Talk:Active galactic nucleus
From Wikipedia, the free encyclopedia
 |
This article is within the scope of WikiProject Physics, which collaborates on articles related to physics. | |
| Start | This article has been rated as start-Class on the assessment scale. | |
| ??? | This article has not yet received an importance rating within physics. | |
|
This article has been rated but has no comments. If appropriate, please review the article and leave comments here to identify the strengths and weaknesses of the article and what work it will need. |
||
Contents |
[edit] Radio galaxies?
There was a question in the article from At18; I moved it here:
- I put infrared and radio galaxies here too, is it the right place?
Certainly better here than nowhere, work in progress ... -- looxix 18:58 Apr 18, 2003 (UTC)
- On the above point, I think Radio galaxy should have it's own article, instead of being redirected to Active galaxy, since the two terms are not interchangable. Radio galaxies are a sub-category (as are quasars, blazars, Bl Lacs, etc..). Unless there's any objections, I can begin work on a Radio Galaxy page and un-redirect once it's reached a semi-mature status. Privong 18:42, 21 Apr 2005 (UTC)
Well, since this doesn't seem to have happened, would anyone object to me setting up a radio galaxy page? There is currently a lot of detail about radio galaxies in this article which obscures the basic point, while most other classes of AGN have their own entries. Mhardcastle 20:43, 1 February 2006 (UTC)
- OK, it's there now... Mhardcastle 23:41, 5 February 2006 (UTC)
[edit] Starburst galaxies
Starburst galaxies aren't active galaxies (as the definition at the top of the article shows; they're just normal galaxies with a large amount of star formation).
Starbursts should really have their own entry, but I don't have time to do it now: I've just removed the misleading comments from the active galaxy page, and tidied it up. -- mjh, some time ago
- Starburst galaxies are active galaxies, they just don't have AGN. This article should be at Active galactic nuclei instead. Don't you remember all the theories on how starburst galaxies could account for AGN type galaxies? They are active, but not single sourced, and they are bright, and spectacular, like AGN galaxies. 132.205.45.110 05:46, 6 Dec 2004 (UTC)
[edit] Synchrotron radiation
There were a couple of misleading statements about synchrotron radiation and high temperatures in the accretion disc. I think this was probably a confusion between the properties of the accretion disc and the jet that is sometimes seen; the jet is synchrotron radiation and can have a very high brightness temperature (nothing to do with actual temperature -- the temperature of the accretion disc is quite low). -- mjh May 23 2004.
[edit] Clarification
I'm no expert but should "An active galaxy is a galaxy where a significant fraction of the energy output is not emitted by the normal components of a galaxy: stars, dust and interstellar gas." be clarified to a numerical proportion? Or is this impossible. A comparison, to a regular galaxy if possible, might help non-experts like me understand this better. Grox 10:07, 13 Feb 2005 (UTC)
- There isn't a concrete numerical factor, but the AGN will generally outshine the host galaxy by ~1000x. Privong 18:22, 21 Apr 2005 (UTC)
- This is only true for the most powerful AGN. Mhardcastle 20:43, 1 February 2006 (UTC)
[edit] New text under `Types of active galaxy'
As this stands it not only is factually wrong in several respects but duplicates (or in some cases contradicts) what's already there under `Optical spectra'. I'm tempted to delete the whole lot unless it gets a lot better before I look at this again Mhardcastle 18:54, 24 October 2006 (UTC)
- Go for it. I was just attempting to clean up what was already there. The Seyfert definitions were reversed before I made the edits. Perhaps it might be better to remove the optical spectra section and instead include that in the 'Types of active galaxies' section. That might be a more logical way to approach it? Privong 11:49, 25 October 2006 (UTC)
[edit] Low-Ionization Nuclear Emission-line Region (LINER)
This article lacks a section on Low-Ionization Nuclear Emission-line Region (LINER)-type galaxies, which are supposedly the most common type of active nuclei galaxy. Any interest? Thanks. — RJH (talk) 20:03, 4 December 2006 (UTC)
[edit] Complete rewrite
Once I started editing this, I couldn't stop. Hope readers approve of the results. It could do with some diagrams and some more references in places. I think it's an improvement on the original, though. I'm afraid it still doesn't mention LINERs, but they should have their own article, which should then be linked here. I'm not enough of an expert on LINERs to write one from scratch. Mhardcastle 22:02, 24 December 2006 (UTC)
[edit] H II nucleus is an AGN?
Is H II nucleus a type of AGN? I notice it in this paper: [http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1997ApJS..112..315H A SEARCH FOR "DWARF" SEYFERT NUCLEI. III. SPECTROSCOPIC PARAMETERS AND PROPERTIES OF THE HOST GALAXIES] These are not covered in the article presently. WilliamKF 01:59, 26 February 2007 (UTC)
- Looks to me as though they are using 'HII nucleus' to mean 'nucleus where the spectrum is consistent with that of an HII region, i.e. a source whose emission lines are powered by star formation. Look at the start of S3. Mhardcastle 08:53, 26 February 2007 (UTC)
