Malin 1

Malin 1 is a giant low surface brightness (LSB) spiral galaxy. It is located 366 Mpc away in the constellation Coma Berenices, near the North Galactic Pole. , it is the largest known spiral galaxy, with an approximate diameter of 650000 ly, thus over six times the diameter of our Milky Way. It was discovered by astronomer David Malin in 1986 and is the first LSB galaxy verified to exist. Its high surface brightness central spiral is 30000 ly across, with a bulge of 10000 ly. The central spiral is a SB0a type barred-spiral.

Malin 1 is peculiar in several ways: its diameter alone would make it the largest barred spiral galaxy ever to have been observed.

Malin 1 was found later to be interacting with two other galaxies, Malin 1B and SDSS J123708.91+142253.2. Malin 1B is located 14000 pc away from the high surface brightness central spiral of Malin 1, which may be responsible for the formation of the galaxy's central bar. Meanwhile, SDSS J123708.91+142253.2 is located within the huge, faint halo of Malin 1 and might have caused the formation of the extended low surface brightness disc through tidal stripping.

Observations by Galaz et al. in April 2014 revealed a detailed view of the spiral structure of Malin 1 in optical bands. The galaxy exhibits giant and very faint spiral arms, with some segments up to 10000 pc in diameter. Other details, such as possible stellar streams and formation regions, are revealed as well. The same authors also say that Malin 1 is larger than thought, with another estimated diameter of around 750000 ly.