NGC 545 is a

lenticular galaxy A lenticular galaxy (denoted S0) is a Galaxy morphological classification, type of galaxy intermediate between an elliptical galaxy, elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. It contains a large-s ...

located in the constellation

Cetus Cetus () is a constellation, sometimes called 'the whale' in English. The Cetus (mythology), Cetus was a sea monster in Greek mythology which both Perseus and Heracles needed to slay. Cetus is in the region of the sky that contains other water- ...

. It is located at a distance of about 250 million

light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...

s from Earth, which, given its apparent dimensions, means that NGC 545 is about 180,000 light years across. It was discovered by German-British astronomer

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

on October 1, 1785. It is a member of the Abell 194 galaxy cluster and is included along with NGC 547 in the

Atlas of Peculiar Galaxies The ''Atlas of Peculiar Galaxies'' is a Astronomical catalog, catalog of peculiar galaxies produced by Halton Arp in 1966. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institut ...

. A weak radio source with

radio jets An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as extended beams along the axis of rotation. When this greatly accelerated matter in the beam approaches the speed of light, astrophysical jets beco ...

has been associated with NGC 545. The short jet crosses the much more prominent jet of NGC 547. Observations of the centre of the galaxy by

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

did not reveal the presence of dust or disk features. In the centre of the galaxy is believed to exist a

supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...

whose mass is estimated to be about 600 million (10^8.79) based on the stellar tidal disruption rate. NGC 545 forms a pair with the equally bright NGC 547, which lies 0.5 arcminutes away. They share a common envelope, however, despite their close position, no tidal features like tails or bridges have been observed. A stellar bridge has been detected between the galaxy pair and

NGC 541 NGC 541 is a lenticular galaxy located in the constellation Cetus. It is located at a distance of about 230 million light years from Earth, which, given its apparent dimensions, means that NGC 541 is about 130,000 light years across. It was disco ...

, which lies 4.5 arcminutes to the southwest (projected distance circa 100 kpc). Observations of the galaxy by the

Chandra X-Ray Observatory The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources ...

revealed sharp surface brightness edges on the northeastern part of the galaxy and an extended tail in the soft band. It has been presumed that these are the result of motion of NGC 545 towards the centre of the cluster that has been identified as the location of NGC 547.

References

External links

NGC 545 on SIMBAD
{{DEFAULTSORT:NGC 545 Lenticular galaxies Interacting galaxies Cetus 0545 01007 308a 005323 +00-04-142 Discoveries by William Herschel Astronomical objects discovered in 1785