The most complex terrestrial astronomical observatory in the world, theAtacama Large Millimeter/submillimeter Array (ALMA), has just officially opened its doors to astronomers. The first image revealed by this telescope offers an image of a galaxy impossible to obtain with telescopes that observe visible and infrared light. Thousands of scientists from around the world have competed to be among the first researchers to exploresome of the darkest, coldest and most hidden secrets of the cosmoswith this new astronomical tool.
About a third of the66 planned ALMA radio antennas-for now located only 125 meters apart, although their maximum separation can reach 16 kilometers- they form the growing group currently installed at an altitude of 5000 meters in the Chajnantor plain, in northern Chile. Despite being still under construction,ALMA is already the best telescope in its class, as evidenced by the extraordinary number of astronomers who have already requested observing time with ALMA.
And it is that ALMA observes the light of the Universe inmillimeter and submillimeter wavelengths, about a thousand times longer than visible light wavelengths. This allows astronomers to study very cold objects in space, such as the dense clouds of cosmic dust and gas where stars and planets form, as well as very distant objects in the early Universe. On the other hand, ALMA is completely different from optical and infrared telescopes. It consists of a set of interconnected antennas that function like a single giant telescope, capable of detecting wavelengths much longer than visible light. Therefore, the images it captures are quite different from the ones we know of the cosmos so far.
The first image
In recent months, the ALMA team has worked intensively in recent months testing the observatory’s systems, preparing for the first round of scientific observations known as Initial Science. One of the results of these tests is the first image published by ALMA, showing theimage of the Antennae galaxies, a colliding duo of galaxies with extraordinarily distorted shapes. While observation in visible light allows us to see the stars in galaxies, ALMA reveals objects that are invisible at that wavelength, such as the dense clouds of cold gas where stars form. The image has shown astronomersmassive concentrations of gas not only in the heart of both galaxies, but also in the chaotic zone where they collide. There, the amount of gas is billions of times greater than the mass of our Sun, constituting a rich reservoir of material for future generations of stars.
The snapshotwas obtained using only 12 interconnected antennas-much less than those that will be used for the first scientific observations- and with much smaller separations between them, for which it is only a glimpse of what is to come. As the observatory grows and new antennas are added, the precision, efficiency and quality of your observations will increase exponentially.
The projects to come
ALMA has been able to accept only a hundred projects for the first nine months of scientific activity. “We are living a historic moment for science, especially for astronomy, and perhaps also for humanity as we began to use the largest observatory in construction to date ,? said Thijs de Graauw, director of ALMA.
One of the projects chosen for the “Initial Science” phase is that of David Wilner, from the Harvard-Smithsonian Center for Astrophysics in Cambridge (USA), who will use the telescope tostudy AU Microscopii , a star 33 light-years awayand it is only 1% the age of our Sun. Around it there is a ring of dust where they could find raw material from planets not yet discovered. Simón Casassus, from the University of Chile, and his team will use ALMA to observethe disk of gas and dust surrounding HD142527 , a young starwhich is 400 light-years away.
Even farther away, 26,000 light-years from us, in the center of our galaxy, liesSagittarius A, a supermassive black hole that is four million times the mass of our Sun, and that with the help of ALMA, Heino Falcke, an astronomer at Radboud University Nijmegen in the Netherlands, will study. And Masami Ouchi, from the University of Tokyo (Japan), will use ALMA to observe Himiko, a very distant galaxy that each year generates equivalent stars about 100 Suns and is surrounded by a giant and bright nebula.
In 2013, ALMA will be an array of 66 ultra-precise radio antennas working in unison over a 16 kilometer stretch, built by ALMA’s multinational partners in North America, East Asia and Europe.
