The James Webb Space Telescope (JWST) has identified a flare emanating from the supermassive black hole located at the center of the Milky Way — which may assist in comprehending the reasons behind these peculiar bursts..
Sagittarius A* possesses a mass equivalent to 4 million suns and is positioned 26,000 light-years from Earth, as stated by NASA. The cloud of dust and gas in orbit around this black hole routinely emits flares, or intense bursts of light, likely caused by disturbances in magnetic fields. Simulations suggest that flares manifest when two magnetic field lines interconnect, releasing a surge of energy, according to researchers from the Max Planck Institute for Radio Astronomy in Germany. Excited electrons travel along these intertwined lines at nearly the speed of light, producing high-energy radiation photons, or light particles.
Up until recently, however, astronomers could only observe these flares in short-wave visible light and long-wave radio signals — but not in the midsection of the electromagnetic spectrum.
“For more than two decades, we have understood the phenomena in radio and in the near infrared, but the link between them was never completely clear or definite,” co-lead author of the study Joseph Michail, a researcher at the Harvard Center for Astrophysics, noted in a statement. “This latest observation in [mid-infrared] fills that void and correlates the two.”
Now though, the JWST is capable of sensing this mid-infrared region — the spectrum range that humans perceive as warmth. The space telescope orbits the sun nearly a million miles (1.5 million kilometers) from Earth and has been conducting observations from that location since 2022. On April 6, 2024, the JWST identified a 40-minute flare from the black hole.
The telescope’s findings corroborated the simulations that indicate that interwoven magnetic field lines drive the flares. The researchers observed connections between fluctuations in the short-wavelength data and the mid-infrared data, suggesting that speeding electrons are indeed releasing photons, or light packets, as they rush along magnetic field lines — this phenomenon is termed synchrotron emission.
“Although our observations signify that Sgr A*’s mid-IR emissions do indeed stem from synchrotron emissions from cooling electrons, there remains much to learn about magnetic reconnection and the turbulence within Sgr A*’s accretion disk,” co-lead author of the study Sebastiano von Fellenberg, a researcher at the Max Planck Institute for Radio Astronomy, remarked in the statement. “This inaugural mid-IR detection, and the fluctuations observed with the SMA [Submillimeter Array], have not only bridged a gap in our comprehension of the phenomena causing the flare in Sgr A* but have also opened new avenues for significant investigation.”
The results, shared on the physics preprint platform arXiv.org, have been approved for publication in The Astrophysical Journal Letters.