UNAM Looks into the Universe. The Exploration of the Cosmos with Sloan Sky Digital Survey

Mexico has played a fundamental role in international astronomy since its earliest times. It’s no accident that a kind of nebula formed from jets of gas ejected by newborn stars was named a Herbig-Haro object. Mexican astronomer Guillermo Haro identified them from Mexican land. It is no coincidence either that several planetary nebulae have been catalogued with the initials of Mexican astronomers Manuel Peimbert and Rafael Costero. And it’s no matter of chance either that Mexican astronomer Silvia Torres Castilleja presided over the International Astronomical Union—the largest and most influential organization of astronomers in the world.

At UNAM, we are moved by such legacy and passion for knowledge, which has motivated us to transcend geographic and technological frontiers to gaze at the sky looking for knowledge. UNAM has been a fundamental partner of the Sloan Digital Sky Survey (SDSS) for over a decade. This is an ambitious international project that reunites some of the most brilliant scientific minds in the world to propose and solve pressing astronomic enigmas that require lots of observations with each edition.

In the current fifth edition, the SDSS-V has pushed three projects: the Milky Way Mapper, the Black Hole Mapper, and the Local Volume Mapper, focused on stellar archaeology, black hole physics, and the interaction between stars and the interstellar medium. Two observatories have been optimized for this—the Apache Point Observatory in the United States, and the Las Campanas Observatory in Chile—that acquire optical and infrared observations. The development of each of these projects has represented a monumental challenge in which scientists at UNAM have had a key role in their design, construction, and operation, as well as in the scientific analysis of new technologies and their products.

Nearly five million stars in the Milky Way are being observed as a part of the Milky Way Mapper. Their light is split into its most essential elements—known as spectra—when it reaches the telescopes. Astronomers can determine  the masses, ages, evolutive states, chemical compositions, and internal structures of stars by analyzing their spectra.

The millions of objects studied in this project outnumber and surpass widely the coverage of previous editions. Thus, it’s possible to have a better understanding of the origin of different stellar generations in the Milky Way and to reconstruct part of its history. This study works as galactic archaeology where stars act as vestiges that allow us to decipher events that happened in the past.

However, galaxies are not only formed by stars but also by gas and dust, which are elements that constantly interact with each other. Understanding these interactions has been historically a challenge since closer galaxies cover huge parts of the sky and in the past only limited regions could be studied in detail.

The Local Volume Mapper has changed this situation with a new optical telescope that captures tridimensional spectra in the galactic plane where the Milky Way, the Magellanic Clouds, and other nearby galaxies are located. 55 million observed spectra allow us to comprehend how galaxies’ internal processes relate to their global phenomena.

Curiosity for the Universe also covers some of the most exotic cosmic phenomena such as quasars and certain bright galactic nuclei with supermassive black holes that devour all surrounding material. As gas and dust fall into the black hole, they form a disc that heats up to extreme temperatures and emits a huge amount of radiation able to overpass the hosting galaxy’s light emission.

The light of nearly three hundred thousand quasars is being studied with the Black Hole Mapper, which allows us to estimate very precisely their mass, rotational speed, and some other key properties. This data is fundamental to reconstruct the formation history and the evolution of black holes since the beginning of the Universe until now, as well as their relation to other observed properties of the galaxies that host them.

UNAM remains at the forefront of large international scientific projects and one of the bases of such leadership is its participation in the SDSS. The data generated by this project is the foundation for a wide number of other ongoing research projects, lots of them led by students and researchers in Mexico.

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