Euclid Telescope has images revealed, with galaxies – 11/07/2023 – Science

After just over four months in space, the ESA (European Space Agency) Euclid space telescope is ready to begin its six-year scientific mission, with the aim of deciphering the “invisible” Universe, formed by mysterious dark matter and dark energy. To celebrate, the Europeans released this Tuesday (7) the first five images produced by the equipment.

The targets were chosen more to show the capacity of the telescope, whose main characteristic is the ability to capture a large area of ​​the sky at once (a little larger than the region occupied by the full Moon and a hundred times larger than the field of view). of the James Webb telescope), than actually collecting scientific results. But that doesn’t mean there isn’t science to be gleaned from them. A scientific article about them, after analysis by the Euclid consortium, should be published at the beginning of next year.

“This is the moment when we have met all the engineering challenges, and we can begin the scientific phase,” said Carole Mundell, ESA’s director of science, during the presentation of the photos, broadcast live on the internet.

And there were many obstacles to making the telescope available to scientists. After being launched on July 1, the satellite traveled a distance of 1.5 million km from Earth, at a point of gravitational balance that allows it to follow the planet at all times as it orbits the Sun (the same region where it went launched Webb). Once there, engineers working on commissioning the systems discovered some problems.

“We had three big challenges, the big elephants in the room. First, the discovery of diffuse light,” said Micha Schmidt, mission operations manager. Apparently, sunlight was affecting the telescope depending on where it was pointed. “This was easily corrected once it was identified by allowing the spacecraft to only turn in a certain direction so that the solar shield hides the reflective area from the Sun.”

“Second, the X-rays, there’s nothing we can do, they make us lose 3% of the observations, which need to be redone. And the third challenge, keeping the spacecraft’s pointing accurate.” To keep the telescope pointed precisely at its targets, the satellite has a star detector, used as orientation references. “The problem was that the system couldn’t distinguish cosmic rays from stars.”

This was always a concern for the mission managers, and at the beginning it was dramatic to see the images shaky and full of risks due to the faulty pointing. But fortunately it was possible to correct the situation with a software update, putting the telescope in order for the scientific mission. “For commissioning, today was the big day,” Schmidt said. The telescope team expects to begin the six-year scientific mission, in a scan that will cover 36% of the sky, in early 2024.

THE FIRST IMAGES

To demonstrate Euclid’s versatility, five observations were produced of objects ranging from the most distant depths of the cosmos to our neighborhood in the Milky Way. The first of them looked at the Perseus galaxy cluster, an image that reveals around a thousand galaxies belonging to it, plus a hundred thousand others in the background. The further away you look, the deeper you can delve into the Universe’s past (because light, traveling at 300,000 km/s, takes a long time to get from there to here), and scientists estimate that some of the galaxies in this image are so far away that light took 10 billion years to get here. It’s a portrait of cosmic childhood, considering that the Big Bang occurred 13.8 billion years ago.

This first image is probably the best demonstration of Euclid’s potential, whose main objective is to map the presence of dark matter and dark energy, two entities that can only be detected indirectly, through gravity or the acceleration of the expansion of the cosmos, and thereby decipher the geometry of the Universe. Hence the name of the mission, in honor of the Greek mathematician Euclid, celebrated as the father of geometry.

The plan is to observe the distance and speed of billions of galaxies in order to build a three-dimensional map of the Universe in various directions. To achieve this, Euclid needs two qualities, according to Carole Mundell: “depth and precision”. “It’s incredible that we can portray such a vast area [do céu] immediately. In the past, these images had to be made in pieces. Euclid appears to be sensitive enough to capture small galaxies, and with precision.”

From this mapping, it will be possible to study the role of dark matter and dark energy (which together account for 95% of the entire content of the cosmos, as opposed to visible matter) and, perhaps, elucidate their nature, allowing us to discriminate between various hypotheses competitors.

The second image released is of the spiral galaxy IC 342, located a modest 11 million light-years away, making it a close neighbor in astronomical terms. It is known as “the hidden galaxy” because of the large amount of dust that blocks part of its light. “Euclid will observe billions of galaxies to reveal the structure of the Universe, and it all starts with one, and this is one,” says René Laureijs, one of the mission’s scientists.

The study of spiral galaxies helps scientists understand the Milky Way itself, which represents an observation challenge because we are inside it. But Euclid won’t just work with these “tidy” galaxies. The third satellite image depicts the irregular galaxy NGC 6822, which is even closer, at 1.6 million light-years. In the cosmic past, irregular galaxies were much more common, serving as building blocks for larger ones. When unveiling the great structures of the Universe, Euclid will have to study many of them.

The fourth image brings us back to the Milky Way, with the globular cluster NGC 6397. Located 7,800 light years from Earth, it contains hundreds of thousands of stars in a very compact region. What is most impressive about the Euclid image is how individual stars can be seen, in an image taken at once, encompassing the entire cluster.

Finally, the fifth image depicts a famous landscape, the Cabeça de Cavalo nebula, a stellar nursery that is 1,375 light-years away, close to Três Marias, in the Orion Constellation. Scientists hope to use this image to discover many young giant planets, as well as baby stars and brown dwarfs (stars larger than planets but smaller than stars, unable to produce their own brightness through nuclear fusion).