Astronomy is increasingly collaborative

This is the view of Brazilian researcher Dimitri Alexei Gadotti, member of the European Southern Observatory team of astronomers.

By Elton Alisson

Agência FAPESP – São Paulo researcher Dimitri Alexei Gadotti is used to spending at least 100 nights over the course of a year with his eyes on monitors that show a series of graphs and images of astronomical objects captured in real time by several of the world’s largest and most powerful telescopes.

With an undergraduate degree in theoretical and experimental physics and a master’s, doctorate and post-doc in astronomy from the University of São Paulo (USP) – the latter two on fellowships from FAPESP – Gadotti is one of the 25 European Southern Observatory (ESO) astronomers in Paranal, Chile.

To conduct his work in support of observations made using the array of telescopes that make up the Paranal Observatory, Gadotti stays for periods of a week to 10 days at the astronomical complex situated on a mountain 2,600 meters high in the middle of the Atacama Desert, 130 kilometers from the Chilean coastal city of Antofagasta.

Like a military base, the Observatory operates 24 hours a day, non-stop, and employs more than 100 professionals, including astronomers, engineers, physicists and maintenance technicians, working in shifts.

The professionals are housed at the ESO Hotel Paranal, a sophisticated hotel built on the grounds of the Observatory, with a design that earned international architecture prizes. The living quarters were even used as a backdrop for Quantum of Solace, the 22nd film in the James Bond British spy series.

In an interview granted to Agência FAPESP during a visit by Brazilian journalists to the ESO facilities in Chile last November, Gadotti talks about how he became an astronomer at the research institution and the work he does at the Observatory.

Agência FAPESP – How did you become an astronomer at the ESO in Chile?
Dimitri Alexei Gadotti – I completed my doctorate at the IAG [Institute of Astronomy, Geophysics and Atmospheric Sciences of USP] on a fellowship from FAPESP, and I visited Chile twice during my research to conduct observations using the ESO Observatory telescopes in La Silla [600 kilometers north of Santiago]. On my first visit, I stayed two nights, and I stayed six on my second visit. After completing my doctorate, I did a post-doc at the IAG, again on a FAPESP fellowship, at the Astrophysics Laboratory in Marseilles, France, and at the Max Planck Institute of Astrophysics in Garching, near Munich, Germany, where I spent four years. By coincidence, the German headquarters of ESO is on the same street as the Max Planck Institute of Astrophysics. That’s why I had many contacts with ESO. I always wanted to work there because it’s an institution that does extremely cutting-edge astronomy. Because of this, I signed up for the ESO fellowship program in 2009 and was selected to go to Chile, where I lived for three and a half years. Just before finishing my fellowship, I applied for a position on the ESO team of astronomers in Chile and was approved, and I officially became part of the team in April 2013.

Agência FAPESP – How many individuals are on the team of astronomers at the ESO Observatory in Paranal?
Gadotti – There are approximately 25 astronomers. There are a lot more engineers than astronomers because the astronomers only work at night, operating the telescopes. The engineers work days and nights, performing maintenance on the 16 scientific instruments attached to the telescopes.

Agência FAPESP – What responsibilities does a member of the ESO astronomer’s team have?
Gadotti – Two-thirds of the time a member of the ESO team of astronomers spends is devoted to the work of the Observatory, which basically consists of supporting the observations. We have to spend 105 nights a year in the Observatory conducting the research for the projects the ESO approves every semester. Every night, we select which projects will be conducted, depending on the conditions for observation and the priority of each project. Usually, the observations are conducted over a block of time or interspersed, more or less every two hours. During the observations, we have to determine whether they are proceeding as expected, whether the data being provided are of the quality required and whether anything unforeseen has happened, for example. If a problem comes up during the observations, we need to take care of it.

Agência FAPESP – How do you work during the observations?
Gadotti – In two ways. The first is in service mode: the astronomer who wrote the project is not present, so we perform the observations for him. The other way we work is in visitor mode: the astronomer who is the project author comes here to conduct his observations, and we have to be at his disposal to explain things and help as needed because the operation of the telescopes is very complex. Non-ESO astronomers cannot come here to work alone.

Agência FAPESP – In addition to giving support to the observations, what other duties do you have?
Gadotti – Each member of the ESO team of astronomers is responsible for one of the 16 scientific instruments on the telescopes. This means that we have to ensure, among other things, that the instrument is working properly, that we don’t waste any time because of technical problems and that the data supplied is of the quality we expect. In addition to this, we have to think about what could be done to improve the instrument and see to its maintenance so that it doesn’t experience technical problems.

Agência FAPESP – Which instrument are you responsible for?
Gadotti – For the FLAMES [Fiber Large Array Multi Element Spectrograph]. This instrument is a multi-object spectrograph that allows you to obtain more than 130 spectra [images] for 100 different objects at a time, and it facilitates the performance of studies that require large amounts of data. Currently, most astronomy research is done from the statistical perspective, and there are numerous errors involved due to the very nature of the observations. We are only able to collect some of the photons that are available in space, and we have to extract an enormous amount of information from them. Because we do observations using the most modern technology available for this purpose, there is a lot of electronic “noise” from data treatment and from postulating hypotheses. Therefore, we need to increase the size of the sample, the number of data, and the number of observation points to reduce this noise and obtain responses that are much more robust. FLAMES is essential to this because, instead of providing one spectrum for one star, it provides over 130 spectra after one hour of observation. There is not much you can do with a single spectrum, but with 130 of them you can answer a series of questions. It also optimizes observation time on the telescope.

Agência FAPESP – What type of astronomical research do you do at the ESO?
Gadotti – I study the evolution of galaxies, mainly from the structural point of view. What I do is analyze images or spectra of galaxies and the structure of galaxies, especially those closest to the Earth, those that we are able to see in more detail. I also study the kinematics [movement] of stars in the galaxy. The idea is to try to understand how the galaxies evolved over time, because they are not static. We see, for example, that there are barred spiral galaxies that are developing that fundamentally affect the life of the galaxy, producing new stars and changing the distribution of mass within the galaxy. The dark matter that is all around the galaxy also influences its dynamics and structure, and we still don’t know what dark matter is. Therefore, we can study dark matter a little and understand what it is through what happens in a galaxy that is inside a halo of dark matter because this halo influences the galaxy’s dynamics and structure. Getting responses about what dark matter is important from the standpoint of astronomy as well as physics. Dark matter is one thing that physicists have also looked for and not yet found. It represents a key topic in science today.

Agência FAPESP – What are the advantages to conducting collaborative astronomical research?
Gadotti – In the case of the S4G, for example, we’ve had more than 600 hours of telescope time, something that is hardly ever granted to one or two astronomers, for example. In order to utilize this observation time, you need to join forces and have quite a large team that is capable of mining the data in several ways. With a large group of specialists in several fields, each can use the same data to respond to different questions. That way, it’s possible to maximize the project results as well as the utilization time on a telescope, which is very expensive.