Artist concept of our Milky Way galaxy

Exotic targets include quasars, black holes and brown dwarfs TWIN TELESCOPES WITH NEAR-INFRARED "EYES" BEGIN ALL-SKY SURVEY

The first of a pair of new telescopes, funded primarily by NASA, has begun an ambitious three-and-a-half year near-infrared survey of the entire celestial sky, peering through the curtain of interstellar dust in the Milky Way galaxy.

The Two-Micron All-Sky Survey (2MASS), based at the University of Massachusetts, Amherst, MA, features two 1.3-meter (51-inch) telescopes, one at a Smithsonian Astrophysical Observatory site atop Mount Hopkins, near Tucson, AZ, and the other at a National Optical Astronomy Observatories site in Cerro Tololo, Chile.

"The sky survey catalogues produced 100 years ago are still useful to astronomers," said 2MASS Project Manager Rae Stiening. "We expect this new, greatly updated survey will be an invaluable resource for the next 100 years."

"Preliminary observations by 2MASS are already suggesting new infrared sources will be discovered," said Program Manager Dr. Michael Klein at NASA's Jet Propulsion Laboratory, Pasadena, CA. "Some of these will be targets for detailed studies for future space observatories, like the Advanced X-Ray Facility (AXAF), the Space Infrared Telescope Facility and the Next Generation Space Telescope."

The survey is designed to catalogue 300 million stars and one million galaxies in the local universe, along with quasars, which are strong, extremely bright radio sources, and galaxies with black holes, the intriguing entities with gravity so powerful not even light can escape.

2MASS will observe many known asteroids and possibly some comets, and it is uniquely sensitive to exotic objects like brown dwarfs, which lack the mass needed to ignite and become full- fledged stars.

The telescopes are equipped with near-infrared detector arrays that will provide the most complete census to date of cool stars in the Milky Way galaxy and provide new data for detailed studies of the galactic structure. Near-infrared emission is at wavelengths roughly two-to-four times longer than visible light and permits astronomers to "see through" the obscuring effects of interstellar dust in the Milky Way galaxy.

As Stiening explained, "Sunsets on Earth look reddish because only red light makes it through the dust in our atmosphere. Infrared observations enable us to penetrate the dust in our galaxy and other galaxies and, therefore, they provide a much clearer view of interior regions."

The 2MASS survey will measure accurately the positions and infrared brightness of stars and galaxies. Combined with complementary ground-based redshift surveys, the 2MASS extra- galactic data will provide a three-dimensional view of large- scale structures in the local universe. The enabling technology for this survey is the breakthrough in large-format infrared detector arrays. These technologies, funded through the U.S. Department of Defense and NASA, are being adapted for astronomical purposes to increase sensitivity dramatically. It's expected the new survey will be some 25,000 times more sensitive than a precursor survey at the California Institute of Technology, Pasadena, CA, nearly 30 years ago. 2MASS uses the type of detectors developed for the Near Infrared Camera and Multi Object Spectrometer on NASA's Hubble Space Telescope.

"Observing time at most telescopes is divided amongst a variety of scientific programs using a suite of different instruments. 2MASS telescopes will be completely dedicated to mapping the sky using one instrument, a three-color infrared camera," said Principal Investigator Dr. Michael Skrutskie, a University of Massachusetts physics and astronomy professor, who leads the science working group that will evaluate the data products. He also managed the design and fabrication effort for the infrared cameras, which are attached to an identical pair of telescopes.

Data will be processed at JPL's Infrared Processing and Analysis Center (IPAC) at Caltech, with a team led by Dr. Roc Cutri, Dr. Charles Beichman and Dr. Thomas Chester. Every two nights, the center will process 60 gigabytes of data, which is more data than processed during the entire Infrared Astronomy Satellite (IRAS) mission of 1983.

The 2MASS survey is funded by NASA's Office of Space Science, the National Science Foundation, the U.S. Naval Observatory and the University of Massachusetts. JPL is managing the program for NASA's Office of Space Science, Washington, DC. Additional information and images are available at the 2MASS website at the following URL's:

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