Using the Gaia DR2 to Observe Stellar Streams & Dark Matter Distribution in the Milky Way

Abigail Ambrose


Using data from the second Gaia data release, we have observations of the positions and motions of many stars within our Galaxy and we can use this information to construct a rotation curve for our Galaxy. From the rotation curves, it is known that the total mass of the Galaxy is more than the expected mass from luminous matter. From these rotation curves, we can also find the dark matter density within the Milky Way. With information about the dark matter density of the Milky Way, we can also study other impacts of dark matter such as changes in the motion of stars. From this, we can gain a further understanding of the detailed dark matter distribution within the Galaxy. By observing how the stars are perturbed within the M68 stellar stream, we can detect dark matter subhalos within the dark matter halo of the Milky Way galaxy. In order to do this, we are using the second Gaia data release to observe the stars within this stream. We are replicating the work done by Price-Whelan & Bonaca (2018) on the GD-1 stellar stream and applying the methodology to the M68 stellar stream. By looking for places where the stars are outside of their expected position within the stream we can begin to see where dark matter subhalos have been, furthering our understanding of the dark matter distribution in the Milky Way.