ateam002 Have you wondered what is around the famous supermassive black hole at the centre of the galaxy M87? Supermassive black holes have an incredible effect on the environment around them. Many of them are shooting powerful jets of plasma into space creating beautiful shapes that resemble clouds or smoke puffs. In this image we have compiled radio observations of the galaxy M87 performed with different telescopes at different frequencies. In all cases, scientists used a technique called "interferometry" which allows them to combine separate radio telescopes to enhance the resolution of the image. When observing at low frequencies, radio telescopes are sensitive to extended structures such as the giant bubbles of plasma detected by LOFAR at 0.05 GHz. Those bubbles of plasma are larger than our own galaxy. At higher frequencies, this extended emission becomes invisible but the resolution increases. This is the reason why the observation of the black hole shadow with the Event Horizon Telescope has been performed at the frequency of 230 GHz.

Credits:
EHT image - EHT collaboration (www.eventhorizontelescope.org)
VLBA image - C. Walker (www.vlba.nrao.edu)
VLA image - F. Owen (www.vla.nrao.edu)
LOFAR image - F. de Gasperin (www.lofar.org)