M87 observed with different radio telescopes

 Messier 87 seen with 'different eyes'.  Left: LOFAR image at a wavelength of 6 Meters. From the central bright spot two jets with sizes >50000 light years emerge on opposite sides. Their origin is the central black hole. Right: The VLA and VLBA images taken at wavelengths of 20cm and 7mm zoom in on details of the emerging jets. The  EHT observation made at 1.3 mm finally resolved the jets birthplace.

For the first time a super-massive black hole located in the center of the galaxy Messier 87 was directly imaged. The image was taken in April 2017 by an array of several telescopes spread over the whole Earth at a wavelength of ~1 millimeter. The telescopes formed together the "Event Horizon Telescope" to make this observation. The image shows a ring-like structure with a dark central region, which is the black hole’s shadow. The shadow is caused by the bending and capture of light by the event horizon. This horizon marks the border to the inside of the black hole, from where no matter or radiation is able to escape. The bright emission ring has a diameter of 42 micro arcsec. A black hole with a mass of 6.5 billion solar masses is required to create the size of the shadow.

The shadow of the black hole in M87 observed with the Event Horizon Telescope (EHT), an array of eight ground-based radio telescopes located in Chile, Mexico, Spain, U.S., and at the South Pole (@ EHT-collaboration).


Further reading:

Max-Planck-Institut für Radioastronomie: Press release.  --  (in German)