| Q2343-BX442 | |
|---|---|
 BX442 (Hubble Legacy Archive) | |
| Observation data (J2000[1] epoch) | |
| Constellation | Pegasus |
| Right ascension | 23h 46m 19.35s[1] |
| Declination | +12° 48′ 00.0″[1] |
| Redshift | 2.1765±0.0001[1] |
| Heliocentric radial velocity | 652348±0.0001 km/s[citation needed] |
| Galactocentric velocity | 652498±6 km/s[citation needed] |
| Distance | 10.7 billion ly (3.3 billion pc) (light travel distance) 18 billion ly (5.5 billion pc) (present proper distance) |
| Apparent magnitude (V) | 24.4R |
| Characteristics | |
| Type | Sc[1] |
| Size | ~50 kly (diameter) |
| Apparent size (V) | 0.015 x 0.01 moa |
| Other designations | |
| HB89 2343+125 BX442, PGC 4668406, SSTSL2 J234619.33+124759.4 | |
BX442 (Q2343-BX442[1]) is a grand design spiral galaxy of type Sc.[1] It has a companion dwarf galaxy. It is the most distant known grand design spiral galaxy in the universe, with a redshift of z=2.1765 ± 0.0001.[1] It is commonly referred to as the oldest known grand design spiral galaxy in the universe,[2] but it is more accurately the earliest such galaxy known to exist in the universe, with a lookback time (the difference between the age of the universe now and the age of the universe at the time light left the galaxy[3]) of 10.7 billion years[1] in the concordance cosmology. This time estimate means that structure seen in BX442 developed roughly 3 billion years after the Big Bang. It is 15 kiloparsecs (50 kly) in diameter, and has a mass of 6 × 1010 solar masses.
- ^ a b c d e f g h i David R. Law; Alice E. Shapley; Charles C. Steidel; Naveen A. Reddy; Charlotte R. Christensen; Dawn K. Erb (2012-07-19). "High Velocity Dispersion in A Rare Grand Design Spiral Galaxy at Redshift z=2.18". Nature. 487 (7407): 338–340. arXiv:1207.4196. Bibcode:2012Natur.487..338L. doi:10.1038/nature11256. PMID 22810697. S2CID 205229562.
- ^ Thomas H. Maugh II (2012-07-18). "Hubble spots spiral galaxy that shouldn't exist". Los Angeles Times. Retrieved 2012-07-19.
- ^ David W. Hogg (2000-12-16). "Distance Measures in Cosmology". Retrieved 2012-12-02.