Twin Quasar
Called Q0957 561, QSO 0957 561 as well, Zwillingsquasar (English Twin Quasar ) or Doppelquasar (English Double Quasar ), is a gravitational lens by a doubly imaged quasar in the constellation Ursa Major, about 10 arcmin north of NGC 3079th Q0957 561 was the first discovered gravitational lens system with multiple images and is today one of the most studied objects of this type
Recent publications express serious doubts as to whether an "ordinary " very massive black hole located in the center of this quasar. It should rather be a new phenomenon that astronomers at the Harvard - Smithsonian Center for Astrophysics, Magnetospheric Eternally Collapsing Object or as short MECO call.
Gravitational lens system
Due to the curvature of space-time by the mass of gravitational lensing caused the two images A and B of the quasar, which are 6 arcseconds apart. There is a time delay of 417.1 ± 0.1 days between the two images. The images have an apparent magnitude of 16.7 like in the component A and 16.5 may in component B. The quasar has a redshift of z = 1.41 (9 billion light years ) on.
The main components of the gravitational lens are a cluster of galaxies at z = 0.36 ( 4 billion light years ) and its cD galaxy (G1 ) and a group of galaxies at z = 0.5. The cD galaxy G1 of the galaxy cluster is only about one arcsecond from the image B of the quasar removed.
Historical classification
First gravitational lens with Quasar
The quasar QSO 0957 561 A / B, called Twin Quasar ( Zwillingsquasar ), in the spring of 1979 by the Anglo-American team led by the British Dennis Walsh and Robert Carswell, and Ray Weymann the Americans using the 2.1 -meter telescope at Kitt discovered peak National Observatory in Arizona / USA. The team noticed that the quasars together are not only unusually dense, but that also the redshift and spectrum in the visible region are strikingly similar. They published the assumption that there is likely to be only a quasar appears twice by a gravitational lens effect.
The Zwillingsquasar quickly attracted the attention of professional astronomers up, we have here but one of the first direct visible evidence of a gravitational lens, as it was described in 1915 by Albert Einstein in his General Theory of Relativity.
Scientific clarification
However, critics pointed to differences between the two quasars in the radio wave range. Thus, a team discovered by David Roberts at the VLA ( Very Large Array) in Socorro, New Mexico / USA, in the summer of 1979, a matter -jet of the quasar A, for which there apparently was no equivalent in quasar B. In addition, the distance between the two images with 6 arc seconds were too large to be generated solely from the galaxy densely found in the quasar B G1.
Only on high-resolution images of the region that were with VLBI ( Very Long Baseline Interferometry ) recorded a team around Marc V.Gorenstein 1983 clearly mirror-symmetric matter jets of quasars A and B. It could also be noted that the galaxy G1 part a cluster of galaxies is that amplifies the light deflection.
The slight spectral differences of quasar A and B explained by the fact that on the two light paths can there are different conditions, such as different density of the intergalactic medium and therefore different extinction.
Time delay of the images
Based on the observation period of over 30 years is now certain that the northern image A of the quasar the earth around 14 months earlier than the southern image B, which obviously covers a 1.1 light years longer path. Published in 2003, Wesley N. Colley, a time delay of 417.09 ± 0.07 days as a result of two 10 -day observation periods in January 2000 and March 2001. Were involved twelve distributed around the earth observatories around the clock a total of 3543 images recordings and then were evaluating.
Schematic illustration of the main luminous structures that have been determined by reverberation microlens analysis:
- Dark compact center with a dipole field lines (dotted yellow)
- Sharp illuminated ring on the inner edge of the accretion disk (White)
- Dark accretion disk
- Outflowing wind structures (Elvis areas / blue), the fluorescence of which contributes to the observed UV - optical continuum
- With compact radio cores and jets (red)
Discovery of possible exo- planet
In 1996, the Zwillingsquasar talked about, as a team from the Harvard - Smithsonian Center for Astrophysics to Rudy E.Schild observed a temporary anomaly in image B, which was not found in Figure A. One possible explanation is the transit of a planet of the galaxy G1 with three Earth masses, through the beam path of image B. This would be 4 billion light years, the farthest planet observed. Other highly significant observations of this sort reinforce the suspicion that dark matter in the form of very distant planet repeatedly traverses the beam path B of the quasar.
MECO hypothesis
Since the nineties, astronomers at the Harvard - Smithsonian Center for Astrophysics study under the direction of Rudy E.Schild continuously Q0957 561 with up to 14 telescopes in international cooperation. By synchronizing the images A and B, the optical resolution of the measured values due to the gravitational lens effect, as in a system of two telescopes, increased. The central object with 3-4 billion solar masses dubbed Rudy plate ( CfA ), Darryl Head ( Marwood Astrophysics Research Center) and Stan Robertson (Southwestern Oklahoma State Univ. ) " Magnetospheric Eternally Collapsing Object " or short MECO. "We call the object is not a black hole, because we found evidence that the object contains an anchored in its interior magnetic field that penetrates the surface of the central collapsing object and the environment of the quasar interacts ," says Shield.
Shield and his colleagues found that the 1000 Å wide matter jets not, as in black holes expected over the poles, begin near the Schwarzschild radius ( around 80AE ) but 8000AE from the center. In addition, the brightly glowing, hot inner edge of the accretion disk has a radius of 2000AE. Both indicates that the central object itself produces a strong, rapidly rotating magnetic field, which holds by a " magnetic propeller effect" the vicinity of the central object of matter free. This is in contradiction to the previous view that the magnetic fields of quasars are produced by ions in the rapidly rotating accretion disk and that this accretion disk ends right at the event horizon of the Schwarzschild radius.
Observability
- Q0957 561 A: 1425-7427021
- Q0957 561 B: 1425-7427023
The area with the sources of the USNO - A2.0.
Because of its low brightness of 16.5 like the twin quasar Q0957 561 is not observed with smaller telescopes. Only from a telescopic opening ( aperture) of 50cm, both components may be separated by long-exposure CCD camera shots under good seeing.
Even with large optical telescopes can be found, as in ordinary stars, only small round Airy disk, hence the name " Quasar " for " quasi -stellar ". All other findings emerge from the scientific analysis of the received electromagnetic waves by this object.
The field galaxies around the main galaxy G1 ( 21.9 mag), which is responsible for gravitational lensing, also results in the use of optical instruments with very large aperture and long exposure time only small faded spots.
The property is listed in the various astronomical catalogs, including USNO - A2.0 (1998) and USNO - B1.0 ( 2003). With the help of USNO ( United States Naval Observatory ) laymen can download photographic images of the star field and study properties of the objects listed below entering the astronomical coordinates.