Researchers address some of the questions surrounding these massive and enigmatic features of the universe by using new, high-powered simulations.

UConn Assistant Professor of Physics Daniel Angles-Alcazar, lead author on a paper published today in The Astrophysical Journal, addresses some of the questions surrounding these massive and enigmatic features of the universe by using new, high-powered simulations.

«Supermassive black holes play a key role in galaxy evolution and we are trying to understand how they grow at the centers of galaxies,» says Angles-Alcazar. «This is very important not just because black holes are very interesting objects on their own, as sources of gravitational waves and all sorts of interesting stuff, but also because we need to understand what the central black holes are doing if we want to understand how galaxies evolve.»

Angles-Alcazar, who is also an Associate Research Scientist at the Flatiron Institute Center for Computational Astrophysics, says a challenge in answering these questions has been creating models powerful enough to account for the numerous forces and factors that play into the process. Previous works have looked either at very large scales or the very smallest of scales, «but it has been a challenge to study the full range of scales connected simultaneously.»

Galaxy formation, Angles-Alcazar says, starts with a halo of dark matter that dominates the mass and gravitational potential in the area and begins pulling in gas from its surroundings. Stars form from the dense gas, but some of it must reach the center of the galaxy to feed the black hole. How does all that gas get there? For some black holes, this involves huge quantities of gas, the equivalent of ten times the mass of the sun or more swallowed in just one year, says Angles-Alcazar.

«When supermassive black holes are growing very fast, we refer to them as quasars,» he says. «They can have a mass well into one billion times the mass of the sun and can outshine everything else in the galaxy. How quasars look depends on how much gas they add per unit of time. How do we manage to get so much gas down to the center of the galaxy and close enough that the black hole can grab it and grow from there?»

The new simulations provide key insights into the nature of quasars, showing that strong gravitational forces from stars can twist and destabilize the gas across scales, and drive sufficient gas influx to power a luminous quasar at the epoch of peak galaxy activity.

Story Source: Materials provided by University of Connecticut. Original written by Elaina Hancock. Note: Content may be edited for style and length.