Searching for Tidal Tails in Globular Clusters Using Gaia DR2

Globular clusters are excellent tracers of the Galactic potential. Their orbital parameters and stellar density profiles can also be used to infer previous interactions with the disk and bulge of the Galaxy as the clusters pass through those regions. Specifically, clusters that experience differential Galactic potential exceeding the gravitational binding of the clusters at any time in their orbits are likely to display traces of tidal deformation. A main challenge in the detection of tidal tails in star clusters is determining which stars in the field belong to the cluster. Most previous studies have relied on photometric parameters to determine cluster membership. With the second Gaia data release in 2018, it is now possible to utilize additional astrometric information to maximize signal from cluster stars. We used a matched filtering algorithm to select stars associated with globular clusters using color, magnitude, parallax, and proper motion from Gaia. We sampled 25 globular clusters with eccentric orbits and recovered tidal tails or overdensities around 9 clusters, consistent with results in the literature. We are currently working on refining the pipeline with the hope to analyze more clusters for potentially undocumented tidal features. With a mature pipeline, it will become increasingly possible to use identified tidal deformations to infer the lifetime of globular clusters within the Milky Way potential and trace the mass distribution within the Galaxy.