GHZ2

GHZ2, also named GLASS-z12 (formerly known as GLASS-z13) is a Lyman-break galaxy discovered by the Grism Lens-Amplified Survey from Space (GLASS) observing prog…

GHZ2
GHZ2
Close-up view of GLASS-z12 from the James Webb Space Telescope
Observation data (J2000 epoch)
ConstellationSculptor
Right ascension00h 13m 59.76s[1]
Declination−30° 19′ 29.1″[1]
Redshift12.117±0.012 (spectroscopic)[2]
12.4+0.1
−0.3[1]
12.42+0.27
−0.14[3]
12.28+0.08
−0.07[4]
Distance
Apparent magnitude (V)27.0 AB (F200W)[1]
Characteristics
Mass≈1.0×109 M☉
Size~3000 ly (1 kpc)
Half-light radius (physical)500 pc
Other designations
GHZ2[6][7] · GLASS-17487[3]
References: [1]

GHZ2, also named 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.[8][9]

It has a spectroscopic redshift of 12.34, making it one of the most distant galaxies and astronomical objects ever discovered. According to current theory, this redshift corresponds to a time about 13.44 billion years ago, approximately 355 million years after the Big Bang, or about 2.57% of its current age.[10]

Discovery

GLASS-z12/GHZ2, was initially discovered as a robust z ≈ 12.0–12.5 candidate by Castellano et al. and Naidu et al. in the GLASS-JWST Early Release Science NIRCam field. The two discovery papers appeared on arXiv the same day. Hence these two names for this galaxy of GLASS-z12 (Naidu et al. 2022) and GHZ2 (Castellano et al. 2022a).[11]

GLASS-z12 derives its name from the GLASS survey that discovered it and its estimated photometric redshift of approximately z = 12.4+0.1
−0.3.[1] GLASS-z12 was initially announced as GLASS-z13 because it was thought to have a higher redshift of z = 13.1.[7][2] This redshift value was later revised down to z = 12.4 in October 2022, resulting in the renaming of this galaxy.[1]

It was discovered alongside another galaxy, GLASS-z10, comparable to GN-z11, also one of the oldest galaxies discovered.[12]

Color composite of JWST-NIRCam images showing GLASS-z12 as a red dot among other galaxies

Spectroscopy by the Atacama Large Millimeter Array

Spectroscopic observations of GLASS-z12 by the Atacama Large Millimeter Array (ALMA) in August 2022 confirmed that the galaxy has a spectroscopic redshift of 12.117±0.012, making it one of the earliest and most distant galaxies ever discovered, dating back to 360 million years after the Big Bang, 13.44 billion years ago.[12][5] 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.[2] Also based on oxygen-related measurements, the age of the galaxy is confirmed.[13][14]

GLASS-z12 has a light-travel distance (lookback time) of 13.4 billion years.[5] However, due to the expansion of the universe, its present proper distance is 32.718 billion light-years.[5]

Spectroscopy by the James Webb Space Telescope

This galaxy was observed again in October 2023 by the James Webb Space Telescope with the NIRSpec and MIRI spectrographs, making it the most distant redshift galaxy of z = 12.34 with full spectroscopic coverage from ultraviolet (UV) to optical.[11][15]

According to current ΛCDM parameters (H0 = 67.4, Ωm = 0.315, ΩΛ = 0.685), this redshift of 12.34 corresponds to a light-travel distance (lookback time) of 13.44 billion years. However, due to the expansion of the universe, its comoving distance is 32.837 Gly.[16]

See also

References

  1. ^ a b c d e f g Naidu, Rohan P.; et al. (November 2022). "Two Remarkably Luminous Galaxy Candidates at z ≈ 10 − 12 Revealed by JWST". The Astrophysical Journal Letters. 940 (1): 11. arXiv:2207.09434. Bibcode:2022ApJ...940L..14N. doi:10.3847/2041-8213/ac9b22. S2CID 250644267. L14.
  2. ^ a b c Bakx, Tom J. L. C.; et al. (2023). "Deep ALMA redshift search of a z ~ 12 GLASS-JWST galaxy candidate". Monthly Notices of the Royal Astronomical Society. 519 (4): 5076–5085. arXiv:2208.13642. doi:10.1093/mnras/stac3723.
  3. ^ a b Donnan, C. T.; et al. (November 2022). "The evolution of the galaxy UV luminosity function at redshifts z ≃ 8 - 15 from deep JWST and ground-based near-infrared imaging". Monthly Notices of the Royal Astronomical Society. 518 (4): 6011–6040. arXiv:2207.12356. Bibcode:2023MNRAS.518.6011D. doi:10.1093/mnras/stac3472.
  4. ^ Harikane, Yuichi; et al. (2023). "A Comprehensive Study of Galaxies at z ~ 9–16 Found in the Early JWST Data: Ultraviolet Luminosity Functions and Cosmic Star Formation History at the Pre-reionization Epoch". The Astrophysical Journal Supplement Series. 265 (1): 5. arXiv:2208.01612. Bibcode:2023ApJS..265....5H. doi:10.3847/1538-4365/acaaa9. S2CID 251253150.
  5. ^ a b c d Wright, Edward L. (2022). "Ned Wright's Javascript Cosmology Calculator". University of California, Los Angeles. Retrieved 24 November 2022. (H0=67.4 and OmegaM=0.315 (see Table/Planck2018 at "Lambda-CDM model#Parameters" )
  6. ^ Castellano, Marco; et al. (July 2022). "Early Results from GLASS-JWST. III. Galaxy Candidates at z ~9–15". The Astrophysical Journal Letters. 938 (2): L15. arXiv:2207.09436. Bibcode:2022ApJ...938L..15C. doi:10.3847/2041-8213/ac94d0. S2CID 250644263.
  7. ^ a b Koren, Marina (22 July 2022). "The Webb Space Telescope Is a Time Machine Observed". The Atlantic. Retrieved 22 July 2022.
  8. ^ O'Callaghan, Jonathan (20 July 2022). "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". New Scientist. Retrieved 12 February 2023.
  9. ^ O'Callaghan, Jonathan (14 September 2022). "JWST's First Glimpses of Early Galaxies Could Break Cosmology - The James Webb Space Telescope's first images of the distant universe shocked astronomers. Is the discovery of unimaginably distant galaxies a mirage, or a revolution?". Scientific American. Retrieved 16 September 2022.
  10. ^ Kempner, Joshua (2022). "Cosmology Calculator". Retrieved 14 July 2024.
  11. ^ a b Castellano, Marco; et al. (10 September 2024). "JWST NIRSpec Spectroscopy of the Remarkable Bright Galaxy GHZ2/GLASS-z12 at Redshift 12.34". The Astrophysical Journal. 972 (2): 143. doi:10.3847/1538-4357/ad5f88. hdl:11573/1724461.
  12. ^ a b Adkins, Jamie (17 November 2022). "NASA's Webb Draws Back Curtain on Universe's Early Galaxies". NASA. Retrieved 23 November 2022.
  13. ^ Staff (25 January 2023). "Astronomers confirm age of most distant galaxy using oxygen". Phys.org. Retrieved 26 January 2023.
  14. ^ Bakx, Tom J.L.C.; et al. (23 December 2022). "Deep ALMA redshift search of a z ~ 12 GLASS-JWST galaxy candidate". Monthly Notices of the Royal Astronomical Society. 519 (4): 5076–5085. arXiv:2208.13642. doi:10.1093/mnras/stac3723. Retrieved 26 January 2023.
  15. ^ Zavala, Jorge A. (30 October 2024). "A luminous and young galaxy at z = 12.33 revealed by a JWST/MIRI detection of Hα and [O III]". Nature Astronomy. 9: 155–164. doi:10.1038/s41550-024-02397-3. PMC 11757150.
  16. ^ Wright, Edward L. (23 July 2018). "Ned Wright's Javascript Cosmology Calculator". Retrieved 14 July 2025.

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