From Harvard-Smithsonian Center for Astrophysics: “The Co-Evolution of Galaxies and Supermassive Black Holes”

Harvard Smithsonian Center for Astrophysics

From Harvard-Smithsonian Center for Astrophysics

An Illustris-TNG simulation of the stellar content of the universe today on the largest scales showing a projection of stars across a 150 million light-years. Scientists using the code have been able to trace the co-evolution of galaxies and their supermassive black holes. The TNG Collaboration

The formation and growth of galaxies in the early universe is a key research topic for future giant telescopes like the Giant Magellan Telescope and space missions like the James Webb Space Telescope.

Giant Magellan Telescope, to be at the Carnegie Institution for Science’s Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high

NASA/ESA/CSA Webb Telescope annotated

Meanwhile, computer simulations of cosmic galaxy development have made considerable progress in our understanding. They show that details of galaxy development are closely tied to the properties of the galaxies, like their sizes and star formation rates. These properties are in turn regulated by the galaxies’ gas content, the gas motions (primarily the angular momentum), and some still uncertain mechanisms that regulate star formation like feedback from the nuclear black hole. Finally, there is growing evidence for correlations between the properties of a supermassive black hole and its host galaxy.

Black holes with millions or even billions of solar masses are found in the centers of most galaxies. The most powerfully active nuclear black holes are in quasars and these have been spotted as far away as the epoch when the universe was less than a billion years old, suggesting that the galaxy- black hole symbiosis was already underway at this early time. Accreting black holes can emit powerful jets or winds that reverse the accretion and drive material outward, sometimes quenching the star formation. These and other lines of evidence help to clarify the co-evolution mechanisms between black holes and galaxies and reveal the joint evolution of the galaxy and the supermassive black hole populations.

CfA astronomers Lars Hernquist and Rainer Weinberger and their colleagues used the large-scale hydrodynamic simulation called IllustrisTNG to trace the development of galaxies and their black holes. The code is able to model the evolution of a wide range of black hole and galaxy properties as the universe ages. They successfully reproduce the observed correlation between star formation rate and galaxy mass. They find, among numerous other trends, that quiescent galaxies (those no longer actively making stars) first go through a phase of shrinking in size before they undergo a quenching event; they also find that in the cosmic epoch of peak star formation (about ten billion years ago) as many as twenty percent of galaxies hosted an active supermassive black hole.

science paper:
Linking Galaxy Structural Properties and Star Formation Activity to Black Hole Activity with IllustrisTNG

See the full article here .

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The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.