<p>Yes of course, there are other forms apart from the four stated above. Basically you have just two kinds: </p>

<ol>
<li>the radio-quiet, and</li>
<li>the radio-loud.</li>
</ol>

<p>But then again, there are two Seyferts</p>

<ol>
<li>Seyfert I, and</li>
<li>Seyfert II</li>
</ol>

<p>Apart from Quasar, Blazar and Radio galaxy, we also have presently,</p>

<ol>
<li>BL Lac (Named after its prototype BL Lacarte (original member of Blazar type)), and</li>
<li>OVV (Optically Variable Violent Quasar or OVV Quasar; subtype of Blazar)</li>
</ol>

<p>Best source to begin with is wikipedia.org of course.</p>

CC BY-SA 3.0
2014-05-22T10:45:05.083Z
What you've mentioned are basically the sub forms of the 4 prominent types. Its their inherent characteristics that distinguishes them into sub categories. My question was about any formats apart from these and if an intermix or aby-product (which is an AGN) is possible?
stp30
CC BY-SA 3.0
2014-05-21T05:31:17.653Z
2014-05-21T05:31:17.653Z
MycrofD
<p>I've read that there are 4 distinct although related forms of AGs : Seyferts, Quasars, Radio and Blazars. Are there any other forms possible? Also do these forms ever intermix to give something new? </p>

CC BY-SA 3.0
2016-10-07T19:59:17.927Z
This is really a question of semantics.  One could say there is just one class.  All AGN are supermassive blackholes in which matter is falling in, resulting in energy being dispersed in various forms.  Each active galaxy does this a little differently and so you could also subclass into a nearly infinite set of classes.  What astronomers use for classes is a somewhat arbitrary but useful set of classes based on where most of the energy is coming out and the strengths of various spectral features.
eshaya
CC BY-SA 4.0
2020-09-12T14:30:48.257Z
I am not sure if the question is still relevant to the OP. @christopherlovell, the wiki is indeed quite detailed. However, I would point to [this excellent review](https://link.springer.com/article/10.1007/s00159-017-0102-9) by Paolo Padovani et al. (2017). The AGN zoo is indeed an amazing and intriguing field and the authors have beautifully captured the essense of it.
lordparthurnaax
CC BY-SA 3.0
2014-06-07T16:36:46.933Z
a quick [wiki](http://en.wikipedia.org/wiki/Active_galactic_nucleus) search gives you an answer to all your questions. Try and make your question more specific
christopherlovell
<galaxy><active-galaxy>
Classification of Active Galaxies
stp30
# Classification of Active Galaxies

(Asked by: username_0 on 2014-05-18)

I've read that there are 4 distinct although related forms of AGs : Seyferts, Quasars, Radio and Blazars. Are there any other forms possible? Also do these forms ever intermix to give something new?

**Tags:** galaxy, active-galaxy
> **Comments:**
> **username_3**: a quick [wiki](http://en.wikipedia.org/wiki/Active_galactic_nucleus) search gives you an answer to all your questions. Try and make your question more specific  
> **username_1**: This is really a question of semantics.  One could say there is just one class.  All AGN are supermassive blackholes in which matter is falling in, resulting in energy being dispersed in various forms.  Each active galaxy does this a little differently and so you could also subclass into a nearly infinite set of classes.  What astronomers use for classes is a somewhat arbitrary but useful set of classes based on where most of the energy is coming out and the strengths of various spectral features.  
> **username_2**: I am not sure if the question is still relevant to the OP. @christopherlovell, the wiki is indeed quite detailed. However, I would point to [this excellent review](https://link.springer.com/article/10.1007/s00159-017-0102-9) by Paolo Padovani et al. (2017). The AGN zoo is indeed an amazing and intriguing field and the authors have beautifully captured the essense of it.  

---

## 1 answers

### Answer by username_4 on 2014-05-21. Score: 3

Yes of course, there are other forms apart from the four stated above. Basically you have just two kinds:

1. the radio-quiet, and
2. the radio-loud.

But then again, there are two Seyferts

1. Seyfert I, and
2. Seyfert II

Apart from Quasar, Blazar and Radio galaxy, we also have presently,

1. BL Lac (Named after its prototype BL Lacarte (original member of Blazar type)), and
2. OVV (Optically Variable Violent Quasar or OVV Quasar; subtype of Blazar)

Best source to begin with is wikipedia.org of course.

> **Comments:**
> **username_0**: What you've mentioned are basically the sub forms of the 4 prominent types. Its their inherent characteristics that distinguishes them into sub categories. My question was about any formats apart from these and if an intermix or aby-product (which is an AGN) is possible?  

---

