The timescales over which galaxies form and evolve are outside the reach of human life. Thus, astronomers need to use indirect methods to derive the history of galaxies. Important events happen during the life of a galaxy and they can change the course of its evolution. In particular, when the central supermassive black hole (SMBH) is active, it can release huge amounts of energy which can affect the surrounding gas and can impact the evolution of the entire galaxy. This effect has been recognised as crucial for explaining why galaxies look the way they do.

Published by the editorial team, 30 August 2017

But how often and for how long is a SMBH active?

"This is not an easy question to answer," says Raffaella Morganti from ASTRON. "Astronomers are working hard to address it by using observations in different wavebands and perform a kind of ‘archaeology’ to trace the signatures of past nuclear activity. Extremely interesting is the role that the low-frequency radio telescopes and, in particular, LOFAR have in this. They offer new possibilities for major steps forward in this field. At low radio frequencies, where low-energy electrons can radiate for longer times, the astronomers can explore the phases in which a radio source is dying and, in some cases, is re-born: an ideal task for LOFAR."

The status of the field and the progress on this fascinating topic are described in a review article appearing this week in Nature Astronomy, “Archaeology of active galaxies across the electromagnetic spectrum (https://www.nature.com/articles/s41550-017-0223-0)” by Raffaella Morganti (a download can also be found at http://rdcu.be/vlUw). Among many things, the review summarises some of the recent results obtained by LOFAR, including those from the ERC-RadioLife group.

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On June 13-17, the LOFAR Family Meeting took place in Cologne. After two years LOFAR researchers could finally meet in person again. The meeting brings together LOFAR users and researchers to share new scientific results.
https://www.astron.nl/dailyimage/main.php?date=20220621

Our renewed ‘Melkwegpad’ (Milky Way Path) is finished! The new signs have texts in Dutch on the one side and in English on the other side. The signs concerning planets have a small, 3D printed model of that planet in their centre.
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The background drawing shows how the subband correlator calculates the array correlation matrix. In the upper left the 4 UniBoard2s we used. The two ACM plots in the picture show that the phase differences of the visibilities vary from 0 to 360 degrees.

Daily image of the week: Testing with the Dwingeloo Test Station (DTS)
One of the key specifications of LOFAR2.0 is measuring using the low- and the highband antenna at the same time. For this measurement we used 9 lowband antenna and 3 HBA tiles.
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