NGC 1808

NGC 1808 is a Seyfert galaxy located in the constellation Columba. The Supernova 1993af appeared in NGC 1808.[3]

NGC 1808HSTCenter
A Hubble Space Telescope image of the center of NGC 1808. Credit: HST/NASA/ESA.
NGC 1808
NGC 1808HSTFull
A Hubble Space Telescope (HST) image of NGC 1808 taken using WFPC2.[1]
Observation data (J2000 epoch)
ConstellationColumba[1]
Right ascension 5h 7m 42.3s[2]
Declination−37° 30′ 47″[2]
Redshift995 ± 4 km/s[2]
Apparent magnitude (V)10.8[2]
Characteristics
Type(R')SAB(s)b
Apparent size (V)6′.5 × 3′.9[2]
Other designations
PGC 16779[2]

References

  1. ^ a b "HubbleSite - NewsCenter - Hubble Captures the Heart of Star Birth". Retrieved 2007-04-05.
  2. ^ a b c d e f "NASA/IPAC Extragalactic Database". Results for NGC 1808. Retrieved 2007-04-05.
  3. ^ Haumy et al., 1996 Astronomical Journal v.112, p.2408

External links

Columba (constellation)

Columba is a small, faint constellation created in the late sixteenth century. Its name is Latin for dove. It is located just south of Canis Major and Lepus.

NGC 7552

NGC 7552 (also known as IC 5294) is a barred spiral galaxy in the constellation Grus. It is at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 7552 is about 75,000 light years across. It forms with three other spiral galaxies the Grus Quartet.

Seyfert galaxy

Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei (very luminous, distant and bright sources of electromagnetic radiation) with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.Seyfert galaxies account for about 10% of all galaxies and are some of the most intensely studied objects in astronomy, as they are thought to be powered by the same phenomena that occur in quasars, although they are closer and less luminous than quasars. These galaxies have supermassive black holes at their centers which are surrounded by accretion discs of in-falling material. The accretion discs are believed to be the source of the observed ultraviolet radiation. Ultraviolet emission and absorption lines provide the best diagnostics for the composition of the surrounding material.Seen in visible light, most Seyfert galaxies look like normal spiral galaxies, but when studied under other wavelengths, it becomes clear that the luminosity of their cores is of comparable intensity to the luminosity of whole galaxies the size of the Milky Way.Seyfert galaxies are named after Carl Seyfert, who first described this class in 1943.

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