Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astrophysicists discover a quasar that acts as a cosmic lens

21.07.2010
The EPFL's Laboratory of Astrophysics has for the first time observed a quasar that is located between the earth and a more distant galaxy and acts as a gravitational lens

A quasar acting as a gravitational lens has now been observed for the first time. This discovery, made by the EPFL's Laboratory of Astrophysics in cooperation with Caltech, represents an advance in the field, since it will allow scientists to weigh and measure a galaxy that contains a quasar. The news is published today in the journal Astronomy & Astrophysics.

Gravitational lenses are common throughout the universe. They are caused by massive objects such as stars or galaxies that bend rays of light passing nearby. If these objects are between the earth and a more distant light source, the light will therefore be brighter and easier to observe, but also very distorted. If the alignment of the various stellar bodies is almost perfect, the image of the source will be multiplied.

The lens phenomenon is not only an interesting result of Einstein's theory of general relativity; it has also been a valuable astrophysical tool with important applications in the search for extrasolar planets and the study of stars, galaxies, clusters of galaxies and quasars. For example, the nature of the distortion, the number of images of the most distant objects and their position in the sky provide essential information about the distribution of matter in the lens galaxy and allow a measurement of its total matter, including dark matter, to be made.

A quasar is the heart of a galaxy, consisting of a supermassive black hole. The small fraction of the galaxy's mass that is close enough to be swallowed up by the black hole emits light before disappearing forever, giving rise to this extremely bright and transient phenomenon.

To date, about a hundred of these quasars emitting light that is concentrated by a lens galaxy located between them and the earth have been discovered. However, this is the first time that the opposite case has been observed, where the quasar is in the foreground and the galaxy behind it. The interest of this discovery lies in the fact that it provides an unprecedented opportunity to "weigh" a galaxy containing a quasar.

This advance was made thanks to the SLOAN Digital Sky survey database (www.sdss.org), which makes three-dimensional sky maps covering more than a quarter of the sky available to scientists and contains nearly a million galaxies and over 120,000 quasars. A sample of some 23,000 of these quasars in the northern hemisphere was selected by the Laboratory of Astrophysics team. In the end, only four of them seemed to act as a gravitational lens.

One of these was studied using the Keck telescope (Caltech) on Mauna Kea peak in Hawaii. These images will be supplemented in the coming months with very high-quality photographs from the Hubble Space Telescope, which will reveal more about the nature of this particular quasar.

Contact:

- Professor Georges Meylan, Director of the EPFL's Laboratory of Astrophysics, georges.meylan@epfl.ch, tel. +41 22 379 24 25 or +41 21 693 06 44 or cell +41 79 856 34 85.

- Frederic Courbin, EPFL's Laboratory of Astrophysics, frederic.courbin@epfl.ch or +41 22 379 24 18

- S. George Djorgovski, California Institute of Technology (Caltech), george@astro.caltech.edu or +1 (626) 395-4415

Links and documents:

- Youtube video:
http://www.youtube.com/watch?v=xRloUn9wPdg

Sarah Perrin | EurekAlert!
Further information:
http://www.epfl.ch

More articles from Physics and Astronomy:

nachricht Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst

nachricht Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>