Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ESA’s new view of the Milky Way - in gamma rays!

12.11.2003


ESA’s gamma-ray observatory Integral is making excellent progress, mapping the Galaxy at key gamma-ray wavelengths.


A portion of Integral’s gamma-ray map of the galaxy. This false colour picture was taken by the spectrometer on board Integral (SPI) between December 2002 and March 2003. The yellow dots correspond to bright known gamma-rays sources, whilst blue areas indicate regions of low emission. Data similar to these, but in a higher energy range, have been used to study where aluminium and iron are produced in the Galaxy.
Credits: ESA/SPI team



It is now poised to give astronomers their truest picture yet of recent changes in the Milky Way’s chemical composition. At the same time, it has confirmed an ’antimatter’ mystery at the centre of the Galaxy.

Since its formation from a cloud of hydrogen and helium gas, around 12 000 million years ago, the Milky Way has gradually been enriched with heavier chemical elements. This has allowed planets and, indeed, life on Earth to form.


Today, one of those heavier elements - radioactive aluminium - is spread throughout the Galaxy and, as it decays into magnesium, gives out gamma rays with a wavelength known as the ’1809 keV line.’ Integral has been mapping this emission with the aim of understanding exactly what is producing all this aluminium.

In particular, Integral is looking at the aluminium ’hot spots’ that dot the Galaxy to determine whether these are caused by individual celestial objects or the chance alignment of many objects.

Astronomers believe that the most likely sources of the aluminium are supernovae (exploding high-mass stars) and, since the decay time of the aluminium is around one million years, Integral’s map shows how many stars have died in recent celestial history. Other possible sources of the aluminium include ’red giant’ stars or hot blue stars that give out the element naturally.

To decide between these options, Integral is also mapping radioactive iron, which is only produced in supernovae. Theories suggest that, during a supernova blast, aluminium and iron should be produced together in the same region of the exploding star. Thus, if the iron’s distribution coincides with that of the aluminium, it will prove that the overwhelming majority of aluminium comes indeed from supernovae.

These measurements are difficult and have not been possible so far, since the gamma-ray signature of radioactive iron is about six times fainter than that of the aluminium. However, as ESA’s powerful Integral observatory accumulates more data in the course of the next year, it will finally be possible to reveal the signature of radioactive iron. This test will tell astronomers whether their theories of how elements form are correct.

In addition to these maps, Integral is also looking deeply into the centre of the Galaxy, to make the most detailed map ever of ’antimatter’ there.

Antimatter is like a mirror image to normal matter and is produced during extremely energetic atomic processes: for example, the radioactive decay of aluminium. Its signature is known as the ’511 keV line.’ Even though Integral’s observations are not yet complete, they show that there is too much antimatter in the centre of the Galaxy to be coming from aluminium decay alone. They also show clearly that there must be many sources of antimatter because it is not concentrated around a single point.

There are many possible sources for this antimatter. As well as supernovae, old red stars and hot blue stars, there are jets from neutron stars and black holes, stellar flares, gamma-ray bursts and interaction between cosmic rays and the dusty gas clouds of interstellar space.

Chris Winkler, Integral’s Project Scientist, says: "We have collected excellent data in the first few months of activity but we can and will do much more in the next year. Integral’s accuracy and sensitivity have already exceeded our expectations and, in the months to come, we could get the answers to some of astronomy’s most intriguing questions."

Franco Bonacina | ESA
Further information:
http://www.esa.int/export/esaCP/SEMF9YWLDMD_Expanding_0.html

More articles from Physics and Astronomy:

nachricht Breaking: the first light from two neutron stars merging
17.10.2017 | American Association for the Advancement of Science

nachricht Filling the early universe with knots can explain why the world is three-dimensional
17.10.2017 | Vanderbilt University

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: 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...

Im Focus: New nanomaterial can extract hydrogen fuel from seawater

Hybrid material converts more sunlight and can weather seawater's harsh conditions

It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...

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

Study suggests oysters offer hot spot for reducing nutrient pollution

17.10.2017 | Life Sciences

Breaking: the first light from two neutron stars merging

17.10.2017 | Physics and Astronomy

World first for reading digitally encoded synthetic molecules

17.10.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>