Tracing the first stars and galaxies of the Milky Way

Understand

We use 30 high-resolution dark matter halos of the $Caterpillar$ simulation suite to probe the first stars and galaxies of Milky Way-mass systems.

• We quantify the environment of the high-$z$ progenitors of the Milky Way and connect them to the properties of the host and satellites today.
• We identify the formation sites of the first generation of Population III (Pop III) stars ($z$ ~ 25) and first galaxies ($z$ ~ 22) with several different models based on a minimum halo mass including a simple model for Lyman-Werner feedback.
• Through this method we find approximately 23,000 $\pm$ 5,000 Pop III potentially star-forming sites per Milky Way-mass host, though this number is drastically reduced to ~550 star-forming sites when Lyman-Werner feedback is included, as it has critical effects at these length scales.