CHEYENNE — Sitting in University of Wyoming astronomy professor Michael Pierce’s laboratory is a 7-foot-long, Thermos-like metal tube that he hopes will help unlock the mysteries of the early universe.
Built from scratch by Pierce and other UW researchers over seven years, the Near-Infrared Imaging Spectrograph can detect light emitted billions of years ago by distant stars and galaxies — light that’s traveled so far that it can no longer be detected by human eyes by the time it reaches Earth.
Pierce plans to use the $1 million spectrograph to survey the skies for evidence of massive clusters of stars slamming together to form early galaxies, as well as to try to count how often stars form and collapse in explosions so giant that their remnants are still speeding across the universe after most other energy has dissipated.
And by collaborating with large telescopes across the country to use the spectrograph, Pierce said, UW students and professors can get access to those telescopes to further their own studies.
“It opens up a whole new avenue of research,” Pierce said.
The spectrograph is useful because it can detect infrared waves — energy from farther away than anything a light-based telescope can detect.
That’s because as light moves through space over time, its wavelengths get longer and longer to the point that they dip below the visible spectrum — what humans and most telescopes can detect — to the infrared spectrum. It’s these faint, distant waves that Pierce’s spectrograph is designed to pick up.
Pierce describes the spectrograph as a sort of giant digital camera hooked up to a telescope. The digital data collected is fed into the spectrograph to create an image researchers can see.
To work, the entire device has to be cooled to the temperature of liquid nitrogen: 300 degrees below zero.
Pierce recently tested the camera at Apache Point Observatory in Sunspot, N.M., where it will be housed later this year. Its wide field of view allowed scientists to capture images about half the size of the full moon.
Pierce and UW are now looking to put the device to work toward two important goals.
First, Pierce hopes to use the spectrograph to do a lot of prep work in advance of NASA’s James Webb Space Telescope, the infrared-only successor to the Hubble telescope.
When the Webb telescope is launched around 2018, requests for access to it will be extremely high, making it vital that it’s used as efficiently as possible.
The UW spectrograph can help by assisting ground-based telescopes in sweeping the skies looking for infrared evidence of galaxy clusters or other interesting celestial bodies. Areas that seem promising can then be followed up with a look from the Webb telescope when it heads into orbit.
NASA astrophysicist Neil Gehrels said the instrument will also be useful in studying gamma ray bursts, which are big explosions that occur in distant galaxies. A satellite detects the explosions, which occur about twice a week, and transmits the location to the ground.
“Then we want to observe them quickly with other telescopes in space and on the ground,” Gehrels told the Laramie Boomerang.
These bursts, the cause of which is still unknown, glow with infrared radiation.
“For the first day or so when you can observe them with telescopes, they’re by far the brightest distant sources in the sky. You can use them to study the galaxy that they’re in and learn about when stars first formed in the universe. You can use them to study the very early universe,” he said.
Pierce estimated there are fewer than 10 similar instruments in the world, and nothing on this large of a scale has ever been built at UW.
UW last had a spectrograph two decades ago, at its Wyoming Infrared Observatory about 25 miles southwest of Laramie.
Pierce built many of the devices at the observatory himself, giving him the expertise needed to build the new spectrograph. Most of the funding for the spectrograph came from a National Science Foundation grant, he said.
During the past 20 years, Wyoming’s observatory facilities have been eclipsed by newer, larger, more technologically advanced telescopes.
Pierce said the spectrograph can get UW students and researchers a foot in the door of those new facilities by trading use of the device for access to the telescopes.
“It allows us to train the next generation of students who are interested in pursuing a career in astronomy,” he said.
At least, for awhile. Like any cutting-edge technology, the UW spectrograph itself will inevitably be overshadowed over the years by newer, better equipment to study the heavens.
“Science marches on,” Pierce said. “Anytime somebody builds something, people look around and say, ‘Well, jeez, we can build something even better.’”