“The Milky Way is nothing more than a mass of innumerable stars”, said Galileo Galilei when he observed our Galaxy for the first time with his telescope.

Four hundred years later, the largest infrared map of the Milky Way was completed after more than 13 years of observation of our Galaxy by the VISTA Variables in the Milky Way (VVV) project and its companion project VVV eXtended (VVVX). This monumental effort has left an invaluable legacy for the astronomical community.

Today, a paper was released that presents a map combining the positions, distances, and proper motions of different types of stars. This work, published in the prestigious European journal Astronomy & Astrophysics, is led by Professor Roberto Saito, from the Federal University of Santa Catarina (UFSC) in Florianópolis, Brazil, and co-authored by 146 people from 15 different countries on four continents. From the Instituto de Astronomía Teórica y Experimental (IATE), Laura Baravalle, María Victoria Alonso, Juan Cabral, Ingrid Vanessa Daza Perilla, Sebastián Gurovich, Marcelo Lares, Celeste Parisi, Luis Pereyra, Eduardo Schmidt, Mario Agustín Sgró, Carlos Valotto and Carolina Villalon are participating.

 

The VVV and VVVX megaprojects were led by Dante Minniti, a graduate of UNC, Academician of the National Academy of Sciences and currently a professor at the Universidad Andrés Bello (UNAB) and principal investigator at the Centre for Astrophysics and Related Technologies (CATA), together with Professor Philip Lucas of the University of Hertfordshire (UH) in the United Kingdom. At its inception, this was the largest observational project in terms of data volume at the European Southern Observatory (ESO). Observations began in 2010 and ended in the first half of 2023. During 420 observing nights, around 200,000 images were acquired, and more than 1.5 billion objects were monitored, generating some 500 TB of scientific data.

This survey produced countless applications for the astronomical community interested in studies of galactic structure:

• Cúmulos globulares, los objetos más antiguos de nuestra Galaxia;
• Estrellas hiperveloces, donde el agujero negro supermasivo central las expulsa de la galaxia;
• Ventanas que nos permiten ver el otro lado de la galaxia a través de todo el polvo y el gas interestelar;
• Estrellas variables RR Lyrae en el centro de la Galaxia, la población más antigua conocida;
• Estrellas enanas marrones y planetas flotantes binarios, los objetos menos luminosos conocidos que no están asociados con ninguna estrella;
• Objetos variables desconocidos que llamamos WIT, acrónimo de “What Is This?” (¿Qué es esto?);
• Miles de galaxias distantes, vistas a través del disco y del bulge de la Vía Láctea;
• Objetos estelares recién nacidos, que son violentamente variables;
• Eventos de microlentes gravitacionales en el corazón de la Vía Láctea;
• Estrellas variables Cefeidas muy distantes, incluso en las antípodas de nuestra galaxia.

The discoveries have resulted in over 300 scientific publications and 30 PhD theses, with 4 of them being conducted at IATE. Imaging, data analysis, and scientific exploration will persist for many years. This work will leave a lasting legacy for the astronomical community, which will continue to utilize this data in various projects. Many of these studies will be enhanced for better understanding with future observations using NASA's Nancy Roman Space Telescope, scheduled for launch in late 2026.