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HD1

Coordinates: Sky map 10h 01m 51.31s, +02° 32′ 36.1″
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For other uses, see HD1 (disambiguation). "HD2" redirects here. For other uses, see HD2 (disambiguation).

HD1
Three-color image of HD1, the most distant galaxy candidate to date, created using data from the VISTA telescope in Paranal Observatory. The red object in the center of the zoom-in image is HD1.
Observation data (J2000 epoch)
ConstellationSextans[1][2]
Right ascension10h 01m 51.31s[1]
Declination02° 32′ 50.0″[1]
Redshift4.0[1]
Other designations
[HIM2022] HD1

HD1 is a high-redshift galaxy, which was once a candidate for the most distant known galaxies yet identified in the observable universe. From early data the redshift was estimated of approximately z=13[3]. Followup JWST spectroscopy found it to be an interloper, and is in fact a passive galaxy at a much lower redshift (z = 4.0)[4][5].

Discovery

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The discovery of HD1 (RA:10:01:51.31 DEC:+02:32:50.0) in the Sextans constellation,[1][2] along with another high-redshift galaxy, HD2 (RA:02:18:52.44 DEC:-05:08:36.1) in the Cetus constellation,[1][2] was reported by astronomers at the University of Tokyo on 7 April 2022. These two galaxies were found in two patches of sky surveyed by the Cosmic Evolution Survey and by the Subaru Telescope in the Subaru/XMM-Newton Deep Survey Field respectively. They were found by looking for objects that are much brighter in the so-called K band of infrared than in the H band (around 1.6 microns), which could indicate a Lyman-break galaxy red-shifted by a factor of around 13. In LBG searches, much lower redshift galaxies with Balmer breaks can be misidentified as higher redshift LBGs. As was the case for HD1 and HD2[4][5]. For this reason they were named "HD 1" and "HD 2" (for "H band dropout", not to be confused with stars HD 1 and HD 2 in the Henry Draper Catalog.[1]

See also

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References

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  1. 1 2 3 4 5 6 7 Harikane, Yuichi; et al. (2 February 2022). "A Search for H-Dropout Lyman Break Galaxies at z ~ 12–16". The Astrophysical Journal. 929 (1): 1. arXiv:2112.09141. Bibcode:2022ApJ...929....1H. doi:10.3847/1538-4357/ac53a9. S2CID 246823511.
  2. 1 2 3 Staff (2008). "Finding the constellation which contains given sky coordinates". DJM.cc. Retrieved 8 April 2022.
  3. ↑ "Most Distant Galaxy Candidate Yet". NAOJ - National Astronomical Observatory of Japan. 7 April 2022. Retrieved 6 July 2026.
  4. 1 2 Harikane, Yuichi; et al. (2024). "JWST, ALMA, and Keck Spectroscopic Constraints on the UV Luminosity Functions at z~7-14: Clumpiness and Compactness of the Brightest Galaxies in the Early Universe". The Astrophysical Journal. 980 (1): 138. arXiv:2406.18352. Bibcode:2025ApJ...980..138H. doi:10.3847/1538-4357/ad9b2c.
  5. 1 2 Sato, Riku A; Inoue, Akio K; Harikane, Yuichi; Shimakawa, Rhythm; Sugahara, Yuma; Tamura, Yoichi; Hashimoto, Takuya; Ito, Kei; Yamanaka, Satoshi; Mawatari, Ken; Fudamoto, Yoshinobu; Ren, Yi W (11 November 2024). "JWST/NIRSpec spectroscopy of intermediate-mass quiescent galaxies at z ~ 3-4". Monthly Notices of the Royal Astronomical Society. 534 (4): 3552–3564. doi:10.1093/mnras/stae2300. ISSN 0035-8711.
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