NGC 4698
Galaxy in the constellation Virgo
From Wikipedia, the free encyclopedia
NGC 4698 is a barred spiral galaxy[5] in the constellation Virgo. It belongs to the Virgo Cluster of galaxies and is positioned near the northeastern edge of this assemblage.[4] Its velocity with respect to the cosmic microwave background is 1,335±23 km/s, which corresponds to a Hubble distance of 64.2 ± 4.6 Mly (19.69 ± 1.42 Mpc).[1] However, 28 non-redshift measurements give a farther mean distance of 73.22 ± 4.17 Mly (22.448 ± 1.279 Mpc).[3] It was discovered by German-British astronomer William Herschel on 18 January 1784.[8]
| NGC 4698 | |
|---|---|
NGC 4698 imaged with the 32-inch Schulman Telescope at Mount Lemmon Observatory | |
| Observation data (J2000 epoch) | |
| Constellation | Virgo |
| Right ascension | 12h 48m 22.9151s[1] |
| Declination | +08° 29′ 14.514″[1] |
| Redshift | 0.003366±0.00000200[1] |
| Heliocentric radial velocity | 1,002[2] km/s |
| Distance | 73.22 ± 4.17 Mly (22.448 ± 1.279 Mpc)[3] |
| Group or cluster | Virgo Cluster |
| Apparent magnitude (V) | 10.6[4] |
| Apparent magnitude (B) | 11.46[5] |
| Characteristics | |
| Type | SA(s)ab[6] |
| Apparent size (V) | 4′.0 × 2′.9[4] |
| Notable features | Seyfert-2 galaxy[7] |
| Other designations | |
| VCC 2070, IRAS 12458+0845, 2MASX J12482293+0829140, UGC 7970, MCG +02-33-024, PGC 43254, CGCG 071-045[1] | |
The morphological classification of NGC 4698 in the De Vaucouleurs system is SA(s)ab,[6] which indicates a purely spiral structure with moderate to tightly wound arms.[9] It is inclined to the line of sight from the Earth by an angle of 53° along a position angle of 170°.[10]
A unique feature of this galaxy is that the stars and dust of the nuclear disk are rotating in a direction that is aligned perpendicularly to the galactic disk. The bulge likewise appears elongated out of the galactic plane. This unusual alignment may have been the result of a past merger event.[5]
NGC 4698 is classified as a Seyfert-2 galaxy with an active galactic nucleus, which displays a prominent emission of radio and X-ray energy from the core while showing narrow emission lines in the optical spectrum.[7] The unified model of Seyfert galaxies proposes that the nucleus of a Seyfert 2 galaxy is obscured by a thick torus of gas and dust. However, the varying X-ray emission of the core of NGC 4698 shows little indication of being obstructed, suggesting instead that the source of the energy emission is generally unobscured but anemic in nature.[11]
Gallery
NGC 4698 (SDSS DR14)
NGC 4698 (HST)
NGC 4698 by a Schulman telescope at Mt. Lemmon, AZ.
