| 3C 309.1 | |
|---|---|
 The quasar 3C 309.1. | |
| Observation data (J2000.0 epoch) | |
| Constellation | Ursa Minor |
| Right ascension | 14h 59m 07.583s |
| Declination | +71° 40′ 19.867″ |
| Redshift | 0.901113 |
| Heliocentric radial velocity | 270,147 km/s |
| Distance | 7.665 Gly |
| Apparent magnitude (V) | 16.78 |
| Apparent magnitude (B) | 17.24 |
| Characteristics | |
| Type | CSS |
| Other designations | |
| LEDA 2821824, 4C 71.15, WMAP 071, QSO B1458+718, 2E 3367, NRAO 464, 1Jy 1458+718 | |
3C 309.1 is a quasar[1] located in the constellation of Ursa Minor. It has a redshift (z) of 0.90[2] and was first identified as an astronomical radio source from the Third Cambridge Catalogue of Radio Sources by in 1966.[3] This object contains a compact steep spectrum (CSS) source,[4] and is classified as one of the brightest and largest of its kind.[2][5]
3C 309.1 has a triple radio structure. It has a radio core found self-absorbed with an extended position angle of 162°±2°. On both sides of the core, there are two relatively extended outer radio lobes having a defined positional angle of 90°.[6]
In sub-arcsecond resolutions, the structure is made up of several components. Three of them are aligned east–west while the others are located along the path of extended emission in a southern direction, clearly detected by two X-ray images. In two of the brightest components, there is polarized emission.[7] However, when viewed at a 5 GHz milliarcsecond (mas) resolution, a bright core is found instead straddled by two other weaker components with a separation of 8.7 kiloparsecs.[8] Sub-milliarcsecond imaging shows the core to be compact with a more extended component located 20 mas to the south.[9]
The jet of 3C 309.1 is one-sided. It is found to be flaring away from the nucleus with a sharp change in brightness, likely caused through various Kelvin–Helmholtz instabilities in confined fluid flow and pressure being exerted in confined medium.[10] In Very Long Baseline Interferometry radio imaging, the jet is shown to extend from the core southwards with a distance of 260 parsecs (60 mas). At eastwards, it bends at 90° before fading rapidly.[8] Furthermore, the jet is extremely polarized.[11][12]
The host galaxy of 3C 309.1 is a flat elliptical galaxy according to Hubble Space Telescope imaging. It has a major axis orientated along the position angle of 130°.[13] Extensive emission-line gas is also seen surrounding the object at high pressure, with a massive cooling rate exceeding 1000 Mʘ yr−1 implying its host galaxy might have been formed within a Hubble time.[14]
