2023-11-07 15:29:32
“It’s a hell of a lot of detail,” says Frank Grupp from the Max Planck Institute for Extraterrestrial Physics in Garching about the first color images from ESA’s Euclid mission. Grupp led the development of the optics of the NISP infrared instrument, which has been flying in space with Euclid since July 1, 2023. And anyone who looks closely can only confirm his statement: the image of the Perseus galaxy cluster is teeming with galaxies. More than 100,000 can be seen in the background, in addition to the thousand members of the bunch themselves.
One is rightly reminded of the images taken by the Hubble Deep Field, in which NASA’s famous space telescope was aimed at a tiny, dark section of sky for a long time. However, there is one crucial difference: the size of the sky section. “If you compare the size of the Hubble Deep Field to the moon, it would be a small crater. For Euclid it is the full moon,” explains Grupp, before adding that the resolution of Euclid with its 1.2 meter mirror is of course slightly lower than that of the Hubble Space Telescope, which is twice as large. Still, it remains impressive. All the more so when you consider that the entire sky survey that Euclid will carry out will be 30,000 times larger than the now published section of the Perseus cluster.
The influence of dark matter on the movements of stars, gas and dust in galaxies can be studied using the example of the spiral galaxy IC 342. : Image: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre
“There is still a lot to expect”
Five hours of observation time were invested in the current image. “If you compare that with the six years of the mission that still lie ahead of us – a lot can be expected,” says Grupp. Euclid aims to help better understand two of the most puzzling phenomena in modern cosmology: dark matter and dark energy. To do this, the mission will observe billions of galaxies whose light has been traveling to us for up to ten billion years.
The star cluster NGC 6397, which consists of hundreds of stars, is around 7,800 light-years away from Earth and is therefore the second closest of its kind. : Image: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre
Scientists will then be able to use weak gravitational lensing – distortions of light from background galaxies caused by the foreground mass distribution – to deduce where and how much dark matter is. The movement of the galaxies in the galaxy clusters also suggests dark matter there. The large-scale distribution of the galaxy clusters will also make it possible to reconstruct the so-called baryonic acoustic oscillations: density waves that were formed shortly after the Big Bang due to the interaction of gravity and radiation pressure and whose traces provide information about the expansion of the universe accelerated by dark energy.
In addition to numerous stars, the irregular galaxy NGC 6822 also has some supernova remnants (purple). : Image: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre
New findings also for stellar astrophysics
However, the scientific potential of the mission goes well beyond this. The images of stars in two different wavelength ranges, in the near infrared and in visible light, will make it possible to catalog entire star populations and thus learn new things about the formation of stars. “A lot has already been done with regard to nearby star formation regions,” says Frank Grupp. “But always only small sections, never an overview of a large region.” And Euclid also offers a lot for scientists who are interested in the end of life of stars: in the recently published images of the irregular galaxy NGC 6822 and the globular star cluster NGC 6397, numerous remnants of supernova explosions can be seen.
Ulf von Rauchhaupt Published/Updated: , Recommendations: 11 Ulf von Rauchhaupt Published/Updated: , Recommendations: 19 Sibylle Anderl Published/Updated: , Recommendations: 32
The first data from Euclid have already been distributed to the various research teams – responsible for weak gravitational lensing, the distribution of galaxy clusters and the determination of redshift – so that they can test and optimize their data processing methods. “Science is already coming out of this,” says Grupp. The first publications are expected in a few months.
One of the most famous astronomical motifs: Euclid also provided a photograph of the Horsehead Nebula in the constellation Orion with many young stars. : Image: ESA/Euclid/Euclid Consortium/NAS
#ESAs #Euclid #mission #space #telescope #delivers #color #images