Huge star-forming regions found in an ancient galaxy.

Huge star-forming regions found in an ancient galaxy.

The left image shows a sharp image of the Einstein ring, made with ALMA. In the foreground is a galaxy, which should be invisible to ALMA. The result of the reconstruction of a distant galaxy image (right) using complex models of magnification and a gravitational lens showed thin structures inside the ring, which we have never seen before: a few dust clouds within the galaxy. Most likely they are giant cold molecular clouds, places of birth of stars and planets.

When the Atacama's large millimeter / submillimeter radio telescope (ALMA) first showed this almost perfect Einstein ring in the depths of space, questions about this geometry of this beautiful object filled the scientific world.

Astronomers have already managed to process the data recorded in a huge observatory located in the Atacama Desert (Chile), a lot of interesting information was obtained using an irregular galaxy called SDP.81, as it contains some of the most distant and massive star-forming regions in the surveyed Universe . This galaxy was formed in the first billion years after the Big Bang. "The reconstructed galaxy image obtained by ALMA is impressive," says Rob Ivison, director of ESO and co-author of 2 recent works on SDP.81. - “The huge capture area of ​​ALMA, the excellent resolution of its antennas, and the constant clear weather over the Atacama Desert - this is what leads to the best detail of the spectrum and both pictures. This means that we get very accurate observations, as well as information about how different parts galaxies are moving. We can study galaxies on the other end of the universe, how they merge and create a huge number of stars. These are the things that make me get up in the morning! "

A gravitational lens is formed when a massive object such as a black hole, a galaxy, or even a cluster of galaxies passes in front of a farther galaxy. Mass can act as a natural “lens” in space-time, increasing the light from a more distant galaxy.

This is because the mass of the “lens” bends the space-time around it, thereby reflecting the light from a more distant galaxy. This cosmic effect was successfully investigated by the Hubble Space Telescope, for example, in the "Frontier Fields" project. It is to spy on galaxies capable of becoming a gravitational lens, hoping to see a super-increase in Hubble’s magnifying capacity. Often, galaxies enlarged by a gravitational lens look too curved, but sometimes, if a distant galaxy is located well, it can form an Einstein ring, named after Albert Einstein, who formulated the equations of general relativity 100 years ago. Gravitational lenses are one of the proofs of Einstein's theories, they show that there is a curvature of spacetime around massive objects, as the physicist predicted.

After a detailed review of the observations of this Einstein ring, the most detailed to date, and using sophisticated light recovery software from SDP.81, astronomers discovered that this galaxy has a huge star-forming nebula, which is very similar to the Orion nebula in our galaxy), only many times more.

Observations of curvature using ALMA helped astronomers understand that these star-formation clots are about 200 light-years in size. The star formation rate there is a thousand times greater than the rate of active zones in any region of our galaxy.

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