UGC 1840 known as Arp 145, are a pair of interacting galaxies located 250 million light-years away from the solar system in the Andromeda constellation.^[1] Made up of two galaxies, UGC 1840 NED01 (PGC 9060)^[2] and UGC 1840 NED02 (PGC 9062),^[3] the two galaxies had recently collided with each other^[4] in which the elliptical galaxy has penetrated through the spiral galaxy's nucleus leaving a hole in its middle, thus forming a ring galaxy.^[5][6] With a diameter of 1.3 arc minutes, close to 100,000 thousand light-years, they are roughly the same size as the Milky Way.^{[7][unreliable source?]}

Both galaxies are included in Atlas of Peculiar Galaxies which was created by Halton Arp.^{[8][unreliable source?]} They fall under the category of objects that have emanating material and both classified as galaxies that have ring systems.