NGC 4555
| Galaxy NGC 4555 |
|
|---|---|
|
|
| SDSS recording | |
| AladinLite | |
| Constellation | Berenike's hair |
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Position equinox : J2000.0 , epoch : J2000.0 |
|
| Right ascension | 12 h 35 m 41.2 s |
| declination | + 26 ° 31 ′ 23 ″ |
| Appearance | |
| Morphological type | E3? |
| Brightness (visual) | 12.4 mag |
| Brightness (B-band) | 13.4 mag |
| Angular expansion | 1.9 ′ × 1.4 ′ |
| Position angle | 125 ° |
| Surface brightness | 13.5 mag / arcmin² |
| Physical data | |
| Affiliation | isolated |
| Redshift | 0.022292 ± 0.000080 |
| Radial velocity | 6683 ± 24 km / s |
|
Stroke distance v rad / H 0 |
(298 ± 21) · 10 6 ly (91.5 ± 6.4) Mpc |
| history | |
| discovery | Wilhelm Herschel |
| Discovery date | April 6, 1785 |
| Catalog names | |
| NGC 4555 • IC 3545 • UGC 7762 • PGC 41975 • CGCG 159-021 • MCG + 05-30-026 • 2MASX J12354118 + 2631227 • GC 3099 • H II 343 • h 1350 • ASK 578044.0 | |
NGC 4555 is an elliptical galaxy in the constellation Haar der Berenike, which is an estimated 298 million light years away. It is extremely isolated from similar objects. Observations through the Chandra Telescope have shown that the galaxy is surrounded by a halo of hot gases. There are temperatures of around 10 million Kelvin .
For an elliptical galaxy, NGC 4555 has large deposits of dark matter . This obviously prevents the gases from escaping from the area. The sighted mass of the galaxy alone is not enough to hold the gases together. It is estimated that the dark matter halo has ten times the mass of all stars in the galaxy. The isolation of NGC 4555 is remarkable. Most elliptical galaxies are part of galaxy clusters . The existing dark matter is proof that individual elliptical galaxies are uniting with dark matter.
The object was discovered on April 6, 1785 by William Herschel with the help of his 18.7-inch reflecting telescope. It was also observed by Max Wolf in 1903 without realizing that it was NGC 4555 , which led to entry IC 3545 in the index catalog .