| EGS-zs8-1 | |
|---|---|
 EGS-zs8-1 viewed by theHubble Space Telescope | |
| Observation data (J2000[1]epoch) | |
| Constellation | Boötes[1]/Ursa Major |
| Right ascension | 14h 20m 34.89s[1] |
| Declination | +53° 00′ 15.4″[1] |
| Redshift | 7.7[1] |
| Heliocentric radial velocity | 2,098,548 km/s (1,303,977 mi/s) |
| Galactocentric velocity | 2,098,671 km/s (1,304,054 mi/s) |
| Distance | 13.1 billion ly (4.0 billion pc) (light travel distance) 29.5 billion ly (9.0 billion pc) (comoving distance) |
| Apparent magnitude (V) | 25.3J |
| Characteristics | |
| Type | Lyman-break galaxy |
| Mass | 8×109 M☉ |
| Size | 15 kly (diameter) |
| Apparent size (V) | 0.004 x 0.0018 |
| Other designations | |
| GCF2012 8053, CANDELS J142034.88+530015.1, SSTSL2 J142034.90+530015.1, SYM2017 9104 | |
EGS-zs8-1 is ahigh-redshiftLyman-break galaxy found at the northernconstellation ofBoötes.[2] In May 2015, EGS-zs8-1 had the highestspectroscopicredshift of any knowngalaxy, meaning EGS-zs8-1 was the most distant and the oldest galaxy observed.[3][4] In July 2015, EGS-zs8-1 was surpassed byEGSY8p7 (EGSY-2008532660).[citation needed]
The redshift of EGS-zs8-1 was measured atz = 7.73, corresponding to alight travel distance of about 13.040 billion light years fromEarth, and age of 13.04 billion years. The galaxy shows a high rate ofstar formation, so it releases its peak radiation at thevacuum ultraviolet part of theelectromagnetic spectrum, near the 121.567 nm (1,215.67 Å)Lyman-alpha emission line due to the intense radiation from newly formedblue stars, hence it is classified as aLyman-break galaxy; high-redshiftstarburst galaxies emitting the Lyman-alpha emission line. Because of thecosmological redshifteffect caused by theexpansion of the universe, the peak light from the galaxy has becomeredshifted and has moved into theinfrared part of theelectromagnetic spectrum.[2] The galaxy has acomoving distance of about 30 billion light years from Earth.[5]
EGS-zs8-1 was born 670 million years after theBig Bang, during the period ofreionization, and it's 15 percent the size of the Milky Way. The galaxy was found to be larger than its other neighbors in that period when the universe was still very young.[4] Its mass at the time the light was emitted is estimated to have been about 15% of theMilky Way's current mass. The galaxy was making new stars at roughly 80 times the rate of the current Milky Way, or equivalent to 800M☉ worth of material turning to stars every year.[5] The light reaching Earth was made by stars in EGS-zs8-1 that were 100 million to 300 million years old at the time they emitted the light.[6] The age of EGS-zs8-1 places it in thereionization phase of creation, a time when hydrogen outside the galaxies was switching from a neutral to ionized state. According to the galaxy's discoverers, EGS-zs8-1 and other early galaxies were likely the causes of reionization.[7][8]
In 2013,Yale astronomer Pascal Oesch spotted an unexpected bright object while looking atHubble Space Telescope images. He then confirmed the existence of the object using theSpitzer Space Telescope.[4]Redshift calculations, using the Multi-Object Spectrometer for Infrared Exploration (MOSFIRE) equipment at theW.M. Keck Observatory inHawaii, were then performed to precisely determine the age of the galaxy.[7] Oesch and his colleagues at Yale and theUniversity of California, Santa Cruz announced the find, which was named EGS-zs8-1, in May 2015 surpassing the previous record for oldest galaxy by about 30 million years.[4]
| Records | ||
|---|---|---|
| Preceded by | Most distant galaxy 2015 | Succeeded by |
2015 in space | ||||||
|---|---|---|---|---|---|---|
Space probe launches |
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| Impact events | ||||||
| SelectedNEOs | ||||||
| Exoplanets | ||||||
| Discoveries | ||||||
| Comets | ||||||
| Space exploration | ||||||
