Your shift at ALMA

by Dr. Rubén Herrero-Illana of  European Southern Observatory (ESO).

Edited by Zaira M. Berdiñas

Hey, wake up! It’s already 6am and the taxi will arrive in 15 minutes to take you to the airport. You checked in as early as possible to ensure a seat by the window on the right side of the plane. The views during the flight between Santiago de Chile and the city of Calama, parallel to the Chilean Andes for two hours, are majestic.

Views of the Andes during the journey. Credits: Rubén Herrero-Illana.

Ahead you of are 8 days of intensive work at ALMA, arguably the most important ground-based astronomical observatory in the world, given that it is an international effort of peaceful cooperation among more than 20 nations to understand our place in the cosmos. ALMA is formed by 66 antennas that can observe any object in the sky simultaneously to obtain data of unprecedented quality. Such an amazing machine is placed in an amazing location: the Chajnantor plateau, at 5000m above sea level in the middle of the Atacama desert, the driest non-polar place in the planet.

The ALMA array at 5000 m altitude in the Chajnantor plateau (right image). A total of 66 antennas form the array which acts as a single giant telescope. The antennas are not in a fixed position; from time to time they are moved  between different stations. “Otto” and “Lore” are the trucks in charge of moving them (see “Otto” working in the left picture). The largest distance between antennas can reach up to 16 kilometers. Credits: ALMA / Rubén Herrero-Illana.

Once you arrive to the ALMA base camp, at the more bearable altitude of 3000m, you drop your backpack in the ‘residencia’, your home in the desert, and head to the control room, where the antennas are remotely commanded. Your shift is about to start. Press that key and check the webcam to make sure the antennas start moving towards the requested coordinates. You are now in control of the most powerful telescope ever built. Feels powerful, uh? It’s also a big responsibility, and you are expected to make the most of every second. Astronomers all over the world compete fiercely to obtain observing time in the (very) oversubscribed call for proposals that is opened every year. You have to choose which project to observe based on the priority that each of them was assigned, but also on the weather conditions and available time before planned stops for engineering operations.

In the foreground of the image on the right we can see some of the temporary “residencia” located at only 3000 m. The building in the background houses the “control room”, from where the antennas are controlled. The interior of this room is shown in the left image, where we can see a telescope operator working during the day. Credits: Diego Delso / Rubén Herrero-Illana.

Today you may observe a project aimed at detecting prebiotic molecules on a forming star, a galaxy being swallowed by its own central black hole, or the formation of a solar system that could have a rocky planet covered with oceans that might harbor life, who knows. Indeed, ALMA is an important contributor to exoplanetary studies. Its superb resolution and sensitivity, combined with the range of frequencies in which it operates, allow astronomers to observe the first stages of planetary formation and analyze the molecules that are being formed there.

After a long day, there is always time to relax. You can go to the gym or the movie session in the ALMA camp, or maybe hike or ride a bike in the surroundings. From time to time it is also possible to visit the 66 antennas that form the telescope. There’s no need to go up there, you can do everything from the control room, but honestly, the breathtaking feeling (in all senses, don’t forget your oxygen mask!) of being above 5000m in a Martian landscape surrounded by a giant telescope, is definitely worth the trip.

Some of the telescope facilities to chill out after a working day. Chileans can barely live without their most typical food: the “asado”. The left image shows the ALMA “quincho”, which is the Chilean name for an open place with a BBQ. On the right, the playroom with table football, a pool table, and a ping-pong table. There are other facilities such as a gym or even a swimming pool. Credits: Rubén Herrero-Illana.

One of the great advantages of radio wavelengths is that they don’t get dispersed by the atmosphere. This means that we can observe 24 hours a day. When you are on a night shift and finish the observations, you like to take a small detour when you come back to the residencia and behold the amazing sky of the Atacama. Again, radio astronomy is not about star gazing, but gives you your dose of humbleness and mental peace, and reminds you why you fell in love with astronomy. Sometimes, after several weeks in your office in front of a computer, you forget about that.

The rooms at the “residencia” are divided into areas. Depending if your shift happened during the night or the day you would be assigned to a different room. Credits: Rubén Herrero-Illana.

Before you realize, it’s Monday again. Your shift is over, your replacement has arrived, and you have a well-deserved rest period. From the window of the plane, this time on the left side, your mind wanders about how much we will learn in the exciting years to come, and what new unknowns will appear. Questions are often more interesting than answers.

About the author

Dr. Rubén Herrero-Illana

Rubén Herrero-Illana is an ESO fellow with duties at ALMA. He obtained his PhD in 2014 at the Instituto de Astrofísica de Andalucía (IAA-CSIC) located in Granada (Spain). He is mainly interested in galaxies which are very luminous in the infrared. In particular, he studies them at different spatial scales, from their overall gas structure to their innermost regions in which he is focused on explaining the connection between their star formation and the galaxy’s active nucleus.

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