Its name is TOROS and it is located on the Macón ridge within the Puna Salteña, at 4650 metres above sea level. Just a few days ago it achieved “first light” by taking images of three astronomical objects. By the end of the year, it will be able to respond to alerts from gravitational wave detectors to
search for the light arising from the collision of compact objects in galaxies as far as 600 million light years.

Gravitational waves were predicted by Einstein over a century ago, and were finally corroborated byLIGO in September 2015. Last week, between April 9th and 11th, the “Transient Optical Robotic Observatory of the South”
(TOROS), achieved first first light and obtained a set of images of Omega Centauri, a globular cluster about 17,000 light years away; NGC 6752, a globular cluster about 14,000 light years from Earth; and a region within the disk of the Milky Way close to the open cluster NGC 3766.

These first images are very special for astronomers and represent a great achievement for a project that began over a decade ago, with the search for one of the best sites in the world to install a telescope (see the origin of CAM).

TOROS is a robotic telescope that will be controlled remotely. Its mirror is 61 cm in diameter and its focal distance is nearly 4 meters. By the end of the year, it will receive a specially designed brand new high-tech CCD camera covering more than a square degree, that will allow it to obtain continuous high quality images of the sky. With these upgrades, TOROS is expected to reach its design sensitivity at the beginning of 2022.

The main goal of the telescope will be to detect the light arising from powerful collisions of compact objects at a large range of distances, initially detected via gravitational waves. Mario Díaz, PI in charge of the TOROS project at the University of Texas – Rio Grande Valley, explains that “this telescope is an aid to throw light on part of the research done in nuclear physics that we are not able to recreate on Earth”. Dr. Diaz added, “the nuclear density of the neutron stars and the incredible “energy fireworks” that are ignited during the crash of these stellar corpses -that danced
together for millions of years, approaching each other progressively until the final catastrophic hug is produced- will allow us to better understand how stars live and die.

In 2016 the laser interferometer gravitational waves observatory ( LIGO) announced to the world the first detection of of gravitational waves, one of the precticions of the general relativity theory of Albert Einstein,

As postulated by the German scientist, gravitational waves are a disturbance of space-time that travels at the speed of light and due to their characteristics, they have the ability to modify (minimally) the spatial dimensions of large objects.

To recognize these variations, LIGO used devices that use lasers (interferometers) to make the most accurate measurements in the world. TOROS aim is to photograph in the optical the astronomical events that originate these gravitational waves.

Therefore, at every time LIGO detects a signal on its instruments, it will send an alert, and TOROS will attempt the observation of the optical counterpart that could have generated the gravitational waves.

The highest telescope of Argentina

TOROS is part of the Astronomical Centre Macón (CAM), a set of installations on Cerro Macón within the Puna Salteña at 4650 metres above sea level. This location was chosen after an exhaustive search for an optimal site for astronomical observations.

This site is characterized by its great atmospheric quality -lack of contamination, low humidity and low turbulence-, as well as its altitude and impressive large number of clear days during the year. It is not
only about being the highest observatory, but also the opportunity it offers for a high quality survey of the southern sky.

The TOROS telescope, an L-600 Planewave mount with a CDK24 OTA, is located inside a dome constructed approximately a year ago. The final installation as well as other technical work planned for
2020 had to be postponed due to the COVID 19 pandemic.

The activities were resumed in a secure manner a few weeks ago. These campaigns made possible the current “first light” images. The observatory is expected to be fully functional at the beginning of 2022.
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As explained by Diego Garcia Lambas, the importance of counting with a high quality telescope, in one of the highest sites with optimum conditions is relevant for the development of astronomy in Argentina, since it will allow a continuous survey of the sky by searching for both, the optical counterpart of the gravitational waves and other events of variability in the deep sky.

Diego Garcia Lambas emphasizes the importance of the joint effort made by different actors of the society in fostering the scientific and technological development of our country.
With respect to the opportunities that the TOROS project opens, Lucas Macri, the person in charge of TOROS at Texas A&M University, highlights that it will allow to “sweep” large regions of the austral
sky in search for light associated with the fusion of two neutron stars, or a black hole with a neutron
star.

We are going to work with the gravitational wave detectors around the globe, at the moment in United States and Europe, but soon Japan and then India, so we know where to look.
In this first stage, TOROS will continuously scan the sky to produce reference images. Simultaneously will keep open the channels in case a gravitational wave event occurs to search the optical part.

Regarding the next steps of the project, Dr. Macri said that the team is going to travel to Macón in May to further tune the telescope and dome, perform other optical tests, and take sequences of images of open clusters.

These sequences will offer us better information about the photometric precision that the telescope can achieve. When the pandemic situation allows it, the survey camera and associated optics will be shipped from Texas. For the survey to be successful, it will be essential to develop software in
Córdoba that allows the optimal use of the telescope and the automatic processing of the large number of images that will be obtained.

The TOROS project is carried out by researchers and technicians from the Institute for Theoretical and Experimental Astronomy (IATE) Conicet / UNC, the University of Texas Rio Grande Valley (UTRGV) and Texas A&M University (TAMU).

In collaboration with the Astronomical Observatory of Córdoba of the UNC, the National University of Salta (UNSA), the Ministry of Science and Technology of Argentina, the Secretary of Science and Technology of the province of Salta, the Ministry of Science and Technology of the province of
Córdoba and the Municipality of Tolar Grande.

El origen del Centro Astronómico Macón

The origins of the Macón Astronomical CenterBetween 2003 and 2009 a team of scientists of IATE and OAC studied the conditions of sky quality at the Macón ridge in collaboration with the European Southern Observatory, ESO. The aim of ESO was a search of preselected candidate sites to place a 40-m class telescope (E-ELT). Macón was among the final three sites considered, and the final decision for the E-ELT was close to Paranal in Chile, among other reasons, due to infrastructure development. This experience fostered researchers from IATE to take advantage of the studies performed and start the “Macón Astronomical Centre” in this high astronomical quality site.