Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Falling onto the dark

04.07.2006
Rare Blob Unveiled: Evidence for Hydrogen Gas Falling onto a Dark Matter Clump?

ESO's VLT has helped scientists to discover a large primordial 'blob', more than 10 billion light-years away. The most likely scenario to account for its existence and properties is that it represents the early stage in the formation of a galaxy, when gas falls onto a large clump of dark matter.

Over the last few years, astronomers have discovered in the distant Universe a few so-called 'blobs'. These are rather energetic but under-luminous objects, of the size of or much larger than our Milky Way galaxy. Their exact nature is still unclear and several scenarios have been proposed to account for their existence.

An international team of astronomers [1] have discovered a new 'blob' located at a distance of 11.6 billion light-years (redshift 3.16). It is thus seen as it was when the Universe was only 2 billion years old, or less than 15% its present age. The newly discovered object is located in the well-studied GOODS South field [2].

The object was discovered using the multi-mode FORS1 instrument on ESO's Very Large Telescope (VLT), in December 2002. The astronomers studied a small part of the GOODS South field in a narrow-band filter centred around 505 nm for more than 8 hours. This special filter allows astronomers to observe emission from hydrogen atoms that are around 11.6 billion light-years away (redshift between 3.126 and 3.174). From December 2004 till February 2005, FORS1 was used again to perform spectroscopy of some of the newly discovered sources, for a total observing time of 6 hours.

With a diameter of 200 000 light-years, the blob is twice as big as our Milky Way and the total energy emitted is equivalent to that of about 2 billion suns. Despite this, the object is invisible in the images taken with various telescopes observing from the infrared to the X-ray wavebands, making it a very peculiar object indeed [3]. It is also the only such object found by the astronomers in their survey.

"We have tried to explain this blob using the most common explanations, such as the illumination by a galaxy with an active nucleus or a galaxy that produce stars at a frantic rate, but none of them apply," says Kim Nilsson (ESO), first author of the paper relating the result. "Instead, we are led to the conclusion that the observed hydrogen emission comes from primordial gas falling onto a clump of dark matter. We could thus be literally seeing the building up of a massive galaxy, like our own, the Milky Way."

[1]: The team comprises Kim Nilsson, Palle Møller, and Cédric Ledoux (ESO), and Johan Fynbo and Jesper Sommer-Larsen (DARK Cosmology Centre, Copenhagen, Denmark).

[2]: The Great Observatories Origins Deep Survey (GOODS) is a public, multiwavelength survey that covers two 150 arcmin2 fields. These fields are centred on the HDF-N (Hubble Deep Field North) and the CDF-S (Chandra Deep Field South). GOODS consists of two major parts: space based imaging and ground based imaging and spectroscopy. The first part is carried out with the NASA Great Observatories, SIRTF, CXO, the NASA/ESA HST, as well as ESA's XMM-Newton. GOODS itself is a SIRTF Legacy program, designed to study galaxy formation and evolution over a very wide range of cosmic look-back time. Ground based observations include optical and near infrared, sub-millimetre and radio observations of the same two fields and are in particular done at ESO with the ESO/MPG 2.2-m telescope at La Silla and ESO's Very Large Telescope at Paranal.

[3]: This is because the objects emits most of its light in the Lyman-alpha hydrogen line, while its continuum emission is too low to be detected.

Press Officer | alfa
Further information:
http://www.eso.org

More articles from Physics and Astronomy:

nachricht Riddle of matter remains unsolved: Proton and antiproton share fundamental properties
19.10.2017 | Johannes Gutenberg-Universität Mainz

nachricht Space radiation won't stop NASA's human exploration
18.10.2017 | NASA/Johnson Space 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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Rapid environmental change makes species more vulnerable to extinction

19.10.2017 | Life Sciences

Integrated lab-on-a-chip uses smartphone to quickly detect multiple pathogens

19.10.2017 | Interdisciplinary Research

Fossil coral reefs show sea level rose in bursts during last warming

19.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>