Institute for Advanced Study Informal Astrophysics Seminar

Seven years ago, while surveying the high-energy sky, the Large Area Telescope (LAT) on the Fermi satellite unexpectedly detected gamma-rays from a nova explosion. Four years later, after several more such detections, the Fermi/LAT team reported that novae constitute a new class of gamma-ray sources. High spatial-resolution radio imaging of one particular nova -- V959 Mon -- has now revealed the origin of these gamma-rays. Our observations showed that V959 Mon produced multiple, distinct outflows. When these outflows collided with each other, the resulting shocks accelerated particles to relativistic speeds, enabling them to generate gamma-rays. Moreover, it appears to be common for classical nova eruptions to produce colliding flows like those in V959 Mon, making novae important laboratories for particle acceleration in shocks. I will describe our findings and their implications.