![]() ![]() As in their previous work with 2D simulations, the researchers find that magnetic-field energy is converted into plasma-kinetic energy during the reconnection of field lines. ![]() The team’s simulations show that the magnetic-field lines are constantly in motion, bending, splitting apart, and joining back up as they move through the plasma and interact with its particles. The model accounts for all currents flowing in the plasma-as well as general relativistic effects that were left out of previous studies, Crinquand says. The team simulates the dynamics of the plasma’s particles and of its magnetic fields, looking at the energy transfer between the particles and the fields. The team assumes that black holes occasionally enter a so-called flaring plasma state, in which most of the plasma becomes force free-meaning that the magnetic forces are so high that they mask the effects of the friction-like forces in accretion. “We want to get more realistic images that we could potentially compare to experimental data,” Crinquand says. Now they turn to 3D simulations and consider radio-wave emission, which ties into the black hole observations made by EHT. In 2D simulations, the team previously found that such a magnetic process could lead to the emission of gamma-ray flares-potentially explaining the observed bursts. This model would not replace the accretion one, but act in tandem with it. When the lines associated with this field break apart and then reconnect-a process known as magnetic reconnection-magnetic-field energy can convert into plasma-kinetic energy that is then emitted as photons. Models of this process predict constant emission signals, which doesn’t seem to fit with observations of high-intensity bursts of gamma rays from black holes.Īnother possibility-and the one that Crinquand and his colleagues consider-is that the energy needed to create this light is extracted from the magnetic field that threads through the plasma. One of those is so-called accretion power, where friction-like forces in the infalling plasma heat the plasma, leading to the emission of photons. There are several mechanisms that physicists think could be behind a black hole’s light. This prediction could be tested by future versions of the Event Horizon Telescope (EHT)-the network of radio dishes used to capture the first black hole images (see Research News: First Image of the Milky Way’s Black Hole). The simulations predict that, under certain conditions, magnetic-field instabilities can induce radio-wave hot spots that rotate around the shadow of the black hole. Now, in 3D simulations of the magnetic fields within this plasma, Benjamin Crinquand of Princeton University and colleagues think they have found the answer: the breaking and reconnecting of magnetic-field lines. One puzzle is why the plasma around black holes glows so brightly. Yet, the number of open problems related to how the dark behemoths behave also marks them as one of the most enigmatic. ×Ĭharacterized by just three parameters-mass, spin, and charge-black holes could be considered one of the Universe’s simpler astrophysical objects. For M87*, the first black hole to be imaged, a complete rotation takes about 5 days. Radio-wave hot spots rotate clockwise around the black hole shadow. Crinquand/Princeton University Simulations showing the time evolution of magnetically induced radio-wave emission from a black hole plasma. ![]()
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