Black hole illustration. Credit: Aurore Simonnet and NASA’s Goddard Space Flight Center
- To search for black holes around the “Spiderweb” galaxy, astronomers have observed for more than 8 days[{” attribute=””>NASA’s Chandra X-ray Observatory.
- Chandra revealed 14 actively growing supermassive black holes — a much higher rate than other similar samples.
- The difference may be caused by collisions between galaxies in the forming cluster or by an excess of colder gas.
- The “Spiderweb” gets its nickname from its appearance in some optical light images.
Credit: X-ray: NASA/CXC/INAF/P. Tozzi et al; Optical (Subaru): NAOJ/NINS; Optical (HST): NASA/STScI
Often, a spiderweb conjures the idea of captured prey soon to be consumed by a waiting predator. In the case of the “Spiderweb” protocluster, however, objects that lie within a giant cosmic web are feasting and growing, according to data from NASA’s Chandra X-ray Observatory.
The Spiderweb galaxy, officially known as J1140-2629, gets its nickname from its web-like appearance in some optical light images. This likeness can be seen in the inset box where data from NASA’s Hubble Space Telescope shows galaxies in orange, white, and blue, and data from Chandra is in purple. Located about 10.6 billion light years from Earth, the Spiderweb galaxy is at the center of a protocluster, a growing collection of galaxies and gas that will eventually evolve into a galaxy cluster.
To search for growing black holes in the protozoan spider’s cluster, a team of researchers observed it for more than eight days with Chandra. In the main panel of this graphic, a composite image of the elemental Spiderweb array shows the X-ray X-rays discovered by Chandra (also in purple) combined with optical data from the Subaru Telescope at Mauna Kea in Hawaii (red, green and white). The large image is 11.3 million light-years across.
14 sources discovered by Chandra. Credit: X-ray: NASA/CXC/INAF/P. Tozzi et al. Optical (Subaru): NAOJ/NINS; Optical (HST): NASA/STSCI
Most of the “blobs” in the optical image are galaxies in the protocluster, including 14 galaxies discovered in the new Chandra deep image. These X-ray sources reveal the presence of matter falling toward supermassive black holes that contain hundreds of millions of times the mass of the Sun. The proto-web cluster exists in an era of the universe that astronomers refer to as the “cosmic noon.” Scientists discovered that during this time – about 3 billion years after the Big Bang – black holes and galaxies were experiencing explosive growth.
The Spiderweb seems to exceed the lofty standards of this active period in the universe. The 14 sources discovered by Chandra (circled in the image below) indicate that about 25% of massive galaxies contain actively growing black holes. This is between twenty-five times higher than the fraction found in other galaxies of roughly similar age and mass range.
14 sources discovered by Chandra. Credit: X-ray: NASA/CXC/INAF/P. Tozzi et al. Optical (Subaru): NAOJ/NINS; Optical (HST): NASA/STSCI
These results indicate that some environmental factors are responsible for the large number of rapidly growing black holes in the spiderweb’s protocluster. One reason may be that the high rate of collisions and interactions between galaxies sweeps the gas toward the black holes at the center of each galaxy, freeing up large amounts of material for consumption. Another explanation is that the proto-cluster still contains large amounts of cold gas that is easily consumed by a[{” attribute=””>black hole than hot gas (this cold gas would be heated as the protocluster evolves into a galaxy cluster).
Close up. Credit: X-ray: NASA/CXC/INAF/P. Tozzi et al; Optical (Subaru): NAOJ/NINS; Optical (HST): NASA/STScI
A detailed study of Hubble data may provide important clues about the reasons for the large number of rapidly growing black holes in the Spiderweb protocluster. Extending this work to other protoclusters would also require the sharp X-ray vision of Chandra.
A paper describing these findings has been accepted for publication in the journal Astronomy and astrophysics. The first author is Paolo Tozzi of the National Institute of Astrophysics in Artre, Italy.
Reference: “700 ks Chandra Spiderweb Field I: Evidence for Extensive Nuclear Activity in the Primary Group” By P. Tozzi, L. Pintericci, R. Gilli, M. Pannella, F. Fiore, G. Miley, M. Nonino, HJA Rottgering, V. Strazzullo, C. Anderson, S. Borgani, A. Calabro’, C. Carilli, H. Dannerbauer, L. Di Mascolo, C. Feruglio, R. Gobat, S. Jin, A. Liu, T.Mroczkowski Norman, E.; plumb, b. Rosati and A. Saroo, accepted, Astronomy and astrophysics.
arXiv: 2203.02208
NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.