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The Challenge of Accurately Identifying Merging Galaxies


Rebecca Nevin (Harvard CfA)

October 30 @ 12:00 PM - 1:00 PM

Merging galaxies play a key role in galaxy evolution, and progress in our understanding of galaxy evolution is slowed by the difficulty of making accurate galaxy merger identifications. Mergers are typically identified using individual imaging techniques, each of which has its own limitations and biases. The stellar kinematics more directly trace the dynamics of galaxies (independent of their visual morphologies) and can be powerful probes of their assembly histories. With the growing popularity of integral field spectroscopy (IFS), it is now possible to introduce kinematic signatures to improve galaxy merger identifications. I use GADGET-3 N-body/hydrodynamics simulations of merging galaxies coupled with SUNRISE dust radiative transfer simulations to create mockup stellar kinematic maps and images to match the specifications of the Mapping Nearby Galaxies at Apache Point (MaNGA) survey, which is the largest IFS survey of galaxies to date. From the mockup galaxies, I have developed the first merging galaxy classification scheme that is based on kinematics and imaging. I will discuss the strengths and limitations of the classification technique and my plans to apply the classification to the >10,000 observed galaxies in the MaNGA survey. I will then discuss my plans to utilize these large samples of merging galaxies (of different stages and mass ratios) to advance our understanding of open questions related to galaxy evolution, such as how star formation and AGN triggering change for different stages and types of mergers.