Malin 1 is peculiar in several ways: its diameter alone would make it the largest barred spiral galaxy ever to have been observed.[4]
Malin 1 was found later to be interacting with two other galaxies, Malin 1B and SDSS J123708.91+142253.2. Malin 1B is located 46,000 light-years (14,000 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 33,000 light-years (10,000 pc) in diameter. Other details, such as possible stellar streams and formation regions, are revealed as well.[9] The same authors also say that Malin 1 is larger than thought, with another estimated diameter of around 750,000 light-years (230,000 pc).[9]
Gallery
Processed image of Malin 1 by Giuseppe Donatiello showing its weak spiral arms.
^The quoted diameter in this infobox was based on NED's provided scale "Virgo + GA + Shapley" of 1.811 kpc/arcsec multiplied with given angular diameters.