Using the X-ray satellite XMM-Newton, astronomers observe the events around the black hole at the centre of our galaxy
Who left the deep scars on the heart of our Milky Way? In their hunt for elusive clues that might reveal the culprit, an international team of astronomers at the Max Planck Institute for Extraterrestrial Physics has been scouring cosmic images of the X-ray satellite XMM-Newton. The prime suspect is the supermassive black hole lurking at the centre of the Milky Way. But a number of massive stars and supernovae do not appear entirely innocent, either.
Zoom into the centre: magnified image of the central 100 light years of the Milky Way centre, where here only the soft X-ray emission is shown. The Galactic black hole and its surrounding emission are located in the brightest central region of the image, and the bipolar lobes appear above and below that location.
© MPE / ESA
Glimpse into the heart of the Milky Way: this X-ray broad-band mosaic image consists of more than a hundred individual XMM-Newton observations within the central degree of the Milky Way. The colours indicate observations at different energies; this map covers a region about 500 hundred light years across. In addition to the X-ray emission from the regions around the supermassive black hole at the centre of the Milky Way this map reveals X-ray binaries, star clusters, supernova remnants, bubbles and superbubbles, non-thermal filaments and many other sources.
© MPE / ESA
The study of the X-ray emission from the Galactic centre is of primary importance for astronomy. One of the first large projects approved and performed by the X-ray satellite XMM-Newton, right after launch, was a scan of the Galactic centre. A team lead by scientists at the Max Planck Institute for Extraterrestrial Physics (MPE) has recently obtained a new scan with XMM-Newton and connected these observations to all archival data to obtain the best maps in both X-ray continuum and line emission produced so far.
With this, the team was able to characterise in detail the fallout from catastrophic events that have released vast amounts of energy. The forensic study led in particular to the discovery of how enormous X-ray emitting bubbles of plasma, tens of light years across, are impacting their environment, creating giant cavities in the gas, dust and cooler plasma at the Milky Way’s centre.
Mass monster caught red-handed
One of the most telling clues from the X-ray images is a pair of bipolar “lobes” that extend for tens of light years above and below the Galactic plane and are centred on the location of the supermassive black hole. Previous circumstantial evidence had implicated the black hole in this mayhem, but the new findings effectively catch it and its stellar gang red-handed in the act of committing acts of violence. In fact, the sources of matter and energy needed to inflate these bipolar lobes with hot, X-ray emitting gas could be either outflows launched from very near the event horizon of the super-massive black hole, winds from massive stars orbiting around the hole, or catastrophic events associated with the death of massive stars close to it.
Warm plasma in the outskirts of the imaged region
The team also discovered fingerprints of warm plasma in the outskirts of the imaged region (hundreds of light years). This indicates that the acts of violence taking place at the centre of the Milky Way have effects that extend far beyond that region. The newly discovered plasma might be associated with an inhomogeneous hot “atmosphere” of hot gas permeating the Galaxy’s central regions, perhaps fed by continuous or episodic outflows of mass and energy from the Milky Way’s core. Similar structures are occasionally observed at the centres of other galaxies. However, thanks to the proximity of the Milky Way centre, the XMM-Newton maps can directly image this phenomenon in superb detail.
Superbubbles at the galactic heart
Another major disturbance in this unruly region has also been discovered: a few “superbubbles”, gigantic cavities tens of light years across that contain hot plasma emitting soft X-rays. One such region has an energy content of at least 1051 erg (approximately the total energy emitted by the Sun in its 10 billion year lifetime)! The evidence indicates that this enormous structure was inflated over the past tens of thousands years by powerful winds from the most massive stars of the spectacular Quintuplet stars cluster and by catastrophic events such as explosions of massive stars. Such large energy releases have a profound impact on the evolution of interstellar matter at the Galactic centre.
So, while the crime scene reconstruction is still being pieced together, with these new X-ray images the astronomers have a much clearer idea of what might have happened over the past couple billion years – and how our Milky Way might continue to evolve in future. One thing is clear: the violence in the neighbourhood of the Galactic centre will undoubtedly continue well into the future.
Dr. Gabriele Ponti
Max Planck Institute for Extraterrestrial Physics, Garching
Phone: +49 89 30000-3899
Dr. Hannelore Hämmerle
Max Planck Institute for Astrophysics, Garching
Phone: +49 89 30000-3980
Fax: +49 89 30000-3569
G. Ponti, M. R. Morris, R. Terrier, F. Haberl, R. Sturm, M. Clavel, S. Soldi, A. Goldwurm, P. Predehl, K. Nandra, G. Belanger, R. S. Warwick und V. Tatischeff
The XMM-Newton view of the central degrees of the MilkyWay
Monthly Notices of the Royal Astronomical Society, 20 August 2015
Dr. Gabriele Ponti | Max Planck Institute for Extraterrestrial Physics, Garching
NASA laser communications to provide Orion faster connections
30.03.2017 | NASA/Goddard Space Flight Center
Pinball at the atomic level
30.03.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Life Sciences
30.03.2017 | Physics and Astronomy
30.03.2017 | Power and Electrical Engineering