Article · Wikipedia archive · Last revised Jul 28, 2026

IOK-1

IOK-1 is a distant galaxy in the constellation Coma Berenices. When discovered in 2006, it was the oldest and most distant galaxy ever found, at redshift 6.96.

Last revised
Jul 28, 2026
Read time
≈ 1 min
Length
249 w
Citations
7
Source
IOK-1
IOK-1 by the Subaru Telescope
Observation data (J2000 epoch)
ConstellationComa Berenices
Right ascension13h 23m 59.8s1
Declination+27° 24′ 56″1
Redshift6.9641
Distance12.88 billion light-years (3.95 Gpc)
Apparent magnitude (V)24.4
Characteristics
TypeLAE
Size4,000 ly (1,200 pc) (diameter)
2,000 ly (610 pc)
(radius)
Apparent size (V)0.001 x 0.001
Other designations
JEM2013 62, OIK2017 NB973-SDF-85821, OMS2009 SDF-635441

IOK-1 is a distant galaxy in the constellation Coma Berenices. When discovered in 2006, it was the oldest and most distant galaxy ever found, at redshift 6.96.2

It was discovered in April 2006 by Masanori Iye at National Astronomical Observatory of Japan using the Subaru Telescope in Hawaii and is seen as it was 12.88 billion years ago. Its emission of Lyman alpha radiation has a redshift of 6.96, corresponding to just 750 million years after the Big Bang. While some scientists have claimed other objects (such as Abell 1835 IR1916) to be even older, IOK-1's age and composition have been more reliably established.34

"IOK" stands for the observers' names Iye, Ota, and Kashikawa.

See also

See also

References

References

  1. "IOK 1". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-07-31.
  2. Hogan, Jenny (2006), "Journey to the birth of the Universe", Nature, 443 (7108): 128–129, Bibcode:2006Natur.443..128H, doi:10.1038/443128a, PMID 16971914
  3. Iye, Masanori; Ota, Kazuaki; Kashikawa, Nobunari; Furusawa, Hisanori; Hashimoto, Tetsuya; Hattori, Takashi; Matsuda, Yuichi; Morokuma, Tomoki; Ouchi, Masami; et al. (2006), "A galaxy at a redshift z = 6.96", Nature, 443 (7108): 186–188, arXiv:astro-ph/0609393v1, Bibcode:2006Natur.443..186I, doi:10.1038/nature05104, PMID 16971942, S2CID 2876103
  4. Press release, National Astronomical Observatory of Japan, September 13, 2006