| RD1 (0140+326 RD1) | |
|---|---|
 RD1 as viewed by theW. M. Keck Observatory | |
| Observation data (J2000epoch) | |
| Constellation | Triangulum |
| Right ascension | 01h 43m 42.8s |
| Declination | +32° 54′ 00.0″ |
| Redshift | 5.34[1] |
| Distance | around 12.5billionlight-years (light travel distance)[2] ~26 billion light-years (presentcomoving distance)[2] |
| Apparent magnitude (V) | 26.1 |
| Other designations | |
| [DS98] 6C 0140+326 RD1 | |
RD1 or0140+326 RD1 is a distant galaxy, it once held the title of most distant galaxy known.[3] RD1 was discovered in March 1998, and is atz = 5.34,[1] and was the first object found to exceedredshift 5.[4] It bested the previous recordholders, a pair of galaxies at z=4.92 lensed by the galaxy clusterCL 1358+62 (CL 1358+62 G1 &CL 1358+62 G2). It was themost distant object known to mankind for a few months in 1998, untilBR1202-0725 LAE was discovered atz = 5.64.
The "distance" of a far away galaxy depends on the chosendistance measurement. With aredshift of 5.34,[1] light from this galaxy is estimated to have taken around 12.5billion years to reach us.[2] But since this galaxy is receding from Earth, the presentcomoving distance is estimated to be around 26 billionlight-years.[2]
