Astrophysical objects can accelerate particles to energies beyond the reach of any ground-based accelerator yet built. What drives this acceleration is an important question in astrophysics. High energy gamma-ray emission is a key diagnostic and can be used to probe the acceleration mechanisms. With this award the University of Iowa particle astrophysics group will use the VERITAS imaging air Cherenkov telescope for a systematic study of pulsar wind nebulae, the most common galactic high energy gamma-ray sources. Studies of Pulsar Wind Nebulae address central questions in high-energy astrophysics including the acceleration mechanism and the propagation of relativistic particles in the interstellar medium. To extend the broader impacts of this work, each year the Iowa group will host an undergraduate summer intern from an underrepresented minority who will be directly involved in the research. This program will draw on the success of the minority recruitment program of the Math Department at Iowa, including their extensive network of colleges with large minority enrollments, and the connections of the Adler Planetarium with minority-serving institutions in the Chicago area. In addition, the group will work to increase public interest in astronomy and broadly disseminate the results of their research through the public astronomical observing program run by the local chapter of the Society of Physics Students.
Pulsar wind nebulae are powered by relativistic particles accelerated in the termination shocks of the winds emanating from rotation-powered pulsars. The Iowa group will study the whole population of pulsar wind nebulae in the northern hemisphere using VERITAS follow-up observations of sources discovered by Milagro and in the near future by HAWC forming an unbiased survey. The goal is to produce a complete inventory of powerful, nearby leptonic particle accelerators in the northern sky. The group will also conduct detailed observations of selected pulsar wind nebulae at multiple wavebands to constrain their physical properties. The Iowa group will also continue to operate and maintain the VERITAS pointing monitors and contribute to VERITAS operations.
