NGC 3783

NGC 3783 is a barred spiral galaxy located about 135^[4] million light years away in the constellation Centaurus.^[8] Its velocity with respect to the cosmic microwave background is 3234 ± 22 km/s, which corresponds to a Hubble distance of 155.6 ± 10.9 Mly (47.70 ± 3.35 Mpc).^[6] In addition, two non-redshift measurements give a distance of 155.74 ± 30.17 Mly (47.750 ± 9.250 Mpc).^[9] It was discovered by British astronomer John Herschel on 21 April 1835.^[10]

NGC 3783
NGC 3783 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
Constellation	Centaurus
Right ascension	11h 39m 01.721s[1]
Declination	–37° 44′ 18.60″[1]
Redshift	0.008506 ± 0.000100[2]
Heliocentric radial velocity	+2,817[3] km/s
Distance	135.7 Mly (41.60[4] Mpc)
Group or cluster	NGC 3783 group
Apparent magnitude (V)	13.43
Characteristics
Type	SBa[5]
Size	~212,800 ly (65.25 kpc) (estimated)[6]
Apparent size (V)	1′.9 × 1′.7[5]
Notable features	Seyfert 1
Other designations
ESO 378- G 014, IRAS 11365-3727, MCG -06-26-004, PGC 36101[7]

NGC 3783 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).^[11] 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]

Artist's impression of the surroundings of the supermassive black hole in NGC 3783 (ESO)

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.^[12] The estimated mass of this black hole, from reverberation mapping, is about 2.8 million times the mass of the Sun.^[13] Interferometric observations yield an inner radius of 0.52 ± 0.16 ly (0.16 ± 0.05 pc) for the orbiting torus of dust.^[14]

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 = 11^h 37^m 12^s, 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.^[15] The NGC 3783 group is located in the Hydra-Antlia region of the Hydra-Centaurus Supercluster.^[16][17]

Gallery

• 
  NGC 3783 as seen by the legacy surveys. The bright star on the lower left is HD 101274
• This video shows an artist's impression of the dusty wind emanating from the black hole at the centre of galaxy NGC 3783