Less than a year after its launch, ESA’s Euclid space mission has just published five new never-before-seen views of the Universe. These images, also available with the services of the Strasbourg astronomical Data Centre, demonstrate Euclid’s ability to unlock the secrets of the cosmos, in particular to identify dwarf galaxies, the most numerous galaxies in the Universe, globular clusters whose origin remains mysterious over very large fields , the remnants of past galactic collisions, or galaxies distorted by gravitational lenses. These are all varied areas of research that complement Euclid’s primary objectives: to study the dark matter and dark energy that govern the evolution of the Universe.
These new images are part of the Early Release Observations of Euclid. They accompany the first scientific data from the mission to be made public, and several scientific articles to be published, including two coordinated by researchers at the Strasbourg Astronomical Observatory.
In total, these first observations targeted 17 astronomical objects, ranging from nearby clouds of gas and dust to distant clusters of galaxies, upstream of the main Euclid survey. The Strasbourg researchers were particularly interested in nearby groups and clusters of galaxies: the Dorado group, and Fornax and Perseus clusters, which contain massive elliptical galaxies around which thousands of satellites and globular clusters orbit. Their census has been determined thanks to Euclid’s exceptional resolving power, almost equivalent to that of the Hubble telescope, but over very large fields. This has made it possible to exclude background galaxies and foreground stars from the catalogues.
The census of small satellite galaxies and globular clusters around large, massive galaxies has many benefits. The frequency of dwarf (satellite) galaxies is a constraint on cosmological models: most past observations disagree with the ‘standard’ Lambda-CDM cosmological model. Dwarf galaxies are also the building blocks that have enabled more massive galaxies to grow. The globular clusters of dwarf galaxies are deposited in the halos of galaxies when these dwarfs are accreted. Over several years, the census carried out by Euclid will make it possible to study these transformations of galaxies according to their environment in the Cosmic Web, i.e. according to whether they are in a cluster of galaxies, in a large filamentary structure or in a very empty region.
Access at CDS
The Euclid ERO images have been integrated into CDS data to make them accessible. Observations in the visible and infrared filters have been combined into colour images, and converted into HiPS format, which makes it possible to zoom in to the full resolution of the Euclid images, and to explore the images from a simple web browser using the Aladin Lite application.
You can use the mouse to zoom in or move around the view. You can also use the buttons above to centre the view on the corresponding objects.ESA press conference
The first scientific results were presented by the European Space Agency (ESA) in a special programme, and Karina Voggel and Teymoor Saifollahi were present to represent the Strasbourg Astronomical Observatory (at 14’30 in the video below).
Publications
Of all the scientific articles published on 24 May to mark the release of the new Euclid images, two in which researchers from the Strasbourg Astronomical Observatory played a leading role stand out:
- Euclid preparation. Detecting extragalactic globular clusters in the Euclid survey. Voggel et al. 2024.
- Euclid: Early Release Observations – Globular clusters in the Fornax galaxy cluster, from dwarf galaxies to the intracluster field. Saifollahi et al. 2024.
Scientific contacts in Strasbourg
- Ariane Lançon – ariane.lancon@astro.unistra.fr
- Karina Voggel – karina.voggel@astro.unistra.fr
- Teymoor Saifollahi saifollahi@unistra.fr
See also the first Euclid ERO images.