2023-10-13 16:15:19
Half a million new stars in Omega Centauri—the largest star cluster in our Milky Way galaxy—some 380 quasars seen through gravitational lenses and the defined position of more than 150,000 asteroids within the solar system. These are some of the exceptional advances recently announced by those responsible for the Gaia mission, the most emblematic project of the European Space Agency (ESA) to map our galaxy in detail and expand the global perspective of the cosmos around us.
The Gaia satellite is one of the most precise and technologically advanced instruments that have been built to date. It was launched into space in December 2013. Since its inception, a team of experts led by Carme Jordi, Xavier Luri and Francesca Figueras, from the Faculty of Physics of the University of Barcelona (UB), the Institute of Sciences, has participated in the mission. of the Cosmos of the UB itself (ICCUB) and the Institute of Space Studies of Catalonia (IEEC).
The new Gaia discoveries advance results of what will be the fourth release of data – the Gaia Data Release (DR4) – which will be made public no earlier than the end of 2025.
A new star map for Omega Centauri
Omega Centauri is the largest globular star cluster in our galaxy, with nearly ten million stars. It is located in the constellation of Centaurus, and its origin and evolution still baffle the astronomical community. But why has it been the subject of study by the Gaia mission?
«The Omega Centauri cluster is one of the nine regions of high stellar density studied by the Gaia mission. Globular clusters, one of the oldest types of astronomical objects in the universe, are especially valuable for reconstructing the Milky Way’s cosmic past. These bright objects, clearly visible in the sky, are still not well known and represent pieces of a gigantic cosmic puzzle that still needs to be completed to obtain full knowledge of the Milky Way,” explains the team from the UB, the ICCUB and the IEEC. .
Omega Centauri. (Photo: ESA / Gaia / DPAC. CC BY-SA 3.0 IGO)
With the new results, the Omega Centauri star map adds half a million new light sources revealed thanks to Gaia’s sophisticated observation mode for celestial cartography. Thus, the cartography known until now is expanded – the nearly 1.8 billion stars revealed in June 2022 by the Gaia Data Release (DR3) – and a complete, large-scale map of Omega Centauri with data on the positions can now be created. , the movements in the sky and the brightness of the new stellar sources.
The exploration of eight other regions of high stellar density will provide surprising results that will be part of the fourth installment of Gaia results (DR4), advances that will help determine the age of the galaxy, in addition to allowing galactic evolution models to be contrasted. and, finally, infer the possible age of the universe itself.
Einstein’s crosses, an extraordinary space-time phenomenon
One of the most spectacular manifestations of physics linked to Albert Einstein’s theory of general relativity is that of gravitational lenses. This is a phenomenon caused by the bending of light when passing near massive objects (stars, galaxies, etc.) that generates a giant magnifying glass effect. Gravitational lenses—applied as research tools in astrophysics—can amplify the brightness of light and capture multiple astronomical images that reveal extraordinary clues about the origin of the universe.
Now, Gaia has identified 381 quasars, whose light would be affected by gravitational lenses – 50 most likely are – which make up the most ambitious set of candidates discovered so far. Five of the possible lenses could be what are known as Einstein crosses, a rare space-time phenomenon that produces an image with four different cross-shaped components.
Asteroids, starlight and radial velocity
The mission has also defined the position of 156,823 asteroids – identified by the Gaia Data Release (DR3) – with a precision until now unknown. In the future, Gaia DR4 will double the number of asteroids studied.
Also noteworthy is the description of the dynamics of 10,000 red binary stars, decisive elements for calculating cosmic distances, confirming stellar characteristics and detailing how stars evolve in the universe. Never-before-published radial velocity data for variable stars, interstellar band analysis, and updated astrometry of solar system objects complete the scientific advances announced prior to the delivery of Gaia DR4.
Thanks to the three data releases from the Gaia mission, we now have an innovative, multidimensional cartographic view of the Milky Way, with unprecedented data on the positions, distances and movements of nearly two billion stars that will help reveal their origin and evolution. of our galaxy. The mission is redefining the foundations of astronomy, even in areas of astrophysics and cosmology not covered by the project. It is based on a great collaborative effort on an international scale to obtain and interpret a high volume of highly complex data, until completing a final catalog that will occupy one petabyte (one million gigabytes).
It is worth remembering that the ICCUB (UB-IEEC) Gaia team, led at the beginning of the mission by Professor Jordi Torra, was awarded the City of Barcelona Prize for experimental sciences and technology in 2013. In addition, the Gaia collaboration was also honored with the 2023 Lancelot M. Berkeley Prize – New York Community Trust for the best work in astronomy. (Source: UB)
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