Research Highlights

Black holes have been fascinating subjects of study, not just because they are cosmic vacuum cleaners, but also as engines of immense power capable of extracting and redistributing energy on a staggering scale. These dark giants are often surrounded by swirling disks of gas and dust, known as accretion disks. When these disks are strongly magnetized, they can act like galactic power plants, extracting energy from the black hole’s spin in a process known as the Blandford-Znajek (BZ) effect.

While scientists have theorized that the BZ effect is the primary mechanism in the energy extraction process, many unknowns remain, like what determines how much energy is funneled into powerful jets—powerful streams of particles and energy ejected along the black hole's poles—or dissipated as heat.

To answer these questions, JILA postdoctoral researcher Prasun Dhang, and JILA Fellows and University of Colorado Boulder Astrophysical and Planetary Sciences professors Mitch Begelman and Jason Dexter, turned to advanced computer simulations. By modeling black holes surrounded by thin, highly magnetized accretion disks, they sought to uncover the underlying physics that drives these enigmatic systems. Their findings, published in The Astrophysical Journal, offer crucial insights into the complex physics around black holes and could redefine how we understand their role in shaping galaxies.

In a new paper in The Astrophysical Journal, JILA Fellow Jason Dexter, graduate student Kirk Long, and other collaborators compared two main theoretical models for emission data for a specific quasar, 3C 273. Using these theoretical models, astrophysicists like Dexter can better understand how these quasars form and change over time.

Quasars, or active galactic nuclei (AGN), are believed to be powered by supermassive black holes at their centers. Among the brightest objects in the universe, quasars emit a brilliant array of light across the electromagnetic spectrum. This emission carries vital information about the nature of the black hole and surrounding regions, providing clues that astrophysicists can exploit to better understand the black hole's dynamics. 

In 2019, a team of researchers used an international network of radio telescopes—called the Event Horizon Telescope—to take the first photo of a supermassive black hole in the center of the elliptical galaxy Messier 87 (M87). On that team of researchers was JILA Fellow Jason Dexter. Since then, Dexter has been studying M87's black hole further using simulations, with code written by researchers at the University of Illinois. As described in a new paper published in the Monthly Notices of the Royal Astronomical Society (MNRAS), Dexter, and his team of graduate students and postdoctoral researchers, collaborated with researchers at the Los Alamos National Laboratory and the University of Illinois to create a new simulation studying the edge of a black hole. 

JILA Fellow Jason Dexter works with the Event Horizon Team to further study the first photograph ever taken of a black hole.