Talk:Seyfert galaxy

message: To Careless Torque:
Please read the referenced paper, which is available in full. I will not engage in edit warring with you. However, please note that the Eddington limit was originally derived for spherical stars, not black holes, and the math presented in the article is the math which is applicable to stars.
:On the Eddington limit in accretion discs, by  D. Heinzeller and  W. J. Duschl
:Although the Eddington limit has originally been derived for stars, recently its relevance for the evolution of accretion discs has been realized. We discuss the question whether the classical Eddington limit – which has been applied globally for almost all calculations on accretion discs – is a good approximation if applied locally in the disc. For this purpose, a critical accretion rate corresponding to this type of modified classical Eddington limit is calculated from thin α-disc models and slim disc models. We account for the non-spherical symmetry of the disc models by computing the local upper limits on the accretion rate from vertical and radial force equilibria separately.
:It is shown that the results can differ considerably from the classical (global) value: The vertical radiation force limits the maximum accretion rate in the inner disc region to much less than the classical Eddington value in thin α-discs, while it allows for significantly higher accretion rates in slim discs. We discuss the implications of these results for the evolution of accretion discs and their central objects.
Since November 30, under a variety of IP addresses, I have diligently copy-edited the article and clarified important points that were unclear. On Dec. 6, I blundered in using the word "disc." Since you will not allow me to correct my own mistake, I am afraid that my assistance is at an end.
199.46.199.232 (talk) 22:55, 8 December 2013 (UTC)
replies: text: Eddington limit was originally derived for spherical stars. Correct. However, the article doesn't talk about spherical stars, talks about Seyfert galaxies. In the context of Seyfert galaxies, the derivation doesn't involve spherical stars, it involves accretion discs. I used the word "disc", which is correct, and the other user kept changing it to "sphere", which is wrong. It was never a case of me not letting him correct his mistake. In fact, I was trying to correct his mistakes, which he kept undoing. 
Careless Torque (talk) 23:33, 8 December 2013 (UTC)
replies: text:  I am in agreement with 199.46.199.232 on this point. The mathematics presented is correct for stars and incorrect for accretion discs. It is applicable to Seyfert galaxies only when carefully qualified with appropriate caveats, which you have removed. Stigmatella aurantiaca (talk) 23:39, 8 December 2013 (UTC)

text: Stigmatella and the IP editor are correct here: the Eddington limit for accretion disks is derived assuming spherical accretion, just as it is for stars. This is a known approximation, but it is widely used and does serve a useful purpose. The nature of this approximation must be made clear in the article. - Parejkoj (talk) 00:26, 9 December 2013 (UTC)

text: Given that Torque has added the main template, I've pruned away all details of the derivation and re-added the IP editor's caveat. Hopefully everybody will be appeased. Stigmatella aurantiaca (talk) 12:11, 9 December 2013 (UTC)

text: The problem with the classical Eddington luminosity is a lot more than just geometric effects. For example, Eddington only considered electron scattering, but in actuality, other radiation processes are involved (Bremsstrahlung). Eddington only considered a hydrogen atmosphere; in actuality the limit depends on chemical composition. For black holes in particular, energy can be lost across the event horizon, which changes things quite a bit. In other words, this is a pretty complex subject, and the details are best left to the main article. The present verbal description gives a pretty good intuitive idea of the basics. Re-adding the derivation would give a false sense of rigor. Stigmatella aurantiaca (talk) 13:00, 9 December 2013 (UTC)

text: Also, if one presents a derivation, the beginning part of the derivation presents the basic assumptions that will be used. Starting off with the statement "Assume that a black hole is surrounded by a disc of luminous gas" and following with equations that assume spherical symmetry is totally unacceptable. It is better not to present any derivation at all than to present a confused sequence of non sequiturs. Stigmatella aurantiaca (talk) 16:15, 9 December 2013 (UTC)
replies: text: I agree with both being included, but there should be mention to the fact that we are deriving the force same as we would for a star either before or during the derivation, this would prevent a false sense of rigor where currently it feels that there is a lack of rigor. It would also provide a manner in which to write the caveat in a more context driven manner, as currently I would say there are issues with both the wording and placement of the caveat. - IndianFace (talk) 17:05, 10 December 2013 (UTC)
replies: text:  The easiest way would be to replace the word "disc" with "sphere", providing the abbreviated calculation, then mentioning that a rigorous calculation would take into account the actual geometry, etc. Stigmatella aurantiaca (talk) 17:41, 10 December 2013 (UTC)

text:  You can't replace "disc" with "sphere" in the context of an accretion disk. That is just wrong. I will work through a more thorough derivation however and make sure I include all caveats, and also mention all the things that the derivation doesn't take into account but occur in accretion discs, and how the answers would be different. Careless Torque (talk) 18:52, 10 December 2013 (UTC)
replies: text:  You can't replace "sphere" with "disc" in the context of the derivation. That is totally unacceptable. The whole point of the Main template is to avoid going "into detail beyond the requirements of the article as we end up repeating ourselves all over Wikipedia." Stigmatella aurantiaca (talk) 20:38, 10 December 2013 (UTC)

text: Actually, yes, you can include the derivation and say it's an approximation which is derived using a sphere, but in this context it is applied to a disc. I admit I didn't phrase this properly in the original version of the article. Of course accretion discs aren't spherical and they are subject to other phenomena, like turbulences and magnetic fields, which the Eddington limit doesn't take into account. Which is why the discs are usually brighten than the Eddington limit (super Eddington luminosities). And no, the point of the main template is not to give users a reason to delete others' work without trying to first rephrase it or improve it, just because it points to another article, which by the way, doesn't really give much detail about the Eddington limit as applied to accretion discs. So all that happened is that work was deleted and it isn't in the main article. So we're not repeating ourselves all over Wikipeidia, we're not saying these details on Wikipedia at all at the moment. The way the article is at the moment (after your edit) throws a formula pretty much out of context, after talking about forces that are never given a formula, and just throws a badly worded and written "caveat" at the end, which again, doesn't make sense in the current formulation of the article. Doing this "is totally unacceptable", to quote you. How about we try to actually work on a good derivation and include all the points that need mention instead of just removing pieces of work and leaving fragments out of context? Careless Torque (talk) 21:23, 10 December 2013 (UTC)
replies: text: As was said previously by another user "The nature of this approximation must be made clear in the article". My point about using the Main template was that going into an extended explanation about stars is unnecessary and the focus should be kept on black holes and Seyferts. I think the original derivation should still be included, and little more than a line saying something akin to "we derive the Eddington luminosity the same as we do for a star", or even before Frad "we assume spherical..." etc etc, would be sufficient. I would advise  to be careful with their planned reworking not to go into too much detail. While the complexities of the Eddington luminosity in regard to accretion discs may not yet be in the main article, you should treat it as if the details would exist there as the intention would be that at some point someone will rewrite the Eddington luminosity article to that of an encyclopedic quality. - IndianFace (talk) 23:07, 10 December 2013 (UTC)

text: Eddington luminosity applies to AGN in general, not just Seyferts. There are actually several sections of this article that would almost be better placed in the Active galactic nucleus article, but this is definitely one of them, since it applies to all accretion-driven AGN.  - Parejkoj (talk) 16:55, 11 December 2013 (UTC)
replies: text: Yes, agree that this mostly belongs in the AGN article. In this article, this maybe deserves a paragraph or so, to summarize the main points. StringTheory11 (t • c) 02:56, 13 December 2013 (UTC)

text: Hi, I do agree that the version you posted above is too long. I am currently working on a shorter version that still includes all the main points and I should hopefully have a draft soon. As you know, this is part of my project and I've been tasked with including at least parts of the derivation in the Seyfert galaxy article, which is why I'm trying to find a way to make it more suitable. I have no problem with including the full derivation in the Eddington luminosity article (and a few words should be included in the AGN article as well), but at the moments I am focusing on my project. Once the project is done I can work on a version we can include in the other articles mentioned as well. Careless Torque (talk) 10:41, 13 December 2013 (UTC)
replies: text:  You might consider pushing the derivation into a Notes section, using hypertext markup instead of <math>LaTeX markup<math>. To see what I mean, in Michelson–Morley experiment, User:D.H and I used notes to include extensive commentary that would have been cluttering and distracting if included in the main article space. Note how it is perfectly OK to simultaneously include grouped and ungrouped notes. The notes can be grouped so that you have note references of form [N 1], [N 2] etc. while the bulk of the references can remain ungrouped. In Fizeau experiment, User:D.H carefully distinguished between primary and secondary sources. Stigmatella aurantiaca (talk) 11:03, 13 December 2013 (UTC)

text: Thanks for the idea, I didn't know how to use notes actually :) I'll have a look at that. Careless Torque (talk) 12:45, 13 December 2013 (UTC)

text: As it seems there is a consensus on pushing the derivation to a note, I have updated the article as such. One of the lines of math is not contained very well in the pop-up window, some people may find issue with this, I'll leave it open to consensus as to whether this is changed. I think it would be best at present to focus on as StringTheory11 put it "a paragraph or so, to summarize the main points", we could do this by looking to the existing paragraph for expansion or rewriting. - IndianFace (talk) 17:00, 14 December 2013 (UTC)
replies: text:  I broke up the long line of math so that it could wrap. Stigmatella aurantiaca (talk) 17:11, 14 December 2013 (UTC)
replies: text: Thanks for that , I hadn't thought of closing it into separate math statements to make it run onto the next line. Do you know if there is a way to change the width of the pop-up window when you hover over a note link? - IndianFace (talk) 18:56, 14 December 2013 (UTC)
replies: text:  Unfortunately, no. If there is a way, it would probably be defined in some CSS style sheet somewhere to which we wouldn't have access. Maybe there is a forum somewhere where I could raise a technical assistance question. Stigmatella aurantiaca (talk) 23:12, 14 December 2013 (UTC)

text:  I've placed my question at Wikipedia:Help_desk#Adjusting_the_width_of_tooltips.3F. Let's see if somebody there can offer some help. Stigmatella aurantiaca (talk) 05:29, 15 December 2013 (UTC)
replies: text:  Got a response from User:ColinFine. It wasn't very encouraging. Stigmatella aurantiaca (talk) 13:58, 15 December 2013 (UTC)
thread_title:  On the Eddington limit in accretion discs 

message: With IndianFace's latest edit pushing the derivation into a note, this section is no longer needed, so I am blanking it. Stigmatella aurantiaca (talk) 17:30, 14 December 2013 (UTC)
thread_title:  Eddington luminosity - this talk section no longer needed 

message: As written, the above section will be one of the largest in the entire article. My feeling is that this could possibly be an undue emphasis on a secondary point. I prefer offloading the derivation to the Eddington luminosity article. Stigmatella aurantiaca (talk) 02:50, 11 December 2013 (UTC)
replies: text: Eddington luminosity applies to AGN in general, not just Seyferts. There are actually several sections of this article that would almost be better placed in the Active galactic nucleus article, but this is definitely one of them, since it applies to all accretion-driven AGN.  - Parejkoj (talk) 16:55, 11 December 2013 (UTC)
replies: text: Yes, agree that this mostly belongs in the AGN article. In this article, this maybe deserves a paragraph or so, to summarize the main points. StringTheory11 (t • c) 02:56, 13 December 2013 (UTC)

text: Hi, I do agree that the version you posted above is too long. I am currently working on a shorter version that still includes all the main points and I should hopefully have a draft soon. As you know, this is part of my project and I've been tasked with including at least parts of the derivation in the Seyfert galaxy article, which is why I'm trying to find a way to make it more suitable. I have no problem with including the full derivation in the Eddington luminosity article (and a few words should be included in the AGN article as well), but at the moments I am focusing on my project. Once the project is done I can work on a version we can include in the other articles mentioned as well. Careless Torque (talk) 10:41, 13 December 2013 (UTC)
replies: text:  You might consider pushing the derivation into a Notes section, using hypertext markup instead of <math>LaTeX markup<math>. To see what I mean, in Michelson–Morley experiment, User:D.H and I used notes to include extensive commentary that would have been cluttering and distracting if included in the main article space. Note how it is perfectly OK to simultaneously include grouped and ungrouped notes. The notes can be grouped so that you have note references of form [N 1], [N 2] etc. while the bulk of the references can remain ungrouped. In Fizeau experiment, User:D.H carefully distinguished between primary and secondary sources. Stigmatella aurantiaca (talk) 11:03, 13 December 2013 (UTC)

text: Thanks for the idea, I didn't know how to use notes actually :) I'll have a look at that. Careless Torque (talk) 12:45, 13 December 2013 (UTC)

text: As it seems there is a consensus on pushing the derivation to a note, I have updated the article as such. One of the lines of math is not contained very well in the pop-up window, some people may find issue with this, I'll leave it open to consensus as to whether this is changed. I think it would be best at present to focus on as StringTheory11 put it "a paragraph or so, to summarize the main points", we could do this by looking to the existing paragraph for expansion or rewriting. - IndianFace (talk) 17:00, 14 December 2013 (UTC)
replies: text:  I broke up the long line of math so that it could wrap. Stigmatella aurantiaca (talk) 17:11, 14 December 2013 (UTC)
replies: text: Thanks for that , I hadn't thought of closing it into separate math statements to make it run onto the next line. Do you know if there is a way to change the width of the pop-up window when you hover over a note link? - IndianFace (talk) 18:56, 14 December 2013 (UTC)
replies: text:  Unfortunately, no. If there is a way, it would probably be defined in some CSS style sheet somewhere to which we wouldn't have access. Maybe there is a forum somewhere where I could raise a technical assistance question. Stigmatella aurantiaca (talk) 23:12, 14 December 2013 (UTC)

text:  I've placed my question at Wikipedia:Help_desk#Adjusting_the_width_of_tooltips.3F. Let's see if somebody there can offer some help. Stigmatella aurantiaca (talk) 05:29, 15 December 2013 (UTC)
replies: text:  Got a response from User:ColinFine. It wasn't very encouraging. Stigmatella aurantiaca (talk) 13:58, 15 December 2013 (UTC)
thread_title:  Discussion on the above proposed text 

message: Parejkoj, StringTheory11 and I have thus far all argued that the current version of the above proposed text is too long. Stigmatella aurantiaca (talk) 10:23, 13 December 2013 (UTC)
thread_title:  Apparent consensus that the proposed section is too long 

message: I have hence replaced the proposed section with the version from the current text in article space, calling it "Revision 1." It seems to me that StringTheory11 is arguing that even this abbreviated version would be too much. He spoke of maybe including only "a paragraph or so, to summarize the main points." Comments? Stigmatella aurantiaca (talk) 10:36, 13 December 2013 (UTC)
replies: text: Hi, I do agree that the version you posted above is too long. I am currently working on a shorter version that still includes all the main points and I should hopefully have a draft soon. As you know, this is part of my project and I've been tasked with including at least parts of the derivation in the Seyfert galaxy article, which is why I'm trying to find a way to make it more suitable. I have no problem with including the full derivation in the Eddington luminosity article (and a few words should be included in the AGN article as well), but at the moments I am focusing on my project. Once the project is done I can work on a version we can include in the other articles mentioned as well. Careless Torque (talk) 10:41, 13 December 2013 (UTC)
replies: text:  You might consider pushing the derivation into a Notes section, using hypertext markup instead of <math>LaTeX markup<math>. To see what I mean, in Michelson–Morley experiment, User:D.H and I used notes to include extensive commentary that would have been cluttering and distracting if included in the main article space. Note how it is perfectly OK to simultaneously include grouped and ungrouped notes. The notes can be grouped so that you have note references of form [N 1], [N 2] etc. while the bulk of the references can remain ungrouped. In Fizeau experiment, User:D.H carefully distinguished between primary and secondary sources. Stigmatella aurantiaca (talk) 11:03, 13 December 2013 (UTC)

text: Thanks for the idea, I didn't know how to use notes actually :) I'll have a look at that. Careless Torque (talk) 12:45, 13 December 2013 (UTC)

text: As it seems there is a consensus on pushing the derivation to a note, I have updated the article as such. One of the lines of math is not contained very well in the pop-up window, some people may find issue with this, I'll leave it open to consensus as to whether this is changed. I think it would be best at present to focus on as StringTheory11 put it "a paragraph or so, to summarize the main points", we could do this by looking to the existing paragraph for expansion or rewriting. - IndianFace (talk) 17:00, 14 December 2013 (UTC)
replies: text:  I broke up the long line of math so that it could wrap. Stigmatella aurantiaca (talk) 17:11, 14 December 2013 (UTC)
replies: text: Thanks for that , I hadn't thought of closing it into separate math statements to make it run onto the next line. Do you know if there is a way to change the width of the pop-up window when you hover over a note link? - IndianFace (talk) 18:56, 14 December 2013 (UTC)
replies: text:  Unfortunately, no. If there is a way, it would probably be defined in some CSS style sheet somewhere to which we wouldn't have access. Maybe there is a forum somewhere where I could raise a technical assistance question. Stigmatella aurantiaca (talk) 23:12, 14 December 2013 (UTC)

text:  I've placed my question at Wikipedia:Help_desk#Adjusting_the_width_of_tooltips.3F. Let's see if somebody there can offer some help. Stigmatella aurantiaca (talk) 05:29, 15 December 2013 (UTC)
replies: text:  Got a response from User:ColinFine. It wasn't very encouraging. Stigmatella aurantiaca (talk) 13:58, 15 December 2013 (UTC)
thread_title:  Continuing discussion using Eddington luminosity - revision 1 

message: Much thanks to Johndric Valdez for adding a genuinely useful and interesting list to the Examples section. 
On the other hand, the long-standing table of "representative Seyfert galaxies from the Markarian catalog" below his list seems totally random to me. There is nothing to indicate why these galaxies and no others from Markarian have been highlighted with detailed information. Are any of them especially close or bright? Do any of the ones with NGC designations have separate Wikipedia articles devoted to them?  Does the table provide links to related articles in the scientific literature? 
No, no, and no.
I propose to delete this table, and that we should do what we can to expand Johndric's list. Stigmatella aurantiaca (talk) 08:52, 12 February 2014 (UTC)
replies: text:  The examples in the table were really just randomly picked to try include as wide a range from the Markarian catalogue as possible. I agree that the new list is better so if you want to remove the table (or add different galaxies etc) go ahead. I do however think that at  least a mention of the Markarian catalogue should be kept, even if the table is deleted. Careless Torque (talk) 11:21, 12 February 2014 (UTC)

text: Also, while the new list is really good, I don't see any references in it. I think we should first try and find some references for each of the galaxies mentioned and the comments about them. Careless Torque (talk) 11:24, 12 February 2014 (UTC)
replies: text:  Deleted table. Please check that my comment about the Markarian catalog is appropriate. Also, I'm starting to research references. It is evident that some of the comments will need to be revised. Stigmatella aurantiaca (talk) 12:17, 12 February 2014 (UTC)
thread_title:  Examples section 

message: It is stated on the Examples section, Messier 77 is stated as the brightest Seyfert galaxy, at apparent magnitude 9.6. However, I've found lots of journals in the Internet claiming the much brighter (apparent magnitude 8.4) and closer Whirlpool Galaxy (Messier 51) as a Seyfert galaxy type 2. Some of the journals are these:
http://arxiv.org/abs/0704.0947
http://www.asiaa.sinica.edu.tw/~satoki/m51multiCO-details.html
http://adsabs.harvard.edu/full/2005ASPC..344...90M
http://iopscience.iop.org/0004-637X/496/1/210/fulltext/
http://iopscience.iop.org/1538-4357/616/1/L55/fulltext/18265.text.html
http://www.johnmurphyastro.info/messier/m51-whirlpool-galaxy
There are strong, and lots of references stating that the Whirlpool galaxy is a Seyfert galaxy. Could we change the information in Messier 77 and put Whirlpool Galaxy as "the brightest Seyfert galaxy in the sky"? Johndric Valdez (talk) 12:45, 18 February 2014 (UTC)
replies: text: Actually, Messier 81 is listed with an apparent magnitude of 6.94... Stigmatella aurantiaca (talk) 23:56, 18 February 2014 (UTC)
replies: text: Yes, the source provided for the M77 claim even states that the Total Apparent Magnitude is 10.32, which, while reasonably bright, isn't remotely close to being the brightest. It even mentions that the nuclear absolute magnitude is rather less than the average of other Seyferts. If the source actually says that M77 is the brightest, I'm not seeing it, and for that reason alone it should be removed from the list. I don't think the claim of "brightest Seyfert" should even be made unless a source is found which specifically states as such. — Huntster (t @ c) 05:23, 19 February 2014 (UTC)
replies: text:  The 1973 paper by de Vaucouleurs cited NGC 1068 (M77) as being the brightest, but since then, a great many active galaxies with obscured nuclei have become recognized as Seyferts; hence the confusion. I'll try rewording. Stigmatella aurantiaca (talk) 05:36, 19 February 2014 (UTC)
replies: text: Out of pure curiosity, where in the paper does it mention M77 being brightest? — Huntster (t @ c) 06:52, 19 February 2014 (UTC)
replies: text:  First sentence. "The large southern spiral NGC 1566, type SAB(s)bc, is the second brightest Seyfert galaxy, being surpassed only by NGC 1068..." and NGC 1068 = M77.   Stigmatella aurantiaca (talk) 09:05, 19 February 2014 (UTC)
replies: text:  /me walks away in shame... — Huntster (t @ c) 16:34, 19 February 2014 (UTC)
thread_title: Brightest Seyfert galaxy?

message: Careless Torque mentioned above that M106 is not a Seyfert Galaxy. However, the article itself states it and has a reference by Roberta Humphreys et al. I think we need to put a picture of M106 here since it is one of the closest and best known Seyfert galaxies. ==Johndric Valdez (talk) 08:14, 5 April 2014 (UTC)
thread_title: About M106

message: To be honest, I doubt now when I put M87 in the examples list. M87 is an elliptical galaxy, which is on a type which is rare to become a Seyfert. I forgot where I got the info that states M87 is a Seyfert. NED's data has an "Sy" on M87, but I think M87 may be more likely a BL Lac object. Is it really a Seyfert? SkyFlubbler (talk) 03:23, 6 September 2014 (UTC)
replies: text: At optical wavelengths, M87 is classified as a LINER based on its emission-line spectrum. You can look up the classification and references on the NED page for M87. It doesn't have anything to do with the evolutionary history of the galaxy: the classification is really just based on the properties of the emission lines in the visible spectrum. Agreed that removing it from this list is the right choice. Aldebarium (talk) 16:24, 7 April 2018 (UTC)
thread_title: M87 Seyfert?

message: I am interested in associations between Quasars and Seyferts, so I tried to access a supplied reference, but the few I tried either took me to the NASA general site or other wikipedia pages. I feel it would further enhance the article if the references were available.51.148.133.34 (talk) 15:35, 31 December 2021 (UTC)
replies: text: Which references didn't work for you? Without knowing which are broken, we cannot fix them. - Parejkoj (talk) 18:19, 3 January 2022 (UTC)
thread_title:  References