Nav: Home

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

November 11, 2003

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."

Note to Editors:
These and other preliminary results, plus a thorough description of the Integral spacecraft and mission are published this month in a dedicated issue of the journal Astronomy and Astrophysics.

At its 105th meeting on 6 October 2003, ESA's Science Programme Committee unanimously decided to extend the Integral mission until December 2008.

The International Gamma Ray Astrophysics Laboratory (Integral) is the first space observatory that can simultaneously observe celestial objects in gamma rays, X-rays and visible light. Integral was launched on a Russian Proton rocket on 17 October 2002 into a highly elliptical orbit around Earth. Its principal targets include regions of the galaxy where chemical elements are being produced and compact objects, such as black holes.

SPI measures the energy of incoming gamma rays with extraordinary accuracy. It is more sensitive to faint radiation than any previous gamma ray instrument and allows the precise nature of gamma ray sources to be determined. SPI's Principal Investigators are: J.-P. Roques, (CESR Toulouse, France), V. Schönfelder (MPE Garching, Germany).
-end-


European Space Agency

Related Supernovae Articles:

Volunteers help ANU find star that exploded 970 million years ago, predating the dinosaurs
Online volunteers have helped astronomers at The Australian National University find a star that exploded 970 million years ago, predating the dinosaurs' time on Earth.
Research reinforces role of supernovae in clocking the universe
New research by cosmologists at the University of Chicago and Wayne State University confirms the accuracy of Type Ia supernovae in measuring the pace at which the universe expands.
Detonating white dwarfs as supernovae
A new mathematical model created by astrophysicists at the American Museum of Natural History details a way that dead stars called white dwarfs could detonate, producing a type of explosion that is instrumental to measuring the extreme distances in our universe.
Surprising neutrino decoherence inside supernovae
Neutrinos produced in the core of a supernova are highly localized compared to neutrinos from all other known sources.
Ancient supernovae buffeted Earth's biology with radiation dose, researcher says
Ancient supernovae likely exposed biology on our planet to a long-lasting gust of cosmic radiation, which also affected the atmosphere.
Blue is an indicator of first star's supernova explosions
An international collaboration led by the Kavli Institute for the Physics and Mathematics of the Universe have discovered that the color of supernovae during a specific phase could be an indicator for detecting the most distant and oldest supernovae in the Universe -- more than 13 billion years old.
Japan OISTER collaboration uncovers the origin of extraordinary supernovae
Using data obtained through OISTER collaboration in Japan, Masayuki Yamanaka, Konan University, and col?eagues demonstrated that the origin of extraordinary supernovae can be explained by the 'accretion scenario.' The researchers discovered an anomalously strong infrared emission from 'the extraordinary supernova' SN 2012dn, which has never been observed in other Type Ia supernovae to date.
Supernova reserve fuel tank clue to big parents
Some supernovae have a reserve tank of radioactive fuel that cuts in and powers their explosions for three times longer than astronomers had previously thought.
Supernovae showered Earth with radioactive debris
An international team of scientists has found evidence of a series of massive supernova explosions near our solar system, which showered the Earth with radioactive debris.
Proof that ancient supernovae zapped Earth sparks hunt for after effects
Astrophysicist Adrian Melott offers assessment of compelling new supernovae evidence to appear in this week's Nature.

Related Supernovae Reading:

Supernovae and Nucleosynthesis (Princeton Series in Astrophysics)
by David Arnett (Author)

This book investigates the question of how matter has evolved since its origin in the Big Bang, from the cosmological synthesis of hydrogen and helium to the generation of the complex set of nuclei that comprise our world and our selves. A central theme is the evolution of gravitationally contained thermonuclear reactors, otherwise known as stars. Our current understanding is presented systematically and quantitatively, by combining simple analytic models with new state-of-the-art computer simulations.


The narrative begins with the clues (primarily the solar system abundance... View Details


Supernovae (Astronomy and Astrophysics Library)
by Albert G. Petschek (Editor)

This book offers an authoritative collection of papers incorporating the latest results and understanding about supernovae, including SN1987A. There are several chapters reviewing all the radio through infrared, visible, and ultraviolet to X-rays and gamma-rays but also neutrinos. Other chapters deal with the classification of supernovae, depending on their spectra and light curves. Three chapters treat supernovae theory, including a novel idea of a `fractal' burning front and another on the behavior of neutron stars. This thorough review of supernovae observations and theory will appeal to... View Details


Supernovae: and How to Observe Them (Astronomers' Observing Guides)
by Martin Mobberley (Author)

This book is intended for amateur astronomers who are readers of Sky & Telescope magazine or similar astronomy periodicals – or are at least at the same level of knowledge and enthusiasm. Supernovae represent the most violent stellar explosions in the universe. This is a unique guide to supernova facts, and it is also an observing/discovery guide, all in one package. Supernovae are often discovered by amateur astronomers, and the book describes the best strategies for discovering and observing them. Moreover, it contains detailed information about the probable physics of supernovae, a... View Details


Supernovae
by Paul Murdin (Author), Lesley Murdin (Author)

Supernovae are gigantic stellar explosions. The effects of these rare events pervade astronomy, creating and spreading the chemical elements, triggering the formation of new stars, creating black holes and pulsars. Originally published in 1978 and first published by Cambridge as this revised edition in 1985, is the story of supernovae. It captures the flavour of ancient astronomy and lays out the accidents, coincidences, false leads and flashes of inspiration that followed as astronomers grasped the implications behind the rare appearance of supernovae. Two supernovae, seen in 1572 and 1604,... View Details


Supernovae: The Explosive End of A Star

The twentieth century brought tremendous advances through scientific research and its technological applications. Science also will have a key role in the development of countries in the XXI century. The universe originated in the Big Bang; the starting material was only hydrogen and helium. Then the stars formed and in them, the more complex chemical elements such as carbon, oxygen, calcium and iron. The final explosion of some stars, a phenomenon called supernova, is the main mechanism of chemical enrichment of the universe and thus the basis for the formation of the sun, planets, life on... View Details


Observing Variable Stars, Novae and Supernovae
by Gerald North (Author), Nick James (Author)

Gerald North's complete practical guide and resource package instructs amateur astronomers in observing and monitoring variable stars and other objects of variable brightness. Descriptions of the objects are accompanied by explanations of the background astrophysics, providing readers with real insight into what they are observing at the telescope. The main instrumental requirements for observing and estimating the brightness of objects by visual means and by CCD photometry are detailed, and there is advice on the selection of equipment. The book contains a CD-ROM packed with resources,... View Details


Exploding Superstars: Understanding Supernovae and Gamma-Ray Bursts (Springer Praxis Books)
by Alain Mazure (Author), Stéphane Basa (Author)

The exceptional cosmic history and the fabulous destinies of exploding stars – supernovae and gamma-ray bursters – are highly fertile areas of research and are also very special tools to further our understanding of the universe. In this book, cosmologists Dr Alain Mazure and Dr Stéphane Basa throw light on the assemblage of facts, hypotheses and cosmological conclusions and show how these ‘beacons’ illuminate their immediate surroundings and allow us to study the vast cosmos, like searchlights revealing the matter comprising our universe.

View Details


A Background on Supernovae: " A Source of Cosmic Creation "
by Edited by Paul F. Kisak (Author), Paul F. Kisak (Afterword)

A supernova is a stellar explosion that briefly outshines an entire galaxy, radiating as much energy as the Sun or any ordinary star is expected to emit over its entire life span, before fading from view over several weeks or months. The extremely luminous burst of radiation expels much or all of a star's material at a velocity of up to 30,000 km/s (10% of the speed of light), driving a shock wave[3]into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant. Supernovae are potentially strong galactic sources of... View Details


The Historical Supernovae (Pergamon international library of science, technology, engineering and social studies)
by David H. Clark (Author), F. Richard Stephenson (Author)

A PB version of official records from Asian astronomy science. View Details


Mysterious Universe: Supernovae, Dark Energy, and Black Holes (Scientists in the Field Series)
by Ellen Jackson (Author), Nic Bishop (Photographer)

The universe is rapidly expanding. Of that much scientists are certain. But how fast? And with what implications regarding the fate of the universe?
Ellen Jackson and Nic Bishop follow Dr. Alex Fillippenko and his High-Z Supernova Search Team to Mauna Kea volcano in Hawaii, where they will study space phenomena and look for supernovae, dying stars that explode with the power of billions of hydrogen bombs. Dr. Fillippenko looks for black holes--areas in space with such a strong gravitational pull that no matter or energy can escape from them--with his robotic telescope. And they study the... View Details

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Attention Please
In an age of constant information and infinite distractions, how can we pay more attention to our ... attention? This hour, TED speakers explore the battle for our awareness during the digital age. Guests include sociologist Zeynep Tufekci, podcast host Manoush Zomorodi, neuroscientist Amishi Jha, designer Tristan Harris, and computer scientist Jaron Lanier.
Now Playing: Science for the People

#475 Mother Nature is Trying to Kill You (Rebroadcast)
This week, we're learning how deadly and delightful our planet and its ecosystem can be. We're joined by biologist Dan Riskin, co-host of Discovery Canada's Daily Planet, to talk about his book "Mother Nature Is Trying to Kill You: a Lively Tour Through the Dark Side of the Natural World." And we'll talk to astronomer and author Phil Plait about Science Getaways, his company that offers educational vacation experiences for science lovers.