Free Astronomy Magazine March-April 2025

41 MARCH-APRIL 2025 ASTRO PUBLISHING T he Instituto de Astrofísica de Canarias (IAC) participates in the study of a galaxy that hosts a supermassive black hole with previously unseen characteristics. by Instituto de Astrofísica de Canarias (IAC) The source is 1ES 1927+654, a galaxy located about 270 million light-years away in the constellation Draco. It harbors a central black hole with a mass equivalent to about 1.4 million Suns. “In 2018, the black hole began changing its properties right before our eyes, with a major optical, ultra- violet, and X-ray outburst,” said Eileen Meyer, an associate professor at UMBC (University of Maryland I n this artist’s rendering, a stream of matter trails a white dwarf (sphere at lower right) orbiting within the innermost accretion disk surrounding 1ES 1927’s supermas- sive black hole. [NASA/Aurore Si- monnet, Sonoma State University] Baltimore County). “Many teams have been keeping a close eye on it ever since.” She presented her team’s findings at the 245 th meeting of the American Astronomical Society in National Harbor, Maryland. A paper led by Meyer describing the radio results was published Jan. 13 in The Astro- physical Journal Letters . After the outburst, the black hole appeared to return to a quiet state, with a lull in activity for nearly a year. But by April 2023, a team led by Sibasish Laha at UMBC and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, had noted a steady, months-long increase in low- energy X-rays in measurements by NASA’s Neil Gehrels Swift Observa- tory and NICER (Neutron star Inte- rior Composition Explorer) telescope on the International Space Station. This monitoring program, which also includes observations from NASA’s NuSTAR (Nuclear Spectro- scopic Telescope Array) and ESA’s (European Space Agency) XMM- Newton mission, continues today with the IAC contributing data in the visible range from its observato- ries. “Despite the intense activity at low and high energies, the emission in the visible range has remained practically constant during the pe- riod 2022-2024, because this emis- sion is dominated by the stellar population of the galaxy,” says IAC researcher José Acosta. The increase in X-rays triggered the UMBC team to make new radio ob- servations, which indicated a strong and highly unusual radio flare was underway. The scientists then began