Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ESA’s Integral discovers hidden black holes

20.10.2003


Integral, ESA’s powerful gamma-ray space telescope, has discovered what seems to be a new class of astronomical objects.


An artist’s impression of the mechanisms in an interacting binary system. The supermassive companion star (on the right-hand side) ejects a lot of gas in the form of ’stellar wind’. The compact black hole orbits the star and, due to its strong gravitational attraction, collects a lot of the gas. Some of it is funnelled and accelerated into a hot disc. This releases a large amount of energy in all spectral bands, from gamma rays through to visible and infrared. However, the remaining gas surrounding the black hole forms a thick cloud which blocks most of the radiation. Only the very energetic gamma rays can escape and be detected by Integral.



These are binary systems, probably including a black hole or a neutron star, embedded in a thick cocoon of cold gas. They have remained invisible so far to all other telescopes. Integral was launched one year ago to study the most energetic phenomena in the universe.
Integral detected the first of these objects, called IGRJ16318-4848, on 29 January 2003. Although astronomers did not know its distance, they were sure it was in our Galaxy. Also, after some analysis, researchers concluded that the new object could be a binary system comprising a compact object, such as a neutron star or a black hole, and a very massive companion star.

When gas from the companion star is accelerated and swallowed by the more compact object, energy is released at all wavelengths, from the gamma rays through to visible and infrared light. About 300 binary systems like those are known to exist in our galactic neighbourhood and IGRJ16318-4848 could simply have been one more. But something did not fit: why this particular object had not been discovered so far?



Astronomers, who have been observing the object regularly, guess that it had remained invisible because there must be a very thick shell of obscuring material surrounding it. If that was the case, only the most energetic radiation from the object could get through the shell; less-energetic radiation would be blocked. That could explain why space telescopes that are sensitive only to low-energy radiation had overlooked the object, while Integral, specialised in detecting very energetic emissions, did see it.

To test their theory, astronomers turned to ESA’s XMM-Newton space observatory, which observes the sky in the X-ray wavelengths. As well as being sensitive to high-energy radiation, XMM-Newton is also able to check for the presence of obscuring material. Indeed, XMM-Newton detected this object last February, as well as the existence of a dense ’cocoon’ of cold gas with a diameter of similar size to that of the Earth’s orbit around the Sun.

This obscuring material forming the cocoon is probably ’stellar wind’, namely gas ejected by the supermassive companion star. Astronomers think that this gas may be accreted by the compact black hole, forming a dense shell around it. This obscuring cloud traps most of the energy produced inside it.

The main author of these results, Roland Walter of the Integral Science Data Centre, Switzerland, explained: "Only photons with the highest energies [above 10 keV] could escape from that cocoon. IGR J16318-4848 has therefore not been detected by surveys performed at lower energies, nor by previous gamma-ray missions that were much less sensitive than Integral."

The question now is to find out how many of these objects lurk in the Galaxy. XMM-Newton and Integral together are the perfect tools to do the job. They have already discovered two more new sources embedded in obscuring material. Future observations are planned.

Christoph Winkler, ESA Project Scientist for Integral, said: "These early examples of using two complementary ESA high-energy missions, Integral and XMM-Newton, shows the potential for future discoveries in high-energy astrophysics."

Christoph Winkler | ESA
Further information:
http://www.esa.int/export/esaCP/SEMPHV1P4HD_index_0.html

More articles from Physics and Astronomy:

nachricht Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT

nachricht Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore

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: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>