Presentation #203.01 in the session Mapping and Modeling the Milky Way’s Tidal Streams.
Galaxies grow through hierarchical mergers, with high-mass galaxies cannibalizing the satellite dwarf galaxies that orbit them. These galactic accretion events leave behind signatures in the form of tidal debris structures that encode information about their progenitors and hosts. Examining these substructures can open a window into the accretion histories of galaxies in the universe, as well as the dark-matter-dominated mass distribution in galaxy halos. By capturing vast numbers of images of tidal debris substructures, upcoming surveys like LSST will provide us with the data required to gain statistically sound constraints on the orbital distributions of satellites. An automated method for analyzing this data is vital for efficiency and consistency. We present an algorithm that can efficiently and reliably measure the properties of tidal debris substructures, yielding results that can be used to constrain the distributions of accreting satellites. Our method is capable of distinguishing shell-like and stream-like tidal debris – the most distinct morphologies – and measuring their luminosities and scales, properties that hint at the shape of the satellite orbit, the duration of accretion, and satellite mass. We demonstrate our algorithm on snapshot images from n-body simulations, and explore how analyzing their observable properties will help us unravel the accretion histories of galaxies in our universe, and allow us to probe theories of hierarchical galaxy formation and their underlying cosmological paradigm.