Abell 1201 in Leo
The galaxy cluster Abell 1201 is located around 2.1 billion light-years from Earth in the constellation Leo. With a redshift of z= 0.167, this
results in an escape velocity of v = 50,500 km/s, which corresponds to one sixth of the speed of light.
The brightest galaxy in ACO 1201 has the designation "LEDA 1430978" and is around 16.5mag bright (blue arrow in drawing). It is a truly
gigantic galaxy with a diameter of 260,000 light-years. Its absolute magnitude is given as M= -24.1mag, which corresponds to a luminosity
of 1.6 trillion! suns. Half of the starlight comes from a region with a diameter of 98,000 light-years. The galaxy is not round, but strongly oval
with an ellipticity of 0.32.
At the center of LEDA 1430978 resides an ultramassive black hole (UMBH) with a mass of almost 33 billion solar masses. In addition, the
galaxy acts as a gravitational lens and deforms a galaxy behind it (d= 4.7 billion light-years) into a narrow arc.
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The galaxy cluster Abell 1201 is easy to find as it is located near the well-known Leo triplet.
At a magnification of 380x, the individual galaxies are not particularly bright, but were still easy to recognize with indirect vision in my 20"
telescope. A total of 5 galaxies were visible, including LEDA 1430978 with its ultra-massive black hole.
