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Mauna Kea’s
Subaru spots cluster
of 1,000 galaxies

The Japanese observatory posts
a picture of the discovery
on the Internet

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By Helen Altonn
Star-Bulletin

An unknown galaxy cluster about five billion light-years from Earth has been photographed by Japan's huge Subaru telescope on Mauna Kea.

The National Astronomical Observatory of Japan in Tokyo announced the discovery by posting a picture on the Internet at http://www.nao.ac.jp.

About 1,000 galaxies are shown in the image, taken by Subaru's optical-infrared telescope, one of the largest in the world.

It has a 27-foot-wide mirror and a unique wide-field camera that can "detect the furthest reach of the universe," said Masahiko Hayashi, Subaru telescope professor for Japan's astronomical observatory.

Named for stars called Pleiades in English, the Subaru telescope saw "first light" in early 1999.

It will go into full operation Dec. 4 with a research program involving astronomers around the world.

"We have a lot of troubles but we are happy because the telescope performance is just what we expected or more," Hayashi said in a telephone interview from the Big Island.

The problems involve initial software and hardware bugs which, he said, "we expected, but hoped not (to have)."

Even so, the telescope is preparing for worldwide use with a significant discovery showing what it can do.

A cluster of galaxies contains more than 50 galaxies within a region about 10 million light-years across.

At the center of the previously unknown cluster detected by Subaru is an elliptic galaxy that's 200,000 light-years across -- twice the size of our galaxy -- emitting yellowish light, said Satoshi Miyazaki, an assistant at the Subaru observatory.

Miyazaki and others monitored the cluster between June and August through the telescope's 80-million-pixel Subaru Prime Focus Camera, called Suprime-Cam.

It's a wide field camera for visible light. The Suprime-Cam can capture images 100 times as large as those taken by the Hubble Space Telescope and monitor celestial objects more than 100 times fainter than stars visible to the naked eye, the scientists said.

Hayashi said it can take large-scale images covering regions of the sky the size of the moon.

"That means we can very easily find a new class of objects and galaxies because of the large field."

Hayashi is interested in planet-forming processes and Miyazaki wants to explore the history of the formation of the universe about 15 billion years ago.

The telescope will go into full operation with 26 projects by the Japanese, U.S., British and Russian researchers, said Norio Kaifu, head of the observatory. They will be conducted on 36 nights until March.

The projects were selected from 114 applications submitted to the observatory by July. It is now accepting applications for joint research projects from April to July next year.

Hayashi said the first projects represent five categories of investigation ranging from solar system to cosmological observations.

University of Hawaii Institute for Astronomy researchers are guaranteed 15 percent of the telescope time under a UH-Japan agreement.

About 20 Hawaii researchers have worked with it the past year, Hayashi said.