IC 1816
Galaxy in the constellation Fornax
From Wikipedia, the free encyclopedia
IC 1816 is a barred spiral galaxy located in the constellation of Fornax. The galaxy is located 245 million light-years from Earth and has a diameter of approximately 136,000 light-years across.[1] It was first discovered by Lewis Swift on 12 October 1896, who classified it as a small faint round object.[3]
| IC 1816 | |
|---|---|
IC 1816 imaged by Dark Energy Survey. | |
| Observation data (J2000 epoch) | |
| Constellation | Fornax |
| Right ascension | 02h 31m 50.97s[1] |
| Declination | −36° 40′ 19.64″[1] |
| Redshift | 0.016945 ± 0.000020[1] |
| Heliocentric radial velocity | 5,080 km/s[1] |
| Distance | 245 Mly |
| Apparent magnitude (V) | 13.1[2] |
| Characteristics | |
| Type | SB(r)ab pec?[1] |
| Size | ~136,000 ly (41.7 kpc) (estimated)[1] |
| Other designations | |
| ESO 355-G025, MCG -06-06-011, AM 0229-365, IRAS 02297-3653, 6dF J0231510-364019, PGC 9634[1] | |
Description
IC 1816 is an isolated face-on spiral galaxy.[4][5] It has three spiral arms with the northwest arm, the brightest and most detached.[5] Two of the arms are distinctive and seem to open up as its spiral structure travels inwards. The galaxy also shows a prominent curved dust lane.[6] There is a clearly resolved ring and a smaller elongated structure interpreted as a nuclear bar.[5] An inner bar might be present given the observation of a small counter-rotation located from its nucleus although a nuclear disk is suggested.[7] The star formation rate for IC 1816 is estimated to be 0.74 Mʘ per year.[8]
The nucleus of IC 1816 is active. It was originally classified as a type 1 Seyfert galaxy[9] but later reclassified as a type 2 Seyfert galaxy due to it lacking broad emission lines.[10] The Seyfert spectrum of the galaxy is found extending as far as 3.4 arcseconds east from the nucleus.[11] A hydrogen alpha component is seen broadening, likely caused by the blending of nitrogen lines.[12]
IC 1816 has an extended narrow line region showing highly ionized gas, indicated by the presence of coronal line emission, with the region mainly centering in its star-forming ring.[13] The gas located in its nuclear region is mainly blueshifted with a peak velocity dispersion of 320 kilometers per second, suggesting the active galactic nucleus of the galaxy is powered through outflows.[4]