Extragalactic Milky Way
There is ongoing debate about the characteristics of the closest Milky Way analogs, not just in terms of their masses and the geometric properties of their stellar discs, but also regarding their detailed kinematics, abundance patterns, and age distributions. At the heart of this discussion lies a Copernican question: to what extent is the Milky Way a typical example of galaxies of its mass, and how representative are its observed properties of the broader population of Milky Way-mass galaxies?
By leveraging the full distribution function obtained using my orbit superposition method, we can analyze the Milky Way in a manner analogous to the study of extragalactic systems. This approach eliminates the need for additional assumptions about stellar populations, as ages and abundances of stellar populations are directly derived from high-quality APOGEE data. Subsequently, we generate a mock datacube, closely resembling those produced by instruments like MUSE, enabling a more direct comparison with observations of external galaxies.
Next, by applying standard tools for fitting the spectra of unresolved stellar populations, such as pPXF, we can reconstruct how the extragalactic kinematics (as shown in the figure above) and age/abundance distributions would appear in the Milky Way if it were observed as an external galaxy...
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Stay tuned for more exciting results about the extragalactic Milky Way!