NGC_3783
NGC 3783
Galaxy in the constellation Centaurus
NGC 3783 is a barred spiral galaxy located about 135[4] million light years away in the constellation Centaurus.[7] It is inclined by an angle of 23° to the line of sight from the Earth along a position angle of about 163°. The morphological classification of SBa[5] indicates a bar structure across the center (B) and tightly-wound spiral arms (a).[8] Although not shown by this classification, observers note the galaxy has a luminous inner ring surrounding the bar structure. The bright compact nucleus is active and categorized as a Seyfert 1 type. This nucleus is a strong source of X-ray emission and undergoes variations in emission across the electromagnetic spectrum.[5]
The source of the activity in this galaxy is a rapidly rotating supermassive black hole, which is located at the core and is surrounded by an accretion disk of dust.[9] The estimated mass of this black hole, from reverberation mapping, is about 2.8 million times the mass of the Sun.[10] Interferometric observations yield an inner radius of 0.52 ± 0.16 ly (0.16 ± 0.05 pc) for the orbiting torus of dust.[11]
This is a member of a loose association of 47 galaxies known as the NGC 3783 group. Located at a mean distance of 117 million light-years (36 Mpc), the group is centered at coordinates α = 11h 37m 12s, δ = –37° 30′ 57.6″: equivalent to about 870×10 3 ly (267 kpc) from NGC 3783. The NGC 3783 group has a mean velocity of 2,903 ± 26 km/s with respect to the Sun and a velocity dispersion of 190 ± 24 km/s. The diffuse X-ray emission of the group is roughly centered on the galaxy NGC 3783.[12]