With Gaia Data Release 2, the astronomical community is entering a new era of multidimensional surveys of the Milky Way. This new phase-space view of our Galaxy demands new tools for comparing observations to simulations of Milky-Way-mass galaxies in a cosmological context, to test the physics of both dark matter and galaxy formation. We present ananke, a framework for generating synthetic phase-space surveys from high-resolution baryonic simulations, and we use ananke to generate a suite of synthetic surveys designed to resemble Gaia DR2 in data structure, magnitude limits, and observational errors. We use three cosmological simulations of Milky-Way-mass galaxies from the Latte suite of the Feedback In Realistic Environments (FIRE) project, which offer many advantages for generating synthetic stellar surveys: self-consistent clustering of star formation in dense molecular clouds, thin stellar and gaseous disks, cosmological accretion and enrichment histories, all in live cosmological halos with satellite dwarf galaxies and stellar halos. We select three solar viewpoints from each simulation to generate nine synthetic Gaia-like surveys. We generate synthetic stars assuming that each simulation’s star particles (of mass 7070 M☉) represent a single stellar population, and we use a kernel density representation to distribute synthetic stars accurately in position and velocity. At each viewpoint, we compute a self-consistent dust extinction map, using the gas metallicity distribution in each simulation. Finally, we apply a simple error model to produce a synthetic Gaia-like survey at each solar viewpoint, though we also provide quantities without error convolution. This results in a catalog of synthetic stars, as if measured by Gaia, that includes both observational properties and a pointer to each generating star particle in the simulation. We also provide the complete snapshot–including star, gas, and dark matter particles–at z = 0 for each simulated galaxy. We describe data access points, the data model, and plans for future upgrades to ananke. These synthetic surveys provide a tool for the scientific community to test analysis methods and interpret Gaia data.
|Original language||English (US)|
|State||Published - Jun 27 2018|
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