Gaia telescope's new data reveals 'goldmine' of over 500,000 undiscovered stars and more

In addition, the European Space Agency space telescope determined the orbits of over 150,000 asteroids and discovered over 380 gravity-lensed quasars.

As the Gaia project continues to build the most complete star catalog ever assembled, it has unveiled a "goldmine" of fresh data on cosmic objects.

The current release, dubbed Gaia's focused product release (FPR), includes locations for over 150,000 solar system asteroids, over 380 new gravitationally lensed quasars, and over half a million new dim stars.

With information on 1.8 billion stars, Gaia's detailed image of the Milky Way galaxy and its cosmic surroundings will enable researchers to delve further into the history of our universe. As it develops, the latest release closes some significant gaps on that map.

The European Space Agency (ESA), which oversees Gaia, claims that the new data offers fascinating and surprising research and discoveries that go well beyond what the space observatory was originally intended to detect.

The third Data Release (DR3) from Gaia, which was released in June 2022, is expanded upon by this new body of study. Even though it was thorough, DR3 missed certain dim stars that were not as brilliant as their surrounding stellar partners and included spaces in the sky that the space telescope had not yet scanned.

Globular clusters, some of the oldest objects in the cosmos, are prime examples of this; their densely concentrated cores of brilliant stars may overwhelm telescopes trying to examine them.

It goes beyond just adding missing areas to Gaia's cosmic map.

Omega Centauri, the most massive globular star cluster in the Milky Way, is home to some 10 million stars, making its core the most densely populated area of space that the star surveyor satellite telescope has yet to explore. This information was included in a recent release from the telescope.

In order to fill in these gaps, ESA researchers directed Gaia's attention to Omega Centauri, which is a relatively near star to Earth at just 15,800 light-years distant and may be used as a stand-in for other such clusters.

Lead author of the study and Gaia collaboration member Katja Weingrill said in a statement, "In Omega Centauri, we discovered over half a million new stars Gaia hadn't seen before— from just one cluster!"

The satellite telescope watched Omega Centauri using a unique mode that enables Gaia to look at a broader area of sky surrounding the heart of the globular cluster each time it came into view, as opposed to focusing on individual stars within the cluster, which is something Gaia specializes in. Thus, the fresh observations contributed to the testing of Gaia's equipment as well as this particular mode.

"We didn't expect to ever use it for science, which makes this result even more exciting," Weingrill stated.

Even though Gaia's three-dimensional map of the Milky Way now includes some previously undiscovered places, scientists are nonetheless interested in the new data since it may be used to better understand the Omega Centauri globular cluster.

"We were able to identify stars that are too near to each other to accurately measure using Gaia's standard pipeline," said Alexey Mints, a member of the Gaia Collaboration and co-author of the study. "We can create a comprehensive large-scale picture of Omega Centauri by analyzing the structure of the cluster, the distribution and motion of its individual stars, and other aspects using the new data. It's making the most of Gaia; we've fully used this incredible cosmic instrument."

From this perspective, the latest FPR data release is really a preview of what lies ahead in Gaia Data Release 4 (DR4). The satellite telescope is presently examining eight more Milky Way areas in a manner akin to its investigation of Omega Centauri. Therefore, DR4 might contribute to the discovery of information about our galaxy, including its exact age, the position of its core, and whether or not it has collided with other galaxies throughout its existence, by examining cosmic building pieces like Omega Centauri.

Gaia as a searcher for gravitational lenses

Gaia was not intended to study the universe on a larger scale, but as evidenced by its FPR disclosures, it may be discovering details about the universe's history and development that are essential to comprehending the cosmos as a whole.

Finding gravitational lenses—highly dense objects like star clusters that may be exploited to enhance light from far-off background sources like extinct galaxies—is one way Gaia may have an influence on cosmology.

This is made possible by an effect that is anticipated by Einstein's general theory of relativity, which holds that mass-based things "warp" spacetime itself; the more massive the item, the more intense the warping. Light from a far-off source travels through the intermediate item and is "bent" on its path towards Earth when a warping device is positioned between it and the source. The degree of deflection is determined by how near the mass source the light's path is. Because of this, light coming from the same source might arrive at Earth at various periods, and an item can appear more than once in an image.

This phenomenon has the ability to magnify that far-off source, making items visible that would otherwise be too weak and far away. Currently, this phenomena is being used to great advantage by the James Webb Space Telescope to examine some of the earliest galaxies in the cosmos. Finding new gravitationally lensed objects, especially quasars, the active centers of galaxies fueled by feeding black holes, is one way that Gaia can help with this. Lensed quasars are difficult to spot because repeated pictures from gravitational lensing tend to cluster together, causing photographs of a single object to look blurred and mistaken.

"Gaia truly seeks out lenses. Despite their apparent similarity to stars, some of the objects we view aren't just stars, according to Gaia, according to research co-author and Gaia collaboration member Christine Ducourant. "In reality, these are incredibly far-off lensed quasars, which are brilliant, active galactic centers driven by black holes.

"We now present 381 solid candidates for lensed quasars, including 50 that we deem highly likely: A goldmine for cosmologists and the largest set of candidates ever released at once."

A list of potential quasar candidates, some of which were included in DR3, was used to pick these possibilities; five of the lensed objects seemed to be uncommon structures known as "Einstein crosses." These happen when a single object's light appears in many locations inside the same picture in the form of a cross. Gaia saw twelve of these Einstein crossings in 2021.

Laurent Galluccio, a study co-author on the Gaia collaboration, stated, "The great thing about Gaia is that it looks everywhere, so we can find lenses without needing to know where to look." "With this data release, Gaia is the first mission to achieve an all-sky survey of gravitational lenses at high resolution."

This illustrates how Gaia might collaborate with Euclid, the ESA's dark matter and dark energy detective, which is scheduled for launch in July 2023, to assist in the study of these enigmatic facets of the cosmos, which make up around 95% of its composition. The satellite telescope can potentially be useful far closer to home, according to recent disclosures from Gaia.

Using Gaia to track red giants, asteroids, and other objects

Details on 156,823 asteroids that were discovered in DR3 are included in the latest Gaia releases. This allows for 20 times more precise orbital constraints and location determination than was possible with earlier studies of these asteroids.

This was accomplished by the ESA space telescope by studying the space pebbles for nearly twice as long as it has before. The European Space Agency (ESA) forecasts that the upcoming Gaia data dump DR4 will double the number of solar system entities recorded by Gaia, including comets and even satellites orbiting the Earth, and double the number of asteroids spotted by the space observatory.

The latest Gaia releases also feature signals from gas and dust that migrate between stars in the Milky Way's disk, as well as measurements of the dynamics of over 10,000 binary red giant stars—the biggest collection of such stellar objects ever compiled.

"Although its key focus is as a star surveyor, Gaia is exploring everything from the rocky bodies of the solar system to multiply imaged quasars lying billions of light-years away, far beyond the edges of the Milky Way," Timo Prusti, the European Space Agency's Gaia project "The mission is providing a truly unique insight into the Universe and the objects within it, and we're really making the most of its broad, all-sky perspective on the skies around us."