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The double quasar 0957+561: a radio study at 6-centimeters wavelength
Science (New York, N.Y.)
|August 31, 1979
Summary
The double quasar 0957+561 may be two separate quasars, not a gravitational lens. Their similar optical and radio properties suggest simultaneous formation with similar initial conditions.
Area of Science:
- Astronomy and Astrophysics
- Cosmology
Background:
- The celestial object 0957+561, known as an optical double quasar, has been theorized to be a single object gravitationally lensed into two images.
- Gravitational lensing is a phenomenon where massive objects warp spacetime, bending light from background sources.
Purpose of the Study:
- To investigate the nature of the optical double quasar 0957+561.
- To differentiate between the gravitational lensing hypothesis and the possibility of two distinct quasars.
Main Methods:
- Utilized the Very Large Array (VLA) of the National Radio Astronomy Observatory to create a detailed radio map of 0957+561.
- Analyzed both optical and radio data to compare the characteristics of the observed sources.
Main Results:
- The radio map revealed unresolved sources coinciding with the optical images, alongside complex extended radio emission.
- While not definitively ruling out gravitational lensing, the observed radio structure is more consistent with two independent quasars.
- The optical and radio properties of the two apparent quasars exhibit strong similarities.
Conclusions:
- The complex radio structure of 0957+561 is more plausibly explained by two separate quasars.
- The similar properties suggest these two quasars likely formed concurrently under similar initial conditions.
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