X-ray images key to understanding evolution of galaxies

Oct 03, 2007
X-ray images key to understanding evolution of galaxies

A global project to map a distant strip of the universe is releasing its data today to scientists and the public to be used as part of Google Sky, a new feature of Google Earth.

The international team is taking deep images of an area of sky known as the Extended Groth Strip, an area that covers the width of four full moons, close to the end of the Big Dipper's handle.

The All-wavelength Extended Groth Strip International Survey (AEGIS) is observing the same region of the sky in the radio, infrared, visible, ultraviolet and X-ray regions of the electromagnetic spectrum, with the goal of achieving a greater understanding of the evolution of galaxies over the last 10 billion years.

Academics from Imperial College London, part of the global team, have used the NASA satellite telescope Chandra to take deep images of the area to detect highly energetic X-ray radiation from objects in the sky.

"We are looking back to a time when the universe was more than half its current age and when galaxies were forming most of their stars," says Professor Kirpal Nandra, from the Department of Physics and who is leading the project from Imperial. He added: "With the X-ray images we are looking at black holes, which are at the centre of galaxies, to try to work out how the growth of black holes is linked to the growth of the galaxy itself."

Dr Elise Laird, also at Imperial and one of the lead researchers on the X-ray project, added: "Some theoretical models predict that black holes can actually stop galaxies forming stars altogether. We're now starting to test these models seriously using the AEGIS data."

Images in the optical, infrared and ultraviolet spectrum measure the sizes and shapes of galaxies, their current rates of star formation and the total number of stars each galaxy has already formed.

In the objects seen by Chandra, X-ray radiation has been produced when gas is spiralling 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 these X-ray images, the bluest objects are the ones most obscured by gas within their host galaxies.

The AEGIS region has now been surveyed more intensively and with more telescopes than any other region of the sky. All the images will form part of Google Sky, launched earlier this year and will further research into galaxies and how they are formed.

Professor Nandra, explains why they are focusing on this particular area of sky: "It all started in the early days of the Hubble Space Telescope with a program to image a strip of the sky to look for distant galaxies. Over the last few years this has snowballed into a huge international project using the world's most powerful telescopes, both on the ground and in space."

He added: "We've worked hard to convince the rest of the scientific community that this is the best place to look at the evolution of galaxies, and now this hard work's really paying off."

Google Sky will now include data from teams from around the world including Imperial College, University of California, Berkeley, University of California, Santa Cruz, the Space Telescope Science Institute, the W.M. Keck Observatory, Harvard Smithsonian Centre for Astrophysics and the California Institute of Technology.

Users can pan and zoom around all of these pictures of the sky to select individual galaxies for closer inspection. This is the first time that there have been multi wavelength images of the sky released in Google Sky. To view the Google Earth Gallery please visit: earth.google.com/gallery/index.html

Source: Imperial College London

Explore further: Computer model shows moon's core surrounded by liquid and it's caused by Earth's gravity

add to favorites email to friend print save as pdf

Related Stories

Astronomers find seven dwarf galaxies with new telescope

Jul 10, 2014

Meet the seven new dwarf galaxies. Yale University astronomers, using a new type of telescope made by stitching together telephoto lenses, recently discovered seven celestial surprises while probing a nearby ...

First H.E.S.S. II data reveal promising pulsar signal

Jul 08, 2014

Following the intensive commissioning phase of the largest Cherenkov telescope worldwide (H.E.S.S. CT5), the H.E.S.S. collaboration has announced the detection of cosmic gamma rays of 30 gigaelectronvolts ...

Comet Pan-STARRS marches across the sky

Jul 04, 2014

(Phys.org) —NASA's NEOWISE mission captured a series of pictures of comet C/2012 K1—also known as comet Pan-STARRS—as it swept across our skies in May 2014.

Recommended for you

Titan offers clues to atmospheres of hazy planets

12 hours ago

When hazy planets pass across the face of their star, a curious thing happens. Astronomers are not able to see any changes in the range of light coming from the star and planet system.

Having fun with the equation of time

12 hours ago

If you're like us, you might've looked at a globe of the Earth in elementary school long before the days of Google Earth and wondered just what that strange looking figure eight thing on its side was.

The source of the sky's X-ray glow

Jul 27, 2014

In findings that help astrophysicists understand our corner of the galaxy, an international research team has shown that the soft X-ray glow blanketing the sky comes from both inside and outside the solar system.

User comments : 0