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Protective layer: Magnetic field of the Jellyfish galaxy JO206

The galaxy JO206 and its ordered magnetic field (green lines) along the gas tail. The pink objects characterize the H-alpha emission, which possibly gives an indication of the formation of new stars. Credit: ESO/GASP collaboration, adapted

Protective layer: Magnetic field of the Jellyfish galaxy JO206

26 October 2020. Gas tails give them their jellyfish-like appearance: So-called jellyfish galaxies are difficult to study because of their low brightness. An international research team has now gai...

Jellyfish galaxies are galaxies that crash into the centre of a galaxy cluster, forming a gas tail. This is created as the galaxy moves towards the centre of the cluster, pushing the interstellar gas in the opposite direction. In this way the galaxies acquire their characteristic appearance, which is reminiscent of a jellyfish. In earlier studies, it has already been proved that this gas tail can lead to star formation - but it was not clear until now which factors could cause this. It is known, for example, that magnetic fields in galaxies can contribute to star formation. But do they also play a role in the gas tails of jellyfish galaxies?

In a recent publication in the scientific journal Nature Astronomy, a German-Italian team is now getting to the bottom of this question. Ancla Müller and Prof. Dr. Ralf-Jürgen Dettmar from the Ruhr University Bochum describe the results together with Prof. Dr. Christoph Pfrommer and Dr. Martin Sparre from the Leibniz Institute for Astrophysics Potsdam (AIP), together with colleagues from the INAF - Italian National Institute of Astrophysics in Padua, Cagliari and Bologna. They analysed the magnetic field structure of the Jellyfish galaxy JO206 and could show that not only did the galactic disk have a strong magnetic field, but so did the gas tail. From the unusually high proportion of polarised radiation, they were able to conclude that the field is aligned very precisely along the tail. "As the galaxy falls on the centre of the galaxy cluster, an interaction takes place with the medium between the individual galaxies and its magnetic field," explains Ancla Müller. This process could amplify the magnetic field of JO206 and also generate the high proportion of polarised radiation.

In order to explain these unusual parameters, computer simulations were then used, by means of which the scientists developed a theory: According to this theory, JO206 rushes at high speed to the centre of the galaxy cluster, causing the magnetic fields to interact, and hot winds from the medium between the galaxies to collects as accumulations of plasma. Parts of this mixture of ions, electrons and neutral particles condense on the outer layers of the gas tail, where they mix with the surrounding matter. "As the jellyfish galaxy flies through the galaxy cluster, its magnetic field wraps around the galaxy like a mantle and is further strengthened and smoothed by the high speed of the galaxy and by cooling effects", explains Prof. Pfrommer. The magnetic layer protects the gas tail from falling apart. According to these results, there would be enough material for star formation in the gas tail of JO206. Further measurements on other objects must now show whether this theory can be confirmed.

 

A visualization of a simulation of a jellyfish galaxy interacting with the hot magnetized gas in a galaxy cluster. Due to the fast motion of the galaxy, the magnetic field (with the 3 components on the left side) is superimposed on the galaxy (density distribution on the right side) and in the pull of the galaxy the magnetic field lines are aligned at the tail of the galaxy (as seen in the middle magnetic field image). Dense gas can survive if it is transported downstream, because the hot gas in the wind cools down due to the interaction. Credit: AIP/M. Sparre

 

Science contact AIP

Prof. Dr. Christoph Pfrommer, 0331 7499 513, cpfrommer@aip.de

Media contact

Franziska Gräfe, 0331 7499 803, presse@aip.de

Publication

Ancla Müller, Bianca Poggianti, Christoph Pfrommer, Björn Adebahr, Paolo Serra, Alessandro Ignesti, Martin Sparre, Myriam Gitti, Ralf-Jürgen Dettmar, Benedetta Vulcani, Alessia Moretti (2020): Highly ordered magnetic fields in the tail of the jellyfish galaxy JO206. Nature Astronomy

DOI: 10.1038/s41550-020-01234-7

https://www.nature.com/articles/s41550-020-01234-7

Press release of the Ruhr-Universität Bochum

https://news.rub.de/english/press-releases/2020-10-26-astronomy-magnetic-fields-jellyfish-galaxy-jo206

 

The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.

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New study verifies prediction from Einstein's General Theory of Relativity

Artistic representation of the Sun, the Earth and the Moon with the space-time curvature of Einstein's General Relativity over the spectrum of sunlight reflected from the Moon (in colours from blue to red). Credit: Gabriel Pérez Díaz, SMM (IAC)

New study verifies prediction from Einstein's General Theory of Relativity

23 October 2020. An international research team has used observational data and simulations to determine the redshift in the Sun's gravitational field with unprecedented accuracy. This effect, pred...

Between 1911 and 1916, Albert Einstein published his General Theory of Relativity, predicting that light travels on curved paths near massive objects. He also expected that spectral lines in the Sun's gravitational field would shift to longer wavelengths (gravitational redshift). In 1911, Einstein predicted a theoretical redshift of approximately two millionths of a wavelength for the Sun.

To determine the redshift, a research team led by the Instituto de Astrofísica de Canarias (IAC) has used observations of the solar spectrum reflected by the moon. The applied instrument HARPS (High Accuracy Radial velocity Planet Searcher) is equipped with a technology for highly accurate wavelength measurement, but is not suitable for direct solar observation. Using the spectrograph the scientists obtained data in which they could measure the wavelength shift of many iron lines with high accuracy. Chemical elements leave traces in the form of lines in the spectrum of stars, and iron lines are particularly suitable for the present study for two reasons: there are many more spectral lines from iron than from any other element, which is why a sufficiently large number of undisturbed lines are available for the measurement. Also, reliable laboratory measurements of their rest wavelengths are available, which is essential to determine the gravitational shift - the difference between the wavelength measured in the laboratory and that measured in the solar spectrum.

In addition to observational data, the study also used precise modelling of the solar spectrum to theoretically predict the wavelength shift of different iron lines. Dr. Matthias Steffen from the Leibniz Institute for Astrophysics Potsdam (AIP) was involved in the publication and, together with colleagues from Heidelberg and Paris, analysed three-dimensional computer simulations that predict the flow velocities and related temperature perturbations in the solar atmosphere, with the latest simulations also taking into account the influence of magnetic fields.

The synthetic spectra subsequently computed from these 3D models showed that weak iron lines are blue-shifted by up to 600 m/s due to convective motions and correlated temperature fluctuations in the solar atmosphere. This almost completely compensates for the redshift of 633 m/s caused by gravity - which is of the same order of magnitude but in the opposite direction. This is one of the reasons why early attempts to prove Einstein's theory with line-shift measurements on the Einstein Tower in Potsdam failed.

The new and extremely accurate wavelength measurements of the solar spectrum could also be used in the future to study the Sun's photosphere. If the theoretical gravitational redshift is assumed to be correct, the new data will enable even more precise studies of the structure and dynamics of the photosphere and to develop refined 3D models of the convective flows at the surface of the Sun.

 

 

One of the models used to compute synthetic solar spectra. The simulations were created at the AIP using the radiative hydrodynamics code CO5BOLD. Dark lanes are the intergranular regions of cooler temperature that harbor magnetic field structures. Credit: AIP


Science contact

Dr. Matthias Steffen, 0331 7499 371, msteffen@aip.de

Media contact

Franziska Gräfe, 0331 7499 803, presse@aip.de

Publication

González Hernández, J. I. et al. (2020): The solar gravitational redshift from HARPS-LFC Moon spectra. A test of the General Theory of Relativity. Astronomy & Astrophysics (in press)

DOI: https://doi.org/10.1051/0004-6361/202038937

Press release of the Instituto de Astrofísica de Canarias (IAC)

https://www.iac.es/en/outreach/news/new-measurements-solar-spectrum-verify-einsteins-theory-general-relativity

 

The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.

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Call for Nominations for 2021 Wempe Award

13 October 2020. The Leibniz Institute for Astrophysics in Potsdam, Germany (AIP) welcomes nominations and applications for the Johann Wempe Award 2021.

In honour of Professor Johann Wempe (1906–1980), the last director of the former Astrophysical Observatory of Potsdam (AOP), the AIP grants the Johann Wempe Award to outstanding scientists.

The award consists of a stipend to facilitate a research visit to the AIP of up to six months. The recipient may be either a promising young scientist who has already made notable achievements or a senior scientist, in recognition of his or her life's work. The recipient is expected to enrich the scientific life of the institute through a series of lectures in their area of expertise.

 

Further information: Call for nominations Johann Wempe Award 2021

Application and nomination materials should be submitted by December 31, 2020.

 

The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.

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New Season of Babelsberg Starry Nights starts online

On Thursday, 15 October 2020, the Babelsberg Starry Nights of the Leibniz Institute for Astrophysics Potsdam (AIP) will begin again. For the time being, the popular lecture series will not take pla...

Dr. Axel Schwope will begin with a lecture on "The new image of the X-ray sky: eROSITA one year in space". After a successful launch and a slightly bumpy commissioning phase, the eROSITA X-ray telescope has produced its first complete map of the X-ray sky. In just half a year, it found more X-ray objects in the sky than all other telescopes combined over the last 60 years. Although the scientific evaluation has only just begun, Axel Schwope can already report on some initial fascinating results and astonishing discoveries.

This season, the Babelsberg Starry Nights will not take place on site at the AIP, but will come straight to your home: on the 3rd Thursday of each month from 6 p.m. the lectures are available at

https://www.aip.de/babelsberger-sternennaechte

and can be viewed at any time afterwards.

 

Further dates: Babelsberg Starry Nights

 

Cosmic X-ray- echo, observed with eROSITA. Credit: G. Lamer, D. Mella


The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.

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Search for traces of microplastics in humans: New joint research project funded

Fluorescent microplastic particles under the Raman microscope. Credit: AIP

Search for traces of microplastics in humans: New joint research project funded

5 October 2020. The PlasMark project, which has been awarded 4.5 million Euros by the Federal Ministry of Education and Research, will start in October 2020 with the aim of investigating the conseq...

The multidisciplinary research team from the fields of physics, biochemistry, biology and pharmacy is focusing on the question of how label-free diagnostics of plastic particles is possible. "We focus on three different state-of-the-art technologies," explains Prof. Martin Roth from the innoFSPEC research centre at the Leibniz Institute for Astrophysics Potsdam (AIP). "In addition to confocal Raman spectroscopy and terahertz spectroscopy, which we know from the so-called body scanners at the airport, the suitability of multispectral light and electron microscopy for this purpose is being investigated.”

All three approaches - partly borrowed from astrophysics - are suitable for making statements about the chemical composition of a particle as well as visualising it. Raman spectroscopy take advantage of the fact that matter interacts with laser light, leaving behind a characteristic fingerprint - a spectrum in the scattered light. In this way it is also possible to assign the plastic particles to their original material - e.g. polyethylene, polystyrene or PVC. While this works well for sufficiently large pieces of plastic, the challenge for the team is to detect these fingerprints for small and minute particles. In addition, successfully scanning tissue samples with conventional Raman microscopes is very time-consuming and can take many hours to days. The innoFSPEC research centre at the AIP has set itself the goal of realising an imaging Raman spectroscopy setup that allows the identification of plastic particles within minutes or seconds. This is made possible by wide field spectrographs from astronomy - where this technique is used in observatories to save valuable observation time.

The joint project supports research at three Centres for Innovation Competence (ZIK) in the new federal states: ZIK plasmatis at the Leibniz Institute for Plasma Research and Technology Greifswald (INP), ZIK HIKE at the University Medical School and University of Greifswald and ZIK innoFSPEC at the Leibniz Institute for Astrophysics in Potsdam (AIP). The first results are expected to be available in two years' time in order to be able to better answer the question to what extent the contamination of the environment and thus of the human body with microplastic particles is one of the causes of neurodegenerative diseases, cardiovascular diseases or even cancer.

 

Press release of the Leibniz Institute for Plasma Science and Technology e.V. (INP)

https://www.inp-greifswald.de/de/aktuelles/presse/pressemeldungen/2020/folgen-von-mikroplastik-und-nanoplastik-im-menschen/

Science contact AIP | innoFSPEC

Prof. Dr. Martin M. Roth, 0331 7499 313, mmroth@aip.de

Media contact

Franziska Gräfe, 0331 7499 803, presse@aip.de

 

The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.

Read more ...