University of Maryland at College Park
Department of Astronomy - High-Energy Astronomy

Recent Explorations

• x-ray astronomy
• galactic center
• gamma-ray astronomy
• white dwarfs
• euve astronomy
• cosmic-ray propagation

Gamma-rays are the most energetic form of electromagnetic radiation. They behave basically the same as light, radio waves or X-rays, but each photon carries more energy or, equivalently, the wave frequency is much higher. Astrophysicists cannot see gamma-rays, of course, so detectors on satellites and balloons high above the Earth's absorbing atmosphere record data. Astronomical objects that emit gamma-rays include decaying radioactive debris associated with stellar explosions, active galactic nuclei, and the sun.

More than two decades ago a gamma-ray line at 511 keV (kilo electron volts) was detected from the center of the Milky Way galaxy. It's source, producing the energy equivalent of about 10,000 suns, continues to remain a mystery. Theorists speculate that positrons (antielectrons) may be produced by one or a small number of black holes, or possibly, the result of several stellar explosions. These positrons fan out across the galaxy like a spider's web, eventually finding "cool" electrons far from their origin with which they annihilate and emit the 511 keV line.

This project is a collaboration with scientists at Goddard Space Flight Center, and is typical of the research in which our students participate. Other projects include leading-edge satellite- or balloon-based explorations in high-energy astrophysics, X-ray astronomy, gamma-ray astronomy, and cosmic-ray physics.

Photo Caption:

A gamma-ray balloon instrument being launched over Alice Springs, Australia. (The center of the Milky Way Galaxy passes directly overhead at these latitudes.) The balloon and the telescope float at 40 km above the Australian Outback for one to two days, as data is sent to the ground. The telescope falls safely to Earth via parachute at the end of the flight.

Adeena Mignogna

"MSEDS (Maryland Students for the Exploration and Development of Space) is an undergraduate student group that gets together once a week to talk about events going on in the space community. We invite speakers, watch movies--next week we're having a paper airplane competition! Each semester we go to the National Radio Observatory in Greenbank, W.V., and stay at housing on site. They have a 40-foot radio telescope we operate ourselves.

The fact that we're in a very active place for the space sciences is ideal for students who want to pursue careers in astrophysics. I want eventually to work in the space program in some fashion. I'm very interested in designing bases or laboratories for use in space, on the moon, or even on Mars. Of course, being an astronaut wouldn't be so bad either!"

Continue on to find out about Planetary Astronomy.