Upgraded Hubble Space Telescope Will Help UMass Amherst Astronomers Understand the Universe
Sept. 9, 2009
| Contact: | Janet Lathrop 413/545-0444 |
AMHERST, Mass. – Today, as NASA announces that a “fully rejuvenated Hubble Space Telescope” with new cameras and other equipment is ready to begin a new decade of observations, two UMass Amherst astronomers, Daniela Calzetti and Todd Tripp, with a colleague at Smith College, are excited to begin using those instruments to explore the origins and evolution of galaxies and stars throughout the Universe.
Winning time for these experiments using the Hubble instruments is intensely competitive, but UMass Amherst’s Calzetti and Tripp, with their fine-tuned complementary projects, and Suzan Edwards at Smith College, together won an extraordinary 20 days of exploration time over the coming year, about 10 percent of total observing time available in one year.
As Calzetti, who studies how galaxies form their stars, puts it, “For every hour that we requested, nine others asked but didn’t get the time. So it’s a great privilege and a great opportunity for us to conduct our experiments and get a better understanding of what is out there. It’s not a new house or a new car, it’s much better than that.”
In May, the crew of NASA’s STS-125 Space Shuttle mission performed its fifth and last servicing mission to the Hubble, replacing old instruments with two new ones, the Wide Field Camera 3 (WFC3) and the Cosmic Origins Spectrograph (COS), and repairing existing ones. Hubble is now almost brand new, with greatly improved capabilities for observing the light from celestial bodies across much of the electromagnetic spectrum, from ultraviolet to the infrared.
Calzetti’s research explores galaxies and how their aspect or shape is linked to the stars they form; for example, why some are flat like pancakes while others are spherical, football-shaped, spirals or amoeba-like blobs. “We have many ideas, but no hard-core facts about these shapes, which seem to be closely related to a galaxy’s life cycle,” she says. Answers will help astronomers understand why big elliptical galaxies are often “red and dead,” that is, retired and spent, for example, while spirals are often gas-rich, vibrant and still actively forming stars.
“Something happens to the lively spirals, we don’t know what, and they suddenly retire,” Calzetti adds. “It’s a mystery at the very heart of understanding our Universe.” She is a member of the WFC3 Science Oversight Committee, an international team whose members led the WFC3 design and development over the past 10 years.
Tripp, the leader of a large program that also includes researchers at the University of California, Notre Dame, Princeton and the Space Telescope Science Institute in Baltimore, uses quasars to study the difficult-to-detect gases and dust that fill the space between stars and outside of galaxies. Quasars are the most luminous objects known in the Universe, and are thus easily observed even at great distances. Like lighthouses on a foggy night, quasars emit the full spectrum of light, but it’s filtered through intervening clouds of gas and dust that absorb some of that light. By aiming COS, Hubble’s powerful new spectrograph, at selected quasars, Tripp and colleagues can “dissect” the light and identify the exact frequencies filtered out by the gas clouds in interstellar and intergalactic space.
These data can tell scientists “an astonishing amount of information,” Tripp says, about the location, movement, speed, composition and origin of the “ecosystems” surrounding galaxies. Ultraviolet light does not penetrate the Earth’s atmosphere, so this can only be studied using an orbiting telescope such as Hubble.
“Previous instruments on the Hubble and other facilities had only limited ability to use this technique,” Tripp adds. “Most of the ordinary matter is in these gas clouds, but ironically, it is essentially invisible to most techniques of astronomy. The only efficient way to study this stuff is to look at the light absorbed from distant quasars. So, very little is known about the state of most of the matter in galaxies and their intergalactic environments. The physics of this material has profound implications regarding the formation and evolution of galaxies, a fundamental aspect of our Universe.”
Edwards, of nearby Smith College, is part of another California-based team. She plans to use the COS to look at ultraviolet light from gas and dust surrounding several dozen young stars in the early stages of planet formation. The goal is to understand how matter flowing both in and away from very young stars helps to the keep them from spinning out of control.
Time on the Hubble’s instruments is accompanied by grant funding to analyze and interpret the data they will obtain, the researchers note.
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