Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Invisible Galaxies That Could Not Hide

16.02.2006


Metal-Rich Distant Galaxy Found With ESO’s VLT


A distant quasar is used as a beacon in the Universe. Galaxies and intergalactic material that lie between the quasar and us will reveal themselves by the features seen in the spectrum.



Astronomers, using the unique capabilities offered by the high-resolution spectrograph UVES on ESO’s Very Large Telescope, have found a metal-rich hydrogen cloud in the distant universe. The result may help to solve the missing metal problem and provides insight on how galaxies form.

“Our discovery shows that significant quantities of metals are to be found in very remote galaxies that are too faint to be directly seen”, said Celine Peroux (ESO), lead-author of the paper presenting the results [1].


The astronomers studied the light emitted by a quasar located 9 billion light-years away that is partially absorbed by an otherwise invisible galaxy sitting 6.3 billion light-years away along the line of sight.

The analysis of the spectrum shows that this galaxy has four times more metals than the Sun. This is the first time one finds such a large amount of ‘metals’ [2] in a very distant object. The observations also indicate that the galaxy must be very dusty.

Almost all of the elements present in the Universe were formed in stars, which themselves are members of galaxies. By estimating how many stars formed over the history of the Universe, it is possible to estimate how much metals should have been produced. This apparently straightforward reasoning has however since several years been confronted with an apparent contradiction: adding up the amount of metals observable today in distant astronomical objects falls short of the predicted value. When the contribution of galaxies now observed at cosmological distances is added to that of the intergalactic medium, the total amounts for no more than a tenth of the metals expected.

Studying distant galaxies is however a difficult task. The further a galaxy, the fainter it is, and the small or intrinsically faint ones won’t be observed. This may introduce severe biases in the observations as only the largest and most active galaxies are picked up.

Astronomers therefore came up with other ways to study distant galaxies: they use quasars, most probably the brightest distant objects known, as beacons in the Universe.

Interstellar clouds of gas in galaxies, located between the quasars and us on the same line of sight, absorb parts of the light emitted by the quasars. The resulting spectrum consequently presents dark ‘valleys’ that can be attributed to well-known elements. Thus, astronomers can measure the amount of metals present in these galaxies – that are in effect invisible - at various epochs.

“This can best be done by high-resolution spectrographs on the largest telescopes, such as the Ultra-violet and Visible Echelle Spectrograph (UVES) on ESO’s Kueyen 8.2-m telescope at the Paranal Observatory,” said Péroux.

Her team studied in detail the spectrum of the quasar SDSS J1323-0021 that shows clear indications of absorption by a cloud of hydrogen and metals located between the quasar and us. From a careful analysis of the spectrum, the astronomers found this ‘system’ to be four times richer in zinc than the Sun. Other metals such as iron appear to have condensed into dust grains.

“If a large number of such ’invisible’ galaxies with high metal content were to be discovered, they might well alleviate considerably the missing metals problem”, said Péroux.

The full text of this release along with an image is available at http://www.eso.org/outreach/press-rel/pr-2006/pr-06-06.html

Henri Boffin | alfa
Further information:
http://www.eso.org/outreach/press-rel/pr-2006/pr-06-06.html

More articles from Health and Medicine:

nachricht Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>