Space telescope “Hubble” has started a new mission, which would shed light on the evolution of the first galaxies in the Universe. And to accomplish this, the space Observatory will use the most massive objects in the Universe – galactic clusters. As can be understood thanks to a new image provided by the telescope.
In the center of the image, which you can see below, is Abell 370, a cluster of several hundred galaxies located about 4 billion light years from Earth. And around this cluster, we can see thousands of galaxies located from us farther.
We can see them thanks to the cluster Abell 370. Hundreds of galaxies in this cluster is located close enough to each other that create a very powerful field of gravity. When the waves of light beyond that field, pass through it, very powerful force of gravity changes the direction of propagation of electromagnetic radiation. This amazing effect is called gravitational lensing and it allows you to see the objects in space, which under normal conditions we see just can’t.
Any sufficiently massive objects in space can create the gravitational lens effect, thanks to which astronomers can explore new corners of the Universe. The higher the mass, the stronger the effect. In the case of Abell 370, the effect is so strong that thanks to him, this image shows the galaxy to which even sensitive eyes of Hubble to get not.
Recently, astronomers have embarked on a new project Beyond the Ultra-deep Frontier Fields And Legacy Observations (or BUFFALO) whose task is the observation of the earliest galaxies of the Universe with the help of six galaxy clusters that create powerful gravitational lenses. Astronomers are very eager to find out what is behind these clusters.
In the above image you can see galaxy clusters Abell 370. The bright yellow-white objects in the picture are huge galaxies containing billions of stars. Objects having a blue tint are a more compact galaxy like our milky Way, with a younger population of stars. Fainter objects with a yellowish tinge – this is an old galaxy, which stops the star formation process.
Galaxy located behind the cluster Abell 370, is also shown in the picture and look like a blurred light sources. Perhaps the most interesting thing here is the object in the left part of the Central region. Astronomers have nicknamed it the Dragon (perhaps there is a kind of analogy with a Chinese dragon). The image of the “dragon” consists of five images taken by a space telescope at different angles. This object is a spiral galaxy that is “stretched” or “smeared” due to the powerful effect of gravitational lensing.
Using the gravitational lens effect, researchers from the Niels Bohr Institute (Denmark) and Durham University (UK) I hope to find out more about when the Universe formed the brightest galaxy as the formation of these galaxies is due to dark matter. Scientists want to know how fast galaxies formed during the first 800 million years after the Big Bang, and better understand the evolution of the lensing effect by using galaxy clusters and dark matter, which they are.
The first step for researchers in the new mission will be the determination of the quantities of dark matter contained in the galactic clusters. The stronger the gravitational lens effect suggests a more powerful force of gravity. Knowing the total mass of the galaxy, as well as the amount of mass, which accounts for the visible objects, scientists can estimate the volume contained in dark matter.
“Expanding the area of observation around these galaxy clusters, we will be able to significantly improve our understanding of the strength of gravitational lensing created by these accumulations, which is an important step to study the most distant galaxies that will be discovered in the course of the project BUFFALO,” says astrophysicist Matilda Auzac from the centre for extragalactic astronomy Durham University.
“In addition, BUFFALO will allow us to accurately determine the distribution of dark matter inside these massive galactic clusters, and to examine in more detail the evolutionary history of these clusters, filling in the missing pieces with modern evolutionary theories”.
The research mission of the BUFFALO will occupy a total of about 160 hours of observations, the researchers say. Images of the galactic cluster Abell 370 in full size, you can watch and download on the official website of the mission.
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