensing Experiment (OGLE) survey. The spatial distribution of the Mira stars is analyzed with a model containing three barred components that include the X-shaped boxy component in the Galactic center (GC), and an axisymmetric disk. We take into account the distance uncertainties by implementing the Bayesian hierarchical inference method. The distance to the GC is $R_0 = 7.66 \pm 0.01 \mathrm{(stat.)} \pm 0.39 \mathrm{(sys.)}$ kpc, while the inclination of the major axis of the bulge to the Sun-GC line-of-sight is $\theta = 20.2^\circ \pm 0.6^\circ \mathrm{(stat.)} \pm 0.7^\circ \mathrm{(sys.)} $. We present, for the first time, a detailed three-dimensional map of the Milky Way composed of young and intermediate-age stellar populations. Our analysis provides independent evidence for both the X-shaped bulge component and the flaring disk (being plausibly warped). We provide the complete dataset of properties of Miras that were used for calculations in this work. The table includes: mean brightness and amplitudes in nine photometric bands (covering a range of wavelength from 0.5 to 12 $\mu$m), photometric chemical type, estimated extinction, and calculated distance with its uncertainty for each Mira variable. The median distance accuracy to a Mira star is at the level of $6.6\%$.
Peer Review Status:
Awaiting Review
Hits
Hits
Downloads
Comment