Iowa astrophysicists provide the eyes for new gamma ray telescope system

Apr 19, 2007
500 Photon Detectors
Iowa State University astrophysicists designed and built four of these cameras for the VERITAS gamma ray telescope system. Each camera contains 500 tube-shaped photo detectors. Credit: Photo contributed by Frank Krennrich/Iowa State University

There's a "First Light Fiesta" in the works at Mt. Hopkins near Amado, Ariz. And Iowa State University astrophysicists will be among those enjoying the celebration of a new telescope system and all the science it will produce.

The $20 million VERITAS telescope system – that's the Very Energetic Radiation Imaging Telescope Array System – at the Fred Lawrence Whipple Observatory south of Tucson doesn't look like the telescope you used in high school. It's made of four reflectors 12 meters across that look like satellite dishes. The reflectors are covered with mirrors that direct light into cameras attached to the front of each dish. Each camera is about 7 feet across and contains 500 tube-shaped photon detectors or pixels. The telescope system is based on techniques Iowa State researchers Richard Lamb and David Carter-Lewis helped develop in the 1980s.

All those detectors for the VERITAS system were built in a laboratory on the fourth floor of Iowa State's Zaffarano Physics Addition. It took about $1 million and a lot of work by Iowa State post-doctoral researchers Tomoyuki Nagai and Martin Schroedter to do it.

Frank Krennrich, an Iowa State professor of physics and astronomy and leader of Iowa State's work on the VERITAS project, said the telescope system will be looking for gamma rays from space.

VERITAS is the northern hemisphere's most sensitive instrument for finding that high energy electromagnetic radiation. And gamma rays do have lots of energy: the energy of visible light is one electron volt; gamma rays have energies of one million to one trillion electron volts.

Even with all that energy, the rays can't penetrate the earth's atmosphere. But when they hit the atmosphere they create showers of electrons and positrons that create a blue light known as Cerenkov radiation. The showers move very fast. And they're not very bright.

So it takes a powerful instrument to find them. The astronomers say VERITAS is proving to be as sensitive as they expected.

"The quality of the data is so much better," Krennrich said. "The more telescopes you have, the higher the resolution for these measurements."

That's good news to Martin Pohl, an Iowa State assistant professor of physics and astronomy who's working to analyze and explain the data from the VERITAS observations, and Asif Imran, an Iowa State doctoral student whose dissertation includes the analysis of VERITAS data.

"Being able to see more precisely allows you to ask more precise questions," Pohl said.

Astrophysicists now know that gamma rays are produced by supermassive black holes, supernova remnants, pulsars, gamma ray bursts and other space objects. The crab Nebula is one source of gamma rays.

Researchers believe more knowledge of gamma rays could help them explore distant regions of space, help them look for evidence of dark matter, determine how much electromagnetic radiation the universe has produced, answer questions about the formation of stars and help explain the origins of the most energetic radiation in the universe.

Without the improvements in data now being produced by VERITAS, "You're like a fish on the beach," Pohl said.

And so these Iowa State astrophysicists have good reason to celebrate the telescope system's first light April 27-29 in the Arizona mountains.

"This is a pretty big deal," Krennrich said. "We have worked 10 years on this."

Source: Iowa State University

Explore further: A new approach in the search for extraterrestrial intelligence: targeting alien polluters

add to favorites email to friend print save as pdf

Related Stories

Tropical Storm Wali no more, but remnants soaked Hawaii

42 minutes ago

On July 19, NOAA's Central Pacific Hurricane Center noted that Wali didn't even make it to the Big Island, but moisture associated with the storm did. NOAA's GOES-West satellite captured an image of the remnant ...

NASA image: Fires in Indonesia, July 2014

43 minutes ago

Terra and Aqua satellites detected 154 hotspots in areas across Riau province on Sunday, July 20, indicating forest and land fires had increased again following a decline in rainfall. The number of detected ...

Climate: Meat turns up the heat

43 minutes ago

Eating meat contributes to climate change, due to greenhouse gasses emitted by livestock. New research finds that livestock emissions are on the rise and that beef cattle are responsible for far more greenhouse gas emissions ...

A molecule's transformation filmed at high resolution

44 minutes ago

François Légaré's team at the INRS Énergie Matériaux Télécommunications Research Centre successfully imaged a chemical reaction with a spatial and temporal resolution greatly exceeding that obtained to date using microscopes. ...

Recommended for you

Satellite galaxies put astronomers in a spin

55 minutes ago

An international team of researchers, led by astronomers at the Observatoire Astronomique de Strasbourg (CNRS/Université de Strasbourg), has studied 380 galaxies and shown that their small satellite galaxies almost always ...

Video: The diversity of habitable zones and the planets

1 hour ago

The field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. A key step towards this characterization is the determination of which planets occupy the Habitable ...

Ultra-deep astrophoto of the Antenna Galaxies

1 hour ago

You might think the image above of the famous Antenna Galaxies was taken by a large ground-based or even a space telescope. Think again. Amateur astronomer Rolf Wahl Olsen from New Zealand compiled a total ...

The most precise measurement of an alien world's size

2 hours ago

Thanks to NASA's Kepler and Spitzer Space Telescopes, scientists have made the most precise measurement ever of the radius of a planet outside our solar system. The size of the exoplanet, dubbed Kepler-93b, ...

User comments : 0