GLOW News Blog

News about the German Long Wavelength Consortium and radio astronomy in Germany

A new webpage on LOFAR surveys has been released to give access for astronomers to papers and data releases relating to sky surveys made with the LOFAR interferometer. The current content focuses on the ongoing HBA 120-168 MHz Tier-1 survey, which is referred to as the LOFAR Two-metre Sky Survey (LoTSS).

The 2018 Red Book on SKA Cosmology has been published (press release). It complements and extends on the cosmology chapter in the SKA Science Book from 2015.

The Bielefeld Cosmology and Astroparticle Physics group contributed to the study of how SKA will enable us to better probe the most fundamental assumptions of modern cosmology.

The Square Kilometre Array will be able to measure the kinematic radio dipole. A dipolar anisotropy is expected due to the motion of the Solar system with respect to the cosmic rest frame of matter. The figure shows the result of 1000 simulations of the reconstructed dipole measured from a wide area SKA survey, with and without identification of local cosmic structures. This measurement allows for a critical test of the cosmological principle, the foundation of all of modern cosmology.


Since 2015 an antenna field of the largest European radio telescope LOFAR is operating in Norderstedt (Schleswig-Holstein). This LOFAR station is operated by the Hamburger Sternwarte (Universität Hamburg) and the Fakultät für Physik of Bielefeld University. Together with  50 similar stations creating a network spread over Europe stunning images of radio outflows from galaxies are now routinely obtained. Graduate student Amanda Wilber and Prof. Marcus Brüggen report on their exciting discoveries in a new video clip.

At the meeting of Board of the International LOFAR Telescope (ILT) on Monday, 16 April 2018, Italy has officially become a member of the ILT. Moreover,  the Italian National Institute for Astrophysics (INAF) has announced to build a LOFAR station at the Medicina Radio Observatory site, 30 kilometres from Bologna. This will significantly improve the image quality since the distribution of international stations becomes much more roundish. 




The GLOW consortium welcomes two new members: On Monday, March 12, Jochen Weller and Stefan Wagner signed the GLOW Agreement for the Fakultät für Physik der Ludwig-Maximilians-Universität München and the Zentrum für Astronomie der Universität Heidelberg, respectively, at the occasion of a meeting on the radio telescope MeerKAT. At the meeting in Würzburg the partners of the Verbundforschungsprojekt D-MeerKAT discussed the exiting prospects with upcoming MeerKAT telescope. The research groups of Jochen Weller and Stefan Wagner are already significantly involved in D-MeerKAT project. 


Stefan Wagner, Ralf-Jürgen Dettmar, Jochen Weller und Matthias Hoeft, Photo: M.Hoeft

In a recent work Kamlesh Rajpurohit (Tautenburg) and collaborators demonstrated how observations with the upgraded Very Large Array (equipped with broadband receivers) can significantly advance our knowledge about cosmic magnetism: The observation shows the spectacular Toothbrush radio relic in remarkable detail. The filamentary structures are very likely related to the distribution of magnetic fields in the cluster periphery and shed light on the origin of these fields. The observation gives a glimpse of how upcoming radio facilities will change our view of the universe! 


Rajpurohit et al. 2018.




GLOW welcomes back Dr. F. de Gasperin who took office on March 1st, 2018 as Junior Professor for Radio Astronomy at the Universität Hamburg. Located at the Hamburger Sternwarte, Francesco will build up a low-frequency radio astronomy group and is going to work with the International LOFAR telescope. Hamburger Sternwarte is contributing to the European LOFAR telescope with a station in Norderstedt. He graduated in 2012 from the LMU München, then came to Hamburg for two years of postdoctoral work in the extragalactic research group of Marcus Brüggen and then, in 2015, went to the University of Leiden (NL) as a Veni Fellow. Francesco has extensive experience with research involving LOFAR. He has developed calibration and imaging techniques, as well as novel technologies to analyse sky surveys at low frequencies. His astrophysical interests cover  Active Galactic Nuclei, galaxy evolution, and cosmology.

Bei Beobachtungen an Galaxienhaufen hat eine internationale Forschungsgruppe unter Leitung von Wissenschaftlern der Universität Hamburg eine neue Klasse kosmischer Radioquellen aufgespürt. Mit dem digitalen Radioteleskop Low Frequency Array (LOFAR) empfingen sie die längsten Radiowellen, die auf der Erde gemessen werden können, und erkannten so einen Galaxien-Schweif, der nach seinem Erblassen mit neuer Energie versorgt worden sein muss. In der aktuellen Ausgabe des Fachmagazins „Science Advances“ beschreibt das Team um Dr. Francesco de Gasperin von der Hamburger Sternwarte und dem Observatorium Leiden (Niederlande) seine Entdeckung.

 Pressemitteilung der Universität Hamburg

Fachartikel: de Gasperin et al. 2017, Gentle reenergization of electrons in merging galaxy clusters, Science Advances, 4.10.2017

GLOW can look back on a successful year with success in the federal Verbundforschung, tremendous progress with LOFAR results, very enjoyable meetings in Bologna, Würzburg and in Berlin, a new momentum for Germany joining the SKA, and new members joining. The HTW Berlin has joined at the GLOW annual meeting in Würzburg and the Ludwigs-Maximilian Universität in München is in the process of joining. Several other institutes have also expressed their wish to join GLOW.
Since the GLOW annual meeting in Würzburg a few months have already passed, so it is time to wrap up the year with a last newsletter for 2017.
--------- NEWS ------------
New LOFAR Station in Latvia 
A contract for building a new LOFAR station in Latvia has been signed. The station in Irbene is expected to become operation in 2019.
LoTSS Survey 
LOFAR surveys are making rapid progress. Catalogues as well as accompanying papers will be released soon. In a so-called “paper splash” a number of articles with LOFAR survey results are going to be published in a dedicated journal volume.
German SKA “Verein" underway
Preparations are underway to form a German SKA “Verein” with the aim to become an associated member of the SKA. Here a community day will take place early in 2018. A date will be announced soon.
BMBF has released a booklet on LOFAR
Earlier this year, the BMBF described LOFAR in a booklet on essential research infrastructures supported by the BMBF.
SKA and CERN have signed Big Data Cooperation agreement
SKA1 is expected to generate about 300 PByte of scientific data per year. Processing and handling such an amounts of data is a challenge.
SKA and CERN will cooperate to develop appropriate strategies, e,g, cloud based processing and regional centers.
DPG has founded Working Group “Physics, modern IT, and Artificial Intelligence"
Momentum for forming this group was picked up during the “Big Data” meeting in Berlin in June 2017.
The working group will meet at the DPG Frühjahrstagung in Würzburg, 2018, March 19-23
SKA and NRAO team up to develop software which can deal with large amounts of data expected for SKA1
------- ANNOUNCEMENTS ----------
A workshop on High-Resolution Surveys with International LOFAR will be held 19–23 March 2018 at the Lorentz Centre in Leiden and is designed to cover both expert discussions on finalising the details of the pipeline for general and heavy use. Several days of tutorials for new users will be included at the end of the week. We should ensure participation from Germany.
The Big Impact of a Big Dish: Science with the Effelsberg 100-m telescope
Next-Generation Cosmology with Next-Generation Radio Telescopes
Interstellar Medium in the Nearby Universe
 The power of radio tomography  -- Towards 3D mapping of cosmic magnetic 
See also
for a list of upcoming events. 
Job Opportunity
The Bielefeld Pulsar Group is advertising a position for a scientific programmer, which could also be interesting to technically-minded post-docs who have an interest in low-frequency pulsar observations and solar-wind studies. Contact Joris Verbiest for details.
You can find this and older newsletters on the GLOW news page
On behalf of the GLOW EC, let me thank you for your all your work you have put in to all the various radio astronomical initiatives over the year. I hope you find some well-deserved rest over the holidays.
A Merry Christmas and a Happy New Year
Marcus (on behalf of the GLOW EC)


The fortress Marienberg in Würzburg provided an impressive environment for the Radio2017 conference and the annual meeting of the GLOW consortium. At the conference with motto "Radio astronomy in the multi-frequency survey era" a wide overview on recent progress in radio astronomy was given. 


See also the meeting webpage: Radio2017

At the GLOW Annual Assembly 2017 in Würzburg  the GLOW Consortium welcomed a new member: the Hochschule für Technik und Wirtschaft Berlin.

Marcus Brüggen, Klaus Semlinger (President of the HTW Berlin), and Matthias Hoeft at the HTW in Berlin, Campus Wilhelminenhof
Photo: H. Hessling


An international team of astronomers led by Francesco de Gasperin (Hamburg and Leiden University) has witnessed an unexpected phenomenon in a merger of two clusters of galaxies. The astronomers discovered a gas trail that slowly extinguished but then lit up again. It is unclear where the energy for the rejuvenation of this trail comes from. 

The astronomers investigated Abell 1033. This is a cluster of galaxies consisting of two smaller clusters that are in the process of merging. Abell 1033 is located in the northern constellation of Leo Minor (near Ursa Major). Clusters of galaxies are the largest structures in the Universe. They can contain hundreds to thousands of galaxies similar to our Milky Way. Smaller clusters can merge together to form a larger cluster.

The astronomers observed that an individual galaxy in Abell 1033 leaves a trail of gas as it traveled through the cluster. On astronomical scale, such a trail resembles the trail of colored smoke behind a stunt plane. It was expected that the gas trail, like the ones behind a stunt plane, would slowly fade and eventually disappear. To their astonishment they saw that the end of the gas trail was brighter than the middle.

"This was totally unexpected," says de Gasperin. "As these clouds of electrons radiate away their energy over time, they should become fainter and disappear. Instead, in this case, after more than a hundred million years, the trail of electrons is glowing brightly."

There is no precise explanation for this phenomenon yet. It seems that the trail brightens near the center of the cluster of galaxies. De Gasperin: "Part of the energy released in the merger event must have transferred to rejuvenate the cloud of electrons.”

This work has been published in Science Advances

Page 2 of 4