Keck Plays Prominent Role at Astronomical Symposium

The Keck Observatory played a starring role – pun intended — during last week’s winter meeting of the American Astronomical Society.

The scientists gathering in Washington DC heard about the Big Island observatory’s role in the study of subjects ranging from the early formation of galaxies, the stars they contain and the planets that orbit them.

University of Hawaii astronomer Regina Jorgenson used the Keck I telescope to obtain the first image showing the structure of a galaxy as it was early in the life of the universe.

The galaxy called DLA2222-0946 is a type of galaxy thought to be a precursor of spiral galaxies like our own Milky Way.

It is so distant and faint that it is virtually invisible, Keck said in a press release, and was initially detected through its absorption of light from a quasar even further away.

The galaxy lies an estimated 10.8 billion light years away, and was formed when the universe was only a fifth of its current age.

Also discussed last week were the findings of a population of early galaxies by a team involving Keck, NASA’s Hubble Space Telescope and astronomers at the University of California, Riverside.

The galaxies are believed to have produced the bulk of new stars during the early years of the universe.

According to Keck astronomers, the galaxies are the smallest, faintest, and most numerous galaxies ever seen in the remote universe.

The 58 young galaxies were photographed by the Hubble using ultraviolet light as they appeared more than 10 billion years ago, which was described as the heyday of star birth.

Just finding the galaxies in the first place took a form of optical trickery known as gravitational lensing, in which the object’s light is multiplied as it passes around another celestial object, in this case a giant galaxy cluster known as Abell 1689.

While the newly discovered galaxies are 100 times more numerous than their more massive cousins, they are also 100 times fainter than galaxies detected in previous deep-field surveys of the early universe. 

“There’s always been a concern that we’ve only found the brightest of the distant galaxies,” said study leader Brian Siana, an assistant professor of physics and astronomy.

“The bright galaxies, however, represent the tip of the iceberg,” Siana said. “We believe most of the stars forming in the early universe are occurring in galaxies we normally can’t see at all.

“Now we have found those ‘unseen’ galaxies, and we’re really confident that we’re seeing the rest of the iceberg.”

 A third topic of discussion at the symposium was confirmation by Keck astronomers of observations by the  Kepler space telescope involving exoplanets, or planets orbiting stars other than our sun.

They found that among the planets found by the now-crippled planet-seeker were five new rocky planets ranging in size from 10% to 80% larger than Earth.

Two of the planets are both 40% larger and have a density similar to lead. They also orbit their stars in less than a week, making them too close to their stars and too hot for life as we know it.