PKS 1127-145 | |
---|---|
Observation data (J2000.0 epoch) | |
Constellation | Crater |
Right ascension | 11h 30m 07.0526s |
Declination | −14° 49′ 27.388″ |
Redshift | 1.180000 |
Heliocentric radial velocity | 353,755 km/s |
Distance | 8.170 Gly |
Apparent magnitude (V) | 17.17 |
Apparent magnitude (B) | 16.90 |
Characteristics | |
Type | Blazar, LPQ, FSRQ |
Notable features | Longest X-ray jet detected in a high redshift quasar |
Other designations | |
INTREF 453, 2E 2471, LEDA 2826758, 4FGL J1129.8-1447, WMAP 157, QSO B1127-1432, PKS 1127-14, OHIO M -146, PMN J1130-1449 |
PKS 1127-145 is a radio-loud quasar [1] located in the constellation of Crater. This is a Gigahertz Peaked Spectrum object [2] [3] with a redshift of (z) 1.187, [4] first discovered by astronomers in 1966. [5] Its radio spectrum appears to be flat making it a flat-spectrum radio quasar, or an FRSQ in short. [6] [7]
PKS 1127-145 displays blazar-like behavior. It is known to undergo a period of gamma ray activity, [8] especially in December 2020 where its daily gamma ray flux reached a peak of (E > 100 MeV) of (1.6 ± 0.3) x 10−6 photons cm−2 s−1. [9] Two flares were detected by Fermi-LAT in May and October 2022. [10] [11]
The radio structure of PKS 1127-145 is found complex. A radio image made by the Very Long Baseline Interferometry (VLBI) shows the object has two components, mainly a bright component and a much weaker component with same brightness temperatures of 1.3 x 1011 Kelvin. No extension is found in northwest direction. [12] There is a presence of a compact core displaying strong increase of flux density [13] with the outermost component being separated into several smaller regions enveloped completely by emission. [9] A stationary feature is also seen located 4 mas from the core via a 22 GHz image taken by VLBI. [14] Circular polarization has also been found in the quasar as well. [15]
An X-ray jet has been discovered in PKS 1127-145 by Chandra X-ray Observatory. [16] With an estimated length of 300 kiloparsecs, this makes the longest one detected so far in any of the high redshift quasars. [17] Advanced CCD Imaging Spectrometer also revealed a complex structure in the X-ray jet from the core with bright knots of different morphologies. Two of the knots showed changes in their profiles while the other knot is found fainter with presence of X-ray emission scattered over a large area. [18]
A more in-depth analysis of the X-ray jet in PKS 1127-145 showed the inner jet of PKS 1127-145 located from the core is found to be extremely polarized and a parallel magnetic field towards the jet's axis. Upon reaching 18 arcseconds from the core, the jet suddenly bends slightly causing the re-brightening of radio emission. In additional, there is a 90° rotation of the magnetic field suggesting it might be compressed to the plane that is found perpendicular to the axis. [9]
PKS 0637-752 is a quasar located six billion light years in the constellation of Mensa. It is noted for having a bright and largest astrophysical jet at redshift of z = 0.651. Discovered by Einstein Observatory in 1980 through X-rays, PKS 0637-752 was the first celestial object to be observed by Chandra X-ray Observatory upon its commissioning in July 23, 1999.
PKS 2126-158, also known as PKS 2126-15, is a quasar located in Capricornus. It has a redshift of 3.268000, which corresponds to the distance of 11.5 billion light years. It is classified as a gigahertz peaked-spectrum quasar (GPS) with a flat-spectrum radio source and a blazar, a type of active galaxy shooting an astrophysical jet towards Earth.
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.
PKS 0405–385 is a blazar in the constellation of Eridanus. This is a compact radio quasar with a redshift (z) of 1.285, an indicator of its significant distance. The radio spectrum of this source appears flat, making it a flat-spectrum radio quasar (FSRQ).
PKS 0736+017 is a blazar located in the constellation of Canis Minor. This object is also a highly polarized compact radio quasar. Its source having a radio spectrum, appears to be flat, making it a flat spectrum radio quasar. It has a redshift of (z) 0.189 and is hosted in a large elliptical galaxy with a half light radius measurement of re = 13 kiloparsecs. The black hole mass in PKS 0736+017 is 7.32+0.89-0.91 x 107 Mʘ based on a full width at half maximum (FWHM) scaling factor and virial relation.
NRAO 530 or PKS 1730-13 is a flat-spectrum radio quasar located in the southern constellation of Serpens. It has a redshift of 0.902. and was first discovered by two astronomers, W.J. Welch and Hyron Spinrad in 1973. It is classified as a blazar because of its optical variability across the electromagnetic spectrum in radio, gamma ray and X-ray bands. This quasar is also further categorized an OVV quasar.
PKS 0208-512 is a blazar located in the southern constellation of Eridanus. It has a redshift of 1.003 and was first discovered in 1975 by astronomers conducting the Parkes 2700 MHz survey in Australia as a bright astronomical radio source. This object is also classified highly polarized with the radio spectrum appearing to be flat, thus making it a flat-spectrum radio quasar.
DA 193 is a blazar located in the constellation of Auriga. It has a high redshift of 2.365. It was first discovered as an unknown astronomical radio source in 1971 by D.G. MacDonell and A.H. Bridle. This is a low polarized quasar containing a classic homogeneous synchrotron self-absorption spectrum. The radio spectrum of this source shows a turnover frequency at 5 GHz and this object has also been referred to as a gigahertz-peak spectrum source.
PKS 1424-418 is a blazar located in the constellation of Centaurus. It has a redshift of 1.522 and was first discovered in 1971 by astronomer Keith Peter Tritton who identified the object as ultraviolet-excessive. This object is also highly polarized with a compact radio source. The radio spectrum of this source appears flat, making it a flat-spectrum radio quasar.
PKS 0537-441 is a blazar located in the constellation of Pictor. It has a redshift of 0.896 and was discovered in 1973 by an American astronomer named Olin J. Eggen, who noted it as a luminous quasar. This is a BL Lacertae object in literature because of its featureless optical spectra as well as both a possible gravitational microlensing and a gravitationally lensed candidate. Its radio source is found compact and is characterized by a spectral peak in the gigahertz range, making it a gigahertz-peaked spectrum source (GPS).
PKS 0420-014 is a blazar located in the constellation of Eridanus. This is a high polarized quasar with a redshift of (z) 0.915, first discovered as an astronomical radio source by astronomers in 1975. The radio spectrum of this source appears to be flat, making it a flat-spectrum radio quasar (FRSQ).
PKS 1622-297 is a blazar located in the constellation of Scorpius. It is one of the brightest objects of its type in the gamma ray region. It has a redshift of (z) 0.815. This blazar was first discovered as a compact astronomical radio source in 1970 by astronomers who were conducting interferometer observations and identified with an optical counterpart in 1984. In addition, the radio spectrum of the source appears flat, making it a flat-spectrum radio quasar (FRSQ).
PKS 0458-020 also known as PKS 0458-02, is a quasar located in the constellation of Orion. It has a redshift of (z) 2.286 and was first identified as an astronomical radio source during the radio survey conducted by Parkes Observatory in 1966. Subsequently the source was shown to display optical behavior before being classfied as a blazar via an optical polarimetry study in 1985. This source also shows radio spectrum appearing to be flat, hence making it a flat-spectrum radio quasar (FRSQ).
PKS 1510-089 is a blazar located in the constellation of Libra, categorized as a highly polarized quasar showing fast variations in polarization angles, with a redshift of (z) 0.361. It was first discovered in 1966 as an astronomical radio source during the Parkes Observatory survey in 1966. The radio spectrum of the source appears flat, thus making it a flat-spectrum radio quasar (FRSQ).
PKS 0454-234 is a blazar located in the constellation of Lepus. It is classified as a highly polarized quasar with a redshift of (z) 1.003. This object was first discovered in 1970 during a 1415 MHz continuum survey conducted by Ohio State University where it was given the designation, OF -292. The radio spectrum of this source is flat, making it a flat-spectrum radio quasar.
4C +28.07 is a blazar located in the constellation of Aries. It has a redshift of 1.213 and was first discovered in 1970 as a compact astronomical radio source during an interferometer observation and designated as CTD 20. The radio spectrum of the source is considered flat, making it a flat-spectrum radio quasar. It is one of the brightest blazars observed in the gamma ray energy band.
PKS 2255-282 is a blazar located in the constellation of Piscis Austrinus. This is a low-polarized quasar at the redshift of 0.926, first discovered in 1975 by astronomers via a spectroscopic observation. The radio spectrum of this source appears as flat, making it as a flat-spectrum quasar but also a Gigahertz Peaked Spectrum source (GPS) with turnover frequency between 22 and 37 GHz.
PKS 0528+134 is a distant blazar located in the Galactic anticenter towards the constellation of Orion. This is a compact radio quasar, classified as radio-loud with a redshift of (z) 2.07 yet having low polarization. It was first discovered in 1977 by astronomers as a radio source and contains a radio spectrum that appears as flat making it a flat-spectrum radio quasar. It has an optical brightness of 19.5.
GB 1508+5714 is an extremely distant blazar located in the constellation of Draco. It has a redshift of (z) 4.30 and is classified as a radio-loud quasar, first discovered in 1995 by astronomers. The radio spectrum of the source appears as flat, making it a flat-spectrum source but also a bright X-ray source.
PKS 1335-127 is a blazar located in the constellation of Virgo with a redshift of (z) 0.539. This is a compact BL Lac object containing a radio source of extragalactic origins; discovered in 1970 during the continuum survey conducted by astronomers from Ohio State University. The object shows a radio spectrum appearing as flat, thus making it a flat-spectrum radio quasar (FRSQ), but also classified as a gigahertz-peaked source (GPS) with high polarization.