UGC 1840

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]

UGC 1840
Hubble Space Telescope image of UGC 1840
Observation data
Constellation	Andromeda
Right ascension	35.79 degrees
Declination	41.36 degrees
Redshift	0.018096
Heliocentric radial velocity	5,420 km/s
Distance	258.5 Mly (79.1 Mpc)
Characteristics
Type	PECULR
Notable features	Collisional ring galaxy
Other designations
Arp 145, IRAS 02200+4108, PGC 9062, PGC 9060, MCG+07-06-002, UGC 1840, Z 538-56, HFLLZOA F264, V Zw 229, 2MASX J02231142+4122047

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