GLASS-z12, also named GHZ2 (formerly known as GLASS-z13) is a

Lyman-break galaxy Lyman-break galaxies are star-forming galaxies at high redshift that are selected using the differing appearance of the galaxy in several imaging filters due to the position of the Lyman limit. The technique has primarily been used to select g ...

discovered by the Grism Lens-Amplified Survey from Space (GLASS) observing program using the

James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, Lis ...

NIRCam NIRCam (Near-InfraRed Camera) is an instrument aboard the James Webb Space Telescope. It has two major tasks, as an imager from 0.6 to 5 micrometre, μm wavelength, and as a wavefront sensor to keep the 18-section mirrors functioning as one ...

in July 2022. It has a

spectroscopic redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

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 The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models based on the Big Bang concept explain a broad range of phenomena, including th ...

, or about 2,57% of its current age.

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 arXiv (pronounced as "archive"—the X represents the Chi (letter), Greek letter chi ⟨χ⟩) is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not Scholarly pee ...

the same day. Hence these two names for this galaxy of GLASS-z12 (Naidu et al. 2022) and GHZ2 (Castellano et al. 2022a). GLASS-z12 derives its name from the GLASS survey that discovered it and its estimated

photometric redshift A photometric redshift is an estimate for the recession velocity of an astronomical object such as a galaxy or quasar, made without measuring its spectrum. The technique uses photometry (that is, the brightness of the object viewed through various ...

of approximately z = . 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. It was discovered alongside another galaxy, GLASS-z10, comparable to

GN-z11 GN-z11 is a high-redshift galaxy found in the constellation Ursa Major. It is among the farthest known galaxies from Earth ever discovered. The 2015 discovery was published in a 2016 paper headed by Pascal Oesch and Gabriel Brammer (Cosmic Dawn ...

, also one of the oldest galaxies discovered. NASA-GLASS-z13-Context-JWST-20220722

Spectroscopy by the Atacama Large Millimeter Array

Spectroscopic Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectrosc ...

observations of GLASS-z12 by the

Atacama Large Millimeter Array The Atacama Large Millimeter/submillimeter Array (ALMA) is an astronomical interferometer of 66 radio telescopes in the Atacama Desert of northern Chile, which observe electromagnetic radiation at millimeter and submillimeter wavelengths. The ar ...

(ALMA) in August 2022 confirmed that the galaxy has a

of , making it one of the earliest and most distant galaxies ever discovered, dating back to 360 million years after the

, 13.44 billion years ago. ALMA observations detected an emission line associated with

doubly ionized oxygen In astronomy and atomic physics, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Ion Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 n ...

(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. GLASS-z12 has a light-travel distance ( lookback time) of 13.4 billion years. However, due to the

expansion of the universe The expansion of the universe is the increase in proper length, distance between Gravitational binding energy, gravitationally unbound parts of the observable universe with time. It is an intrinsic and extrinsic properties (philosophy), intrins ...

, its present proper distance is 32.718 billion light-years.

Spectroscopy by the James Webb Space Telescope

This galaxy was observed again in October 2023 by the

with the

NIRSpec The NIRSpec (Near-Infrared Spectrograph) is one of the four scientific instruments flown on the James Webb Space Telescope (JWST). The JWST is the follow-on mission to the Hubble Space Telescope (HST) and is developed to receive more information ...

and

MIRI Miri () is a coastal city in north-eastern Sarawak, Malaysia, located near the border of Brunei, on the island of Borneo. The city covers an area of , located northeast of Kuching and southwest of Kota Kinabalu. Miri is the second largest ...

spectrographs, making it the most distant redshift galaxy of z = 12.34 with full spectroscopic coverage from ultraviolet (UV) to optical. According to current

ΛCDM The Lambda-CDM, Lambda cold dark matter, or ΛCDM model is a mathematical model of the Big Bang theory with three major components: # a cosmological constant, denoted by lambda (Λ), associated with dark energy; # the postulated cold dark ma ...

parameters (''H''₀ = 67.4, Ω_{''m'' =} 0.315, Ω_Λ = 0.685), this redshift of 12.34 corresponds to a light-travel distance ( lookback time) of 13.44 billion years. However, due to the

, its

comoving distance In standard cosmology, comoving distance and proper distance (or physical distance) are two closely related distance measures used by cosmologists to define distances between objects. ''Comoving distance'' factors out the expansion of the univ ...

is 32.837 Gly.

References

{{2022 in space Sculptor (constellation) Dwarf galaxies Discoveries by the James Webb Space Telescope

Discovery

Spectroscopy by the Atacama Large Millimeter Array

Spectroscopy by the James Webb Space Telescope

See also

References