PKS 0805−07
Quasar in the constellation of Monoceros
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PKS 0805−07 also known as PMN J0808−0751 and 4FGL J0808.2−0751, is a quasar located in the constellation of Monoceros. With a redshift of 1.83, light has taken at least 10 billion light-years to reach Earth.[1]
| PKS 0805−07 | |
|---|---|
PKS 0805−07 captured by Pan-STARRS | |
| Observation data (J2000.0 epoch) | |
| Constellation | Monoceros |
| Right ascension | 08h 08m 15.54s |
| Declination | −07° 51′ 09.89″ |
| Redshift | 1.837000 |
| Heliocentric radial velocity | 550,719 km/s |
| Distance | 10.053 Gly (light travel time distance) |
| Apparent magnitude (V) | 0.388 |
| Apparent magnitude (B) | 0.513 |
| Surface brightness | 18.4 |
| Characteristics | |
| Type | Blazar, FSRQ |
| Notable features | Blazar emitting gamma rays |
| Other designations | |
| WMAP 133, TXS 0805−077, PGC 2825379, PKS B0805−077, NVSS J080815−075109, 3FGL J0808.2−0751, 4FGL J0808.2−0751, PMN J0808−0751, MRC 0805−077, 2MASSi J0808155−075109, Cul 0805−076, IRCF J080815.5−075109 | |
Characteristics
Classified a high redshift blazar,[2][3] a type of powerful radio-loud active galactic nuclei containing a relativistic jet, pointing towards the direction of Earth,[4] PKS 0805−07 shows emitted radiation, mainly detected in gamma-rays (E>~100 MeV)[5] as detected by Large Area Telescope.[6] The quasar is known to have an extreme variability across its entire electromagnetic spectrum.[7][8] Based on the strength of optical spectral lines, which the equivalent width (EW) of the spectral line is found greater or less than 5 Å, PKS 0805−07 is further classified a flat-spectrum radio quasar (FSRQ) containing strong emission-lines.[9][10][11]
Like many other FSRQs, PKS 0805−07 contains characteristics like a high bolometric luminosity,[12] and thermal activity that is related to an accretion disk in the quasar's optical and ultraviolet (UV) spectra.[13][14] It is also known to have characteristic radio polarization at 1.4 GHz, P1.4 > 1%[15] and a spinning black hole.[16]
As studied by researchers for its emission properties, PKS 0805−07 exhibits lower electron energy (γ p ≲ 1.6 × 103) compared to BL Lacertae objects (BL Lacs) with a separation of Γ = -0.127 log ly + 8.18 in γ-ray luminosity versus photon index plane with a success rate of 88.6\%.[17] It also has a stronger magnetic field (B) with smaller electron-to-magnetic energy ratio (U e/U B) than BL Lacs.[18] Moreover, PKS 0805−07 shows a core-jet morphology with at least five observing epochs at 15 GHz between January 1996, and August 2019, observed by Very Long Baseline Array.[19] The quasar also has a core-dominated source, showing asymmetric features than lobe-dominated sources, which is caused by modest relativistic motion (β ≡ 0.20) within its radio lobes.[20]
Observations
Since April 2009, PKS 0805−07 was shown to have high levels of gamma-ray activity when detected by Large Area Telescope. Amongst other quasars, PKS 0805−07 has one of the fastest superluminal motions at that time.[21]
Between 17 and 19, November 2022, an ongoing bright gamma-ray from PKS 0805−07 was observed by AGILE satellite. This source had a flux measured of F( > 100 MeV) = (2.7 +/- 0.8) × 10−6 photons/cm2/s and around 6 sigma.[22]