Talk:HD1

Created talk-page

Created the talk-page for the "HD1" article - Stay Safe and Healthy !! Drbogdan (talk) 19:19, 7 April 2022 (UTC)

ITN discussion - New Link (4/16/2022)

If interested - a discussion is considering presenting "HD1 (galaxy)" as an "ITN news note" at => "Wikipedia:In the news/Candidates/April 2022#HD1 (galaxy)" - editors are more than welcome to present their views and comments of course - iac - Stay Safe and Healthy !! - Drbogdan (talk) 23:00, 8 April 2022 (UTC)

"Oldest" galaxy

Just want to raise a clarification, since this is widely reported by the media. Because this galaxy is right at the end of the reionization era end of the Dark Ages, the era where the first stars are still forming, isn't it more correct to say that this is the youngest galaxy we have observed, rather than "oldest"? We are looking at a galaxy that is 70 million years old, at least its observed light. And it would be incorrect to assume that this galaxy still exists as of the present day. We don't look at a childhood photo of the oldest human and describe that this is the oldest human we have ever recorded. SkyFlubbler (talk) 02:27, 9 April 2022 (UTC)

 Done - I agree. I have changed it to "most ancient". Alexcalamaro (talk) 08:06, 9 April 2022 (UTC)

Wait wat... isnt that the same as oldest? · · · Omnissiahs hierophant (talk) 08:28, 9 April 2022 (UTC)

 Done - seems the word "earliest" may be better - text now adjusted in the main HD1 article - also, for support of the word adj, see my related => "Template:Nature timeline" (see copy on the right) - iac - Stay Safe and Healthy !! - Drbogdan (talk) 12:26, 9 April 2022 (UTC)

Right ascension and Declination of HD1 and HD2

In this article there are descriptions HD1 (10:01:51.31 +02:32:50.0) and HD2 (02:18:52.44 -05:08:36.1). Are these expressions common in the astronomical community? If not, is it possible to add RA and DEC to them with links to Right ascension and Declination like HD1 (RA:10:01:51.31 DEC:+02:32:50.0)?―― Phoenix7777 (talk) 09:53, 9 April 2022 (UTC)

 Done - @Phoenix7777 and SkyFlubbler: (and others) - Thanks for the suggestion - yes - *entirely* agree - added suggested edit to the "HD1 (galaxy)#Discovery" section - adding to the infobox may be ok for HD1, but not as well for HD2 I would think, since the article features HD1 (and only secondarily HD2) - however - flexible with this of course - iac - Stay Safe and Healthy !! - Drbogdan (talk) 12:16, 9 April 2022 (UTC)

It would be better off to just remove them and leave it as a data in the infoboxes (as for all hard numerical data). We should just, however, describe what constellation are they located to simplify stuff. SkyFlubbler (talk) 10:08, 9 April 2022 (UTC)

Attention from expert

Considering the vital importance of these old galaxies at determining how the early universe formed, which is exciting in itself, this galaxy may shed light on earlier star formation as well. I am surprised at the lack of attention this article is getting, although it is being edited and viewed by a few I would have expected far more attention. Considering its importance I think it should be looked at by someone with more qualifications than I do. Space pierogi (talk) 16:01, 11 April 2022 (UTC)

Photometric, not Spectroscopic

The article incorrectly lists HD1's spectroscopic redshift as 13.27 - this the estimated photometric redshift, not the fsr more accurate spectroscopic redshift. As far as I'm aware HD1 is still awaiting spectroscopic confirmation by the JWST, as noted in the article further on. 2A02:C7D:A901:CC00:ED61:EBE7:F976:E36F (talk) 01:13, 18 August 2022 (UTC)

New spectroscopic redshift z = 4.0

This page must be updated according to https://arxiv.org/abs/2406.18352 that gives a Zspec = 4.0 to HD1.

NB. The photometric redshifts come from our best efforts to fit a "typical galaxy" to a broadband data set. Sometimes there is a degeneracy between high-redshift and low-redshift solutions. In this case we look for a "Lyman break", where each photon can excite hydrogen, which is consistent with a high-redshift solution. Balmer breakage (n = 1 at infinity, instead of n = 0 at infinity) can also be an option, as for HD1. This means that we observe a different transition than we expected. The spectroscopic features do not show (many) such degeneracies, and we see much sharper features. This decreases the uncertainty (typically Δzspec of 0.001 instead of Δzphot = 1 to 0.1), although degeneracies still exist. --luxorion — Preceding unsigned comment added by 2001:7E8:C626:A701:DBA:11B0:9852:9AB4 (talk) 10:29, 18 January 2025 (UTC)

I have updated the intro to reflect the new reality. The spectroscopic redshift is pretty solid, there is an emission line. These objects were always contraverial, and it's not surprising. Now that we know it is not a super high redshift galaxy, all the discussion of those properties and implications based on the earlier estimate are wrong. I am going to delete the two sections which are now irreverent, because they would have to be completely rewritten. The reality is now that this isn't such an interesting galaxy, and it doesn't really need a wiki page, certainly not a long one. LazyAstronomer (talk) 22:03, 6 July 2026 (UTC)

Requested move 20 November 2023

The following is a closed 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 after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: moved. (closed by non-admin page mover) Bensci54 (talk) 17:54, 27 November 2023 (UTC)

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HD1 (galaxy) → HD1 – There is no need for a disambiguator, since HD1 already redirects here. 117daveawesome (talk) 07:46, 20 November 2023 (UTC)

• Support or possibly disambiguate with Euro1080 which was formerly the target of the rediret though the galaxy appears primary based on Google. Crouch, Swale (talk) 17:46, 20 November 2023 (UTC)

  Or just move to HD1 (disambiguation) 117daveawesome (talk) 11:23, 27 November 2023 (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.