Resolving Stellar Populations in the Nuclear Region of NGC 4258

We present Near-Infrared Camera (NIRCam) imaging of NGC 4258. Located at a distance of 7.2 Mpc, NGC 4258 is an ideal and nearby laboratory to study the effects of AGN feedback in both regulating star formation as well as expelling gas from the host galaxy, i.e., negative feedback. With the unprecedented resolution of NIRCam, we observe [Fe II], Paschen-alpha, molecular hydrogen, PAH emission, and Bracket-alpha. Our work looks at the impact of shocks in both the star formation spiral arm and anomalous spiral arm on the current and past star formation within NGC 4258. We have discovered a that the anomalous spiral arms seen in previous radio observation of NGC 4258 are correlated to NIRCam observations of [Fe II] and molecular hydrogen, implying the radio emission is more likely due to shocks. With color magnitude diagrams (CMDs), we show that NGC 4258 has a variety of stellar populations: young stellar object, asymptotic giant branch stars, red giant branch stars, red clump stars, as well as possible detection of super giant stars. We fit models to the young stellar object photometry and find these young protostars to be 10 –30 Msun. With a distance of 7.2 Mpc, we are likely observing stellar clusters which are 10 – 30 Msun. We study the young stellar objects and older asymptotic giant branch stars on parsec scales as well as galactic scales to understand the processes driving star formation: galactic merger, AGN feedback, as well as winds and jets from massive O stars.