Astronomers have discovered a super massive black hole (SMBH) at the center of the well-known Cosmic Horseshoe Einstein Ring system.

Using gravitational lensing effects and stellar kinematics (how an SMBH affects the motion of stars around it) and data on asymmetrically placed lensed images of another distant galaxy, the mass of the SMBH is estimated at 36 billion solar masses, close to a new record. The galaxy itself is estimated at 5.2 trillion solar masses.

https://academic.oup.com/mnras/article/541/4/2853/8213862?login=false
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The diagram below illustrates the principle of an Einstein ring, formed when light from a distant object en route to an observer is bent by gravitational forces of an intervening object (e.g., a galaxy). This occurs because a massive body bends spacetime, as predicted by Einstein's theory of general relativity.

When the observer and objects are aligned, multiple images of the distant object can be seen in the shape of a ring.

https://en.wikipedia.org/wiki/Einstein_ring
https://galileo-unbound.blog/2021/04/05/the-lens-of-gravity-einsteins-rings/
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The following diagram is my guess for why the two images for the other distant galaxy appear asymmetrically placed around the main Einstein Ring in post #1.

The other distant galaxy must be located slightly off-center from the line of sight through the intervening massive galaxy.

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