The striking dust-obscured center of the galaxy NGC 4826, shown in this image from the Hubble Space Telescope, has inspired several inventive monikers including the Black Eye Galaxy and the Evil Eye Galaxy. At just 27 million light-years from Earth, NGC 4826 provides an excellent opportunity to study the connection between the structure of a galaxy and the properties of its central supermassive black hole. Kayhan Gültekin (University of Michigan) and collaborators paired infrared and optical data from multiple sources with dynamical modeling to assess the galaxy’s structure and calculate the mass of its central black hole. The data revealed multiple components to the galaxy’s structure, including a disk, an ellipsoidal bulge of stars protruding from the disk, and a second, slightly flattened bulge called a pseudobulge that is itself composed of multiple components. With a supermassive black hole mass of 8.4 million solar masses — roughly twice the mass of the Milky Way’s central black hole — NGC 4826 possesses the least-massive black hole to be measured via stellar dynamical modeling. To learn more about the intricate structure of this galaxy and what these measurements imply for the study of low-mass supermassive black holes, be sure to check out the full article linked below.
Citation
“The Black Hole Mass and Photometric Components of NGC 4826,” Kayhan Gültekin et al 2024 ApJ 974 16. doi:10.3847/1538-4357/ad67dc