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The BBC News article First ever black hole image released shows the instantly-iconic radio image of the (almost certainly) supermassive black hole at the center of the M87 galaxy, just released by the Event Horizon Telescope collaboration, also shown below.

Though it calls it a "first image", the article also shows a similarly edible-looking† donut-shaped image taken earlier, presumably using a different technology. However the caption doesn't explain what that is.

†https://i.sstatic.net/J5TEe.gif

Does anyone recognize the earlier image and/or know what imaging technology and wavelengths were used to construct it? Is it roughly the same scale? Are these comparable donut-hole images?

enter image description here

Astronomers have suspected that the M87 galaxy has a supermassive black hole at its heart from false colour images such as this one. The dark centre is not a black hole but indicates that stars are densely packed and fast moving. Credit: DR JEAN LORRE/SCIENCE PHOTO LIBRARY

mystery image of M87 (central black hole?)

The first ever picture of a black hole: It's surrounded by a halo of bright gas. Credit: EHT

Overly entheusiastic Wikipedia edit?

enter image description here

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    $\begingroup$ This is the best image we have of the M87 core and jet: en.wikipedia.org/wiki/Messier_87#/media/File:M87_jet.jpg . I believe the false colour image above is a map of stellar velocities, showing their orbits around the black hole, but I'm not sure where I read this. The field of view would be vastly wider than the EHT image, I'm guessing they couldn't resolve stars near the core due to the overwhelming brightness of the jet. $\endgroup$
    – MichaelB76
    Commented Apr 11, 2019 at 7:28
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    $\begingroup$ It looks like the source for that image is sciencephoto.com/media/333661/view/…, which explains: "The variation in intensity of colour towards the central core of the galaxy indicates the increased degree of packing of the stars. Calculations have indicated that the central stars (in the black core) are so tightly packed & fast moving that they must be influenced by the gravitational field of a massive black hole." $\endgroup$
    – rchard2scout
    Commented Apr 11, 2019 at 19:14
  • $\begingroup$ @rchard2scout Yep, that certainly looks like it. The caption doesn't reveal as much as I'd like but it's a good start. Thanks! $\endgroup$
    – uhoh
    Commented Apr 11, 2019 at 21:04

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Your top image is this from Dr Jean Lorre stock science images. Just a photo showing stars and the optical jet with a 22 MB CCD camera through a small telescope. It is unfortunate that he chose a false color brightness scale with black at the top intensity. But, that black region does not correspond to the true blackness in the interferometric image which has resolution 100,000 times higher.

For comparison, here's a False-col. optical image of spiral galaxy NGC 1097 by the same "artist", also with the dark center where the visible light intensity is actually a maximum.

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  • $\begingroup$ Okay I think you've nailed it quite nicely! I like this space art better, personally ;-) $\endgroup$
    – uhoh
    Commented Apr 12, 2019 at 23:20
  • $\begingroup$ The M87 image appears to have been processed to show the jet more clearly. However, I'm a little dubious the jet is really that wide, no other image I've come across shows it like that. Would be interesting to hear how it was shot and what processing steps were taken. I couldn't begin to guess what the motivation behind the NGC 1097 image is. $\endgroup$
    – MichaelB76
    Commented Apr 15, 2019 at 6:58
  • $\begingroup$ Tried searching for 'Dr Jean Lorre' and all I could find were a couple image credits in a 1994 astronomy book, unfortunately the images won't display in my preview: books.google.co.uk/… $\endgroup$
    – MichaelB76
    Commented Apr 15, 2019 at 7:02

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