3C 138 | |
---|---|
Observation data (J2000.0 epoch) | |
Constellation | Taurus |
Right ascension | 05h 21m 09.886s |
Declination | +16° 38′ 22.052″ |
Redshift | 0.759000 |
Heliocentric radial velocity | 227,543 km/s |
Distance | 6.739 Gly |
Apparent magnitude (V) | 18.84 |
Apparent magnitude (B) | 19.37 |
Characteristics | |
Type | Opt. var, Sy 1.5 |
Other designations | |
4C +16.12, PKS B0518+565, LEDA 2817552, DA 170, Cul 0518+565, NRAO 205 |
3C 138 is a quasar [1] located in the constellation of Taurus. It has a redshift of (z) 0.76. [2] The radio spectrum of this source appears both compact and steep, making it a compact steep-spectrum radio quasar. [3] [4] [5] It is also one of the few 3C objects showing a defined and turn-over in its electromagnetic spectrum at low frequencies. [2]
3C 138 is known to shown linear polarization at high degrees although the source of it remains a mystery. When correcting the Faraday rotation for this object, the electric field position angle is ~170°, indicating the magnetic field direction as ~ 80°. [2] The source of 3C 138 is shown to emit gamma rays with a powerful flare detected in 2012. [6]
The radio structure of 3C 138 is unresolved at both 0.151 and 0.408 GHz. However, when detected through higher frequencies, it is revealed to be largely linear. [7] The structure is then further divided into separate components consisting of a bright radio core and a radio jet [8] which is polarized and showing a slight increase from 12 percent at 5 GHz to 14 percent at 15 GHz. [9] There are several extended knots present within the main jet emission region extending 400 milliarcseconds in a 65° position angle. A low surface-brightness counter-jet is located in an opposite direction from the region. [10] Furthermore, 3C 138 has a compact radio lobe located east and a much fainter, diffused radio lobe located west. [11]
3C 138 is one of the four primary calibrators used by the Very Large Array. The other three are 3C 48, 3C 147 and 3C 286. For all visibilities of other sources, they are calibrated via observed visibilities of one of the four calibrators. [12]
3C 286, also known by its position as 1328+307 or 1331+305, is a quasar at redshift 0.8493 with a radial velocity of 164,137 km/s. It is part of the Third Cambridge Catalogue of Radio Sources.
3C 147 (B0538+498) is a compact steep-spectrum (CSS) quasar that was discovered in 1964. It is located in the constellation Auriga not far in the sky from the 5th magnitude star Omicron Aurigae.
NGC 3862 is an elliptical galaxy located 300 million light-years away in the constellation Leo. Discovered by astronomer William Herschel on April 27, 1785, NGC 3862 is an outlying member of the Leo Cluster.
PKS 1353−341, also known as LEDA 88936 is a quasar located in the southern constellation Centaurus. It has an apparent magnitude of 18.5, making it only visible in powerful telescopes. Based on the object's luminosity, it is estimated to be 3.7 billion light years distant from the Solar System. It is receding from the Milky Way with a heliocentric radial velocity of 59,531 km/s
NGC 708 is an elliptical galaxy located 240 million light-years away in the constellation Andromeda and was discovered by astronomer William Herschel on September 21, 1786. It is classified as a cD galaxy and is the brightest member of Abell 262. NGC 708 is a weak FR I radio galaxy and is also classified as a type 2 Seyfert galaxy.
III Zw 2 is a Seyfert 1 galaxy located in the Pisces constellation. It has a redshift of 0.089 and is notable as the first of its kind to exhibit a superluminal jet.
3C 345 is a blazar/flat spectrum radio quasar located in the constellation of Hercules. It is noted for hosting a superluminal jet and its variability in almost all wave bands.
IRAS F11119+3257 or simply as F11119+3257, is a galaxy located in constellation Ursa Major. With a redshift of 0.187580, it has a light travel time distance of 2.5 billion light-years and is considered an ultraluminous infrared galaxy (ULIRG).
IRAS 09104+4109 is a galaxy located in the constellation Lynx. With a redshift of 0.440797, the light travel time for this galaxy, corresponds to 4.8 billion light-years from Earth. It is the brightest cluster galaxy in MACS J0913.7+4056 galaxy cluster and classified as a hyperluminous infrared galaxy.
PKS 0438-436, also known as PKS J0440-4333, is a quasar located in constellation Caelum. With a high redshift of 2.86, the object is located 11.2 billion light-years from Earth and is classified as a blazar due to its flat-spectrum radio source, (in terms of the flux density as with α < 0.5 and its optical polarization.
PKS 2215+020, known as PMN J2217+0220, is a quasar located in the Aquarius constellation. Its redshift is 3.570000, meaning the object is located 11.6 billion light-years away from Earth. It is classified as a flat spectrum radio source quasar.
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 1402+044 is a quasar located in the constellation of Virgo. It has a redshift of 3.207, estimating the object to be located 11.3 billion light-years away from 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.
3C 459 known as IRAS 23140+0348, is a radio galaxy located in the constellation Pisces. It is located 2.74 billion light years from Earth and is classified as a Seyfert 2 and LINER galaxy.
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.
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.
QSO B0153+744 is a quasar located in the constellation of Cassiopeia. It has a redshift of (z) 2.338 and has an optical brightness of mR = 17.5 magnitude. It was first discovered as an astronomical radio source in 1988. The radio spectrum of the source appears as flat when seen at centimeter wavelengths but optically thin at millimeter wavelengths. This object is also classified as radio-loud and exhibits low polarization, making it a low polarized quasar (LPQ).
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 2004-447 is a narrow-line Seyfert 1 galaxy located in the constellation of Sagittarius. It has a redshift of (z) 0.24 and is the radio-loudest gamma ray emitting AGN known in the southern hemisphere. It was first identified as an astronomical radio source during a very-long-baseline interferometry survey in 1989. The radio spectrum appears to be powerful and compact, making it a compact steep spectrum source. The X-ray emission for this source is described by a simple power-law in the energy range.