We present the results of the hierarchical clustering analysis of the Gaia DR2 data to search for clusters , co-moving groups , and other stellar structures .
The current paper builds on the sample from the previous work , extending it in distance from 1 kpc to 3 kpc , increasing the number of identified structures up to 8292 .
To aid in the analysis of the population properties , we developed a neural network called Auriga to robustly estimate the age , extinction , and distance of a stellar group based on the input photometry and parallaxes of the individual members .
We apply Auriga to derive the properties of not only the structures found in this paper , but also previously identified open clusters .
Through this work , we examine the temporal structure of the spiral arms .
Specifically , we find that the Sagittarius arm has moved by > 500 pc in the last 100 Myr , and the Perseus arm has been experiencing a relative lull in star formation activity over the last 25 Myr .
We confirm the findings from the previous paper on the transient nature of the spiral arms , with the timescale of transition of a few 100 Myr .
Finally , we find a peculiar \sim 1 Gyr old stream of stars that appears to be heliocentric .
It is unclear what is the origin of it .