Origin of intense light in supermassive black holes and tidal disruption events revealed by study

A new study that could be used to measure essential properties of black holes and serve as a litmus test of Albert Einstein’s predictions in extreme gravitational environments has been produced by physicists and astronomers at The Hebrew University of Jerusalem (HU). 

It is a significant “breakthrough” for understanding Tidal Disruption Events (TDEs) involving supermassive black holes. The new simulations, for the first time ever, accurately replicate the entire sequence of a TDE from stellar disruption to the peak luminosity of the resulting flare. 

The study has unveiled a previously unknown type of shockwave within TDEs, settling a longstanding debate about the energy source of the brightest phases in these events. It confirms that shock dissipation powers the brightest weeks of a TDE flare.

The mysteries of supermassive black holes have long captivated astronomers, offering a glimpse into the deepest corners of our universe. Now, a new study led by Dr. Elad Steinberg and Dr. Nicholas C. Stone at HU’s Racah Institute of Physics “sheds new light on these enigmatic cosmic entities,” they said. 

It has just been published in the prestigious journal Nature under the title “Stream-Disk Shocks as the Origins of Peak Light in Tidal Disruption Events.” 

Supermassive black holes, ranging from millions to billions of times the mass of our Sun, have remained elusive despite their key role in shaping galaxies. Their extreme gravitational pull warps spacetime, creating an environment that defies conventional understanding and presents a challenge for observational astronomers.

The dramatic phenomenon called TDE 

Enter TDEs, a dramatic phenomenon that occurs when ill-fated stars venture too close to a black hole's event horizon and are torn apart into thin streams of plasma. As this plasma returns towards the black hole, a series of shockwaves heat it up, leading to an extraordinary display of luminosity – a flare that surpasses the collective brightness of an entire galaxy for weeks or even months.

The study conducted represents a significant leap forward in understanding these cosmic events, said Steinberg and Stone. For the first time, their simulations have recreated a realistic TDE, capturing the complete sequence from the initial star disruption to the peak of the ensuing luminous flare. This was all made possible by pioneering radiation-hydrodynamics simulation software developed by Steinberg at HU.

This research has uncovered a previously unexplored type of shockwave within TDEs, revealing that these events dissipate their energy at a faster rate than previously understood. By clarifying this aspect, the study resolves a long-standing theoretical debate, confirming that the brightest phases of a TDE flare are powered by shock dissipation – a revelation that sets the stage for comprehensive exploration by observational astronomers.

These findings pave the way for translating TDE observations into precise measurements of crucial black hole properties, including mass and spin. 

Steinberg and Stone’s study not only unravels the intricate dynamics of TDEs but also opens a new chapter in our quest to comprehend the fundamental workings of supermassive black holes. Their simulations mark a crucial step towards harnessing these celestial events as invaluable tools for deciphering the cosmic mysteries lurking at the heart of galaxies.