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Archive 1

Requested move (2006)

The following discussion is an archived debate of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the debate was Move all. —Wknight94 (talk) 23:22, 12 August 2006 (UTC)

Discussion

Please discuss this move at Talk:Globular Cluster M2.

The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

habitable?

because of the heavy amount of x-rays is it possible life can exist there? —The preceding unsigned comment was added by 71.105.29.94 (talk) 05:52, 7 December 2006 (UTC).

Very unlikley, at least not as we know it. It seems the X Rays are produced by the exceptional ionised particle jet ejection energy. See also update ref signal velocity to make it consistent with the 'Superluminal velocity' page a far better explanation than any other offered so far that also seems to resolve some anomalies.Docjudith (talk) —Preceding undated comment added 11:30, 8 February 2010 (UTC).

I'm not sure how much can speculate about this. All we can say for certain is that space travel would be subject to higher levels of radiation. But a planet may well provide sufficient shielding against the X-ray radiation for life to have evolved. However, the impact of the jet may be another matter.—RJH (talk) 16:55, 17 January 2011 (UTC)

Components

The best reference for the mass of the supermassive black hole is still the Macchetto et al. (1997) paper, based on rotation of the gas disk. More recent attempts to obtain the black hole mass from the stellar motions (e.g. Gebhardt & Thomas 209) have gotten discrepant and inconsistent results, probably because the stellar data do not resolve the black hole sphere of influence and do not show any clear sign of its presence. These new results are not widely believed in the astrophysical community and should not be reported here, unless a section is added that critically discusses the modelling issues and the shortcomings of the data.130.183.86.193 (talk) 13:54, 27 June 2010 (UTC)

That seems reasonable, but could I ask why you removed the following?
However, only a fraction of this mass is in the form of stars, as Messier 87 has an estimated mass to luminosity ratio of 6.3 ± 0.8. That is, about one part in six of the galaxy's mass is in the form of stars that are radiating energy.[1]
This is significant, cited information and it needs a reason for exclusion. If it is to be excluded, something needs to be added to replace it.—RJH (talk) 17:04, 27 June 2010 (UTC)
How about this? [1] -- Polluks ★ 12:31, 17 January 2011 (UTC)
Yes, it's based on the Gebhardt et al. (2011) paper, which gives a SMBH mass that is fairly consistent with the current value in the article. However, a small concern is that this paper doesn't appear to have been peer reviewed yet, since it isn't published in an astronomy journal.—RJH (talk) 16:58, 17 January 2011 (UTC)

Good Article review

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

GA Review

This review is transcluded from Talk:Messier 87/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Casliber (talk · contribs) 03:37, 14 September 2010 (UTC)

Okay, I'll make straightforward copyedits as I go and post queries below. Please revert if I change meaning inadvertently. Casliber (talk · contribs) 03:37, 14 September 2010 (UTC)

"'This is the largest and brightest galaxy within the northern Virgo Cluster, located about 55 million light years away from Earth - the way it reads, it isn't clear whether M87 or the Virgo Cluster (or both) is what is 55 million light years from earth. "  Done
"Messier 87 galaxy has no distinctive dust lanes... - do we need the "galaxy" here? Not written as such elsewhere.  Done
This identification was confirmed by 1953 - odd wording. You mean "The soruce was confirmed as coming from M87" (?)  Done, reworded.
The only known visual observation of the jet was by Russian-American astronomer Otto Struve using the 254 cm (100 in) Hooker telescope - how/why?
and may indicate that the black hole has been accelerated by the jet - I don't follow - you mean "moved" or "displeced" or ..what?
The Virgo Cluster section could be expanded a little - M87's role in it, closest neighbours etc.

Okay - typing "Messier 87" into the Web of Science search engine yields the following:

1. Title: STRUCTURAL PARAMETERS OF THE MESSIER 87 GLOBULAR CLUSTERS Author(s): Madrid JP, Harris WE, Blakeslee JP, et al. Source: ASTROPHYSICAL JOURNAL Volume: 705 Issue: 1 Pages: 237-244 Published: NOV 1 2009 Times Cited: 4

2. Title: Radio Imaging of the Very-High-Energy gamma-Ray Emission Region in the Central Engine of a Radio Galaxy Author(s): Acciari VA, Aliu E, Arlen T, et al. Source: SCIENCE Volume: 325 Issue: 5939 Pages: 444-448 Published: JUL 24 2009 Times Cited: 19

3. Title: A method for deriving accurate gas-phase abundances for the multiphase interstellar galactic halo Author(s): Howk JC, Sembach KR, Savage BD Source: ASTROPHYSICAL JOURNAL Volume: 637 Issue: 1 Pages: 333-341 Part: Part 1 Published: JAN 20 2006 Times Cited: 11

4. Title: THE MORPHOLOGY OF ELLIPTIC GALAXIES INDIFFERENT ENVIRONMENTS Author(s): DAVOUST E Conference Information: World of Galaxies II Meeting, SEP 05-07, 1994 LYON, FRANCE Source: ASTROPHYSICAL LETTERS & COMMUNICATIONS Volume: 31 Issue: 1-6 Pages: 183-186 Published: 1995 Times Cited: 0

5. Title: HIGH-RESOLUTION OBSERVATION OF THE OPTICAL JET OF THE GALAXY MESSIER 87 Author(s): LELIEVRE G, NIETO JL, WLERICK G, et al. Source: COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE II Volume: 296 Issue: 23 Pages: 1779-1786 Published: 1983 Times Cited: 12

6. Title: THE HALO GLOBULAR-CLUSTERS OF THE GIANT ELLIPTICAL GALAXY MESSIER 87 Author(s): STROM SE, FORTE JC, HARRIS WE, et al. Source: ASTROPHYSICAL JOURNAL Volume: 245 Issue: 2 Pages: 416-& Published: 1981 Times Cited: 123

7. Title: PHOTOMETRIC ANALYSIS OF THE JET IN MESSIER-87 Author(s): DEVAUCOULEURS G, NIETO JL Source: ASTROPHYSICAL JOURNAL Volume: 231 Issue: 2 Pages: 364-371 Published: 1979 Times Cited: 48

8. Title: LUMINOSITY DISTRIBUTION IN THE CENTRAL REGIONS OF MESSIER-87 - ISOTHERMAL CORE, POINT SOURCE, OR BLACK-HOLE Author(s): DEVAUCOULEURS G, NIETO JL Source: ASTROPHYSICAL JOURNAL Volume: 230 Issue: 3 Pages: 697-712 Published: 1979 Times Cited: 54

9. Title: ENERGY-DISTRIBUTION OF JET IN MESSIER 87 Author(s): KANEKO N, NISHIMUR.M, TOYAMA K Source: PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN Volume: 25 Issue: 2 Pages: 175-180 Published: 1973 Times Cited: 5

10. Title: PHOTOMETRY OF OUTER CORONA OF MESSIER 87 Author(s): DEVAUCOU.G Source: ASTROPHYSICAL LETTERS Volume: 4 Issue: 1 Pages: 17-& Published: 1969 Times Cited: 22

11. Title: MESSIER-87 - GALAXY OF GREATEST KNOWN MASS Author(s): BRANDT JC, ROOSEN RG Source: ASTROPHYSICAL JOURNAL Volume: 156 Issue: 2P2 Pages: L59-& Published: 1969 Times Cited: 18

12. Title: ON SYNCHROTROIN RADIATION FROM MESSIER-87 Author(s): BURBIDGE GR Source: ASTROPHYSICAL JOURNAL Volume: 124 Issue: 2 Pages: 416-429 Published: 1956 Times Cited: 143

13. Title: POLARIZATION IN THE JET OF MESSIER-87 Author(s): BAADE W Source: ASTROPHYSICAL JOURNAL Volume: 123 Issue: 3 Pages: 550-& Published: 1956 Times Cited: 79

Why on Earth would you run such a search? For a start, the astronomy databases (ADS, SIMBAD, NED) are far more sensible places to look than WoS. Secondly, there are thousands of papers on M87. Here is a straightforward ADS object search, which found 4238 papers. Even restricting the search to only papers with 'M87' or 'Messier 87' in the title (let alone the abstract) leaves 913 papers [2]. Good luck digesting all of those! Modest Genius talk 16:03, 16 September 2010 (UTC)
(belatedly) I have used WoS for biology articles, my usual area of editing on wikipedia. I am a bit of a neophyte on astronomy articles. But in any case, all of these show some other material worth looking at. Casliber (talk · contribs) 21:55, 16 October 2010 (UTC)


1. Well written?:

Prose quality: - it's okayish but could do with some tightening
Manual of Style compliance:

2. Factually accurate and verifiable?:

References to sources:
Citations to reliable sources, where required:
No original research:

3. Broad in coverage?:

Major aspects: - I am sure there is a bunch of material for this article which could be added, particularly on components section.
Focused:

4. Reflects a neutral point of view?:

Fair representation without bias:

5. Reasonably stable?

No edit wars, etc. (Vandalism does not count against GA):

6. Illustrated by images, when possible and appropriate?:

Images are copyright tagged, and non-free images have fair use rationales:
Images are provided where possible and appropriate, with suitable captions:

Overall:

Pass or Fail: -I think the best thing is to let this nomination slide for the time being as there is no movement. I am actually interested in doing it myself but can't see that happening for a monht or two, so maybe I will wokr on it and nominate it myself sometime. Casliber (talk · contribs) 22:23, 16 October 2010 (UTC)
Thanks for the review Casliber. I'm unclear why it was nominated if there was no interest in correcting the issues.—RJH (talk) 18:28, 18 October 2010 (UTC)

PS: As a postscript, I think the concerns I raised are fixed now. As I haven't done any active editing. I'm happy to take a closer look and review when put up again. I'll try and give it a shove toward FAC if I can and look to think what else might be of help. Casliber (talk · contribs) 20:21, 8 December 2010 (UTC)

Thank you again Casliber.—RJH (talk) 18:34, 10 December 2010 (UTC)
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.


— Preceding unsigned comment added by GA bot (talk • contribs) 03:46, 14 September 2010 (UTC)

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

GA Review

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Reviewing
This review is transcluded from Talk:Messier 87/GA2. The edit link for this section can be used to add comments to the review.

Reviewer: Casliber (talk · contribs) 19:21, 10 December 2010 (UTC)

Okay, it seems a good labour-saving act to continue where we left off last review. The article as noted is much improved. I'll have a last read through again to see if I can see anything else:

  • One thing that strikes me is trying to get a sense of how large or small the galaxy is compared with our milky way. Do any sources have that comparison or discuss the size?
    • I added an estimate of the extended stellar halo for the Milky Way.—RJH (talk)
  • Link or explain the word collaminated.
    • Sorry, that was a typo. I linked it.—RJH (talk)
  • Within the galaxy, silicate grains are expected to survive for no more than 46 million years because of the X-ray emission from the core -I think this would leave a lay-reader wondering why and thirsting for more knowledge. Can we quench that thirst at all?
    • The answer appears to be that they don't know. It is either destroyed by the hostile environment, or ejected from the galaxy. But I added a statement with the original source.—RJH (talk)
  • The combined mass of dust in this galaxy is no more than 70,000 times the mass of the Sun - again, it is hard to visualise this unless there is some comparison - this is a little, right? Maybe a note on the Milky Ways (footnote if you like)
  • Messier 87 may have encountered Messier 84 in the past. - again, curious statement - do we just know this from trajectories or is there other interesting evidence.
    • I tried to clarify and expand upon the text.—RJH (talk)
  • Just reminded me - is this number of globular clusters typical for elliptical galaxies, or is it still unusual?
    • I believe the number of globular clusters is proportionate to the size of the galaxy. M87 is not a typical elliptical galaxy.—RJH (talk)
  • I was just winding up when I saw -"This image shows the eruption of a galactic “super-volcano” in M87" as the image caption. Is there info on this that can be added. Amazing pic it would be good to discuss.
    • I revised the caption to give a straight-forward explanation.—RJH (talk)

Otherwise looking very promising. Casliber (talk · contribs) 20:28, 10 December 2010 (UTC)

1. Well written?:

Prose quality:
Manual of Style compliance:

2. Factually accurate and verifiable?:

References to sources:
Citations to reliable sources, where required:
No original research:

3. Broad in coverage?:

Major aspects:
Focused:

4. Reflects a neutral point of view?:

Fair representation without bias:

5. Reasonably stable?

No edit wars, etc. (Vandalism does not count against GA):

6. Illustrated by images, when possible and appropriate?:

Images are copyright tagged, and non-free images have fair use rationales:
Images are provided where possible and appropriate, with suitable captions:


Overall:

Pass or Fail: - in summary, I think it meets GA criteria. I'll cross my fingers on some more star population attributes turning up for FAC. Casliber (talk · contribs) 01:21, 12 December 2010 (UTC)

Other

"The galactic envelope extends out to a radius of about 490 kly, where it has been truncated." in the second paragraph needs a better wording. Truncated by what? A physical phenomenon, some arbitrary definition, or an artefact from observation equipment? 88.112.37.71 (talk) 15:33, 14 October 2011 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.


— Preceding unsigned comment added by GA bot (talk • contribs) 19:30, 10 December 2010 (UTC)

Comment on I. Balanowski

I think that "I. Balanowski", who discovered a supernova in M87 in 1922, may be the same person as "Inna Lehmann-Balanowsky" or "Inna Lehman-Balanowskaja" from Pulkovo observatory. But I haven't been able to confirm this yet. "I. Balanowski" is used to publish in Astronomische Nachrichten, but the source is Pulkowo. "Inna Lehmann-Balanowskaja" is used for publications from the Bulletin de l'Observatoire central Poulkovo, although the name also appears in a pair of Astronomische Nachrichten publications. She seems to be well published, but there's no real biographical information. There is 848 Inna, however, which is named after Inna Nikolaevna Leman-Balanovskaya (1881-1945).[3] Unfortunately, it turns out she was the wife of Pulkovo astronomer Innokentij Andreevich Balanovskij, which confuses things further. Regards, RJH (talk) 21:36, 15 November 2011 (UTC)

It looks like there was a purge of Pulkovo astronomers during 1936-37.[4] I. A. Balanovskii, the chairman of the astrophysics department, was among those arrested by the NKVD on 11/7/1936 and sentenced to ten years by a military tribunal. His wife, I. N. Leman-Balanovskaia, was arrested 9/1937. She died shortly after her sentence was completed in 1945. A tragic tale, all told, but I think now that the "I. Balanowski" was likely the husband. For example, Shklovskii (1980) p. 389 references I. A. Balanovskii, Ein merkwürdiger veränderlicher oder Neuer Stern, originally published by I. Balanowsky.[5] Regards, RJH (talk) 03:20, 21 November 2011 (UTC)

Ex Cathedra

This article is appalling in its relentless assertions about M87 made without relating how the science was done, without stating how one thing was inferred from another. At the very least, it is a wasted opportunity to achieve excellence for the Wikipedia. Is it a good article that simply could be better? No. This article damages science and scientists. "M87" as written is an example of science as take-it-or-leave-it authoritarianism. The adventure of discovery is missing, the failure to relate how knowledge evolved or where it came from slights the role of M87 itself in the history of astronomy, the use of rational thought to make connections that have validity and consistency is not illustrated, the way in which knowledge now presented ex Cathedra actually grew in certainty, that also is missing. Worst of all, the idea that our understanding is incomplete -- some shred of humility before Nature -- is missing. Yes, this is a good summary of what we know at this time, but I never treated my graduate students this way. IMHO, Wikipedia at its best is not just a snapshot in time of where we are, it is also a hand extended to others to carry on and contribute.
Jerry-va (talk) —Preceding undated comment added 22:10, 26 March 2012 (UTC).

Well it's unfortunate that you think so, but to me your opinion smells distinctly of flame bait. For that reason I'm not going to pursue this further. Regards, RJH (talk) 22:25, 26 March 2012 (UTC)
You acknowledge that the article is "a good summary of what we know at this time." I disagree with your view that Wikipedia should aspire to be more than this. It's an encyclopedia, not a collection of treatises. Overly rambling and ambitious articles actually defeat the purpose of giving the reader a concise introduction to a topic. --Yaush (talk) 17:39, 27 March 2012 (UTC)

Black hole and Ejected Star cluster

I don't normally edit astronomy related articles (beyond copy edits) so I'm not going to immediately add any new information, but I do think that this merits consideration for inclusion in the article. The piece in question was published at earthsky.org and is about the first detection of a star cluster getting ejected from its galaxy. Also, the article mentions that there are two supermassive black holes at the center of the galaxy while the wikipedia article only mentions one. Link: http://earthsky.org/space/entire-star-cluster-thrown-out-of-its-galaxy --MorrisIV (talk) 19:55, 1 May 2014 (UTC)

LARGE error in jet energy?

The M87 wiki at present says in https://en.wikipedia.org/wiki/Messier_87#Observation_history "The total energy output of these electrons was estimated as 5 × 10^56 eV.[18]"

I looked up that actual old article at http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1956Obs....76..141B&link_type=ARTICLE&db_key=AST and it says "... from relativistic electrons... total energy is about 5.1 x 10^56 ergs..."

ERGS are *much* larger energy units than eV. 5.1e+56 ergs = 5.1e+49 joules = 3.2e+68 eV. https://en.wikipedia.org/wiki/Energy_units

Which is correct? Was there a typo in the 1956 paper?

And by the way, 5.1e+56 ergs is 1.3e+23 times Sol's output per second! So, over what time period is the observed jet energy summed?

regards, YodaWhat (talk) 16:02, 10 June 2014 (UTC)

The size of the galaxy relative to the length of the jet

To a layman (me) the statement that the jet is about 5,000 light years long seems to be at odds with the apparent size of the galaxy as seen in the photo. Since the Milky Way galaxy is about 100,000 light years across, its diameter would seem to be 20 times the length of the jet. Yet the diameter of the M87 galaxy (a 'supergiant' galaxy) in the photo 'seems' to be much less than the length of its jet. A word of explanation would be welcome. ClarkoEye (talk) 01:56, 4 February 2015 (UTC)

No, the stellar halo of M87 is WAY bigger than what you see in the photo. For instance, look at the bottom photo of M87 with other Virgo Cluster galaxies. You cannot see the jet there. SkyFlubbler (talk) 12:42, 20 June 2015 (UTC)

Messier 87 vs M87 and other things

Some things to think about WRT buffing this page for FAC:

  • Thinking about what we should call it through the article. I've always used the abbreviated "M87" - what about other folks?
  • Needs a section on satellite galaxies and its local environment.

Other ideas welcome...Cas Liber (talk · contribs) 01:28, 5 June 2015 (UTC)

I'd say Messier 87 for article title per what seems to be the convention in Category:Messier objects. Headbomb {talk / contribs / physics / books} 01:53, 5 June 2015 (UTC)
@Headbomb: - agree on article title, but what I mean is what we call it all the way through the article. Cas Liber (talk · contribs) 04:46, 5 June 2015 (UTC)
I went through the source, and here's some important stuff that don't seem to be in the article yet:
  • Satellites, like you mention.
  • Counter-jet. We have a little, but not enough.
  • Detail on knots in jet. While we have one knot's info, we need info on the knots in general.
  • Accretion disk around the black hole and how it relates to the mentioned "extended interstellar matter"
  • More on the 1919 supernova.
StringTheory11 (t • c) 04:28, 5 June 2015 (UTC)
The problem with "M" is that it is frequently used in military weapons, so "Messier" is better terminology for article titles. So use "Messier 87" as the article title, and M87 in text since its shorter and also common -- 70.51.46.11 (talk) 05:11, 5 June 2015 (UTC)
Oh, in the article? Personally I'd do Messier 87 the first time, abbreviated for the rest, but really whatever feels natural. Headbomb {talk / contribs / physics / books} 09:27, 5 June 2015 (UTC)
Yeah that seems to be consensus (as well as being intuitive) so done now. Cas Liber (talk · contribs) 15:30, 5 June 2015 (UTC)
@StringTheory11: - we can expand para 2 of properties regarding the different ways used to calculate distance (cepheids, GCs etc.) and the different results. Late here so going to sleep.Cas Liber (talk · contribs) 15:30, 5 June 2015 (UTC)
Just browisng recent studies - this seems important. Cas Liber (talk · contribs) 06:29, 10 June 2015 (UTC)

M87 in astronomy and in military are so irrelevant that they are hardly or unlikely to create confusion. The commander of the US Army will not order to fire an M87 gun to that galaxy. There are other catalogues that are similar, for instance, Caldwell catalogue abbrviated as C, ex. C103, which I think also happens to be a designation for Chinese aircraft. But who cares? China doesn't care about Caldwell. SkyFlubbler (talk) 11:01, 10 June 2015 (UTC)

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Paragraph on growth mode may better fit in section Properties rather than in Components

Hi

I suggest that some material on growth mode of elliptical galaxies {Active elliptical galaxies of a form similar to M87 are believed to form as a result of one or more mergers between smaller galaxies. There is now little dust remaining to form the diffuse nebulae where new stars were created, so the stellar population is dominated by old, population II stars that contain relatively low abundances of elements other than hydrogen and helium. M87's elliptical shape is maintained by random orbital motions of its member stars, in contrast to the more orderly rotational motions found in a spiral galaxy such as the Milky Way} and relevant image on random motion of stars, be moved from section Components to the end of the section Properties, where it will be more fitting since the discussion of capture of smaller spiral galaxy and young stars is present there. Alternatively, it can be done other way around as well.

Thanks --ubedjunejo (talk) 01:22, 9 January 2018 (UTC)

Table of metal abundances

Question: is the table of metal abundances really adding useful value to the article for the general reader? My view is that it would be better to just explain in the text of the article that the elemental abundances in the inner part of the hot gas halo are roughly similar to Solar abundances (perhaps with a bit more detail about oxygen and/or iron) and give references to published work where people interested in the details can get more information. Given that the table is there, the table title or caption should specifically state that these are abundances measured for the hot gas, since the elemental abundances in the stars will not be the same, and are measured using different methods. However, I wanted to bring up the other option of possibly just deleting the table since it seems like a level of technical detail that maybe isn't warranted here. Aldebarium (talk) 19:58, 5 July 2018 (UTC)

Copying a comment from WP:ERRORS

Apparently I need to get a consensus for a change here first, so here we are.

De Vaucouleurs' model is a special case of Sersic's model, with Sersic index n=4.

"Elliptical galaxies do not "[diminish] in luminosity away from the center."

Luminosity is a measure of the total electromagnetic energy emitted by an object over time, and will inevitably increase as you add more photons (that is, if you add the light from further out to the light from nearer in).

What does decrease is the surface brightness. In general an elliptical Galaxy will follow De Vaucouleurs' law (or more generally Sersic's law) although the situation is slightly more complicated for M87, with an extended cD envelope in addition to a stellar core, as this reference explains: [6] 31.107.169.27 (talk) 16:14, 1 September 2018 (UTC)

I support your goal to correct the misstatement. But are you proposing simply replacing "luminosity" with "surface brightness", or do you propose adding detail similar to your quoted explanation? At the moment I harbor no opinion about whether a very concise explanation or just active references would be best. (And in general this article lies outside my areas of competence, so I defer to those well studied in this area.) --H Bruce Campbell (talk) 14:37, 2 September 2018 (UTC)
Perhaps a simple word swap is best here. Ceoil (talk) 14:46, 2 September 2018 (UTC)

Sorry if I was unclear. A word swap - replacing "diminishing in luminosity" with "diminishing in surface brightness" - is exactly what I am advocating. That is the way it is discussed in the sources I have seen, and I haven't yet seen a source saying that elliptical galaxies diminish in luminosity away from the center.

We do not need a long explanation in the lead section, but it would be good to add more from other sources on the photometry of M87 and its surface brightness profile. For example, the background discussed in [7] and some of the papers mentioned therein.

Here is the inconclusive reaction to my main page error report before it was summarily deleted.[8] 31.107.169.27 (talk) 23:44, 2 September 2018 (UTC)

Apparent magnitude

Checking NED, I find a citation for the apparent magnitude in the visible spectrum of 7.19. This is a significant deviation from the previously cited value of 9.59. I have changed the value to what I have found in the source, but maybe I am missing something? --dab (𒁳) 08:13, 9 April 2019 (UTC)

@Dbachmann: There's something odd there. Despite NED stating otherwise the paper cited[9] doesn't claim V=7.19 for magnitude. Instead it publishes G=8.79 and Z=7.19, ie. green and near-infrared values. There's also a footnote "Finally, the magnitudes listed in the next to last column exclude the nucleus".
To make things more complicated SIMBAD claims 8.63 V but the cited paper[10] is ultraviolet. I've reported the later error. I'll see if I can find a better source for this. --mikeu talk 13:53, 11 April 2019 (UTC)

recent news

The black hole in M87 has been studied by the Event Horizon Telescope [11] — Preceding unsigned comment added by 2001:982:845B:1:D4AD:1F88:38F1:83D3 (talk) 13:29, 10 April 2019 (UTC)

Please see this discussion regarding the provisional designation of the core source as M87*. The radio telescope data used to construct the image was collected during a campaign in April 2017; it took two years to analyze the data before publishing the results today. --mikeu talk 17:13, 10 April 2019 (UTC)

Indeed, and M87* should be the nucleus for a new {{main}}-subtopic, while Messier 87 retains its scope of discussing the entire object, and not primarily the WP:RECENTISM. --dab (𒁳) 12:18, 11 April 2019 (UTC)

Convert macro for sizes in the Black Hole section

I tried to edit the section so I could compare the radius to solar system distances, but to my surprise the { { Convert macro was already there. Can someone look ?

And it could use a diagram of distances, black hole, ergosphere. Or is this ring only between these two?

Thanks! Wizzy…☎ 17:41, 11 April 2019 (UTC)

Contradiction on observations of the Jet

The article states: "In 1918, the American astronomer Heber Curtis of Lick Observatory noted M87's lack of a spiral structure and observed a "curious straight ray ... apparently connected with the nucleus by a thin line of matter." " And: "Before 1991, the Russian-American astronomer Otto Struve was the only person known to have seen the jet visually, using the 254 cm (100 in) Hooker telescope." Both statements cannot be correct, so which is right? Stub Mandrel (talk) 10:57, 14 April 2019 (UTC)

I don't think there's a contradiction here. Curtis's discovery of the jet was from taking a photograph of M87 and seeing the jet on the photograph. The Struve story seems to refer to a visual observation, meaning putting his eye up to the eyepiece of a telescope and seeing the jet directly by eye. (I haven't looked up the reference cited for this story to verify that this is what it means, but I'm pretty sure this is what it means.) Aldebarium (talk) 11:06, 14 April 2019 (UTC)

New article for Pōwehi

So, this discussion was going to happen eventually, so I might as well start it now so that a consensus can be reached before any potential edit wars and/or messy sequences of edits come about. Pōwehi obviously passes the notability barrier as it is the very first directly imaged black hole, and thus the object that most strengthened the argument for the existence of black holes since they were first theorised. However, is there enough content and information today for a separate article to be able to take hold? If not, how should the many hundreds of stub articles on astronomical objects be treated if this one does not pass the size measure? – PhilipTerryGraham (talk · articles · reviews) 03:37, 13 April 2019 (UTC)

It's not a matter of size, it's a matter of how much information we have about the object. We now have the image, and we may get more images later to tell us other wavelengths or what happens through time. So there is probably going to be enough information for an article.
However, the name... As best I can tell, that name is due to one of the astronomers who is a member of the team, promoting this on his own. It does not seem to have come from the EHT team, so I wouldn't be using that name just yet, in fear of WP:PROMO, WP:CIRCULAR and similar gotchas. For the moment, think of the name M87*, which is what was used in the published articles. Tarl N. (discuss) 04:05, 13 April 2019 (UTC)
@Tarl N.: But M87* is also a controversial name, as it has been interpreted as some as a provisional designation, as it is not an IAU-designated name as per the general guidelines on astronomical object naming conventions. I think it is too soon to say M87* is the common name for something that has for the longest time been referred to as "the black hole at the center of M87", ect., as the name has only been thrown around the past few days. This is in contrast to Sagittarius A*, which has had that name for a long time, and most likely the name upon which the M87* name is based on. Basically, both names have roughly the same argument for being the article title – I just simply prefer a verifiable "real" name rather than a verifiable name made up of sequenced letters and numbers, and I'm sure others would too. – PhilipTerryGraham (talk · articles · reviews) 04:30, 13 April 2019 (UTC)
Please see Talk:Event_Horizon_Telescope#How_real_is_the_"Pōwehi"_nickname? and in particular How do you name a black hole? It is actually pretty complicated. M87* is not controversial. --mikeu talk 06:23, 13 April 2019 (UTC)
Referring to this black hole as "Pōwehi" is like renaming every mention of "Higg's Boson" on Wikipedia to "The God Particle". According to some reports, the person who named it Pōwehi is a linguist. Is he authority on naming astronomical objects? Certainly not. AhmadLX-)¯\_(ツ)_/¯) 13:55, 13 April 2019 (UTC)
indeed, and let’s not rush to using excitable newspaper sources. With all due respect the NYT is not a RS for this topic. Ceoil (talk) 00:51, 14 April 2019 (UTC)
ps, I think we are all kind of saying the same thing, I see consensus against using "Pōwehi". Ceoil (talk) 11:22, 14 April 2019 (UTC)
"A more formal approval for the name would have to come from the International Astronomical Union, Dr. Bower said. A submission to the union would come only if the consortium of more than 200 scientists and 13 funding institutions involved in the project agreed to support it, he said."[12] --mikeu talk 15:32, 13 April 2019 (UTC)
@Tarl N., Ceoil, PhilipTerryGraham, and Mikeu: Does this mean we remove this Powehi thing for now? I think we should, until there is something official from the EHT team or IAU endorsing this nickname. AhmadLX-)¯\_(ツ)_/¯) 14:10, 14 April 2019 (UTC)
Of course. Ceoil (talk) 14:18, 14 April 2019 (UTC)
I agreee. --mikeu talk 15:11, 14 April 2019 (UTC)
The radio silence from EHT on the proper name is... remarkable. My crystal ball suspects that there is not a concensus among the collaboration to support this name. For whatever that opinion is worth, as I obv. can't reference it. My links to the quotes from the IAU representative should be given due WP:WEIGHT. That's a significant statement. A reputable journalist would not attribute “For the case of M87*, which is the designation of this black hole..." to "the IAU’s Lars Christensen" if this were merely a single astronomer's personal opinion. --15:23, 14 April 2019 (UTC)
Yes, and there is a reason for that silence. As I said above, its not about what journalists rush to think. Note also, this article is an FA, and thus should strive beyond recentism. Ceoil (talk) 15:54, 14 April 2019 (UTC)
Agreed. Given that Christensen is an active member of the IAU commission on Communicating Astronomy with the Public [13] we should regard his statements as the official position of the entire body responsible for nomenclature. Regardless of what journalists consider significant. --mikeu talk 16:04, 14 April 2019 (UTC)
I'd generally favor removing it. The reporting I've seen all points to opportunistic self-promotion rather than consensus naming by the discoverers. Tarl N. (discuss) 18:04, 14 April 2019 (UTC)

So, this is getting incredibly off-topic. I've now changed the proposal to "Pōwehi" to "M87*" since there seems to be a consensus above that this is the preferred title of the proposed new article. Anyways, there's barely any discussion about the actual point of this discussion – whether or not its too soon to have a new, separate article. – PhilipTerryGraham (talk · articles · reviews) 20:44, 14 April 2019 (UTC)

Go for it, but just don't title "Pōwehi's Black Hole". Ceoil (talk) 21:25, 14 April 2019 (UTC)
(edit conflict)Eventually, for certain there will be an article. At the moment, what we have: It's a black hole with a measured mass; It has a relativistic jet; it's in M87; it has a picture. To my liking, this is pretty close to a stub. I personally would wait until we get a bit more information about it, but it's a borderline call. If you do create an article, the name would certainly deserve a paragraph describing the issues surrounding M87*/Pōwehi and IAU. Tarl N. (discuss) 21:28, 14 April 2019 (UTC)
I agree that the notability is clearly there, but the essential content (mass of the BH, the EHT results, the description of the jet) is already covered very nicely in the M87 article and I wouldn't like to see that content removed from the M87 article. The main reason to create a separate article might be to include more in-depth and detailed information than is appropriate for the M87 article. That might be warranted at this stage but if people are advocating for that, it might be helpful to discuss what new content would be included that wasn't already covered adequately in the existing M87 article. A more detailed description of the physics of what's seen in the EHT image might be useful content for a separate article, since there is probably a lot of public interest & questions about this. Aldebarium (talk) 21:35, 14 April 2019 (UTC)
Aldebarium, yes, and there is noting wrong with stubs. We can anticipate significant mounts of research given recent media attention. Ceoil (talk) 21:42, 14 April 2019 (UTC)
I have a weak preference for waiting on the split. My hesitancy is partly that I expect much more information in the near future as data collected last year is released and other researchers publish reactions. I also like the idea of having an FA be the landing page while the topic is so hot, rather than a stub. It not only puts our best work forward, it is also rigorously patrolled for quality. It is still getting 20k page hits per day compared to just a couple hundred pre-announcement. There's no pressing need to split it off in the next couple of weeks, maybe even longer as it could take months for peer reviewed sources. For additional content I'd like to see a simplified infographic similar to The Anatomy of a Black Hole Accretion System[14] that explains the "glow" as originating in the photon ring and the "shadow" as the event horizon. A sample simulation to scale with the image would show how the glow is a blurred rendering of a significantly thinner region. --mikeu talk 01:11, 15 April 2019 (UTC)
There is nothing wrong with having a stub, but in my opinion this new stub will be a duplicate of M87#Supermassive black hole. There is not much info available except, as pointed out above, mass, spin, radius, image, jet and of course media frenzy ;) Apart from that, there seems to be consensus on removing nickname "Powehi" from the current article. AhmadLX-)¯\_(ツ)_/¯) 14:57, 15 April 2019 (UTC)
Note: there's a dangling redirect to the section at Pōwehi. --mikeu talk 13:34, 16 April 2019 (UTC)

Request for removing of a "black hole image" of an Event Horizon Telescope from Wiki page

Not done

This image must not be published by Wikipedia while the EHT's team don't show us exact algorithms they used for reconstruction of it. An EHT's image is biased and probably due to aberration error.

Simulation of gravitation lens inside accretion disk

https://qph.fs.quoracdn.net/main-qimg-9f25b9f6b3cc85121faf316a3cd38e1a

Spherical aberration in an optical telescope

https://qph.fs.quoracdn.net/main-qimg-1bdbb362446b48d94593ba1d8ff24c20

Above frames are from this video, without almost nothing image processing except color balance.

https://www.youtube.com/watch?v=MFmFpuST67M

Why Wikipedia disseminates information that has not been confirmed by external scientists, but only from an Event Horizon Team,which are an interested party in disguise their error?

https://www.quora.com/Why-cant-the-image-they-present-to-you-as-an-image-of-a-black-hole-be-a-black-hole-image-at-all-and-how-should-an-image-of-a-black-hole-look-for-us-as-external-observers 84.238.150.11

Untrue. https://iopscience.iop.org/article/10.3847/2041-8213/ab0f43 puggo (talk) 14:41, 1 May 2019 (UTC)

Proposal to place Supermassive black hole and Jet in one section

Before the imaging of the black hole, the jet was the most prominent feature of M87 and was given its own section, while black hole, with no observational evidence, was treated as a secondary feature and placed in section "Components". Now that the black hole has been observed, I propose that the two should be placed in a new section "Core" with subsections "Jet" and "Supermassive black hole" (historical ordering) or "Supermassive black hole" and "Jet" (logical ordering). Alternative would be to move "Jet" to section "Components". Pinging @Aldebarium, Ceoil, Mu301, and Tarl N.:. Of course, any other comments also welcome. AhmadLX-)¯\_(ツ)_/¯) 17:20, 28 April 2019 (UTC)

Support creating a regiged sect for Core; within which I would prefer logical ordering. Ceoil (talk) 17:25, 28 April 2019 (UTC)
I'd agree with making "Jet" a subsection of "Components", that sounds good. I don't think "Jet" should be a subset of "Core" because the jet is a pretty large feature that isn't just contained within the galaxy's core: it is launched from the immediate surroundings of the black hole, but it affects the interstellar medium on much larger scales in the host galaxy, and the Jet section covers this range of scales pretty well. So there's no specific need for a "Core" section in this case- just move "Jet" under the "Components" section. Aldebarium (talk) 17:47, 28 April 2019 (UTC)
My inclination would be to move Jet to Components and place it 2nd after the black hole. This leads logically from cause to effect. The jet extends nearly to the visible edge making it difficult to consider it soley part of the core. --mikeu talk 21:33, 1 May 2019 (UTC)
Thank you all for the comments. Ceoil seems mikeu and Aldebarium have got a point here. AhmadLX-)¯\_(ツ)_/¯) 12:48, 6 May 2019 (UTC)
Jet moved into Components. Thanks. AhmadLX-)¯\_(ツ)_/¯) 17:36, 7 May 2019 (UTC)

Split or not?

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

I'm going to be WP:BOLD and close this section as oppose given that it has been open for two months without any strong support. Please feel free to reopen if you think that further discussion could produce a different outcome. --mikeu talk 05:18, 13 November 2019 (UTC)

The discussion about whether to split the black hole section to a new article M87* is now almost four months old but doesn't seem to have reached a consensus. Should it be split or not? JIP | Talk 10:54, 9 August 2019 (UTC)

  • Oppose: I don't see any benefit of doing so at present. The section is barely three paragraphs long, and the contents are an intrinsic element of the galaxy's AGN status. Praemonitus (talk) 05:10, 8 September 2019 (UTC)
  • Oppose until more information is published that we can use to expand the content. Having a GA as a landing page puts the object into context and I don't see much value added to having a standalone page. As I said in April: "My hesitancy is partly that I expect much more information in the near future as data collected last year is released and other researchers publish reactions." I don't see that anything that has changed since then. Given that it took two years after collecting the data to publish the image we could have a bit of a wait.[15] Having said that, I could be persuaded. I'm just not seeing a compelling reason to do this at this time. I'd like to know if @Tarl N.: @Ceoil: @PhilipTerryGraham: @AhmadLX: and other participants in the original discussion have new opinions. --mikeu talk 23:01, 25 October 2019 (UTC)
  • Oppose – I’ve since changed my opinion on having an dedicated article on M87*. I originally anticipated there to be much more information after the EHT observation, having expected numerous scientific studies to have been published in the months afterward. Unfortunately, that has not happened, and when I attempted to draft out an article a while back, all I could come up with was a unsatisfactorily short article with only small “Characteristics” and “Observation” sections – any “Observation” section would mostly be based on content already at Event Horizon Telescope, anyways. There’s simply too little information to justify a seperate article at this present time, and the current paragraph of characteristics and observation of M87* in this article is satisfactory. – PhilipTerryGraham (talk · articles · reviews) 23:13, 25 October 2019 (UTC)
  • Oppose. As discussed above, no new details. Separate article will be completely redundant. AhmadLX-(Wikiposta) 00:05, 26 October 2019 (UTC)
  • Oppose. Per all of the above. There simply isn't enough information to make an article. The re-direct to the section in M87 seems still appropriate. Separately, reading that section, it might be worth qualifying the designation of as "provisional" or "de facto", since I haven't noticed any official action about that becoming the permanent name. Regards, Tarl N. (discuss) 01:30, 26 October 2019 (UTC)
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

mention of name Pōwehi?

Pōwehi currently redirects here, but the name isn't mentioned here. It is mentioned at Event Horizon Telescope. I don't know any more than the rest of you (and surely less than some) about the reasons for or use of the name, but it's unhelpful for a rd to take the reader to someplace other than the article that discusses the name, and it's odd for the discussion of the name to be in some article other than the one covering the object itself. If we redirected Pōwehi to the EHT article, then we'd have the odd situation of a synonym directing the reader *away* from the article on its referent. I don't know the best solution, and wouldn't want to trivialize an FA, but at the least I think that there should be a mention of the name in whichever article the rd takes the reader to. — kwami (talk) 00:47, 13 November 2019 (UTC)

These are interesting and important points to consider. It might be a good time to reexamine the issue now that some time has passed. My first inclination is to not include Pōwehi which would imply that I support deleting the rd. But I don't (at the moment) have a strong opinion on this. I could be persuaded that a brief mention is warrented. Thanks for bringing this up. --mikeu talk 01:01, 13 November 2019 (UTC)
The name appears to be self-promotion by a Hawaiian professor. At the time, I didn't see anything from the telescope team suggesting they even considered the name, much less endorsed it, all references I could track down came back to a single press conference by an unaffiliated professor announcing the name. Has this changed, and there is actually something from someone associated with the project who endorses the name? Tarl N. (discuss) 01:27, 13 November 2019 (UTC)
From the earlier discussion, and the external links there, it would seem that someone on the discovery team approach him for a name, and was quite pleased with his suggestion, not that the prof inserted himself into the news coverage or was self-promoting. So, if some of the team decide on a name, but the whole team (which is quite large) doesn't get on board with it, is it worth a mention? Considering that we note that KBO's were nicknamed "Easterbunny", "Santa" and "Snow White", it would seem odd to draw the line here. — kwami (talk) 03:58, 13 November 2019 (UTC)
The name is part of the Kumulipo (primordial creation chant of the Hawaiians), as noted by Jessica Dempsey, deputy director of James Clerk Maxwell Telescope, which is operated by the East Asian Observatory. Would anyone object to a redirect to Event_Horizon_Telescope#Messier_87*, where several of the telescopes which make up the EHT consortium (James Clerk Maxwell Telescope, and Submillimeter Array) are located, on the slopes of Mauna Kea? --Ancheta Wis   (talk | contribs) 03:39, 13 November 2019 (UTC)
Kumulipo, line 135: Po =dark, wehi =faint, reduplicated means 'very', so powehiwehi (a female name) means very faint darkness. --Ancheta Wis   (talk | contribs) 04:40, 13 November 2019 (UTC)
Again, I think it would be odd to redirect there when the referent of the name is here. Ppl may become frustrated when they look it up, are taken there, then need to locate a link to bring them back here, where they expected to land in the first place. Maybe we could say s.t. like "It has been informally given the Hawaiian name Powehi (see EHT)"? Any discussion, sources, controversy etc. could then be covered in that article. — kwami (talk) 04:01, 13 November 2019 (UTC)
I think even "informally given the name" gives too much credence. That name was specified here for a time, and about half the references I tracked down cited Wikipedia as their source. We really don't want to get into WP:CIRCULAR. As for the claim that someone on the discovery team approached him for the name, such a claim was made, but I did not see any specifics (such as whom, or whether other team members approved). It all came down to the press conference by the language professor. As such, at the time, it had a strong odor of WP:PROMO. We need references that show this wasn't a self-authorized and propelled naming effort by someone unrelated to the project. The IAU will eventually come up with an official name, in the meantime, the project used the informal "M87*" in their publications. Tarl N. (discuss) 05:50, 13 November 2019 (UTC)

It's easy enough to find stuff that doesn't depend on Kimura.

The gov of Hawaii even declared "Powehi Day",[16] which gives it some minor external relevance as well.

Simons and Kimura have worked together before.[17]

The only criticism I've found so far is at newsbytesapp.com, timeline/Science/44828/201790/m87-black-hole-s-name-stirs-debate, where they want it named after a musician instead.

Given that the EAO and several ppl at the JCM telescope used the name, I don't know how we can claim that it's just self-promotion by Kimura. The fact that sites mirror WP is irrelevant -- if we didn't allow coverage of things mirrored from WP, we'd need to delete all our articles.

I find it quite believable that ppl at the other telescopes in the EHT array may not be overjoyed at having M87* given a Hawaiian name, as if the JCMT were the only telescope involved. And certainly if we can find any refs to that effect, they should be included. Meanwhile I added a hatnote so readers will have the option of reading about the name if they choose. — kwami (talk) 21:03, 13 November 2019 (UTC)

After looking into this further I don't see that much has changed since this quote: "For the case of M87*, which is the designation of this black hole, a (very nice) name has been proposed, but it has not received an official IAU approval,” says Christensen of the IAU. “Typically these things take quite a while.” I don't see significant adoption of the nickname by the scientific community.[18][19] Most of the mentions are local to Hawaiʻi news and press releases from a small subset of the observatories involved in the discovery.[20] The EHT collaboration is large and there doesn't seem to be consensus among the collaboration that this is the preferred name to propose to the IAU.[21] Any mention of Pōwehi should be brief and clearly state that it has not become as widely adopted in the literature as M87*.[22][23][24][25] (or even descriptive phrases such as "M87 black hole"[26] etc.) I would support a mention based on the endeavors to include indigenous knowledge in scientific efforts[27][28] if the statement is clear about both the (lack of) official status and (uncommon)[29] usage. --mikeu talk 22:30, 13 November 2019 (UTC)

Update: the redirect incorrectly pointed to the article instead of the section. I've fixed that.[30] I would prefer the hatnote to go in the section, not at top. --mikeu talk 22:35, 13 November 2019 (UTC)
I don't think this is self-promotion by the proponent of the name, since it continues to be used informally by other astronomers and in other contexts, as has been noted above. The main point is just that it is not an official name for this astronomical object, so the WP article should not portray it as such. I do think that having Kimura's name at the very top of the M87 article (as was just recently added to explain the redirect from "Pōwehi") gives undue weight to this entire topic, and I think it would be better to just remove that redirect statement at the top of the article, since that will just be a distraction to general readers of the article. Finally, my two cents on one other item: in my view M87* should be the name of the radio source at the core of M87, which is not the same as being the name of the black hole itself. See the article on Sagittarius A*, which defines it as the radio source, which is at the location of the black hole, i.e., Sgr A* is not the name of the black hole itself, although it is used informally for that sometimes. Aldebarium (talk) 22:44, 13 November 2019 (UTC)
I also don't consider this self-promotion. But there is an effort to promote culture through naming/renaming opportunities on telescope sites on indigenous lands. This is a notable and concerted effort that doesn't appear to have reached the level of becoming a WP:COMMONNAME in this case as ʻOumuamua and Kaʻepaokaʻāwela did.
Interesting point about the radio object distinction. However, the RSs uses phrases like "The first image of the black hole (BH) M87*"[31] and "In this paper, we derive constraints on the nature of M87* (the supermassive object at the centre of the galaxy M87)"[32] and "dark shadow around the supermassive black hole M87*"[33]. --mikeu talk 23:14, 13 November 2019 (UTC)

Mikeu and Aldebarium, I agree with everything you just said. Any mention should be brief and note that usage is informal, though whether we should have an actual mention or a hatnote at the top of the section I don't know. — kwami (talk) 23:57, 13 November 2019 (UTC)

I moved the hatnote down to the section for now. Does anyone have a suggestion on wording? --mikeu talk 02:15, 14 November 2019 (UTC)
I'm concerned that the anonymous "astronomers consulted with" Kimura. Naming of an astronomical traditionally has two paths: A provisional name assigned by the discoverers, and an official name assigned by an IAU committee (sometimes bending in the direction of the the provisional name). As best I can tell, Pōwehi follows neither path, it sprang from an unrelated source. We should not be rewarding that source by publicizing their creation. We see this periodically in star names, where someone paid a random registry to name a particular star, and then is terribly offended when Wikipedia refuses to acknowledge their new naming of the object. The examples mentioned above (Hawaii governor and a deputy director for a telescope) do not represent the discoverers. Tarl N. (discuss) 02:58, 14 November 2019 (UTC)
Buying a star for personal vanity is a long way from astronomers giving a star a native name to honor the local people at the telescope. You're right that this hasn't gone through proper channels, but then a lot of star names haven't gone through proper channels. It's too early to know where this will go, and it may end up being a historical blip that at best warrants a footnote. Until then, however, we will have people looking up the name on WP, and we need to provide them with something so they know what's going on. If we can document misbehavior, we certainly need to cover that, though of course we need to be aware of living-bio issues. I've seen nothing that suggests misbehavior on Kimura's part. Yes, he's promoting the Hawaiian language, and I'm sure was quite happy to have astronomers approach him about this latest newsworthy find, and was happily voluble about it. And I doubt there was any real misbehavior on the part of the astronomers either, and we've got ppl from both the JCMT and Franco-Canadian telescopes, though the astronomers contributing from the Atacama might feel dissed. — kwami (talk) 07:39, 15 November 2019 (UTC)
The claim here is not that the name is adopted by the entire EHT team but that a subset are frequently using the nickname. This is hardly on par with a scam star registry. They've had three proposed names for other objects accepted by the IAU so far. Please see Hawaiian Culture‐Based Celestial Naming presented at AAS[34] which describes the establishment of a formal collaboration between linguists and astronomers.[35] The IAU is particularly receptive to accepting non-western name proposals.[36] Kimura, Imiloa Astronomy Center, and prominent published astronomers at Mauna Kea are regularly using this name. It may never get submitted or accepted by IAU but that is not going to stop them from using it or our readers from searching for it. There's no requirement that astronomers only use officially sanctioned proper names (nor could it be enforced) which is why I can cite numerous RSs that use the nicknames like Black Eye Galaxy and Evil Eye Galaxy to refer to M64. WP includes names that are used by professionals, not merely ones that have received a stamp of approval from a committee. There is simply no one-to-one mapping between IAU processes and WP notability. That is merely a detail for designating the description of the kind of name: official, provisional, nickname. --mikeu talk 15:58, 15 November 2019 (UTC)

The IAU has no provision for naming galaxies or black holes, so evidently it's not going to be submitted. Rather, it's an informal name much like Whirlpool Galaxy and Horsehead Nebula, which names haven't been approved by the IAU either.

This morning I spoke to an astronomer who works with some of the people on the discovery team. This is all second-hand, but he thought it was Simons who approached Kimura, and that Simons had consensus from much of the team (though it was a big team). He hadn't heard anything about anyone at say Atacama objecting to giving it a Hawaiian name. His impression was that they weren't going to submit the name to the IAU because there's no provision for doing so. — kwami (talk) 23:56, 15 November 2019 (UTC)

@AhmadLX, Ceoil, and PhilipTerryGraham: pinging participants in the last discussion to get a broader range of opinions. --mikeu talk 01:10, 16 November 2019 (UTC)

Powehi has not neared the universality of Whirlpool or Horsehead, and will probably not in near future. I would prefer deleting the redirect and keeping mention of the black hole as just central black hole or black hole M87*. AhmadLX-(Wikiposta) 14:00, 21 November 2019 (UTC)
We need the rd for people looking up the name. It's in the news. Censoring it from WP is irresponsible. We can mention it as trivia, or say that it's not official (because there are no IAU-official names for such things), or whatever to clarify its use, just as we do for many obscure star names that haven't been adopted by the IAU. But we need to say something. — kwami (talk) 04:12, 23 November 2019 (UTC)

There's some decent coverage of this from back in April. E.g., M87*? Powehi? There are no rules on naming black holes. "The [IAU] usually takes care of names, but only for stuff inside our solar system and stars outside it. It doesn’t have a committee set up to handle other objects, like black holes, galaxies or nebulas." "Powehi ... is the black hole’s Hawaiian name, not its official name, explained Jessica Dempsey, who helped capture the image as deputy director of the James Clerk Maxwell Telescope on Mauna Kea."

So maybe we could just say, "known in Hawaiian as Powehi. The IAU does not accept names for galaxies or black holes."? — kwami (talk) 04:24, 23 November 2019 (UTC)

FRBs in M87 observed in 1979

Now that the Fast radio burst is a thing, someone may wish to note this. Linscott and Erkes of Dudley, observing at Arecibo, reported in 1979 their observations of 'millisecond radio bursts from M87'. Published in AJ Mar. 15, 1980. http://adsabs.harvard.edu/full/1980ApJ...236L.109L Twang (talk) 19:04, 8 January 2020 (UTC)

Number of stars

I was surprised that this article did not have a citation for the updated number of stars: a quick search returned refs from ESA[2] and NASA.[3] --Ancheta Wis   (talk | contribs) 03:12, 12 March 2021 (UTC)

Milky Way Black Hole Announcement Today

Hi,

I hope I wasn't out of turn in editing one sentence of this featured article this morning that stated this galaxy's black hole is the only one imaged thus far. I didn't notice it was featured until after submitting that quick edit. I very rarely edit, so I wasn't sure if it was wrong to do so on a featured article... Goddale120 (talk) 14:05, 12 May 2022 (UTC)

Mass of M87 in relation to our own galaxy

I was surprised at the high mass of M87 being quoted on the various news programmes, so I checked here. This paragraph seems just as confusing and self contradictory. Presumably the boundary is fuzzy and can't be easily defined, but could we improve on this?

the mass is (2.4±0.6)×1012 times the mass of the Sun,[44] which is double the mass of the Milky Way galaxy.[50] As with other galaxies, only a fraction of this mass is in the form of stars: M87 has an estimated mass to luminosity ratio of 6.3 ± 0.8; that is, only about one part in six of the galaxy's mass is in the form of stars that radiate energy.[51] This ratio varies from 5 to 30, approximately in proportion to r1.7 in the region of 9–40 kiloparsecs (29,000–130,000 light-years) from the core.[45] The total mass of M87 may be 200 times that of the Milky Way.[52]

--Andromedean (talk) 06:52, 14 May 2022 (UTC)

Hi. There is no contradiction. The first value is for the inner region only (see the accompanying table). The latter value is for entire galaxy including the stellar region and the surrounding gas halo.AhmadLX-(Wikiposta) 14:12, 14 May 2022 (UTC)
I'm fully aware of that. There is a hundred fold difference between the two mass readings (x2 and x200) that isn't represented in the table. Andromedean (talk) 16:14, 14 May 2022 (UTC)

Possible stellar velocity map inconsistency

Not looking for an explanation of the physics here but is the key in the stellar velocity diagram in the Properties section the opposite of its caption? The colored key labels show Away for portions of the map largely Towards in the caption, and vice-versa, could that be a typo. StrontiumDogs (talk) 16:11, 10 May 2024 (UTC)

  1. ^ Cite error: The named reference apj700_2 was invoked but never defined (see the help page).
  2. ^ ESA M87
  3. ^ NASA (Oct 19, 2017) Messier 87
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