Evidence of giant galaxy’s birth seen

Press, 10 January 1987, Page 5

Evidence of giant galaxy’s birth seen

NZPA-AP Pasadena, California Astronomers believe they have witnessed the birth of a giant galaxy, detecting evidence that perhaps one billion stars were born within a huge gas cloud 114 billion trillion kilometres from Earth. “We’re talking about the turn-on of an entire galaxy, or at least that’s what we think,” said Professor Hyron Spinrad, astronomy professor at the University of California at Berkeley. The object is too far away for scientists to be positive what it is, but they believe they have found “the first evidence for a massive galaxy seen during its formation stages long ago and far away,” Professor Spinrad said during the American Astronomical Society’s annual meeting. The possible "protogalaxy,” known as radio wave source 3C 326.1, was discovered by Patrick McCarthy, Hyron Spinrad, Wil van Breugel, Michael Strauss, at Berkeley; S. George Djorgovski, of the Harvard-Smithsonian Centre for Astrophysics; and James Liebert, of the University of Arizona. The object is 12 billion light years from Earth. A light year is the distance light travels in one year, so the birth of the galaxy astronomers think they detected actually happened 12 billion years ago, quite early in the history of the universe.

Astronomers believe stars form in giant clouds of gas and dust as pockets of material in those clouds collapse inward because of gravity. “When it collapses far enough, the gas heats up to the point where it can turn on thermonuclear reactions,” creating a star, Professor Spinrad said. The researchers focused on 3C 326.1 with the Very Large Array radio telescope in New Mexico and with optical telescopes at Lick Observatory near San Jose and at the Multiple Mirror Observatory and Kitt Peak National Observatory in Arizona. Using special filters, they detected mostly extreme blue light from the object and some other

wavelengths, or colours. The blue light indicates most of the object is a huge cloud of electrically charged hydrogen gas about three times bigger than our own Milky Way galaxy. The other colours of light indicate that about 1 billion stars have been bom within the gas cloud, Professor Spinrad said. The cloud is about 100 times brighter than the starlight, suggesting the cloud is in the earliest stages of galaxy formation, and will continue to contract to spawn many more stars. “It’s on its way to becoming a giant galaxy and hasn’t quite got there yet,” Professor Spinrad said.