NGC 7456

Galaxy in the constellation Grus From Wikipedia, the free encyclopedia

NGC 7456 is a spiral galaxy in the constellation of Grus. Its velocity with respect to the cosmic microwave background is 944±18 km/s, which corresponds to a Hubble distance of 45.4 ± 3.3 Mly (13.92 ± 1.01 Mpc).[1] Additionally, 23 non-redshift measurements give a farther mean distance of 50.33 ± 2.11 Mly (15.430 ± 0.648 Mpc).[2] It was discovered by British astronomer John Herschel on 4 September 1834.[3][4]

ConstellationGrus
Right ascension23h 02m 10.3631s[1]
Declination−39° 34′ 09.804″[1]
Redshift0.003999±0.000007[1]
Quick facts Observation data (J2000 epoch), Constellation ...
NGC 7456
A spiral galaxy. It shines brightly at the centre, and most of its disc also glows in warm colours. Its two spiral arms, which wind outwards from the centre, are made up mostly of large patches of bright blue specks. They also contain thin, reddish clouds of dust, and bright pink bubbles of glowing gas, where stars are forming. Distant galaxies can be seen around the galaxy as small orange spots, on a dark background.
NGC 7456 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
ConstellationGrus
Right ascension23h 02m 10.3631s[1]
Declination−39° 34′ 09.804″[1]
Redshift0.003999±0.000007[1]
Heliocentric radial velocity1,199±2 km/s[1]
Distance50.33 ± 2.11 Mly (15.430 ± 0.648 Mpc)[1]
Group or clusterLDC 1547 group
Apparent magnitude (V)12.78[1]
Characteristics
TypeSA(s)cd[1]
Size~117,100 ly (35.91 kpc) (estimated)[1]
Apparent size (V)5.5′ × 1.6′[1]
Notable featuresMultiple X-ray sources
Other designations
ESO 346- G 026, IRAS 22594-3950, MCG -07-47-011, PGC 70304[1]
Close

NGC 7456 is a Seyfert II galaxy, i.e. it has a quasar-like nucleus with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable.[5]

X-ray sources

NGC 7456 contains as many as five ultraluminous X-ray sources. ULX-1 exhibits pronounced variability, with its flux changing over intervals ranging from several hundred seconds to a few kiloseconds, representing one of the most extreme flux fluctuations recorded among ULXs. Two of the five sources are considered transient ULX candidates.[6]

LDC 1547 group

NGC 7456 is a member of the LDC 1547 galaxy group, which contains 16 galaxies, including NGC 7404 [fr], NGC 7410, NGC 7418, NGC 7421, NGC 7424, NGC 7462 [fr], IC 1459, IC 5264 [fr], IC 5269 [fr], IC 5270 [fr], IC 5271 [fr], IC 5273 [fr], and 3 galaxies from the ESO Catalogue.[7][8]

Image gallery

See also

References

External links

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