BX442

Q2343-BX442
BX442 (Hubble Legacy Archive)
Observation data (J2000[1] epoch)
ConstellationPegasus
Right ascension23h 46m 19.35s[1]
Declination+12° 48′ 00.0″[1]
Redshift2.1765±0.0001[1]
Heliocentric radial velocity652348±0.0001 km/s[citation needed]
Galactocentric velocity652498±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
TypeSc[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.

  1. ^ 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.
  2. ^ Thomas H. Maugh II (2012-07-18). "Hubble spots spiral galaxy that shouldn't exist". Los Angeles Times. Retrieved 2012-07-19.
  3. ^ David W. Hogg (2000-12-16). "Distance Measures in Cosmology". Retrieved 2012-12-02.