Mock catalogs of sophisticated galaxy simulations provide unique opportunities for observational projects, in particular, the ability to test for or constrain the impact of selection functions, field plans, and algorithms on the scientific inference being made. One of the most realistic galaxy simulations to date is the Latte simulation suite that uses the FIRE2 framework to produce Milky Way galaxies (Wetzel et al. 2016). Recent efforts have translated these simulations into catalogs of observables, collectively known as the Ananke simulations, that provide the key Gaia observables for the star particles in the simulations (Sanderson et al. 2020); these include radial velocity, proper motion, chemistry (10 chemical elements are tracked in the simulation), parallax, and photometry in the Gaia bands, among others. Because the input physics and the global structure of the model galaxy are known, these mock catalogs provide a rare experimental laboratory to make connections between the resolved stellar populations and global galaxy studies -- the key driver in the Milky Way as a Galaxy working group (MWAG). With Nikakhtar et al. (2021), the Ananke simulations are updated with APOGEE-2 specific properties (e.g., selection photometry) and are suitable for broad use. With this VAC, we provide the APOGEE-suitable simulations along-side the APOGEE-2 data providing a unique tool for Galactic inferences.
Each of the 9 synthetic surveys (3 different simulations, 3 different Solar positions per sim) has a total of 10 subfiles sliced by heliocentric distance for easier transport. The number of rows in each slice for the full-sized surveys (see Sanderson et al. 2020, Table 6 for full stats) ranges 50 million to 1 billion elements.
Data model basics: There are 73 columns as listed in Ananke original (https://fire.northwestern.edu/ananke/), plus the following new columns relevant for APOGEE: 10 APOGEE-measured abundances, 10 measurement uncertainties per star (20 cols), (2) 2MASS JHKs observed magnitudes, intrinsic (unreddened) magnitudes, true (reddened/extincted but not error-convolved) magnitudes, photometric uncertainties for all stars (12 cols), (3) Column applying Ted Mackereth’s APOGEE sky footprint, selection function (1 Boolean column) for an estimated total of 106 columns.
Please note: this VAC will become available on the CAS through SciServer in 2022, along with tutorials and use cases. If you are planning to use this VAC for your science, we recommend that you interact with the catalog using SciServer instead.
