Twin Quasar
Encyclopedia
The Twin Quasar also known as SBS 0957+561, or TXS 0957+561 (also Q0957+561 or QSO 0957+561 A/B), was the first identified gravitationally lensed
object.
bends light so that two images of the quasar appear in the sky. This is known as gravitational lensing, and is a consequence of Einsteinian warped space-time. The quasar lies at redshift
z = 1.41(8.7 billion ly), while the lensing galaxy lies at redshift z = 0.355 (3.7 billion ly). The lensing galaxy with apparent dimension of 0.42×0.22 arcminutes lies almost in line with the B image, lying 1 arcsecond off. The quasar lies 10 arcminutes north of NGC 3079
, in the constellation
Ursa Major
. The astronomical data services SIMBAD
and NASA/IPAC Extragalactic Database
(NED) list several other names for this system.
The Twin Quasar's two images are separated by 6 arcseconds. Both images have an apparent magnitude
of 17, with the A component having 16.7 and the B component having 16.5. There is a 417 ± 3 day time lag between the two images.
(type cD) lying within a cluster of galaxies that also contribute to the lensing.
in Arizona/USA. The team noticed the two quasars not only being unusually close to each other, but redshift
and visible light spectrum for these objects were surprisingly similar. They published their assumption of "the possibility that they are two images of the same object formed by a gravitational lens
".
The Twinquasar soon caught attention of professional astronomers, since it was one of the first directly observable gravitational lens effects, first described in 1915 by Albert Einstein
in his General Theory of Relativity.
Critics however indicated the difference between the two quasars in radio frequency
. In mid 1979 a team around David Roberts at the VLA
(Very Large Array) near Socorro, New Mexico/USA discovered a relativistic jet
emerging from quasar A with no corresponding equivalent in quasar B. Furthermore the distance between the two images, namely 6 arcseconds, was too great to have emerged from the galaxy G1, a galaxy found closely by quasar B.
Finally a team around Marc V. Gorenstein found axial symmetric (mirrored-imaged) relativistic jets in 1983 with the aid of high resolution pictures produced by VLBI (Very Long Baseline Interferometry). It was further discovered that galaxy G1 is part of a galaxy cluster
which intensifies the deflection.
Slight spectral differences between quasar A and quasar B can be explained by different densities of the intergalactic medium in the light paths, resulting in differed extinction
.
30 years of observation made it clear that image A of the quasar reaches earth about 14 months earlier than the corresponding image B, obviously resulting in a range difference of 1.1 ly
.
In 1996 a team at Harvard-Smithsonian Center for Astrophysics
around Rudy E. Schild discovered a temporal anomaly which led to a controversial, and unconfirmable theory that there is a planet
approximately three Earth masses in size in the lensing galaxy. The results remain speculative because the chance alignment that led to its discovery will never happen again; although hope is nurtured that fine structures in the early universe could be made observable with the aid of gravitational lensing effects. If it could be confirmed, however, it would make it the most distant known planet, 4 billion ly away.
announced findings which suggest that the object at the heart of Q0957+561 is not a supermassive black hole
, as is believed to be the case for all quasars, but a magnetospheric eternally collapsing object
. Schild's team at the Harvard-Smithsonian Center for Astrophysics
found that the jets originated 8000 AU from the poles of the centre, in a region 1000AU across, and that "this quasar appears to be dynamically dominated by a magnetic field internally anchored to its central, rotating supermassive compact object" (R. E. Schild
). The accretion disc ends at 2000AU from the centre, and the inner edge is intensely radiating.
Gravitational lens
A gravitational lens refers to a distribution of matter between a distant source and an observer, that is capable of bending the light from the source, as it travels towards the observer...
object.
Quasar
QSO 0957+561 A (SBS 0957+561 A) and QSO 0957+561 B (SBS 0957+561 B) are the two components of a double-imaged quasar, meaning that an intervening mass concentration between Earth and the quasarQuasar
A quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...
bends light so that two images of the quasar appear in the sky. This is known as gravitational lensing, and is a consequence of Einsteinian warped space-time. The quasar lies at redshift
Redshift
In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...
z = 1.41(8.7 billion ly), while the lensing galaxy lies at redshift z = 0.355 (3.7 billion ly). The lensing galaxy with apparent dimension of 0.42×0.22 arcminutes lies almost in line with the B image, lying 1 arcsecond off. The quasar lies 10 arcminutes north of NGC 3079
NGC 3079
NGC 3079 is a barred spiral galaxy about 50 million light-years away, and located in the constellation Ursa Major. A prominent feature of this galaxy is the "bubble" forming in the very center .-Center Bubble:...
, in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Ursa Major
Ursa Major
Ursa Major , also known as the Great Bear, is a constellation visible throughout the year in most of the northern hemisphere. It can best be seen in April...
. The astronomical data services SIMBAD
SIMBAD
SIMBAD is an astronomical database of objects beyond the Solar System...
and NASA/IPAC Extragalactic Database
NASA/IPAC Extragalactic Database
The NASA/IPAC Extragalactic Database is an on-line astronomical database for astronomers that collates and cross-correlates astronomical information on extragalactic objects...
(NED) list several other names for this system.
The Twin Quasar's two images are separated by 6 arcseconds. Both images have an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of 17, with the A component having 16.7 and the B component having 16.5. There is a 417 ± 3 day time lag between the two images.
Lens
The lensing galaxy, YGKOW G1 (sometimes called G1 or Q0957+561 G1), is a giant ellipticalElliptical galaxy
An elliptical galaxy is a galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile. They range in shape from nearly spherical to highly flat and in size from hundreds of millions to over one trillion stars...
(type cD) lying within a cluster of galaxies that also contribute to the lensing.
History
The quasars QSO 0957+561A/B were discovered in early 1979 by an Anglo-American team around Dennis Walsh, Robert Carswell and Ray Weyman, with the aid of the 2.1 m Telescope at Kitt Peak National ObservatoryKitt Peak National Observatory
The Kitt Peak National Observatory is a United States astronomical observatory located on 2,096 m Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, southwest of Tucson...
in Arizona/USA. The team noticed the two quasars not only being unusually close to each other, but redshift
Redshift
In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...
and visible light spectrum for these objects were surprisingly similar. They published their assumption of "the possibility that they are two images of the same object formed by a gravitational lens
Gravitational lens
A gravitational lens refers to a distribution of matter between a distant source and an observer, that is capable of bending the light from the source, as it travels towards the observer...
".
The Twinquasar soon caught attention of professional astronomers, since it was one of the first directly observable gravitational lens effects, first described in 1915 by Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
in his General Theory of Relativity.
Critics however indicated the difference between the two quasars in radio frequency
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
. In mid 1979 a team around David Roberts at the VLA
Very Large Array
The Very Large Array is a radio astronomy observatory located on the Plains of San Agustin, between the towns of Magdalena and Datil, some fifty miles west of Socorro, New Mexico, USA...
(Very Large Array) near Socorro, New Mexico/USA discovered a relativistic jet
Relativistic jet
Relativistic jets are extremely powerful jets of plasma which emerge from presumed massive objects at the centers of some active galaxies, notably radio galaxies and quasars. Their lengths can reach several thousand or even hundreds of thousands of light years...
emerging from quasar A with no corresponding equivalent in quasar B. Furthermore the distance between the two images, namely 6 arcseconds, was too great to have emerged from the galaxy G1, a galaxy found closely by quasar B.
Finally a team around Marc V. Gorenstein found axial symmetric (mirrored-imaged) relativistic jets in 1983 with the aid of high resolution pictures produced by VLBI (Very Long Baseline Interferometry). It was further discovered that galaxy G1 is part of a galaxy cluster
Galaxy cluster
A galaxy cluster is a compact cluster of galaxies. Basic difference between a galaxy group and a galaxy cluster is that there are many more galaxies in a cluster than in a group. Also, galaxies in a cluster are more compact and have higher velocity dispersion. One of the key features of cluster is...
which intensifies the deflection.
Slight spectral differences between quasar A and quasar B can be explained by different densities of the intergalactic medium in the light paths, resulting in differed extinction
Extinction (astronomy)
Extinction is a term used in astronomy to describe the absorption and scattering of electromagnetic radiation by matter between an emitting astronomical object and the observer. Interstellar extinction—also called Galactic extinction, when it occurs in the Milky Way—was first...
.
30 years of observation made it clear that image A of the quasar reaches earth about 14 months earlier than the corresponding image B, obviously resulting in a range difference of 1.1 ly
Ly
Ly may refer to:* Ly the Fairy, a character from Rayman 2: The Great Escape* Lý Dynasty, a dynasty of Vietnam* Ly * Libya, ISO 3166-1 country code** .ly, the Top-level domain for Libya...
.
In 1996 a team at Harvard-Smithsonian Center for Astrophysics
Harvard-Smithsonian Center for Astrophysics
The Harvard–Smithsonian Center for Astrophysics is one of the largest and most diverse astrophysical institutions in the world, where scientists carry out a broad program of research in astronomy, astrophysics, earth and space sciences, and science education...
around Rudy E. Schild discovered a temporal anomaly which led to a controversial, and unconfirmable theory that there is a planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
approximately three Earth masses in size in the lensing galaxy. The results remain speculative because the chance alignment that led to its discovery will never happen again; although hope is nurtured that fine structures in the early universe could be made observable with the aid of gravitational lensing effects. If it could be confirmed, however, it would make it the most distant known planet, 4 billion ly away.
MECO possibility
R. E. SchildR. E. Schild
Rudolph E. Schild, PhD is an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. He has authored or contributed to over two hundred and fifty papers. He is married to mezzo soprano Jane Struss, who teaches voice at Longy School of Music....
announced findings which suggest that the object at the heart of Q0957+561 is not a supermassive black hole
Supermassive black hole
A supermassive black hole is the largest type of black hole in a galaxy, in the order of hundreds of thousands to billions of solar masses. Most, and possibly all galaxies, including the Milky Way, are believed to contain supermassive black holes at their centers.Supermassive black holes have...
, as is believed to be the case for all quasars, but a magnetospheric eternally collapsing object
Magnetospheric eternally collapsing object
Magnetospheric Eternally Collapsing Objects or MECOs are proposed alternatives to black holes advocated by Darryl Leiter and Stanley Robertson. They are a variant of eternally collapsing objects or ECOs proposed by Abhas Mitra in 1998. Mitra had devised an ostensive proof that black holes cannot...
. Schild's team at the Harvard-Smithsonian Center for Astrophysics
Harvard-Smithsonian Center for Astrophysics
The Harvard–Smithsonian Center for Astrophysics is one of the largest and most diverse astrophysical institutions in the world, where scientists carry out a broad program of research in astronomy, astrophysics, earth and space sciences, and science education...
found that the jets originated 8000 AU from the poles of the centre, in a region 1000AU across, and that "this quasar appears to be dynamically dominated by a magnetic field internally anchored to its central, rotating supermassive compact object" (R. E. Schild
R. E. Schild
Rudolph E. Schild, PhD is an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. He has authored or contributed to over two hundred and fifty papers. He is married to mezzo soprano Jane Struss, who teaches voice at Longy School of Music....
). The accretion disc ends at 2000AU from the centre, and the inner edge is intensely radiating.
See also
- Hypothetical planetHypothetical planetA hypothetical Solar System object is a planet, natural satellite or similar body in our Solar System whose existence is not known, but has been inferred from observational scientific evidence. Over the years a number of hypothetical planets have been proposed, and many have been disproved...
- Multiple images (gravitational lensing)
- Cloverleaf quasarCloverleaf quasarThe Cloverleaf quasar is a bright, gravitationally-lensed quasar.- Quasar :Molecular gas detected in the host galaxy associated with the quasar is the oldest molecular material known and provides evidence of large-scale star formation in the early universe.Thanks to the strong magnification...
External links
- Q0957+561: Die historisch erste Linse mit Quasar - The University of CologneUniversity of CologneThe University of Cologne is one of the oldest universities in Europe and, with over 44,000 students, one of the largest universities in Germany. The university is part of the Deutsche Forschungsgemeinschaft, an association of Germany's leading research universities...
. - Q0957+561 - CCD Image Based on 45-min total exposure - March/2007.
- Q0957+561 A,B