NGC 3557 is a large elliptical galaxy in the constellation of Centaurus. Its velocity with respect to the cosmic microwave background is 3398 ± 23 km/s, which corresponds to a Hubble distance of 50.12 ± 3.53 Mpc (~163 million light-years). However, 20 non-redshift measurements give a distance of 32.905 ± 2.289 (~107 million light-years). The galaxy was discovered by British astronomer John Herschel on 21 April 1835.

The SIMBAD database lists NGC 3557 as a Seyfert I Galaxy, i.e. it has a quasar-like nuclei with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable. Additionally, NED lists NGC 3557 as a LINER galaxy, i.e. a galaxy whose nucleus has an emission spectrum characterized by broad lines of weakly ionized atoms.

NGC 3557 Group

NGC 3557 is the largest and brightest galaxy in a group of galaxies that bears its name. The NGC 3557 group (also known as LGG 229) includes at least eleven galaxies, including NGC 3533[fr], NGC 3557B[d], NGC 3564[fr], NGC 3568 and NGC 3573[fr].

Supernova

One supernova has been observed in NGC 3557.

Image gallery

  • NGC 3557 (right), NGC 3564 (lower-left), and NGC 3568 (upper-left).

See also

External links

  • Media related to NGC 3557 at Wikimedia Commons
  • NGC 3557 on WikiSky: , , , , , , , ,