The Milky Way ’ s central molecular zone ( CMZ ) , i.e .
the star-forming nuclear ring at R \lesssim 200 pc , has emerged in recent years as a unique laboratory for the study star formation .
In this paper we use the simulations presented in Tress et al .
2020 to investigate star formation in the CMZ .
The simulations include the gas flow in the whole inner disc ( R \leq 5 kpc ) of the Milky Way , which allows us to assess how the large-scale environment affects the formation of stars in the CMZ .
We comfortably reach sub-parsec resolution , which allows us to resolve individual molecular clouds .
Our main findings are as follows .
( 1 ) By studying the spatial and temporal distribution of stars formed along the CMZ ring , we find that most of the star formation happens downstream of the apocentres , consistent with the ‘ ‘ pearls-on-a-string ’ ’ scenario .
( 2 ) Our simulations do not support the notion that an absolute evolutionary timeline of star formation triggered by pericentre passage can be identified as gas clouds orbit in the CMZ ring .
( 3 ) Within the timescale of our simulation ( \sim 100 Myr ) , the depletion time of the CMZ is constant within a factor of \sim 2 .
This suggests that variations in the star formation rate are primarily driven by variations in the mass of the CMZ , caused for example by changes in the bar-driven inflow rate , AGN feedback , or other external events , and not by variations in the depletion time .
( 4 ) We study the trajectories of newly born stars in our simulations .
We find several examples that have age , line-of-sight velocity and proper motion velocity compatible with the Arches and Quintuplet clusters .
Our simulation suggests that these prominent clusters originate near the collision sites where the bar-driven inflow accretes onto the CMZ , at symmetrical locations with respect to the Galactic centre , and that they have already decoupled from the gas in which they were born .