Talk:IC 1101

message: It might be nice to get a picture of it on here, there are plenty floating around...
124.171.148.18 (talk) 08:49, 14 August 2010 (UTC)
thread_title: Comments

message: "IC 1101 owes its size to many collisions of much smaller galaxies about the size of the Milky Way and Andromeda galaxies."
I thought that merging galaxies resulted in a smaller-sized galaxy.  Am I wrong? -Theanphibian (talk • contribs) 02:35, 14 January 2011 (UTC)
replies: text: I was thinking a bit differently.  I was thinking about comparing the size of a galaxy to the size of its parent galaxies before they merged.  I had thought that a galaxy merger (creation of a new galaxy) results in the new galaxy being smaller in diameter than the parents (if the parents are of similar size).  I now realize that someone may also think "size" refers to the mass, in which case the new galaxy is almost exactly the mass of the parent galaxies summed together.  Saying that IC 1101 was created by smaller parent galaxies may be trivial correct in the sense that size refers to mass.  It may also be larger in the sense of volume or diameter, but I could not say. -Theanphibian (talk • contribs) 19:03, 21 February 2011 (UTC)
thread_title:  Cause of size 

message: I rather thought ~ 1 billion light years... --Gereon K. (talk) 09:18, 12 April 2012 (UTC)
thread_title:  113.2 billion light years away? 

message: NGC 6251 in Ursa Minor is 3 Mpc (9 million light-years across), much larger than IC 1101. I've changed it. ==Johndric Valdez (talk) 05:46, 18 December 2013 (UTC)
replies: text: I don't know where you got that size for NGC 6251 from, but it's quite incorrect. I've blanked the size section of NGC 6251: see my comment on your talk page for more. - Parejkoj (talk) 04:53, 13 February 2014 (UTC)
thread_title: Largest galaxy ever?

message: I think we have a good example of Citogenesis here: per the literature (Uson, Bough & Kuhn 1991), the diffuse light radius of IC 1101 is somewhere around 500kpc (~300" measured radius, 320Mpc modern distance), which is maybe ~1.5 Mly if we're feeling generous. But there are hundreds (thousands?) of articles across the web quoting the 6 million light year figure. Could some other wikipedia sleuth figure out where this number originally came from?
We should correct this article, and the dozen or so other wiki pages that reference and quote the erroneous number. Not much we can do about the rest of the web, though... - Parejkoj (talk) 04:53, 13 February 2014 (UTC)
replies: text: I've not looked into the sources in detail, but NED gives the major diameter as 1.2 arcmin, citing a paper from 1991 so way before Citogenesis is a concern. At a Hubble flow distance of 320 Mpc, that corresponds to about 110 kpc. Of course it's a matter of semantics to define a line between the edge of a galaxy and the intracluster light, but that does seem way out. Maybe someone confused the visible galaxy with the cluster x-ray emission? Modest Genius talk 17:56, 13 February 2014 (UTC)

text: Moderately recent paper stating 600kpc:
http://iopscience.iop.org/0004-637X/616/1/178
Lithopsian (talk) 22:26, 13 February 2014 (UTC)
replies: text: Which cites that claim to  which claims to measure a de Vaucouleurs profile to about 200 arcsec radius, which they equate to d=475 h-1 kpc. That does work out as about 600kpc, but even the authors only claim this as 'possibly' the largest galaxy then known. Still, that's an original and reliable source at least! Modest Genius talk 00:48, 14 February 2014 (UTC)

text: After some searching, I think I can summarize the situation as something like this: In 1990, Uson, Bough, and Kuhn published a short article in Science (), the abstract of which says, "... the faint halo of this giant can be traced out to a distance of more than 1 megaparsec", which works out to a diameter of ~ 6 Mly. This was picked up by the media; e.g., the 1990 NY Times article in the External Links section, which report the size as "six million light years". The more detailed follow-up paper by the same authors in 1991 (Uson, Bough & Kuhn 1991) seems to walk the claim back a little. They give 260 arcsec as the *minor-axis* limit; since they say the galaxy has an axis ratio of 2, that means a semi-major axis of 520 arcsec. The "d=475 h-1 kpc" claim in the abstract of that paper [actually 425 h-1 kpc] is for the *mean* radius: (a b)1/2, which would be ~ 370 arcsec. So, depending on whether you want to use the mean radius or the semi-major axis, you get radial sizes of ~ 530 or 740 kpc, and diameters of 3.5 or 4.8 Mly. Peter Erwin (talk) 10:23, 12 December 2014 (UTC)
thread_title:  Citogenesis example here? 

message: @ Huntster.  
Please explain this earlier reversion of this edit of mine.
"…approximately 320 Megaparsecs,  from Earth." 
to 
"...approximately   from Earth. " 
The standard unit of measure for galaxy distances in Megaparsecs, not Gigalightyears. I.e. Andromeda Galaxy (in kpc, as it is less than 1.0 Mpc.), Centaurus A: "Distance estimates to NGC 5128 established since the 1980s typically range between 3–5 Mpc." , etc.
Also the given NED reference  in the table "Quantities Derived by Redshift for IC 1101", express the 'Hubble Flow Distance and Distance Modulus' as 320±22.4 Mpc., verifying this is the case. There is no evidence of gigalightyear used here at all, and even if it was, it not a recognised galaxy scale. (many sources) Hence 320 Mpc in the first instance is perfectly correct. 
As said in Galaxy page Introduction; "The observable universe contains hundreds of billions (more than 1011) of galaxies. Most are 1,000 to 100,000 parsecs in diameter and usually separated by distances on the order of millions of parsecs (or megaparsecs)." confirms this.
Another, "A distance of one million parsecs is commonly denoted by the megaparsec (Mpc). Astronomers typically express the distances between neighbouring galaxies and galaxy clusters in megaparsecs." 
Yes there are many galaxy pages that say things in terms of light-years and their units, but the 'standard' is Mpc for galaxies.
I would remind you if you make such edit changes, you should say what was changed. It helps track edits properly.
Look forward to your response in me not reverting this.
As to the rest of the edit, I completely agree with the changes you made.
(If I seem terse, it is because I dealing with too many would-be edit warriors, today. Sorry.)
Cheers.
Arianewiki1 (talk) 11:00, 21 January 2015 (UTC)
replies: text: Yes, be calm, it was just an error on my part. I've fixed it. Sorry for the delay, I never received the ping from this. — Huntster (t @ c) 07:36, 24 January 2015 (UTC)
replies: text:  Actually, I have zero problem about this, and I thank you for the reedit. Don't understand the non-ping, but sometimes this happens (probably somehow an error of mine.) Either way, the figures give the correct distance, so changing them is not desperate. After sometime to think about this, I have likely been too aggressive here and on some of my earlier comments. I'll try to improve towards the edits from now on. Thanks. :) Arianewiki1 (talk) 11:37, 25 January 2015 (UTC)
thread_title:  Concerning edit : Changed distance from megaparsecs Why? 

message: Hi Ashill
Could you please explain where you got the value "200,000 ± 40,000 (half-light radius)" from the reference. 
for the figures now quoted in the article. What units are they?
I've never seen this parameter associated with galaxies anywhere.
I can't see these figures taken in the article, where they calculated, as the sizes are in kpc.?
(I looked through the article twice. i don't see it )
There is new comments here by Primefac and me. at; 
:From the cited source, with calculations converting size in arcmin to ly in the comment. The units (ly) are in the table header (a silly place, in my opinion, but that's how it's defined in the galaxy infobox). Which parameter have you never seen? —Alex (ASHill | talk | contribs) 03:24, 22 January 2015 (UTC)
replies: text: (The number is exactly the one in the comment you just pointed to; that's the reference I used.) —Alex (ASHill | talk | contribs) 03:28, 22 January 2015 (UTC)
replies: text: I've added another bit to the text, citing Uson et al (1991) (as suggested above) and quoting them as saying IC 1101 is "possibly one of the largest and most luminous galaxies in the universe." (That's one of the last sentences of the peer-reviewed Astrophysical Journal follow-up paper, ie not the original Science paper or the popular media reporting on it.) —Alex (ASHill | talk | contribs) 04:00, 22 January 2015 (UTC)
thread_title:  Reference Quoted Figures 

message: I found this recent data on the net from the SDSS7 survey on ViZier, that could be useful.
"Parameters of spiral galaxies from SDSS7", by Hall, et al. (2012). This release gives the i-band parameters (Table 1), which is readily found in ViZieR. (). 
This quotes in the table, masses, velocities and radii. (You might have to add the object IC 1101 in the first field.)
Oddly, this is in with a bunch of spirals, which I don't understand.
I's add it but someone might revert it. ;) Arianewiki1 (talk) 04:55, 26 January 2015 (UTC)
thread_title:  Possible New Data to Drop 

message: A recent edit copied character-for-character the list from list of largest known galaxies. I see no reason why that list needs to be duplicated here, so I've removed it (now twice). I'll also incorporate a link to the list into the text. (There are also issues with the list pertaining to the different and subjective definitions of "size" of a galaxy, but that's a topic in relation to this list that belongs at Talk:List of largest known galaxies.) —Alex (ASHill | talk | contribs) 14:37, 4 March 2015 (UTC)
replies: text: Agreed, there's no reason for such (bulky) duplication of effort when a link to that article will suffice. — Huntster (t @ c) 16:26, 4 March 2015 (UTC)
thread_title:  List of largest galaxies 

message: I agree that it is best to avoid use of scientific notation in prose.  The problem arises from the use of the Convert template with non-existent units involving the kilolight, megalight and gigalight.  There is no such thing as a kilolight and therefore also no kilolight-year.  A possible compromise is a light-kiloyear but I prefer to avoid the issue and write out as thousands of light-years. Dondervogel 2 (talk) 19:18, 12 April 2015 (UTC)
replies: text: I think that scientific notation is preferable to making up units like the kly or Gly (even though I have seen at least one textbook that uses those units); "thousand lightyears" or "billion lightyears" is also OK. But really, the standard units kpc, Mpc, and Gpc are just fine for distances that large; it's not like readers are likely to have a clear conception of what one million lightyears means anyway. However, "lightyear" or "light-year" is the unit, so if we were to attach an SI prefix to it, it would be kilolightyear or kilolight-year. —Alex (Ashill | talk | contribs) 14:03, 13 April 2015 (UTC)
replies: text:  The issue affects many other articles, so is worth thinking through carefully.  The problem is caused IMHO by the Convert template which encourages proliferation on Wikipedia of the units kly, Mly and Gly beyond all proportion of their adoption outside WP.  At the moment this article has parsecs leading (with appropriate SI prefix kpc, Mpc or Gpc) with the number of thousands, millions or billions of light-years in brackets.  I think this works well. Dondervogel 2 (talk) 14:20, 13 April 2015 (UTC)
replies: text: I agree on all counts. —Alex (Ashill | talk | contribs) 14:23, 13 April 2015 (UTC)
replies: text:  Great.  I left a note at WP:Astronomy to see what others think. Dondervogel 2 (talk) 14:26, 13 April 2015 (UTC)

text: "Kilolight-year" = "kilo(light-year)", not "(kilolight-year)", and is 1000 light-years (and you know it). There is no actual problem with it, and anyone familiar SI prefixes and the abbreviation for the light-year, will understand things like "Mly". Whether it should be used depends on the context, IMO. I'd say that if spelling it out makes it tedious to read (for example because many values are mentioned), then don't spell it out. As for ly vs. pc, it is best to present both. If I read something in only parsecs, I always ask myself how many light-years that is, so that I can compare it to sizes I know, such as the diameter of the Milky Way and the distance to Andromeda. --JorisvS (talk) 15:11, 13 April 2015 (UTC)
replies: text:  Sure I understood what was intended - otherwise I would not have been able to fix it.  The issue is whether Wikipedia should be in the business of inventing or promoting neologisms when there's a perfectly good alternative.  Dondervogel 2 (talk) 16:23, 13 April 2015 (UTC)
replies: text: What's the perfectly good alternative? And how is using SI prefixes and normal abbreviations a neologism? --JorisvS (talk) 17:26, 13 April 2015 (UTC)
replies: text:  The perfectly good alternative is "30 thousand light years" instead of "30 kly".  The neologism is that kly is hardly ever used outside WP (in contrast with kpc which is common).  For example this search for kPc, Mpc, Gpc and parsec yields more than 300 scientific publications, increasing to more than 50,000 hits for this search for kPc, Mpc.  By comparison, it's hard to find any hits at all from similar searches for kly, Mly, Gly and light-year.  Try it, and you'll see what I mean.   Dondervogel 2 (talk) 18:47, 13 April 2015 (UTC)
replies: text: That's not quite a fair comparison; the academic literature (which you're searching) doesn't use light years much at all either. (Though ly is very difficult to search for, since it appears all the time.) The relevant comparison is really to popular science books, perhaps intro-level astronomy textbooks, and the like that aren't terrified of numbers (like news reports generally are) but are intended for a general audience (unlike scholarly articles), since that's more representative of the target audience (I think) of Wikipedia's astronomy articles. But I agree that kly, etc are very uncommon; I know of only one source that uses them (Zeilik's Astronomy: The Evolving Universe general-audience textbook). Even that textbook includes "light year", "parsec", "kiloparsec", and "megaparsec" but not "kilolightyear" or "megalightyear" in its glossary. And the same author uses pc, kpc, Mpc, etc exclusively in his textbook intended for astronomy majors. But getting into comparing to sources on what is fundamentally a style choice is not a rabbit hole I'm eager to open based on recent experience, to say the least. —Alex (Ashill | talk | contribs) 19:20, 13 April 2015 (UTC)

text: I don't oppose, in general, writing "30 thousand light years". I do think that we should switch to abbreviations when it otherwise becomes very tedious reading because there are too many "thousand light years"s or the like in there (I know, it's subjective, but as a rule of thumb), when used alongside (other) abbreviated units, and in infoboxes and the like. And when abbreviations are used I think it is a service to our readers to include the value in light-years alongside its parsec value. --JorisvS (talk) 08:29, 14 April 2015 (UTC)

text: Funny that.  My recollection of that discussion was that it was mainly about whether to use ly or l.y., but you're quite right - the heading was clearly about use of SI prefixes.  They are very rare, never needed, and therefore should not be used.  As you can see the problem has not gone away, and the present discussion arose because an edit of mine replacing 'kly' with 'e3ly' was reverted in order to avoid scientific notation in prose.  I understand that point, which is why I am seeking a solution to the endemic problems caused by Convert. Dondervogel 2 (talk) 17:53, 15 April 2015 (UTC)
thread_title:  Scientific notation and the kilolight 

message: Isn't IC 1101 over 4,000,000 ly in radius? Here it says 218,000 ly. Please clarify this.
Thanks!
PNSMurthy  (talk) 02:42, 23 July 2020 (UTC)
replies: text: See the discussion above: there's a lot of incorrect secondary sources, and we want to state consistent definitions for "size" across wikipedia. - Parejkoj (talk) 16:01, 23 July 2020 (UTC)
replies: text: Very well Parekjkoj. I understand there are some things that are hard to identify as reliable. Size is one of them, and many people exaggerate size for reasons I don't quite know. I may as well cite a youtube video saying the largest known galaxy is 'GBYSDZGyuadtquadytyiu' I guess. I think, that, if IC 1101's size is so shady, we should temporarily remove it until the size is confrimed?PNSMurthy  (talk) 02:32, 28 July 2020 (UTC)
replies: text: We include what we can that reliable sources tell us. What is in the article is the most recent scientific data; if we remove it waiting for "more accurate" data to come out, we could be waiting many years. Astronomy is always going to involve the slow improvement of knowledge, so it tends to be ever changing. — Huntster (t @ c) 11:01, 28 July 2020 (UTC)
replies: text: Very well. I understand the largest galaxies are not exactly the most popular subject for astronomers. We should leave the most accurate size on the sheet. By the way, is the effective radius strictly for the inner galaxy, or the inner galaxy and halo? Uson et all gives 4,000,000 lightyears.PNSMurthy  (talk) 02:37, 29 July 2020 (UTC)
replies: text: The inner galaxy. The halo, by its nature, is very difficult to pin down its extent. That's part of the problem...the original multi-million ly radius included the halo, but since halos aren't typically included in measurements for other galaxies, does it make sense to use it here? Because it is so distant and the halo so bright, it was hard to tell where the galaxy proper ended, and the halo began. — Huntster (t @ c) 05:07, 29 July 2020 (UTC)
replies: text: Thank you for clarifying:)PNSMurthy  (talk) 05:35, 29 July 2020 (UTC)
thread_title:  Size 

message: Why was the section 'Discovery' removed on 9 December 2020 with the comment it is superfluous?  IMO this is relevant information - I have therefore undone this edit.
2A02:C7D:8916:3F00:404B:DAFE:3792:BC24
Blammy1 (talk) 14:08, 10 December 2020 (UTC)
replies: text: The only relevant part and well-cited of that paragraph is the discovery date by Herschel. Discussion of its inclusion in the New_General_Catalogue#Index_Catalogue doesn't add anything; of course it's in the IC catalog, that's in the name! The universeguide.com cite does not provide links to where it got the various data from and has a bunch of nonsense (e.g. "Naked Eye Visibe: Requires 8m Telescope" is totally wrong given that Herschel was able to see it, and it quotes the incorrect 1.9 Mly radius). Rooting around there briefly, I'd say that page is definitely not a reliable source for anything astronomical. The subsequent two sentences add nothing beyond recapitulating the results of the Great Debate, which had nothing to do with this object in particular, and the added arxiv citation has nothing to do with this point. I've removed the paragraph again. If there are reliable sources that do say something about its history, please include them. - Parejkoj (talk) 17:52, 11 December 2020 (UTC)
thread_title:  Removal of 'Discovery' section 

message: The current lead image is b/w, thus can not properly illustrate:
Like most large galaxies, IC 1101 is populated by a number of metal-rich stars, some of which are seven billion years older than the Sun, making it appear golden yellow in color.
Candidates are listed on the right. 51Oq (talk) 06:41, 9 February 2021 (UTC)
thread_title:  Replace b/w lead image with color image 

message: I check pages listed in :Category:Pages with incorrect ref formatting to try to fix reference errors. One of the things I do is look for content for orphaned references in wikilinked articles. I have found content for some of :IC 1101's orphans, the problem is that I found more than one version. I can't determine which (if any) is correct for this article, so I am asking for a sentient editor to look it over and copy the correct ref content into this article.
Reference named "NED":
From NGC 4365: 
From Arp 271: 
From NGC 4777: 
From NGC 4343: 
From NGC 4701: 
From NGC 5806: 
From NGC 4780: 
From NGC 4380: 
From Abell 1835: 
From SDSS J1229+1122: 
From Abell 2147: 
From NGC 4918: 
From NGC 4746: 
From Abell 1689: 
From NGC 4643: 
From NGC 4845: 
From NGC 5619: 
From NGC 5030: 
From NGC 4866: 
From NGC 5575: 
From Abell 2029: 
From NGC 5384: 
I apologize if any of the above are effectively identical; I am just a simple computer program, so I can't determine whether minor differences are significant or not. AnomieBOT⚡ 22:20, 5 July 2022 (UTC)
thread_title:  Orphaned references in [[:IC 1101]] 

message: As we know, IC 1101's gigantic halo is commonly (incorrectly) quoted as the galaxy's size, thus making it widely known to the media and public. While the size of the halo is quoted to be 2 million light-years (600 kpc), citing Uson et al (1991)’s paper regarding the diffuse light within Abell 2029, I feel like Juan Uson’s other paper on Abell 2029 regarding IC 1101 is the actual source on the galaxy’s massive halo size. This is because I don’t see a diameter of the halo quoted in the other paper which has a “verification needed” sign near it on the page. Unfortunately, the paper is locked up, which means that I was unable to retrieve details from the paper, except for a mention of IC 1101’s halo being able to be traced out to 1 mega parsecs away from the galaxy’s center. This is interesting, so I am requesting somebody who has access to the paper to take a screenshot of the paper’s details so that we can add it to the article.
:Note: you can't just use physical sizes in an article from the 90s, you have to start with angular sizes and appropriately scale them to the distance given the redshift, because the cosmological parameters used in those papers are incorrect. - Parejkoj (talk) 22:45, 8 January 2023 (UTC)
replies: text: Thanks. Just curious, why are they incorrect?--The Space Enthusiast (talk) 03:16, 9 January 2023 (UTC)
replies: text: Because the cosmology used in those papers was before the discovery of dark energy, so the redshift-distance relation they use is wrong, and thus the angular diameter to physical size conversion is wrong. This is related to the original problem with this article (just using the physical size, without correcting for a more modern cosmology). - Parejkoj (talk) 17:03, 9 January 2023 (UTC)
replies: text: Thanks. I think that there needs to be more research on galaxy sizes. The Space Enthusiast (talk) 17:35, 9 January 2023 (UTC)
thread_title: Halo size?

message: I just have an inner gut feeling that we should not trust the values of this paper, which gave a ~2.8 million light year diameter for IC 1101. For one it gives either very small or very large values, which makes most galaxies cited in the paper as dwarf galaxies, while others giants, despite some being prominent clusters.
The effective radius might be an intracluster light radius. As an example Abell 2589 was listed at 725.91 kpc despite the cluster having no BCG whatsoever. I believe they measured NGC 7647 which is just in the vicinity, which is actually a foreground unrelated galaxy. On the second table Abell 3562, whose central galaxy is ESO 444-72, was listed at a ridiculous ~1160 kpc, which is just nuts (the galaxy is 196 kpc diameter at NED). SkyFlubbler (talk) 02:57, 2 April 2023 (UTC)
replies: text: Thanks. Dullo 2017 mentioned it. I might remove it now. The Space Enthusiast (talk) 04:30, 2 April 2023 (UTC)
thread_title:  Regarding Donzelli et al. (2011) 

message: Hello. I am the editor who has recently expanded the article. Almost 2 weeks ago, User:Parejkoj suggested that my edits made this article too long, and thus I deleted my previous revisions of the article. I have slowly begun to re-add them however, and the page has become bloated again. I am not intentionally inflating the article, it's just that IC 1101 is a well-studied galaxy and I thought that the various studies on this galaxy need to have attention. I also expanded this galaxy's page so that its identity could be split away from the "largest galaxy".--The Space Enthusiast (talk) 19:53, 1 May 2023 (UTC)
replies: text: It looks okay to me...idk tho User:Hamterous1 (discuss anything!🐹✈️) 11:49, 11 April 2024 (UTC)

text: I don't see it as inflated at all. It would be one thing if the article was spammy, but it discusses the scientific attributes and observation history. — Huntster (t @ c) 19:33, 20 April 2024 (UTC)
replies: text: Me too User:Hamterous1 (discuss anything!🐹✈️) 21:28, 20 April 2024 (UTC)
thread_title: Possibly too long