What do I do?

I am an Astrophysicist and Data Scientist. I investigate the properties of Sagittarius A* , the supermassive black hole at the center of our own Galaxy. My work consists of running computer simulations to understand the physics of the hot gas orbiting around this black hole. I also calibrate, analyze & visualize data from astronomical observations of Sagittarius A* made using radio telescopes.

Sagittarius A*

Sagittarius A* (commonly known as Sgr A*) is the supermassive black hole at the center of the Milky Way. Its mass is 4 million times larger than the mass of our Sun, and being at the center of our Galaxy makes it the closest supermassive black hole to us. For this reason, it is an excellent "laboratory" to study the physics of what happens in the vicinity of black holes.

Left: The Galactic Center (X-ray/Infrared/Optical composite). Credit: NASA/JPL-Caltech/ESA/CXC/STScIa.

Very Long Baseline Interferometry

Very Long Baseline Interferometry (VLBI) is a special technique used to make astronomical observations. It is done by linking radio telescopes located at very large distances from each other (sometimes thousands of kilometers) so that we can create a virtual telescope of incredibly high resolving power. Some examples of VLBI facilities are the Very Long Baseline Array (VLBA) in the USA, the European VLBI Network (EVN), the East Asia VLBI Network and the Event Horizon Telescope (EHT). In the case of the EHT, the radio telescopes are located in many places around the world (Chile, Spain, Arizona, Hawaii, Mexico and the South Pole), which results in a virtual telescope with the size of the Earth. This allows astronomers to reach the highest resolving power ever achieved.

Right: VLA radio dish. Credit: Knate Myers.

Observing at radio wavelengths

Making observations at radio wavelengths (from meters to millimeters) is very useful because we can do it from the Earth without being affected too much by the atmosphere. Although, the better the weather, the better the quality of the observations. Radio telescopes can also observe during the day, and at these wavelengths astronomers can study physical processes that are different from those we can see with optical, infrared or X-ray telescopes. Radio waves are not affected by absorption caused by interstellar dust, which is great if we want to study the Galactic Center because there are dust clouds between Earth and the center of our Galaxy which impide observations at other wavelengths. In addition, the most common element in the Universe, hydrogen, emits radiation at radio wavelenths. The Event Horizon telescope is an Earth-sized virtual telescope working at 1.3 millimeters with the goal of imaging the supermassive black hole at the center of our own galaxy (Sagittarius A*) and the one at the center of the nearby galaxy M87.

Left: Full VLA array in New Mexico, USA. Credit: NRAO.