Talk:Canis Major Overdensity

Comments
Very on the ball! User:Wetman

I got some information for the table at --BrendanRyan 14:41, 26 July 2005 (UTC)

Dwarf galaxy?
The opening mentions that it's a Dwarf galaxy, but that article says a dwarf galaxy consists of around 10 million stars (compared to the Milky Way which has 200-400 million), whereas this article states Canis Major may contain 1 billion (10 million × 100) stars, which is considerably larger than the Milky Way itself, let alone a "dwarf" galaxy. &mdash; Vystrix Nexoth 08:13, Nov 22, 2004 (UTC)
 * The problem is that the Dwarf galaxy page needs some serious cleanup and contains factual errors. The Milky Way has 200-400 billion stars, not million, and there are globular clusters that contain more than 10 million stars; I'm not sure, but I imagine a dwarf galaxy could range up to 10 billion stars. Neurophyre 18:19, 27 Nov 2004 (UTC)

Request for Additional Information
Some additional information on this galaxy - especially on the Monoceros Ring, briefly referred to in this article - would be greatly appreciated. Thank you. Brasswatchman July 31, 2005. 11:23 AM EST. Canis Major Dwarf galaxy is a very small galaxy on the verge of becoming part of the milky way itself. — Preceding unsigned comment added by 50.128.210.33 (talk) 00:58, 5 November 2012 (UTC)

Where's that line?
The table has the line Constellation 	 and I can't see it when editing the article.--BrendanRyan 08:36, 20 August 2005 (UTC)

New Dwarf Galaxy mergeing with Milky Way
Does the January 2006 discovery of the drawrf galaxy merging with ours count as a closer galaxy? See Milky Way article. WilliamKF 20:24, 24 January 2006 (UTC)


 * This refers to the Virgo Stellar Stream

overdensity is a warping of the disc and not a dwarf galaxy?

 * Deriving The Shape Of The Galactic Stellar Disc (SkyNightly) Mar 17, 2006

Images?

 * http://antwrp.gsfc.nasa.gov/apod/ap031117.html
 * http://astro.u-strasbg.fr/images_ri/canm-e.html
 * http://astro.u-strasbg.fr/images_ri/image1sun_big_nocap.jpg

Dubious
A major recent paper on the outer galaxy and especially on the Canis Major region rejects the idea that there is a dwarf galaxy in this direction. Instead the "overdensity" of stars in this region is caused by the extension of the Orion Spur in this direction. See:

http://adsabs.harvard.edu/abs/2008ApJ...672..930V

I suggest that this article be deleted.

Kevin Jardine

Galaxy Map

http://galaxymap.org

80.61.70.22 (talk) 16:41, 30 June 2008 (UTC)


 * Specific rejection of there being a dwarf galaxy, is not given in the text of the abstract linked to... so will need someone else who has access to the full article to comment further (but generally notable secondary sources trump single primary sources - wikipedia being about knowledge, which may be flawed, rather than scientific truth - ie not WP:SPOV). Are there any other refs for this view being more widely accepted ? David Ruben Talk 17:33, 30 June 2008 (UTC)

Quite frankly a great deal is claimed of the CMa Dwarf in this article, with no citations given, including supposed associated Galactic Globular Clusters. Just about the only place a citation is stated as being needed is when someone points out there have been several papers saying it is an overdensity of stars, and even if not such, that the papers saying it is a dwarf galaxy do not sufficiently show it to be so.

That's a bit rife in wikipedia for astronomy though, it occurs in the exoplanet sections too. Any "gee-whizz" claim gets plenty of airing, any nay sayers get deleted or requested for hard citations, and then like here, the conjectural positive stuff is apologised for and the evidence of negative stuff pedantically dismissed with nitpicking.

Science is about testing. The onus is upon the claims to be substantiated, reasonable doubt is still reasonable doubt, but in the earlier comments here it seems there are different rules for the nay saying evidence compared to the yay saying evidence.

Here's a citation, btw. http://arxiv.org/abs/0803.1509 —Preceding unsigned comment added by 86.166.130.187 (talk) 16:46, 2 January 2009 (UTC)

Still dubious
A quick search of the recent scientific literature on the Canis Major "overdensity" shows at least 8 scientific papers concluding that this phenomenon is not a dwarf galaxy or at least is more consistent with other explanations. I'm sure that a more thorough search would find more. I suggest that this article should either be deleted or at very least needs to be thoroughly rewritten to explain that a dwarf galaxy is simply one of several possible explanations for the overdensity.

See:

http://adsabs.harvard.edu/abs/2009AJ....137.4412M

http://adsabs.harvard.edu/abs/2008MNRAS.390L..54P

http://adsabs.harvard.edu/abs/2008ASPC..393..251L

http://arxiv.org/abs/0801.2084

http://adsabs.harvard.edu/abs/2007A%26A...472L..47L

http://adsabs.harvard.edu/abs/2006MNRAS.368L..77M

http://adsabs.harvard.edu/abs/2006A%26A...451..515M

http://adsabs.harvard.edu/abs/2008ApJ...672..930V

Kevin Jardine

Galaxy Map

http://galaxymap.org

86.93.21.227 (talk) 14:24, 23 February 2010 (UTC)

Not a galaxy
I think at this point there is enough volume of scientific studies questioning the galaxy status of Canis Major to at least warrant its own section. Maybe: Galaxy status or Galaxy vs overdensity debate or something along that line. Thoughts? Gaba p (talk) 22:46, 15 April 2012 (UTC)
 * If nobody opposes this, I'll add said section in a couple of days. Gaba p (talk) 13:04, 18 April 2012 (UTC)

Hypothetical?
The lead says that it is a hypothetical galaxy and yet it has also been discovered. Last I checked you can't be a theory and a fact at the same time. If the galaxy exists shouldn't "hypothetical" be removed? Or is it only a hypothetical dwarf galaxy, meaning it's status is unknown? If so would it not read better as "is a dense region of stars, potentially a dwarf galaxy..." or something like that? Coinmanj (talk) 04:49, 5 October 2012 (UTC)


 * I re-wrote the Discovery section a bit. Is it clearer now? Gaba p (talk) 10:46, 5 October 2012 (UTC)


 * Much, thanks. Coinmanj (talk) 22:38, 5 October 2012 (UTC)


 * You're welcome. Gaba p (talk) 00:14, 6 October 2012 (UTC)

Yes you can be a theory and a fact at the same time. Theory describes facts. It does not serve as a placeholder until fact is established. Unnilnonium (talk) 14:30, 7 February 2020 (UTC)

Requested move

 * The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section. 

The result of the move request was: moved. Although the category name was not directly included in this RM, I will change it also as bold editorial choice. If there is further disagreement over that choice, a new RM is welcome. Xoloz (talk) 17:26, 16 March 2014 (UTC)

Canis Major Dwarf Galaxy → Canis Major Overdensity – Whatever this is it is definitely an overdensity and this is the name it is discussed under in many sources. It is also called the Canis Major Dwarf Galaxy by those who contend it is a galaxy. I suggest it is safer to frame the article as about the overdensity and then discuss the arguments which support and oppose its status as a possible galaxy, as I think the name currently is misleading Cas Liber (talk · contribs) 21:11, 21 February 2014 (UTC)


 * this paper gives a good sumary of the investigations supporting or not supporting the nature of the galaxy. Also see this, though am not sure of the consensus. Anyway, I am not strongly in favour either way but thought the move probably a good thing. Cas Liber (talk · contribs) 21:16, 21 February 2014 (UTC)


 * Support GScholar yields 139 hits for "CANIS MAJOR dwarf galaxy" and 121 hits for "CANIS MAJOR overdensity"; neither seems dominant. A move to the more conservative overdensity seems reasonable, but a redirect from Canis Major dwarf galaxy seems warranted, too, as a plausible search term. --Mark viking (talk) 21:28, 21 February 2014 (UTC)
 * Agree absolutely with a redirect and meant to note that above. It is clearly popular and folks wish that it were proven (which it doesn't appear to be and may never be). Cas Liber (talk · contribs) 08:02, 22 February 2014 (UTC)


 * Comment a rename would not work with some of the sub articles, considering Monoceros Ring, etc that presume this is a galaxy. It'd have to be some sort of significant organization to create a stellar stream, such as a globular if it's not a galaxy... The categorization would be ponderous as well, as things not in the Overdensity would not be categorized under it, while things stripped from the Dwarf Galaxy can be categorized under it. If it isn't a Dwarf, then these things supposedly stripped from it cannot be categorized under Overdensity, as a globular wouldn't have had a globlular or open cluster stripped from it. Clearly if the article is renamed, the category cannot be renamed, the organization of the category, excepting the stellar stream, requires this thing to be a galaxy. -- 70.50.151.11 (talk) 09:18, 23 February 2014 (UTC)
 * To have to fiddle around and adjust a set of connected articles and categories is not uncommon in situations like these - not simple but not hugely onerous either. Cas Liber (talk · contribs) 18:27, 23 February 2014 (UTC)
 * Would we leave Category:Canis Major Dwarf Galaxy as the name of the category? I don't think it'd work as Category:Canis Major Overdensity -- 70.50.151.11 (talk) 04:25, 24 February 2014 (UTC)


 * Support. Although theorized to be dwarf galaxy, this is not certain yet, and we should remain conservative on the issue, to avoid misinforming readers. StringTheory11 (t • c) 18:16, 23 February 2014 (UTC)


 * Support. Agree that titles should be conservative, avoid possibly misleading readers.  --SmokeyJoe (talk) 23:23, 12 March 2014 (UTC)
 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

PGC 5065047
I can't find "PGC 5065047" listed in any astronomical catalogs, including PGC/LEDA. What is the citation for this PGC number? Nicole Sharp (talk) 06:06, 2 February 2024 (UTC)