Using a huge gigapixel image of nine VISTA survey telescope, installed at Paranal Observatory of ESO , an international team of astronomers has cataloged more than 84 million stars located in the central regions of the Milky Way.
This huge data set contains more than ten times more stars than previous studies and is an important step towards the knowledge of our host galaxy. The image gives the viewer a vision which can be ‘zoom’, approaching the center of our galaxy. It is so great that, if we wanted to print it with the typical resolution of a book, would measure 9 meters long and 7 meters wide.
“Looking in detail at the thousands of stars around the center of the Milky Way, we can learn much more about the formation and evolution , not only of our galaxy, but also on spiral galaxies in general.
Many spiral galaxies, including our host galaxy, the Milky Way, have a high concentration of old stars surrounding the center , which astronomers call center. Understanding the formation and evolution of the Milky Way’s core is vital for understanding the galaxy as a whole. However, getting detailed observations of this region is not a simple task.
“Observing the core of the Milky Way is very difficult because it is obscured by dust . “To penetrate the heart of the galaxy, we need to look in the infrared range of the light, which is less affected by dust.”
ESO has the VISTA survey telescope (Visible and Infrared Survey Telescope for Astronomy), which has a large mirror (4.1 m diameter), a wide field of view and very sensitive infrared detectors, which makes it the best tool available to accomplish this task . The team of astronomers is using data from the VISTA Variables in the Milky Way (VVV), one of six public surveys conducted by VISTA.
The data have been used to create a huge color picture of 108,200 by 81,500 pixels, containing a total of nearly nine billion pixels. This is one of the largest astronomical images ever produced . The team used these data to compile the largest catalog created until the concentration of stars in the central region of the Milky Way.
To assist in the analysis of this huge catalog, the brightness of each star in plasma versus color diagram for about 84 million stars to create color-magnitude diagram . This analysis contains more than ten times more stars than any previous study, and is the first time that has been done throughout the core.
The color-magnitude diagrams are invaluable tools frequently used by astronomers to study the different physical properties of the stars, astheir temperatures, masses and ages .
“Each star occupies a particular point in this diagram at any point in their life. The place where it falls depends on how bright and hot it is . Given that new data offer instant star all at once, we can do a census of all the stars in this part of the Milky Way, “explains Dante Minniti.
The new color-magnitude diagram of the core contains a treasure trove of information on the structure and content of the Milky Way . An interesting result revealed by the new data indicates the number of weak red dwarf stars that exist in the area. These candidate stars to hold small exoplanets, objects that can be discovered using the transit technique.
“Another aspect that makes the VVV survey is so important is that it is one of the ESO VISTA public surveys. This means that all data are made publicly available through the ESO archive.