Talk:Galaxy

GLASS-z12 is now the oldest galaxy discovered

This newly discovered galaxy formed before EGS-zs8-1: GLASS-z12 Jcgam (talk) 19:53, 15 April 2024 (UTC)

It would be the earliest observed, not necessarily the oldest. 02:02, 16 April 2024 (UTC)

I've removed the previous entries for EGS-zs8-1. Frankly, I don't think this article should be the target of such statements; it's meant to cover galaxies in general terms, not specific record holders. Praemonitus (talk) 16:21, 16 April 2024 (UTC)

Thanks for the cleanup: that whole "early universe" section could use a lot of trimming. - Parejkoj (talk) 17:21, 16 April 2024 (UTC)

We've Just Seen The First Galaxies in The Universe Being Born

I reverted a change that included a link to a May 2024 newspaper article entitled "We've Just Seen The First Galaxies in The Universe Being Born". This content is summary of a news article about primary publication. It's not encyclopedic. The only information in the content is the date really. Johnjbarton (talk) 14:56, 28 May 2024 (UTC)

@Johnjbarton: (and others) - Thank You about your comments about my recent edit (and your related rv) about some recent publications - yes - *entirely* agree - no probem whatsoever - Thanks again for all - and - Stay Safe and Healthy !! - Drbogdan (talk) 16:09, 28 May 2024 (UTC)

After learning more I think there is an additional issue to keep in mind: I think the term "first galaxies" is not correct really, it's more like observations of the earliest phases of galaxy life. There are no "second, third, ... galaxies", only galaxies whose distance from us means we see them later in life. Johnjbarton (talk) 19:37, 13 June 2024 (UTC)

References

how can be galaxy is flat like a disc?

if galaxy is flat than how thick is it ? 204.174.232.2 (talk) 01:02, 5 June 2024 (UTC)

Please read the article. If you search for "thick", there it is. Johnjbarton (talk) 01:20, 5 June 2024 (UTC)

Early galaxy formation

@Sgubaldo In my opinion, the first two paragraphs of the section "Early galaxy formation" is news, not encyclopedia content. The section should summarize reliable reviews on "Early galaxy formation" not naturally unreliable news stories from last month. We just discussed this issue above in the topic "We've Just Seen the First Galaxies..." Johnjbarton (talk) 14:03, 5 June 2024 (UTC)

@User:Johnjbarton This is the state it was in when I first came across it, I just updated it. I'm happy for it to be changed to more of an overview of the top-down/bottom-up processes talked about in the last two paragraphs. Sgubaldo (talk) 14:10, 5 June 2024 (UTC)

Ok thanks. I started looking into the refs and mostly they are good. I'll resummarize them to focus on the science and challenges rather than dates. Johnjbarton (talk) 15:20, 5 June 2024 (UTC)

Actually the third paragraph is out of date as well. In the 20+ years since the 1999 reference the galaxy formation theory and observation has changed.

I now think that "Early galaxy formation" is over emphasized. The "Formation" section needs to be expanded. As far as I can tell on the theory side, "early galaxies" are special primarily because they are "early", not because their "formation" is unique. Johnjbarton (talk) 00:00, 7 June 2024 (UTC)

Ok I have completed my rewrite. I replaced the news content with summaries from two recent reviews. I tried to keep it shallow consistent with this being a summary of Galaxy formation and evolution (which also needs work to be sure). Please review. Johnjbarton (talk) 17:28, 12 June 2024 (UTC)

Thank you for the work, will have a closer look later today. Sgubaldo (talk) 17:35, 12 June 2024 (UTC)

Had a look; I'm happy with the changes. Thanks again. My only concern is whether we need the 'early galaxy formation' subtitle? We could probably just leave it all under 'formation' (or viceversa)? Also, courtesy ping to @Praemonitus and @Parejkoj who might want to take a look as well based on their discussion in April detailed above. Sgubaldo (talk) 00:05, 13 June 2024 (UTC)

"Early galaxy" formation is treated special, but as far as I can tell this means the same as "galaxy formation" except in the case of mergers. I removed the section heading as you suggested. Johnjbarton (talk) 19:36, 13 June 2024 (UTC)

Bananas

I just reverted an edit based on this New Scientist article:

• Banana-shaped galaxies are helping unpeel the mysteries of dark matter: Astronomers have been spotting strange banana-shaped galaxies and the evidence seems to indicate that filaments of dark matter make them take this shape By Alex Wilkins= 5 August 2024 https://www.newscientist.com/article/2442369-banana-shaped-galaxies-are-helping-unpeel-the-mysteries-of-dark-matter/

New Scientist is very uneven and often simply wrong, as in this case.

The primary references behind the New Scientist article are:

• Pozo, Alvaro, et al. "A smooth filament origin for prolate galaxies" going bananas" in deep JWST images." arXiv preprint arXiv:2407.16339 (2024).
• Pandya, Viraj, et al. "Galaxies going bananas: inferring the 3d geometry of high-redshift galaxies with JWST-CEERS." The Astrophysical Journal 963.1 (2024): 54.

The first is unpublished and the second one 11 citations. The 'bananas' bit comes from Pandya:

• "The prolate population traces out a "banana" in the projected $b/a{\text{--}}\log a$ diagram with an excess of low-b/a, large $\log a$- galaxies.

Thus there are no "banana-shaped galaxies" here to "unpeel".

In addition Pandya et al's analysis is simply too new for an encyclopedia. Once we see reviews that cite the work we can reference them and include the topic where appropriate. Johnjbarton (talk) 23:38, 11 August 2024 (UTC)