Two New UF Instruments To Aid Quest For Cosmic Origins

May 5, 2003

GAINESVILLE, Fla. — Astronomers probing the most distant and ancient regions of the universe and the origins of galaxies, stars and planets will soon have two powerful new tools.

After spending nearly five years building it, a team of University of Florida scientists this month installed the world’s most advanced mid-infrared camera on the Gemini Telescope in Chile, one of the largest telescopes in the world.

Meanwhile, the Gemini Observatory, the international consortium that oversees two telescopes in Chile and Hawaii, has announced it will provide UF researchers $3.1 million to design and build a bigger, more-powerful version of a UF-developed infrared spectrometer that has been in use for nearly three years. The new tool will significantly increase the number of distant stars or galaxies that astronomers can investigate each night, leading to new information on the origins of galaxies, planets and other celestial bodies.

“Without these instruments, these telescopes are basically light collectors – they collect the light and bring it to focus,” said Richard Elston, a UF professor of astronomy and a leader of UF’s growing astronomical instrumentation program. “You have to build these instruments to do the scientific analysis, and that’s what we’re doing here.”

Astronomers interested in how galaxies or celestial bodies form typically can’t rely on visible light, because the objects they study are too far away, don’t emit much visible light, or are concealed by clouds of gas or particles.

As a result, astronomers often look for answers in lower frequency infrared light, which is emitted by all objects that generate heat. Using telescopes and instruments modified to receive this infrared light, astronomers can “see” many galaxies or celestial bodies that are otherwise invisible, because infrared light penetrates dust clouds and travels huge distances. By analyzing the different spectra of this light, astronomers can draw conclusions about these objects’ sizes, distances from the Earth, chemical compositions, temperatures and so on.

The new UF-built instruments are designed to enhance such infrared observations. They will be used first at Gemini South, which is on Chile’s Cerro Pachon mountain and is the twin of Gemini North on Hawaii’s Mauna Kea. These telescopes, which have mirrors that are about 27-foot in diameter, are among the largest in the world.

Charlie Telesco, a UF professor of astronomy, led the development of the instrument – called the Thermal Region Camera and Spectrograph, or T-ReCS – just installed on Gemini South. He said T-ReCS is expected to prove particularly useful for investigating celestial objects that have temperatures less than 200 degrees Fahrenheit, very cool by celestial standards. These include, for example, the giant, swirling discs of dust that surround stars as they form and are thought to coagulate into planets. “By imaging the dust in discs around distant stars, we can understand how planets form,” Telesco said.

Telesco added that T-ReCS also will help astronomers investigate more distant, much more faint stars. Many of these stars, and other distant objects, are so far away their light takes millions or even billions of years to reach Earth. As a result, astronomers can, in effect, use them as time travel machines to learn not only about their origins but also the genesis of the universe.

Elston conceived and developed the Florida Multi-object Imaging Grism Spectrometer – FLAMINGOS for short – designed for telescopes smaller than the Gemini’s, such as the 13-foot mirror telescope at the Cerro Tololo Inter-American Observatory near Gemini’s Cerro Pachon.

At the heart of the spectrometer is a thin metal plate with tiny holes precisely calibrated to line up with the distant galaxies or stars astronomers are studying. The plate blocks out all light except what comes from these targets. As a result, astronomers can observe and gather data from many galaxies, stars or other celestial objects at once, whereas without the instrument they could focus only on one object at a time. Instead of looking at 10 objects a night, FLAMINGOS enables astronomers to examine hundreds. That’s important because astronomers need a big sample size. “If you want to know what the sun looked like when it formed, you can’t go find the sun in its earliest form – you have to look at a whole bunch of objects and find the ones that you think are like the sun,” Elston said.

The spectrometer already has led to important new discoveries. Although astronomers continue to crunch the data, findings from the past year include six stars at critical stages in the process of forming planets, doubling the number that had been found previously.

The results have been so encouraging that the Gemini Observatory asked Elston and his colleague on the project, UF astronomy Professor Steve Eikenberry, to double the size of the spectrometer so it can be used effectively on the Gemini telescope. Expected to weigh 2 tons and measure 8 feet long, the new spectrometer, FLAMINGOS 2, will allow astronomers using Gemini to gather data from as many as five times the number of objects as FLAMINGOS – or 30 times more objects than possible using any other spectrometer in the world.

The impact of both the new mid-infrared camera and the new spectrometer will extend beyond discrete discoveries. The Gemini and other major telescopes are extremely expensive to operate. Elston said. By allowing astronomers to gather more data from each night of observation, the instruments open the door to more ambitious investigations, he said. “Now, you can go out and do things that would have been impossible before,” Elston said.