IRAS 12112+0305 is agalaxy merger located in theconstellation ofVirgo. Itsredshift is (z) 0.0723,[2] which means the object is located 970 millionlight years from Earth.[1] It was first discovered by astronomers in 1987 from theIRAS bright galaxy sample.[3] and has aLINER spectrum.[4]
IRAS 12112+0305 is anultraluminous infrared galaxy.[5] It is classified as a post-merger involving two collidingspiral galaxies.[6][7] Its appearance is distorted and it has twotidal tails; one showing an extension of 18 kiloparsecs to the north and another showing a looped arc stretching 30 kiloparsecs in a southern direction.[8] Ultraviolet imaging showsstar-forming clusters are present in the southern tail.[9] The optical spectrum of the galaxy is described asLINER and astarburst based on itsmid-infrared spectrum.[10]
The galaxy has two galactic nuclei found to have a separation of less than 3kiloparsecs with the northern nucleus being more luminous than the southern.[7][11] Further evidence showed the northern nucleus is shaped into a crescent while the southern nucleus is described as becoming point-like when at longerwavelengths.[9] A compact knot ofradio emission is seen dominating the northern nucleus.[12]
Optical imaging byHubble Space Telescope (HST) and integral field opticalspectroscopy by the INTEGRAL fiber-fed system showed the main body of the galaxy is clustered within three dominant regions. The first two regions, associated with the two nuclei, are located north and south respectively, along theposition angle of 45°. The third region is located 3arcseconds north of the southern region at a 20° position angle. I-band imaging by Hubble reveals the southern region as compact with highsurface brightness, while the two regions are composed of several faintionized gas components that are found evenly distributed along an arc-like structure and measuring around 8 kiloparsecs.[2]
Radio imaging at highfrequencies, shows a double structure with the two radio components having a separation gap of 4.4 kiloparsecs. These components havespectral indexes of 0.58 ± 0.11 and 0.80 ± 0.01 respectively, based on astronomers convolving three radio maps into a common resolution. Theradio spectrum of the source is found to have a low frequency turnover at 290MHz with a higher break frequency.[11]
