El Gordo is the Fat One

 

El Gordo is the Fat One

It is well-known that we use galaxy clusters for better understanding dark matter. However, it can be done in both directions. Astronomers also use dark matter as a tool to understand clusters of galaxies. The discovery of a huge clump of dark material 2.4 billion miles away from Earth is a result of two clumps formed from dark matter from the collisions of galaxies. This may be a sign that dark matter can be sticky and help to explain how galaxies formed. This was discovered for the first time in 2007, in the middle of a collection called Abell 520. These discoveries were confirmed using multiple telescopes such as the Hubble. It helps astronomers understand the formation of galaxy clusters.

Astronomers can use the motions of galaxy clusters to calculate the size of the universe by combining all that we know about them! It is possible to combine almost all concepts we have discovered about galaxy clusters.

1) The Cosmic Microwave Background: A uniform microwave background that is consistent throughout the universe.

2) The Kinematic Sunyaev–Zel'dovich Effect (kSZ). As photons from the CMB scatter off hot gases in a cluster, their relative motion adds an extremely slight shift to the wavelength.

3) Dark matter: this mysterious matter that cannot be seen is what keeps the universe together

4) Dark energy: A mysterious force pulling the universe apart

5) Galaxy cluster composition - galaxies, intracluster media, dark matter, dark energy and dark matter

To begin, the kSZ factor is activated in the intracluster media (hot gas around galaxies). Gas is ionized when temperatures reach tens or millions of degrees. Photons from CMB scatter its electrons and give it an energy boost. The amount and speed of the energy imparted will depend on how fast the galaxy cluster moves, but not on how far away it is from Earth. Therefore, the kSZ Effect conveys information about the galaxy cluster's structure, motion, and doesn't require any standard candles to measure the immense distances in our Universe.

Astronomers can conclude from this study that the effect of kSZ is consistent the cosmological model that states the universe is dominated dark energy and darkness.