Astronomy:NGC 4491

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Short description: Galaxy in the constellation of Virgo
NGC 4491
SDSS NGC 4491.jpg
SDSS image of NGC 4491.
Observation data (J2000 epoch)
ConstellationVirgo
Right ascension 12h 30m 57.1s[1]
Declination11° 29′ 01″[1]
Redshift0.001658/497 km/s[1]
Distance55,420,000 ly[2]
Group or clusterVirgo Cluster
Apparent magnitude (V)13.5[1]
Characteristics
TypeSB(s)a[1]
Size~7,140 ly (estimated)[1]
Apparent size (V)1.7 x 0.9[1]
Other designations
PGC 41376, UGC 7657, VCC 1326[1]

NGC 4491 is a dwarf barred spiral galaxy[2] located about 55 million light-years away[3] in the constellation Virgo.[4] NGC 4491 was discovered by astronomer William Herschel on March 15, 1784.[5] NGC 4491 is located in a subgroup of the Virgo Cluster centered on Messier 87 known as the Virgo A subgroup.[2]

Tidal interactions

NGC 4491 is a strongly barred galaxy. The bar may have grown from the tidal influence of other galaxies in the Virgo Cluster.[2]

Possible Seyfert activity

The infrared-radio properties of NGC 4491 possibly suggest the presence of an AGN in the galaxy. However, spectral analysis of the galaxy does not support this view since emission lines are absent or very weak and narrow.[2]

See also

References

External links