The 50 Year Evolution of the Luminous Supernova Remnant J1228+441 in NGC 4449

Over the past 50 years, the luminous supernova remnant SNR J1228+441 has been observed at multiple radio frequencies and is the brightest radio source in the irregular galaxy NGC 4449. Based on VLBI observations, the remnant is estimated to have an age of less than 100 years (Mezcua, Lobanov, and Marti Vidaland, 2013, MNRAS, 436, 2454) and is one of the youngest supernova remnants that can be studied. By combining new VLA measurements with previously published observations, we now have a 50 year baseline of observations. We will present the new light curves at multiple frequencies, which confirm past findings of a steady decline in radio emission over the last half-century. We will discuss the rate of decline and the spectral index evolution for SNR J1228+441.