Punting Black Holes

As summer approaches, we can see examples of punting in more than just local playing fields. In addition to balls being punted halfway across a field, it looks more and more like 6 billion solar mass black holes can also be punted to vast distances across a galaxy.

Now black holes are, as the name implies, completely black. The good news is that they can be spotted anyway for the cases in which the surrounding gas or even stars get too close to the black hole and start funneling onto it. In such cases the black hole can become piercingly bright.

In fact the black hole is so bright that there is too much glare to see the fainter galaxy underlying it. Recently, astronomers have found a way to block out this extra glare from the ultra-bright supermassive black hole.

Somewhat surprisingly, in a couple of cases a considerable offset is measured in the center of the galaxy compared to the center of the black hole. The only way this can be explained is if the black hole was kicked out of the center. How can this happen to a 6 billion solar mass object, afterall?

Well it turns out that it is not just gas and stars that can infall onto the central supermassive black hole. Also, other smaller black holes settle into the center and get consumed by the central supermassive one.

If the impactor is fairly large, then the coalescence of the two objects can induce a strong ‘kick-off’ velocity that punts the whole combined heavyweight black hole out of the galaxy center. In fact, if our own supermassive black hole at the center of the Milky Way would suffer such a collision, this kick-off velocity would be powerful enough to send the entire supermassive black hole beyond the orbit of the Sun. That corresponds to a 33,000 light year punt - Go Team!

Dr. Brenda Frye

About Dr. Brenda Frye

Brenda L. Frye is an observational cosmologist at the Department of Astronomy/Steward Observatory, University of Arizona. She earned her Ph. D. in Astrophysics from the University of California at Berkeley, assisted by a National Science Foundation Graduate Research Fellowship.

Her thesis work involved measuring the concentration of the total mass of visible plus dark matter in the fields of massive galaxy clusters, a program requiring the use of some of the largest telescopes in the world.

Moving a mile from her Ph. D. institution, she assumed a postdoctoral position with the Supernova Cosmology Project at Lawrence Berkeley National Laboratory under the direction of Professor Saul Permutter.

She then treked across the country to take a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship and a Princeton Council on Sciences and Technology Fellowship both at Princeton University.

Moving further east, she became a Lecturer in Physics at Dublin City University in Dublin, Ireland, where a number of European collaborations were formed.

From there she crossed back across the pond to the west coast of the U. S. to become a tenure-track Assistant Professor of Physics at the University of San Francisco.

Her travels have now landed her at her Alma Mater in Tucson, where she teaches and does research. The aims of her research continue to be to use gravitational telescopes in space as 'lenses' to study the properties of dark matter and those of distant galaxies back to when the universe was <900 million years old.

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