Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

(Re)solving the jet/cocoon riddle of a gravitational wave event

22.02.2019

An international research team including astronomers from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has combined radio telescopes from five continents to prove the existence of a narrow stream of material, a so-called jet, emerging from the only gravitational wave event involving two neutron stars observed so far. With its high sensitivity and excellent performance, the 100-m radio telescope in Effelsberg played an important role in the observations.

In August 2017, two neutron stars were observed colliding, producing gravitational waves that were detected by the American LIGO and European Virgo detectors. Neutron stars are ultra-dense stars, roughly the same mass as the Sun, but similar in size to a city like Cologne.


Image of the source obtained from the combination of thirty-three radio telescopes from five continents. The source can be seen a bit left of the center as a red spot in the false color image.

Giancarlo Ghirlanda/Science


World-wide distribution of all facilities that participated in this observation.

Paul Boven (JIVE)

This event is the first and only one of this type that has been observed so far, and it happened in a galaxy 130 million light years away from Earth, in the constellation of Hydra.

Astronomers observed the event and the subsequent evolution across the entire electromagnetic spectrum, from gamma-rays, X-rays to visible light and radio waves. Two hundred days after the merger, observations combining radio telescopes in Europe, Africa, Asia, Oceania, and North America proved the existence of a jet emerging from this violent collision.

These findings are now published in the scientific journal Science by an international team of astronomers, led by Giancarlo Ghirlanda from the Italian National Institute for Astrophysics (INAF).

This neutron star merger represented the first case where it was possible to associate a detection of gravitational waves to an object emitting light. The event has confirmed scientific theories that have been under discussion for tens of years, and the association of neutron star mergers with one of the most powerful explosions in the Universe: gamma-ray bursts.

After the merger, a huge amount of material was expelled into space, forming a shell around the object. Astronomers have been tracing its evolution at different wavelengths. However, there were still some remaining questions concerning this event that could not be clarified by any previous observations.

"We expected part of the material to be ejected through a collimated jet, but it was unclear whether this material could successfully pierce through the surrounding shell." explains Ghirlanda. “There were two competing scenarios: In one case, the jet cannot break through the shell, instead generating an expanding bubble around the object. In the other, the jet is successful in penetrating the shell and then propagates further into space”, expands Tiziana Venturi (INAF).

Only the acquisition of very sensitive radio images with very high resolution would discard one scenario or the other. This required the use of a technique known as very long baseline interferometry (VLBI) that allows astronomers to combine radio telescopes all around the Earth.

The authors of this publication conducted global observations in the direction of the merger on 12 March 2018 using thirty-three radio telescopes from the European VLBI Network (that connects telescopes from Spain, the United Kingdom, The Netherlands, Germany, Italy, Sweden, Poland, Latvia, South Africa, Russia, and China), e-MERLIN in the UK, the Australian Long Baseline Array in Australia and New Zealand, and the Very Long Baseline Array in the USA.

„Our 100-m radio telescope in Effelsberg participated in the observations and was a key element, due to its high sensitivity and excellent performance“, says Carolina Casadio, a member of the research team from the Max Planck Institute for Radio Astronomy (MPIfR).

The data from all telescopes were sent to JIVE, The Netherlands, where the most advanced processing techniques were used to produce an image with a resolution comparable to resolving a person on the surface of the Moon. In the same analogy, the expanding bubble would appear with an apparent size equivalent to a truck on the Moon, whereas a successful jet would be detected as a much more compact object.

"Comparing the theoretical images with the real ones, we find that only a jet could appear sufficiently compact to be compatible with the observed size.", explains Om Sharan Salafia from INAF in Italy. The team determined that this jet contained as much energy as produced by all the stars in our Galaxy during one year. “And all that energy was contained in a size smaller than one light year.” says Zsolt Paragi, also from JIVE.

„Within Europe we utilize the RadioNet consortium for an efficient use of our members’ radio telescopes. The observations descibed here combine radio observatories all over Europe and world wide. They require a well-coordinated effort of the collaborating observatories and institutions to achieve such exciting results”, explains Anton Zensus, Director at MPIfR and coordinator of the RadioNet consortium.

In the coming years, many more of these neutron star binary mergers will be discovered. “The obtained results also suggest that more than 10% of all these mergers should exhibit a successful jet.”, explains Benito Marcote from JIVE. "These types of observations will allow us to unveil the processes that take place during and after some of the most powerful events in the Universe.", concludes Sándor Frey from the Konkoly Observatory in Hungary.


Very long baseline interferometry (VLBI) is an astronomical method by which multiple radio telescopes distributed across great distances observe the same region of sky simultaneously. Data from each telescope is sent to a central "correlator" (e.g. at JIVE or at MPIfR) to produce images with higher resolution than the most powerful optical telescopes.

The European VLBI Network (EVN) is an interferometric array of radio telescopes spread throughout Europe, Asia, South Africa and the Americas that conducts unique, high-resolution, radio astronomical observations of cosmic radio sources. Established in 1980, the EVN has grown into the most sensitive VLBI array in the world, including over 20 individual telescopes, among them some of the world's largest and most sensitive radio telescopes. The EVN is administered by the European Consortium for VLBI, which includes a total of 15 institutes, including the Max Planck Institute for Radio Astronomy in Bonn, Germany.

Thirty three radio telescopes participated in this observation: Yebes (Spain), Jodrell Bank (UK), e-MERLIN (UK), Westerbork (The Netherlands), Effelsberg (Germany), Medicina (Italy), Onsala (Sweden), Noto (Italy), Toruń (Poland), Irbene (Latvia), Hartebeesthoek (South Africa), Zelenchukskaya (Russia), Urumqi (China), Badary (Russia), Kunming (China), Tianma (China), Ceduna (Australia), Hobart (Australia), Parkes (Australia), Mopra (Australia), Australia Telescope Compact Array (Australia),Warkworth (New Zealand), Mauna Kea (USA), Brewster (USA), Owens Valley (USA), Kitt Peak (USA), Pie Town (USA), Karl G. Jansky Very Large Array (USA), Los Alamos (USA), Fort Davis (USA), North Liberty (USA), Green Bank (USA), Hancock (USA), and St. Croix (USA).

The research leading to these results has received funding from the European Commission Horizon 2020 Research and Innovation Programme under grant agreement No. 730562 (RadioNet).

Wissenschaftliche Ansprechpartner:

Dr. Carolina Casadio,
Max-Planck-Institut für Radioastronomie, Bonn.
Fon: +49 228 525-473
E-mail: casadio@mpifr-bonn.mpg.de

Prof. Dr. Eduardo Ros,
Max-Planck-Institut für Radioastronomie, Bonn.
Fon: +49 228 525-125
E-mail: ros@mpifr-bonn.mpg.de

Originalpublikation:

„(Re)solving the jet/cocoon riddle of the first gravitational wave electromagnetic counterpart“, G. Ghirlanda, et al., Science, 21 February 2019 (DOI 10.1126/science.aau8815)

http://science.sciencemag.org/cgi/doi/10.1126/science.aau8815

Weitere Informationen:

https://www.mpifr-bonn.mpg.de/pressreleases/2019/3

Norbert Junkes | Max-Planck-Institut für Radioastronomie

More articles from Physics and Astronomy:

nachricht A cavity leads to a strong interaction between light and matter
22.10.2019 | Universität Basel

nachricht A new stable form of plutonium discovered at the ESRF
21.10.2019 | European Synchrotron Radiation Facility

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: A cavity leads to a strong interaction between light and matter

Researchers have succeeded in creating an efficient quantum-mechanical light-matter interface using a microscopic cavity. Within this cavity, a single photon is emitted and absorbed up to 10 times by an artificial atom. This opens up new prospects for quantum technology, report physicists at the University of Basel and Ruhr-University Bochum in the journal Nature.

Quantum physics describes photons as light particles. Achieving an interaction between a single photon and a single atom is a huge challenge due to the tiny...

Im Focus: Solving the mystery of quantum light in thin layers

A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)

It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

New deep-water coral discovered

22.10.2019 | Life Sciences

DNA-reeling bacteria yield new insight on how superbugs acquire drug-resistance

22.10.2019 | Life Sciences

Heat Pumps with Climate-Friendly Refrigerant Developed for Indoor Installation

22.10.2019 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>