The Spectacular Tidal Tails of Globular Cluster M3 (NGC 5272)

Abstract

We provide a detailed analysis of the tidal tails of the globular cluster M3 (NGC 5272). We first discover clear extratidal structures with a slight S shape near the cluster. This inspires us to examine the existence of its long tidal tails. We highlight potential stream stars using the proper motions (PMs) of a model stream combined with the cluster’s locus in a color–magnitude diagram (CMD). A 35° long leading tail and a 21° long trailing tail are successfully detected at the same time. Their corresponding overdensities can be recognized in CMD and PM space after subtracting the background. We estimate the stream width, star number density, and surface brightness for both tails, as well as the distance variation along the entire stream. We then verify the connection of M3 and the Svöl stream. Finally, we tabulate 11 member stars belonging to the M3 tidal stream with available spectroscopic observations.

Keywords

• Globular star clusters
• Stellar streams
• Milky Way stellar halo