1
00:00:00,433 --> 00:00:03,436
An AGN can have 
several different structures.

2
00:00:03,703 --> 00:00:06,306
The brightest feature 
is the accretion disk.

3
00:00:09,242 --> 00:00:11,978
In this Event Horizon 
Telescope radio image,

4
00:00:11,978 --> 00:00:14,848
we see the accretion
disk around a supermassive

5
00:00:14,848 --> 00:00:17,851
black hole called M87*.

6
00:00:18,585 --> 00:00:21,988
This plane of gas and dust 
orbits the black hole

7
00:00:21,988 --> 00:00:25,658
and heats up through 
gravitational and frictional forces.

8
00:00:26,026 --> 00:00:27,694
Above and below the disk,

9
00:00:27,694 --> 00:00:29,896
an AGN can have a corona.

10
00:00:29,896 --> 00:00:34,968
This superheated plasma of loose electrons emits a lot of X-rays.

11
00:00:35,268 --> 00:00:39,039
It's way less dense than the 
accretion disk but way hotter.

12
00:00:40,974 --> 00:00:44,544
Despite AGN being some of the
 brightest objects in the universe,

13
00:00:44,544 --> 00:00:47,247
they can also 
sometimes hide behind

14
00:00:47,247 --> 00:00:48,548
a dusty torus.

15
00:00:48,748 --> 00:00:52,352
Now a torus is a thick,
bagel-shaped structure

16
00:00:52,352 --> 00:00:55,355
that is so dense we can't see the AGN

17
00:00:55,455 --> 00:00:59,325
unless the bagel’s hole is facing
one of our telescopes

18
00:00:59,859 --> 00:01:02,896
or you seek the energetic 
X-ray signals.

19
00:01:03,830 --> 00:01:05,832
Now scientists 
using NASA's
NuSTAR mission

20
00:01:06,266 --> 00:01:09,302
think that as many as 
50% of black holes

21
00:01:09,302 --> 00:01:12,138
are obscured by a torus.

22
00:01:12,439 --> 00:01:14,808
All of that is nothing 

23
00:01:14,808 --> 00:01:16,576
compared to the achievements

24
00:01:16,609 --> 00:01:17,911
of a jet!

25
00:01:18,778 --> 00:01:19,712
See that?

26
00:01:20,246 --> 00:01:22,849
That bright line is a black hole

27
00:01:22,849 --> 00:01:25,618
throwing a huge jet of particles

28
00:01:25,618 --> 00:01:28,088
moving at nearly the speed of light.