Arecibo Observatory Contributes to the Exploration of Black Holes Started by this Year’s Nobel Prize Winners in Physics

Astrophysics

In December, the 2020 Nobel Prize in Physics will be awarded to three scientists who were able to first shed light on black holes.

One half of the award will be given to Sir Roger Penrose from the University of Oxford, who in 1965, used mathematics and Einstein's general theory of relativity to predict the existence and describe the nature of black holes.

The second half of the award will be given to Dr. Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics in Germany and Dr. Andrea Ghez from the University of California Los Angeles for their discovery that a supermassive black hole resides at the center of our galaxy, the Milky Way. Their team mapped the movement of stars near the galaxy’s center and were able to conclude that the stars were being swung around by the intense gravity of an invisible, massive object. This provided the first observational evidence for the existence of the supermassive black hole at the heart of the Milky Way.

Following the prediction and discovery of the first black hole, an entire subfield of astronomy emerged around the exploration of these alluring phenomena. Astronomers have now found significantly more massive black holes at the centers of other galaxies - and in some unique galaxies - more than one.

Dr. Sravani Vaddi, a postdoctoral fellow at the Arecibo Observatory, studies what happens when two of these supermassive black holes - or SBH, for short - inhabit the same galaxy.

“When we spot two SBHs within the same galaxy, we believe we’re observing the advanced stages of a major galaxy merger” Vaddi says. When two or more galaxies collide, their central black holes can start devouring the stars around them, causing the SBHs to grow rapidly.

“How do these supermassive black holes evolve when they are near one another? How do they affect the surrounding galaxy? These are some of the questions that I am addressing with my research,” says Vaddi.

To answer those questions, Vaddi and her colleagues must probe the area closest to the supermassive black holes within these distant galaxies, so they need observations with very high resolution.

No single telescope has the capability to obtain the required data, but the Arecibo Observatory with its highly sensitive equipment, plays a critical role in the work-around scientists have devised to study the phenomena. They use an array of telescopes from across the planet in a technique known as Very Long Baseline Interferometry (VLBI) to obtain ultra high-resolution observations.

“The Arecibo Observatory is one station within the European VLBI network. We achieve the highest sensitivity and resolution possible when we include Arecibo because it is one of the largest radio dishes in the world and because of its distance from all of the other radio telescopes in the network, respectively,” Vaddi says.

"The Arecibo Observatory is one station within the European VLBI network. We achieve the highest sensitivity and resolution possible when we include Arecibo because it is one of the largest radio dishes in the world and because of its distance from all of the other radio telescopes in the network, respectively," - Dr. Sravani Vaddi, Postdoctoral Fellow at the Arecibo Observatory

The observatory is currently offline, because broken cables have damaged the facility. Engineers are working on how to best stabilize the facility. With these high-resolution observations, Vaddi and her colleagues can study the high-energy jets of electromagnetic radiation that are emitted from the region around the supermassive black holes.

“This research that we do with the Arecibo Observatory isn’t just related to the most recent Nobel Prize,” she says. “As a reminder, the 2017 Physics Nobel Prize was awarded for the discovery of gravitational waves.”

Vaddi says that during galaxy merging events, the supermassive black holes can spiral into one another, triggering gravitational waves. The North American Nanohertz Observatory for Gravitational Waves (NANOGrav), which relies on the Arecibo Observatory and the Green Bank Telescope, indirectly measures gravitational waves by studying how they affect nearby pulsars. “The NANOGrav project provides scientists a platform to work with both light and gravitational waves,” says Vaddi. “In modern astronomy, studies using both light and gravitational wave information are crucial to our understanding of these dramatic celestial collisions.”

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Article written by Dr. Tracy Becker - AO Collaborator / SwRI Research Scientist Contact: tbecker@swri.edu Director of Communications Ricardo Correa Observatorio de Arecibo 787-878-2612 ext. 615 rcorrea@naic.edu

Keywords: arecibo, observatory, NANOGrav, black, holes, VLBI, gravitational, waves, Nobel, prize, Einstein, germany, Ghez, Milky, way