Regiomontanus
Ματαιοδοξία ματαιοδοξιών! Όλα είναι ματαιοδοξία.
A new release of data (3rd) from the Gaia mission.
"The main goal of the Gaia mission is to make the largest, most precise three-dimensional map of our Galaxy by surveying an unprecedented one per cent of the galaxy's population of 100 billion stars."
"Data from more than 1.8 billion stars has been used to create this map of the entire sky. It shows the total brightness and colour of stars observed by ESA's Gaia satellite and released as part of Gaia's Early Data Release 3 (Gaia EDR3).
Brighter regions represent denser concentrations of bright stars, while darker regions correspond to patches of the sky where fewer and fainter stars are observed. The colour of the image is obtained by combining the total amount of light with the amount of blue and red light recorded by Gaia in each patch of the sky.
The bright horizontal structure that dominates the image is the plane of our Milky Way galaxy. It is actually a flattened disc seen edge-on that contains most of the galaxy's stars. In the middle of the image, the Galactic centre appears bright, and thronged with stars.
Darker regions across the Galactic plane correspond to foreground clouds of interstellar gas and dust, which absorb the light of more distant stars. Many of these clouds conceal stellar nurseries where new generations of stars are currently being born.
Dotted across the image are also many globular and open clusters, as well as entire galaxies beyond our own. The two bright objects in the lower right of the image are the Large and Small Magellanic Clouds, two dwarf galaxies orbiting the Milky Way.
Gaia EDR3 was made public on 3 December 2020 and includes the position and brightness of more than 1.8 billion stars, the parallax and proper motion of almost 1.5 billion stars, and the colour of more than 1.5 billion stars. It also includes more than 1.6 million extragalactic sources."
-----------
"The new Gaia data have allowed astronomers to trace the various populations of older and younger stars out towards the very edge of our galaxy – the galactic anticentre. Computer models predicted that the disc of the Milky Way will grow larger with time as new stars are born. The new data allow us to see the relics of the 10 billion-year-old ancient disc and so determine its smaller extent compared to the Milky Way's current disc size.
The new data from these outer regions also strengthen the evidence for another major event in the more recent past of the galaxy.
The data show that in the outer regions of the disc there is a component of slow-moving stars above the plane of our galaxy that are heading downwards towards the plane, and a component of fast-moving stars below the plane that are moving upwards. This extraordinary pattern had not been anticipated before. It could be the result of the near-collision between the Milky Way and the Sagittarius dwarf galaxy that took place in our galaxy's more recent past.
The Sagittarius dwarf galaxy contains a few tens of millions of stars and is currently in the process of being cannibalised by the Milky Way. Its last close pass to our galaxy was not a direct hit, but this would have been enough so that its gravity perturbed some stars in our galaxy like a stone dropping into water.
Using Gaia DR2, members of DPAC had already found a subtle ripple in the movement of millions of stars that suggested the effects of the encounter with Sagittarius sometime between 300 and 900 million years ago. Now, using Gaia EDR3, they have uncovered more evidence that points to its strong effects on our galaxy's disc of stars.
"The patterns of movement in the disc stars are different to what we used to believe," says Teresa Antoja, University of Barcelona, Spain, who worked on this analysis with DPAC colleagues. Although the role of the Sagittarius dwarf galaxy is still debated in some quarters, Teresa says, "It could be a good candidate for all these disturbances, as some simulations from other authors show.""
ESA Science & Technology - Gaia's new data takes us to the Milky Way's anticentre and beyond
"The main goal of the Gaia mission is to make the largest, most precise three-dimensional map of our Galaxy by surveying an unprecedented one per cent of the galaxy's population of 100 billion stars."
"Data from more than 1.8 billion stars has been used to create this map of the entire sky. It shows the total brightness and colour of stars observed by ESA's Gaia satellite and released as part of Gaia's Early Data Release 3 (Gaia EDR3).
Brighter regions represent denser concentrations of bright stars, while darker regions correspond to patches of the sky where fewer and fainter stars are observed. The colour of the image is obtained by combining the total amount of light with the amount of blue and red light recorded by Gaia in each patch of the sky.
The bright horizontal structure that dominates the image is the plane of our Milky Way galaxy. It is actually a flattened disc seen edge-on that contains most of the galaxy's stars. In the middle of the image, the Galactic centre appears bright, and thronged with stars.
Darker regions across the Galactic plane correspond to foreground clouds of interstellar gas and dust, which absorb the light of more distant stars. Many of these clouds conceal stellar nurseries where new generations of stars are currently being born.
Dotted across the image are also many globular and open clusters, as well as entire galaxies beyond our own. The two bright objects in the lower right of the image are the Large and Small Magellanic Clouds, two dwarf galaxies orbiting the Milky Way.
Gaia EDR3 was made public on 3 December 2020 and includes the position and brightness of more than 1.8 billion stars, the parallax and proper motion of almost 1.5 billion stars, and the colour of more than 1.5 billion stars. It also includes more than 1.6 million extragalactic sources."
-----------
"The new Gaia data have allowed astronomers to trace the various populations of older and younger stars out towards the very edge of our galaxy – the galactic anticentre. Computer models predicted that the disc of the Milky Way will grow larger with time as new stars are born. The new data allow us to see the relics of the 10 billion-year-old ancient disc and so determine its smaller extent compared to the Milky Way's current disc size.
The new data from these outer regions also strengthen the evidence for another major event in the more recent past of the galaxy.
The data show that in the outer regions of the disc there is a component of slow-moving stars above the plane of our galaxy that are heading downwards towards the plane, and a component of fast-moving stars below the plane that are moving upwards. This extraordinary pattern had not been anticipated before. It could be the result of the near-collision between the Milky Way and the Sagittarius dwarf galaxy that took place in our galaxy's more recent past.
The Sagittarius dwarf galaxy contains a few tens of millions of stars and is currently in the process of being cannibalised by the Milky Way. Its last close pass to our galaxy was not a direct hit, but this would have been enough so that its gravity perturbed some stars in our galaxy like a stone dropping into water.
Using Gaia DR2, members of DPAC had already found a subtle ripple in the movement of millions of stars that suggested the effects of the encounter with Sagittarius sometime between 300 and 900 million years ago. Now, using Gaia EDR3, they have uncovered more evidence that points to its strong effects on our galaxy's disc of stars.
"The patterns of movement in the disc stars are different to what we used to believe," says Teresa Antoja, University of Barcelona, Spain, who worked on this analysis with DPAC colleagues. Although the role of the Sagittarius dwarf galaxy is still debated in some quarters, Teresa says, "It could be a good candidate for all these disturbances, as some simulations from other authors show.""
ESA Science & Technology - Gaia's new data takes us to the Milky Way's anticentre and beyond
