Featured Research

from universities, journals, and other organizations

Dozens Of Gravitationally Lensed Galaxies Discovered In Distant Universe

Date:
February 20, 2008
Source:
ESA/Hubble Information Centre
Summary:
Astronomers have compiled a large catalogue of gravitational lenses in the distant universe. The catalogue contains a staggering 67 new gravitationally lensed images found around massive elliptical and lenticular-shaped galaxies. This sample demonstrates the rich diversity of strong gravitational lenses. If this sample is representative, there would be nearly half a million similar gravitational lenses in total over the whole sky.

In this image, six examples of the rich diversity of 67 strong gravitational lenses found in the COSMOS survey. The lenses were discovered in a recently completed, large set of observations as part of a project to survey a single 1.6-square-degree field of sky (nine times the area of the full moon) with several space-based and Earth-based observatories. Gravitational lenses occur when light travelling towards us from a distant galaxy is magnified and distorted as it encounters a massive object between the galaxy and us. These gravitational lenses often allow astronomers to peer much further back into the early universe than they would normally be able to. The COSMOS project, led by Nick Scoville at the California Institute of Technology, used observations from several observatories including the Hubble Space Telescope, the Spitzer Space Telescope, the XMM-Newton spacecraft, the Chandra X-ray Observatory, the Very Large Telescope (VLT), and the Subaru Telescope. In total 67 gravitational lenses were found.
Credit: NASA, ESA, C. Faure (Zentrum fόr Astronomie, University of Heidelberg) and J.P. Kneib (Laboratoire d’Astrophysique de Marseille)

The lenses come from a recently completed, large set of observations as part of a huge project to survey a single 1.6 square degree field of sky (nine times the area of the full Moon) with several space-based and Earth-based observatories. The COSMOS project, led by Nick Scoville at the California Institute of Technology, USA, used observations from several observatories including the Hubble Space Telescope, as well as the Spitzer Space Telescope, the XMM-Newton spacecraft, the Chandra X-ray Observatory, the Very Large Telescope (VLT), the Subaru Telescope and CFHT.

A team of European astronomers led by Jean-Paul Kneib (Laboratoire d'Astrophysique de Marseille) and Cιcile Faure (Zentrum fόr Astronomie, University of Heidelberg) analysed the results from Hubble's Advanced Camera for Surveys (ACS). From ACS high-resolution images, complemented by the extensive ground-based follow-up observations, astronomers have identified 67 strong gravitationally lensed galaxies. These were found around very massive galaxies that are usually elliptical or lenticular in shape and often exhibit a paucity of gas and dust without spiral arms or discs. The strong lensing produced by massive galaxies is much more common than the usual giant "arc" gravitationally lensed galaxies that Hubble has previously observed; but they are generally more difficult to find as they extend over a smaller area and have a wide variety of shapes.

Gravitational lensing occurs when light travelling towards us from a distant galaxy is magnified and distorted as it encounters a massive object between the galaxy and us. These gravitational lenses often allow astronomers to peer much further back into the early Universe than they would normally be able to.

The massive objects that create the lenses are usually huge clusters of massive galaxies. "We typically see the gravitational lens create a series of bright arcs or spots around a galaxy cluster. What we are observing here is a similar effect but on much smaller scale -- happening only around a single but very massive galaxy," says Jean-Paul Kneib.

Of the 67 gravitational lenses identified in the COSMOS survey, the most impressive lenses show the distorted and warped light of one or two background galaxies. At least four of the lenses give rise to Einstein rings, a complete circular image of a background galaxy, which is formed when the background galaxy, a massive foreground galaxy and the Hubble Space Telescope are all aligned perfectly.

Hubble astronomers went through a unique process to identify these incredible natural lenses. First, possible galaxies were identified from a galaxy catalogue, comprising more than two million galaxies. "We then had to look through each individual COSMOS image by eye and identify any potential strong gravitational lenses," said Cιcile Faure. Finally, checks were made to see if the foreground galaxy and the lensed galaxy were really different or just one galaxy with an odd shape. "With this sample of gravitational systems identified by the human eye, we now plan use the sample of lenses to train robot software to find more of these lenses across the entire Hubble image archive, and we may find even more strong lensing systems in the COSMOS field," added Jean-Paul Kneib.

The new results confirm that the Universe is filled with gravitational lensing systems. Extrapolating these new findings to the whole sky, predicts no less than half a million similar lenses in total. The future prospects for finding more of these systems are thus excellent.

The study of these gravitational lenses will give astronomers a first-rate opportunity to probe the dark matter distribution around galactic lenses. Once astronomers find even larger numbers of these smaller, stronger lenses they can be used to create a census of galaxy masses in the Universe to test the predictions of cosmological models.


Story Source:

The above story is based on materials provided by ESA/Hubble Information Centre. Note: Materials may be edited for content and length.


Cite This Page:

ESA/Hubble Information Centre. "Dozens Of Gravitationally Lensed Galaxies Discovered In Distant Universe." ScienceDaily. ScienceDaily, 20 February 2008. <www.sciencedaily.com/releases/2008/02/080219155653.htm>.
ESA/Hubble Information Centre. (2008, February 20). Dozens Of Gravitationally Lensed Galaxies Discovered In Distant Universe. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2008/02/080219155653.htm
ESA/Hubble Information Centre. "Dozens Of Gravitationally Lensed Galaxies Discovered In Distant Universe." ScienceDaily. www.sciencedaily.com/releases/2008/02/080219155653.htm (accessed September 23, 2014).

Share This



More Space & Time News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Hyped-Up Big Bang Discovery Has A Dust Problem

The Hyped-Up Big Bang Discovery Has A Dust Problem

Newsy (Sep. 22, 2014) — An analysis of new satellite data casts serious doubt on a previous study about the Big Bang that was once hailed as revolutionary. Video provided by Newsy
Powered by NewsLook.com
NASA's MAVEN Spacecraft Has Finally Reached Mars

NASA's MAVEN Spacecraft Has Finally Reached Mars

Newsy (Sep. 22, 2014) — After a 10-month voyage through space, NASA's MAVEN spacecraft is now orbiting the Red Planet. Video provided by Newsy
Powered by NewsLook.com
Raw: SpaceX Rocket Carries 3-D Printer to Space

Raw: SpaceX Rocket Carries 3-D Printer to Space

AP (Sep. 22, 2014) — A SpaceX Rocket launched from Cape Canaveral, carrying a custom-built 3-D printer into space. NASA envisions astronauts one day using the printer to make their own spare parts. (Sept. 22) Video provided by AP
Powered by NewsLook.com
SpaceX Cargo Ship Blasts Off Toward Space Station

SpaceX Cargo Ship Blasts Off Toward Space Station

AFP (Sep. 21, 2014) — SpaceX's unmanned Dragon cargo ship blasts off toward the International Space Station, carrying a load of supplies and science experiments for the astronauts living there. Duration: 00:35 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins