ESA title
Densest objects seen by Integral
Science & Exploration

Science with Integral – five years on

17/10/2007 1245 views 0 likes
ESA / Science & Exploration / Space Science / Integral

With eyes that peer into the most energetic phenomena in the universe, ESA’s Integral has been setting records, discovering the unexpected and helping understanding the unknown over its first five years.

Integral was launched on 17 October 2002. Since then, the satellite has helped scientists make great strides in understanding the gamma-ray universe - from the atoms that make up all matter, giant black holes, mysterious gamma-ray bursts to the densest objects in the universe.

The atoms that make us

Our galaxy
Our galaxy

Surveying the entire galaxy looking for the radioactive isotope aluminium 26 with Integral, scientists have been able to calculate that a supernova goes off in our galaxy, once every 50 years.

According to Integral, something is creating a lot of gamma rays at the centre of our galaxy - the suspect is positrons, the antimatter counterparts of electrons. Scientists have been baffled as to how vast numbers of such particles can be generated every second and how these sources would be distributed over the sky to match the gamma-ray map.

The densest objects in the universe

Artist's view of Integral
Artist's view of Integral

Within months of operation, Integral solved a thirty-year-old mystery by showing that the broadband gamma-ray emission observed towards the centre of the galaxy was produced by a hundred individual sources. A catalogue of close to 500 gamma-ray sources from all over the sky, most of them new, was then complied.

Scientists now know that a rare class of anomalous X-ray pulsars, or magnetars, generates magnetic fields a thousand million times stronger than the strongest steady magnetic field achievable in a laboratory on Earth. These sources show, unexpectedly, strong emission in the Integral energy range.

Integral revealed that a sub-class of X-ray binary stars, called super-giant fast X-ray transients, previously thought to be extremely rare, is actually common in our galaxy. The satellite has also discovered a completely new class of high-mass X-ray binaries, called highly absorbed X-ray binaries.

Giant black holes

Hidden black holes in the local universe
Hidden black holes in the local universe

Integral has seen about 100 of the brightest supermassive black holes, the main producers of gamma radiation in our universe, in other galaxies. But while looking for them in nearby galaxies, surprisingly few have been found.

They are either too well-hidden or are only present in the younger galaxies which populate the more distant universe.

Using Earth as a shield
Using Earth as a shield

Galaxies throughout the universe are believed to be responsible for creating the diffuse background glow of gamma rays, observed over the entire sky. Integral used the Earth as a giant shield to disentangle this faint glow. Making the measurements possible was a technological and operational feat.

The data will help understand the origin of the highest energy background radiation and possibly, provide new clues to the history of growth of supermassive black holes since the early epochs of the Universe.

Mysterious bursts

A gamma-ray burst
A gamma-ray burst

Although not designed to be a gamma-ray-burst ‘watchdog’, scientists realised that Integral could perform this task if assisted by sufficiently powerful software. ESA set a new record for speed and accuracy with the Integral Burst Alert System on 3 December 2003 when a burst was detected, localised and astronomers were alerted in 18 seconds.

The event, called GRB 031203, was faint and close, in cosmological terms, which suggests that an entire population of low energy gamma-ray bursts has so far gone unnoticed.

On 27 December 2004 Integral was hit by the strongest flux of gamma rays ever measured by any spacecraft and it even measured radiation that bounced off the Moon. The culprit was a magnetar, SGR 1806-20, located 50 000 light years away on the other side of our Milky Way. Thanks to this outburst, astronomers now think that some gamma-ray bursts might come from similar magnetars in other galaxies.

Integral has also been able to take images of gamma ray bursts, while the telescope was not pointed in the right direction. This was done using radiation that passed through the side of Integral’s imaging telescope and struck the detector.

Christoph Winkler, ESA’s Integral Project Scientist says “Integral has indeed played a major role in modern gamma-ray astronomy. So much has happened in the span of five years but much more is still to come.”

For more information:

Christoph Winkler, ESA Integral Project Scientist
Email: Christoph.Winkler @ esa.int

Related Links

Densest objects seen by Integral
Science & Exploration

Science with Integral – five years on

17/10/2007 1245 views 0 likes
Read
Artist's impression of a blazar
Science & Exploration

Gamma-ray lighthouse at the edge of our universe

03/10/2007 2627 views 2 likes
Read
Tracing massive stars in the Galaxy
Science & Exploration

Radioactive iron, a window to the stars

25/06/2007 6444 views 8 likes
Read
The third Integral/IBIS survey catalogue
Science & Exploration

Integral expands our view of the gamma-ray sky

20/02/2007 1880 views 0 likes
Read
Fast-spinning neutron star
Science & Exploration

Integral points to the fastest spinning neutron star

16/02/2007 4519 views 7 likes
Read
Artist's impression of a pulsar 'eating' a companion star
Science & Exploration

Star eats companion

06/09/2005 7034 views 7 likes
Read
Integral’s monitoring of the Galactic Centre
Science & Exploration

Integral sees the Galactic centre playing hide and seek

18/01/2007 1941 views 0 likes
Read
Integral’s view of X-ray nova IGR J17497-2821
Science & Exploration

Integral catches a new erupting black hole

27/11/2006 3067 views 2 likes
Read
Integral's black hole census
Science & Exploration

ESA steps towards a great black hole census

07/09/2006 2240 views 0 likes
Read
Dust torus around a supermassive black hole
Science & Exploration

Where are the supermassive black holes hiding?

26/07/2006 3217 views 2 likes
Read
Integral's imager can see around corner
Science & Exploration

Integral sees a GRB out of the corner of its eye

16/06/2006 1378 views 1 likes
Read
Artist's view of an anomalous X-ray pulsar as seen by Integral
Science & Exploration

Integral catches stellar 'corpses' by the tail

16/03/2006 1668 views 0 likes
Read
Integral flight control team during manoeuvres
Science & Exploration

Exceptional manoeuvres enable unique Integral science

10/02/2006 708 views 0 likes
Read
Radioactive decay as measured by Integral from Al 26 decay, and the signature of galactic rotation.
Science & Exploration

Integral identifies supernova rate for Milky Way

04/01/2006 5030 views 3 likes
Read

Related Links