Earlier in the week, NASA announced its Chandra X-ray Observatory had found thousands of black holes, and released an image of the highest concentration of supermassive black holes ever seen. At the just-concluded 229th meeting of the American Astronomical Society (AAS), the gigantic objects were in focus again Saturday when researchers announced the discovery of two supermassive black holes relatively close to our own galaxy.
Using NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), two research teams focused on two different galaxies: IC 3639, which is 170 million light-years away, and NGC 1448, which is only 38 million light-years from Earth. These are much closer than the supermassive black holes seen in the Chandra image, many of which date back to soon after the Big Bang.
“These black holes are relatively close to the Milky Way, but they have remained hidden from us until now. They’re like monsters hiding under your bed,” Ady Annuar, a graduate student at Durham University in the United Kingdom, who presented the results at the AAS meeting in Grapevine, Texas, said in a statement.
The two supermassive black holes discovered are at the center of, and power, extremely bright objects — in the same class as quasars and blazars — called active galactic nuclei. These objects are so bright due to the radiation across the full electromagnetic spectrum emitted by particles that become really hot in the regions near the black hole. But they are believed to be surrounded by a doughnut-shaped concentration of thick gas and dust which makes them invisible from certain angles.
IC 3639, a galaxy with an active galactic nucleus which has an obscured supermassive black hole, is seen in this image combining data from the Hubble Space Telescope and the European Southern Observatory. Photo:
“Just as we can’t see the sun on a cloudy day, we can’t directly see how bright these active galactic nuclei really are because of all of the gas and dust surrounding the central engine,” Peter Boorman, a graduate student at the University of Southampton in the U. K. who led the IC 3639 study, said in the statement.
The team led by Annuar studied NGC 1448 and found that the nearby galaxy also has a large population of young stars that are just about 5 million years old (our sun and the solar system are about 5 billion years old), which suggests that the galaxy is producing new stars even as the supermassive black hole at its center is feeding on gas and dust.
NGC 1448, a galaxy with an active galactic nucleus hidden by gas and dust, is seen in this image combining data from the Carnegie-Irvine Galaxy Survey in the optical range and NuSTAR in the X-ray range. Photo: Carnegie-Irvine Galaxy Survey/NASA/JPL-Caltech
“It is exciting to use the power of NuSTAR to get important, unique information on these beasts, even in our cosmic backyard where they can be studied in detail,” Daniel Stern, NuSTAR project scientist at NASA's Jet Propulsion Laboratory, Pasadena, California, said.
