Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Black holes turn up the heat for the Universe

15.05.2012
HITS astrophysicists discover a new heating source in cosmological structure formation

So far, astrophysicists thought that super-massive black holes can only influence their immediate surroundings. A collaboration of scientists at the Heidelberg Institute for Theoretical Studies (HITS) and in Canada and the US now discovered that diffuse gas in the universe can absorb luminous gamma-ray emission from black holes, heating it up strongly.


A supermassive black hole is surrounded by a dust ring (torus). The collapse of gas onto the black hole launches an energetic jet of matter and radiation, which is transported over cosmological distances. A jet that is pointing into our direction is called a "blazar". copyright: ESA/NASA, the AVO project and Paolo Padovani


Simulated line forest of a quasar spectrum. The blue spectrum represents a universe without blazar heating, the red one a universe with blazar heating. It is evident that the additional heating process ionizes neutral hydrogen, implying less absorption of the UV light emitted by the quasar. Picture: HITS

This surprising result has important implications for the formation of structures in the universe. The results have just been published in "The Astrophysical Journal“ and „Monthly Notices of the Royal Astronomical Society”.

Every galaxy hosts a supermassive black hole at its center. Such black holes can emit high-energy gamma rays and are then called blazars. Whereas other radiation such as visible light and radio waves traverses the universe without problems, this is not the case for high-energy gamma rays. This particular radiation interacts with the optical light that is emitted by galaxies, transforming it into the elementary particles electrons and positrons.

Initially, these elementary particles move almost at the speed of light. But as they are slowed down by the ambient diffuse gas, their energy is converted into heat, just like in other braking processes. As a result, the surrounding gas is heated efficiently. In fact, the temperature of the gas at mean density becomes ten times higher, and in underdense regions more than one hundred times higher than previously thought.

A Journey into the Cosmic Youth

"Blazars rewrite the thermal history of the universe", emphasizes Dr. Christoph Pfrommer (HITS), one of the authors. But how can this idea be tested? In the optical spectra of quasars there is a plethora of lines, called the "line forest". The forest originates from the absorption of ultra-violet light by neutral hydrogen in the young Universe. If the gas becomes hotter, weak lines in the forest are broadened. This effect represents an excellent opportunity to measure temperatures in the early Universe, while it was still growing up.

The astrophysicists at HITS checked this newly postulated heating process for the first time with detailed supercomputer simulations of the cosmological growth of structures. Surprisingly, the lines were broadened just enough so that their properties perfectly matched those of the observed lines. "This allows us to elegantly solve a long-standing problem with the quasar data", says Dr. Ewald Puchwein, who conducted the large simulations on the supercomputer at HITS.

How Black Holes Influence the Formation of Galaxies

What are the further consequences of this new heating process? The forest of lines in the quasar spectra originates from density fluctuations in the Universe. In the course of cosmic evolution, the densest fluctuations collapse to form galaxies and galaxy clusters, as observed in the local Universe. Diffuse gas that is too hot cannot collapse. Hence, the formation of dwarf galaxies is slowed or even entirely suppressed. This could be the key to the solution of another long-standing problem in the theory of galaxy formation: why do we observe fewer dwarf galaxies in the vicinity of the Milky Way and in the underdense regions than predicted by cosmological simulations?

Prof. Volker Springel, scientific group leader at HITS, explains: "The process of blazar heating is especially exciting since this single effect is able to simultaneously solve several different puzzles in cosmological structure formation." The group plans to further improve their simulation models for a still deeper understanding of the nature of blazar heating and its implications for today's Universe.

Press contact:
Dr. Peter Saueressig
Public Relations
Heidelberg Institute for Theoretical Studies (HITS)
Tel.: +49-6221-533-245
Fax: +49-6221-533-298
peter.saueressig@h-its.org
www.h-its.org
Scientific contact:
Prof. Dr. Volker Springel
Heidelberg Institute for Theoretical Studies (HITS)
Tel: +49-6221-533-241
volker.springel@h-its.org
www.h-its.org
The series of scientific articles:
The Lyman-alpha forest in a blazar-heated Universe. E. Puchwein, C. Pfrommer, V. Springel, A. E. Broderick, and P. Chang, 2012, MNRAS, in print, arXiv:1107.3837 http://arxiv.org/abs/1107.3837

The Cosmological Impact of Luminous TeV Blazars III: Implications for Galaxy Clusters and the Formation of Dwarf Galaxies. C. Pfrommer, P. Chang, and A. E. Broderick, 2012, ApJ, in print, arXiv:1106.5505 http://arxiv.org/abs/1106.5505

The Cosmological Impact of Luminous TeV Blazars II: Rewriting the Thermal History of the Intergalactic Medium. P. Chang, A. E. Broderick, and C. Pfrommer, 2012, ApJ, in print, arXiv:1106.5504 http://arxiv.org/abs/1106.5504

The Cosmological Impact of Luminous TeV Blazars I: Implications of Plasma Instabilities for the Intergalactic Magnetic Field and Extragalactic Gamma-Ray Background. A. E. Broderick, P. Chang, and C. Pfrommer, 2012, ApJ, in print, arXiv:1106.5494 http://arxiv.org/abs/1106.5494

Dr. Peter Saueressig | idw
Further information:
http://www.h-its.org
http://www.h-its.org/english/press/pressreleases.php?we_objectID=877

More articles from Physics and Astronomy:

nachricht Innovative LED High Power Light Source for UV
22.06.2017 | Omicron - Laserage Laserprodukte GmbH

nachricht Spin liquids − back to the roots
22.06.2017 | Universität Augsburg

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: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

New technique makes brain scans better

22.06.2017 | Medical Engineering

CWRU researchers find a chemical solution to shrink digital data storage

22.06.2017 | Life Sciences

Warming temperatures threaten sea turtles

22.06.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>