2
$\begingroup$

Today the first picture of the Sagittarius A black hole was released. Although somewhat similar to the first picture of the M87 black hole released three years ago, to my eye there's a notable difference in the bright spots of the accretion disc. In the M87 picture enter image description here the bright zone is (I dare say) uniformly distributed in the half lower region of the accretion disc, while there's a uniformly distributed darker region in the accretion disc's upper half. If I understand this picture correctly, this is Doppler beaming, and it means that we're viewing the accretion disc head on, with the matter in the lower region moving towards us and the matter on the upper region moving away from us. The matter's speed on the disc is what makes the difference in brightness noticeable.

Now, here is the Sagittarius A picture.enter image description here

Notice that here we have three bright spots in the accretion disk rather than one. What I think is happening is that in this case, we're not viewing the accretion disc head on, we're viewing it at an angle, giving it an elliptical shape (in contrast, both the accretion disc and shadow are pretty circular in the M87 picture). Since we're viewing it at an angle, the difference in brightness due to Doppler beaming would not be uniformly distributed in half regions, rather it would depend on the orientation we're observing the black hole, giving us these three bright spots, right? If my hypothesis is wrong, what is making these three bright spots appear?

Thanks in advance.

$\endgroup$
5
  • 1
    $\begingroup$ I’m voting to close this question because this is a duplicate of New black hole image. $\endgroup$ May 12 at 16:32
  • 2
    $\begingroup$ Does this answer your question? New black hole image $\endgroup$
    – Rishi
    May 12 at 16:33
  • $\begingroup$ Sorry, I didn't search thoroughly enough. Should I delete my question? $\endgroup$
    – RMC777
    May 12 at 16:34
  • $\begingroup$ @RMC777 Not necessarily. The community will likely close it as a duplicate, but the existence of your question might make it easier for other users to find the linked question. Once this question is closed, it will still be readable, but will show a link to the question with answers $\endgroup$ May 12 at 16:35
  • $\begingroup$ Understood. I'll leave it up then. Thank you to the people who linked the other question. $\endgroup$
    – RMC777
    May 12 at 16:37

0

Browse other questions tagged or ask your own question.