<p>This question was asked more roughly 8 years ago, and for 2 years there is a review article around which I found worth mentioning and summarizing. The manuscript is called <em><a href="https://arxiv.org/abs/1909.08639" rel="nofollow noreferrer">Redefining the torus:  A unifying view of AGN in the infrared and sub mm</a></em> and work of <a href="https://en.wikipedia.org/wiki/Sebastian_F._H%C3%B6nig" rel="nofollow noreferrer">Sebastian Florian Hönig</a>. Here an excerpt of the abstract:</p>
<blockquote>
<p>The advent of high-angular resolution IR and sub-mm interferometry allows for spatially-resolvedobservations  of  the  parsec-scale  environment  of  active  galactic  nuclei  (AGN),  commonly  referred  toas the “torus.”  While molecular lines show the presence of large, massive disks, the IR observationsappear to be dominated by a strong polar component that has been interpreted.</p>
</blockquote>
<p>The main result seems to be the following schematic picture (Fig. 4 of the manuscript) of the AGN which is an overlay of various observations:</p>
<p><a href="https://i.sstatic.net/rQn6z.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/rQn6z.png" alt="Fig 4 of arXiv:1909.08639" /></a></p>
<ol>
<li>The purple ring are observations in the near-IR.</li>
<li>The yellow torus and the gray dashed lines are from <span class="math-container">${\rm H}_2$</span> emission.</li>
<li>The main brownish cone is from mid-IR.</li>
<li>The redish wobbly plane with the red (solid) arrows and the purple (dashed) arrows are sub-mm obseravtions (<span class="math-container">${\rm CO/HCN/HCO^+}$</span>)</li>
<li>Bright green dots on the <span class="math-container">$x$</span>-axis are <span class="math-container">${\rm H_2 O}$</span> maser emissions.</li>
</ol>

CC BY-SA 4.0
2021-03-19T08:59:02.700Z
2021-03-19T12:20:34.163Z
2021-03-19T12:20:34.163Z
B--rian
<p>How much do we know about the structure of the torus surrounding the <a href="https://en.wikipedia.org/wiki/Active_galactic_nucleus" rel="nofollow noreferrer">Active Galactic Nucleus</a> (AGN)? Is the shape defined or still under speculations? And are there different structures for this torus possible i.e., does it vary from galaxy to galaxy?</p>

CC BY-SA 3.0
2014-05-28T10:22:03.843Z
stp30 you've been asking a lot of general questions about AGN recently; it may be best to wait until you have a more specific question in mind. For example, typing 'AGN Torus' in to google gives a number of recent papers and discussions about the range of shapes of torii observed and theorised in the past decade
christopherlovell
<galaxy><accretion-discs><galaxy-center><active-galaxy>
Structure of the torus of the Active Galactic Nucleus
stp30
# Structure of the torus of the Active Galactic Nucleus

(Asked by: username_0 on 2014-05-28)

How much do we know about the structure of the torus surrounding the [Active Galactic Nucleus](https://en.wikipedia.org/wiki/Active_galactic_nucleus) (AGN)? Is the shape defined or still under speculations? And are there different structures for this torus possible i.e., does it vary from galaxy to galaxy?

**Tags:** galaxy, accretion-discs, galaxy-center, active-galaxy
> **Comments:**
> **username_1**: stp30 you've been asking a lot of general questions about AGN recently; it may be best to wait until you have a more specific question in mind. For example, typing 'AGN Torus' in to google gives a number of recent papers and discussions about the range of shapes of torii observed and theorised in the past decade  

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## 1 answers

### Answer by username_2 on 2021-03-19. Score: 1

This question was asked more roughly 8 years ago, and for 2 years there is a review article around which I found worth mentioning and summarizing. The manuscript is called *[Redefining the torus: A unifying view of AGN in the infrared and sub mm](https://arxiv.org/abs/1909.08639)* and work of [Sebastian Florian Hönig](https://en.wikipedia.org/wiki/Sebastian_F._H%C3%B6nig). Here an excerpt of the abstract:

> The advent of high-angular resolution IR and sub-mm interferometry allows for spatially-resolvedobservations of the parsec-scale environment of active galactic nuclei (AGN), commonly referred toas the “torus.” While molecular lines show the presence of large, massive disks, the IR observationsappear to be dominated by a strong polar component that has been interpreted.

The main result seems to be the following schematic picture (Fig. 4 of the manuscript) of the AGN which is an overlay of various observations:

[![Fig 4 of arXiv:1909.08639](https://i.sstatic.net/rQn6z.png)](https://i.sstatic.net/rQn6z.png)

1. The purple ring are observations in the near-IR.
2. The yellow torus and the gray dashed lines are from ${\rm H}\_2$ emission.
3. The main brownish cone is from mid-IR.
4. The redish wobbly plane with the red (solid) arrows and the purple (dashed) arrows are sub-mm obseravtions (${\rm CO/HCN/HCO^+}$)
5. Bright green dots on the $x$-axis are ${\rm H\_2 O}$ maser emissions.


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