Now watch 10 bln years of galactic evolution on Google Sky

The All-Wavelength Extended Groth Strip International Survey or AEGIS has distributed online, colour images documenting the 10 billion years of galactic evolution. It is part of the first public release of data from a massive project to map a distant region of the universe.

Washington, Oct 4 : The All-Wavelength Extended Groth Strip International Survey or AEGIS has distributed online, colour images documenting the 10 billion years of galactic evolution. It is part of the first public release of data from a massive project to map a distant region of the universe.

The scientists observed the same small region of sky using all available wavelengths of the electromagnetic spectrum - from X-rays to ultraviolet, visible, infrared, and radio waves.

The survey focused on the Extended Groth Strip, an area the width of four full moons near the "handle" of the Big Dipper constellation.

Four colour images from four different satellite telescopes, as well as numerous data catalogue tabulating the properties of and distances to tens of thousands of galaxies, were made available on both the AEGIS Web site and Google Sky, a downloadable program that allows home computer users to explore these distant galaxies up close and in sharp detail.

The scientists created the most detailed of the four colour images being released: A visible-light mosaic of 63 separate snapshots from the Hubble Space Telescope. It is the largest unbroken colour mosaic ever made with Hubble images and provides images of approximately 50,000 faraway galaxies, including infant and adolescent galaxies just taking on their mature forms.

AEGIS' second image shows the same galaxies through the ultraviolet eyes of NASA's Galaxy Evolution Explorer (GALEX).

Young stars produce ultraviolet light in abundance; GALEX brightness therefore provides a measure of the rate at which each galaxy is forming stars. Galaxies that contain relatively few young stars or are obscured by dust or intergalactic gas will appear redder in the GALEX image.

The brightness of galaxies in the third image, taken with the Infrared Array Camera on NASA's Spitzer Space Telescope, is closely related to the total amount of stars they have formed. The colours of a galaxy as seen through infrared eyes reveal information on both its contents (stars and dust) and its distance from us.

The fourth image, produced with data from NASA's Chandra X-ray Observatory, reveals the highly energetic X-ray radiation produced when gas spirals into a super massive black hole, like those believed to lie at the centre of almost every galaxy. Many of the X-ray-emitting objects lie buried within otherwise normal-looking galaxies. In the X-ray images, the bluest objects are the ones most obscured by gas within their host galaxies.

More information about the survey, science results to date, and links to additional images and data is available for download from the AEGIS Web site at aegis.ucolick.org.

The AEGIS data release is also featured this week on the Google Earth Gallery at earth.google.com/gallery/index.html. Google Sky users can view and explore the Groth Strip in ultraviolet, visible, infrared, or X-ray light - or combine perspectives.

"Each wavelength provides unique information about the characteristics of distant galaxies," said Pitt physics and astronomy professor Jeffrey Newman.

Future AEGIS data releases will feature images taken with other wavelengths such as radio waves.

The scientists are also preparing a master catalogue that combines information from all of AEGIS's many views of the sky. As future images are prepared, they and the growing data catalogues will all be linked through Google Sky.

ANI