It is not the first of its kind, but it is the first space observatory of its kind in the southern hemisphere, which will make it possible to complete the gamma ray map of the entire universe and thereby obtain valuable information on the most violent processes that gave rise to the Milky Way. Installed in the Chilean desert, at 4,770 meters above sea level, in a place called Pampa La Bola, the Southern Wide-field Gamma-ray Observatory or SWGO, will begin construction in 2026 and will be join the Atacama Astronomical Park, which includes three other observatories already in operation plus two under construction.
Its design consists of 3,763 sealed water ponds that will receive the explosions of astroparticles generated by violent phenomena in the universe such as, for example, those that occur in the center of galaxies. The flashes of gamma rays, after penetrating the atmosphere, give way to subatomic particles that, upon entering the ponds, will produce a blue light (Cherenkov light) that will be detected by sensors. By recording this cascade of secondary particles simultaneously, it will be possible to deduce the energy of each gamma ray and the direction of origin from its cosmic source.
After ruling out two other countries in the region, the consortium of 15 nations involved in the project, which brings together more than 200 scientists, announced the construction of the SWGO for a value of 60 million dollars in the north of the country, which consolidates Chile as the world center of astronomical observation.
Doctor in astrophysics Bruno Dias, academic at the Andrés Bello University and president of the Chilean Astronomical Society (SOCHIAS), tells ABC that the construction of SWGO will be gravitational to complete the map of the sky that until now has been observed only in the hemisphere. north by two observatories with similar technology located in Tibet (LHAASO) and Mexico (HAWC).
Light has wavelengths that are not visible to the human eye, such as UV or infrared rays, which are more energetic than the rainbow, what is visible, but ultra gamma rays have more energy than the previous ones, so you can see holes with them. blacks, active galaxy nuclei and star formation zones. Gamma rays are information messengers that allow us to understand various phenomena and processes that occur in the universe, Dias clarifies.
SWGO’s work in the field of gamma rays could complement in the future everything done by a telescope that will be located at the Cherenkov Telescope Array (CTA) observatory, already under construction in northern Chile and which brings together the efforts of a series of Spanish universities and institutions.
The best view of the Milky Way
Claudio Dib, academic at the Federico Santa María University and representative of Chile on the SWGO steering committee, highlights to ABC the importance of this project as it is the first in this hemisphere. One of the most important sources of gamma rays are the centers of galaxies, and the center of the closest galaxy we have is ours, the Milky Way, whose center can only be seen from the southern sky, he explains.
Dib tells this newspaper that, although the complex will be completely finished in 2028, the first observations can already be made in 2027. The facilities will cover approximately one square kilometer of surface at the necessary height to carry out their work because the astroparticles almost do not They reach sea level.
The astrophysicist specifies that this technology will be used because it has some advantages over telescopes which have a limited field of view and can only see at night when there is no moon since they become dazzled, to put it colloquially.
Although the telescope achieves greater precision and direction, the technology that the SWGO will use can detect the cascade of gamma rays at all times, day and night, even in the rain, regardless of the direction from which it comes because the observatory’s field of view captures everything. which is in the sky at more than 30 elevation above the horizon.
Dib recognizes the difficulties involved in both building the facilities, whose ponds will be filled with water brought from the town of Calama, and investigating at that height, because human beings require oxygen.
The SWGO will be the third highest altitude observatory in the world, surpassed by the University of Tokyo Atacama Observatory (TAO), which is located in the same area at 5,640 meters above sea level, and the Atacama Large Millimeter Array (ALMA), the radio telescope with 66 antennas that is located at 5,000 meters above sea level on the Chajnantor Plain, a few kilometers southwest of SWGO.
This new step in world astronomy will be the subject of analysis at the International Astronomical Summit that will take place in Chile in 2030 and will receive more than 3 thousand scientists from around the world, considering that by that time the country will have more than half of the capacity world astronomy installed and 30 nations participating in one of those observatories. In this context, facilities such as the ALMA active since 2011, the Cosmology Large Angular Scale Surveyory (CLASS) since 2019, the Large Synoptic Survey Telescope (LSST) since 2021 and the Extremely Large Telescope (ELT) operational in 2028 or the Giant Magellan Telescope stand out. (GMT) from 2029.