GLASS-z12

{{Short description|Lyman-break galaxy that is one of the oldest galaxies known}}

{{Infobox galaxy

| name = GLASS-z12

| image = NASA-GLASS-z13-Closeup-JWST-20220722.jpg

| image_size = 250

| caption = Close-up view of GLASS-z12 from the James Webb Space Telescope

| constellation name = Sculptor

| epoch = J2000

| ra = {{RA|00|13|59.76}}

| dec = {{DEC|-30|19|29.1}}

| z = {{val|12.117|0.012}} (spectroscopic)
{{val|12.4|0.1|0.3}}
{{val|12.42|0.27|0.14}}
{{val|12.28|0.08|0.07}}

| h_radial_v =

| gal_v =

| dist_ly = {{plainlist|

• ≈{{convert|33.2|e9ly|e9pc|lk=on|abbr=unit}}
  {{in5|3}}(present proper distance)
• {{nowrap|≈{{convert|13.6|e9ly|e9pc|abbr=unit}}}}
  {{in5|3}}(light-travel distance)}}

| group_cluster =

| type =

| mass = ≈{{val|1.0|e=9}}

| mass_light_ratio =

| half_light_radius_pc = 500 pc

| size = ~3000 ly (1 kpc)

| stars =

| appmag_v = 27.0 AB (F200W)

| appmag_b =

| absmag_v =

| size_v =

| notes =

| names = GHZ2{{·}}GLASS-17487

| references =

}}

GLASS-z12 (formerly known as GLASS-z13) is a Lyman-break galaxy discovered by the Grism Lens-Amplified Survey from Space (GLASS) observing program using the James Webb Space Telescope's NIRCam in July 2022.{{cite news |last=O'Callaghan |first=Jonathan |title=JWST has found the oldest galaxy we have ever seen in the universe - Discoveries from the James Webb Space Telescope are pouring in, with an analysis of the latest data revealing a galaxy that dates back to just 300 million years after the big bang – the oldest we have ever seen |url=https://www.newscientist.com/article/2329601-jwst-has-found-the-oldest-galaxy-we-have-ever-seen-in-the-universe/ |date=20 July 2022 |work=New Scientist |accessdate=12 February 2023 }} Spectroscopic observations of GLASS-z12 by the Atacama Large Millimeter Array (ALMA) in August 2022 confirmed that the galaxy has a spectroscopic redshift of {{val|12.117|0.012}}, making it one of the earliest and most distant galaxies ever discovered, dating back to just 350 million years after the Big Bang, 13.6 billion years ago. ALMA observations detected an emission line associated with doubly ionized oxygen (O III) at 258.7 GHz with a significance of 5σ, suggesting that there is very low dust content in GLASS-z12, if not the early universe as well. Also based on oxygen-related measurements, the age of the galaxy is confirmed.{{cite news |author=Staff |title=Astronomers confirm age of most distant galaxy using oxygen|url=https://phys.org/news/2023-01-astronomers-age-distant-galaxy-oxygen.html |date=25 January 2023 |work=Phys.org |accessdate=26 January 2023 }}{{cite journal |author=Bakx, Tom J.L.C. |display-authors=et al. |title=Deep ALMA redshift search of a z ~ 12 GLASS-JWST galaxy candidate |url=https://academic.oup.com/mnras/article/519/4/5076/6958810?login=false |date=23 December 2022 |journal=Monthly Notices of the Royal Astronomical Society |volume=519 |issue=4 |pages=5076–5085 |doi=10.1093/mnras/stac3723 |accessdate=26 January 2023 |doi-access=free |arxiv=2208.13642 }}

GLASS-z12 derives its name from the GLASS survey that discovered it and its estimated photometric redshift of approximately z = {{val|12.4|+0.1|-0.3}}. GLASS-z12 was initially announced as GLASS-z13 because it was thought to have a higher redshift of z = 13.1. This redshift value was later revised down to z = 12.4 in October 2022, resulting in the renaming of this galaxy.

GLASS-z12 has a light-travel distance (lookback time) of 13.6 billion years. However, due to the expansion of the universe, its present proper distance is 33.2 billion light-years. It was discovered alongside another galaxy, GLASS-z10, comparable to GN-z11, also one of the oldest galaxies discovered.

File:NASA-GLASS-z13-Context-JWST-20220722.jpg images showing GLASS-z12 as a red dot among other galaxies]]

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