Arp Peculiar galaxies

Arp Peculiar galaxies

Here I collect some of my photos of peculiar galaxies from the Arp catalogue.

Arp 76

NGC 4569, or Messier 90. This is a rather peculiar galaxy in Virgo, close to the Coma border. The nearby "satellite" galaxy IC3583, is a 13th magnitude irregular galaxy. These two galaxies are however probably not gravitationally  connected. They are too far apart. The outer arms of M90 are very soft and lack the usual knotted structure of starforming regions, so typical for normal spirals. The strong interaction from the Virgo group cluster galaxies have blown away some of the interstellar medium from the outer arms, making them rather featureless. Also, noteworthy is the fact that this galaxy has a spectral blue-shift, suggesting it is not receding but approaching us.

Arp 78

NGC 772, also Arp 78, has a very prominent single arm. Interestingly Halton Arp classified the object with the description "Spiral Galaxy with small, high surface-brightness companion on arm". The bright elliptical feature below the galaxy, is in fact a satellite galaxy, NGC 770, which is one of the satellites gravitationally connected to the main galaxy. NGC 770 is suggested to be responsible for the apparent bright single arm.

Arp 78

Here the galaxy is represented in logarithmic scaling. The inner structure and the core is nicely presented. Note the very faint outer arm that revolves almost around the whole galaxy

Arp 86

The classification is "Large High Surface Brightness companion on arm". Arp 86 consists of NGC 7752 and NGC 7753, and is found in Pegasus. It is similar to the well known Messier 51.

Arp 242, the Mice

Here are the galaxies NGC4676A (right) and NGC4676B (left) in Coma Berenices. They show an unusual strong interaction and are hard to photograph, since they are at magnitude 14. The core is less than 30" in size, and the tails are about 2' long. This galaxy pair was photographed in rather mediocre weather conditions, but they show up rather nice.

   LRGB image

   Luminance only (negative) image

Arp 273

A beautiful pair of galaxies in the constellation Andromeda, UGC1810 and UGC1813 at about 300 million light years away. The smaller galaxy has probably passed through the larger one. The magnitude is about 13.7

Arp 319

Arp 319 is the upper right double galaxy NGC 7318 in Stephan's qunitet, also known as Hickson 92.

Arp 152, M87 jet

This is the famous black hole jet in Messier 87 in Virgo. Also designated Virgo A, or Arp 152. The jet is only about 15" long and about  a bow second in width.

Arp 337, M82

This is Messier 82 in Ursa Major.