Einstein Cross


The Einstein Cross is a gravitationally lensed quasar that sits directly behind ZW 2237+030, Huchra's Lens. Four images of the same distant quasar appear around a foreground galaxy due to strong gravitational lensing. This system was discovered by John Huchra and coworkers in 1985.
Another Einstein cross discovery was announced March 18, 2019.
While gravitationally lensed light sources are often shaped into an Einstein ring, due to the elongated shape of the lensing galaxy and the quasar being off-centre, the images form a peculiar cross-shape instead.

Details

The quasar's redshift indicates that it is located about 8 billion light years from Earth, while the lensing galaxy is at a distance of 400 million light years.
The apparent dimensions of the entire foreground galaxy are 0.87 × 0.34 arcminutes, while the apparent dimension of the cross in its centre accounts for only 1.6 × 1.6 arcseconds.
The Einstein Cross can be found in Pegasus at,.
Amateur astronomers are able to see some of the cross using telescopes; however, it requires extremely dark skies and telescope mirrors with diameters of or greater.
The individual images are labelled A through D, the lensing galaxy is sometimes referred to as QSO 2237+0305 G.

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