NGC 5778
Galaxy in the constellation Boötes
From Wikipedia, the free encyclopedia
NGC 5778 is a large elliptical galaxy in the constellation of Boötes. The galaxy has a redshift of (z) 0.059[1] and it was first discovered by the American astronomer Lewis Swift in June 1886 who depicted it as faint and small, next to a star, and also discovered by the French astronomer Guillaume Bigourdan in May 1890.[3] It is the brightest cluster galaxy (BCG) of the galaxy cluster, Abell 1991 and as such dominates the center.[4][5]
| NGC 5778 | |
|---|---|
The elliptical galaxy NGC 5778 | |
| Observation data (J2000 epoch) | |
| Constellation | Boötes |
| Right ascension | 14h 54m 31.48s[1] |
| Declination | +18° 38′ 32.50″[1] |
| Redshift | 0.059210[1] |
| Heliocentric radial velocity | 17,751 ± 5 km/s[1] |
| Distance | 881.5 ± 61.7 Mly (270.27 ± 18.92 Mpc)[1] |
| Group or cluster | Abell 1991 |
| Absolute magnitude (V) | 14.3[2] |
| Characteristics | |
| Type | cD;BrClG [1] |
| Size | ~364,000 ly (111.5 kpc) (estimated)[1] |
| Other designations | |
| NGC 5825, UGC 9590, Abell 1991:[AAV2011] BCG, CGCG 105-066, GIN 372, PGC 53279, MCG +03-38-050[1] | |
Description
NGC 5778 is a type-cD galaxy of Abell 1991. It is a radio galaxy containing a compact central radio source with a low radio power of 23.41 W Hz-1 and a total radio flux density estimated as 38 mJy based on observations made with the Very Large Array (VLA).[4][6] It also contains a core-jet structure based on a high resolution radio map with a linear size of 8 kiloparsecs.[7] A radio core has been detected and has a total flux density of 11.4 mJy.[5]
The optical spectrum of the galaxy displays emission lines.[8] The U – R and U – I color gradients of the galaxy are estimated to be -0.35 ± 0.06 and -0.23 ± 0.08 magnitudes respectively.[9] The X-ray emission extends outwards by 180 arcseconds, with further detections of X-ray knot features located in the northern direction from its nucleus.[4] The galaxy also has a calculated central velocity dispersion of 222 ± 8 kilometers per second with a total star formation rate that is less than 1.66 Mʘ per year derived from its infrared luminosity.[10] The stellar velocity dispersion is 279 ± 25 kilometers per second.[11]