HE0435-1223 is a quadruple-lensed quasar and rare Einstein Cross located in the constellation Eridanus[1] at a distance of approximately 2.33 billion light years away from Earth.

[2] HE 0435-1223 was discovered in October 2008 by astronomer Patrick Foley during a study and search for gravitational quadruple lenses in deep sky objects.

[6][7] In 2017, scientists studied the emission lines as well as the inert zone of the quasar using the MMT Observatory.

By recombining the emissions from the different images, the team of scientists were able to carry out fairly precise measurements.

By studying the microwaves emitted by HE0435-1223, they were able to estimate the speed and temperature of the black hole's accretion disk.