UW Astronomer Awarded NSF Grant to Study Quasars

Mike Brotherton hopes to shed some light on distant quasars by, in simplest terms, looking at some light.

The University of Wyoming astronomy professor and his collaborator at the University of North Texas recently were awarded a five-year National Science Foundation (NSF) grant for $800,000 to continue research being done by them at the Gemini North Observatory on Mauna Kea in Hawaii. The 8-meter telescope is one of the largest in the world, and Brotherton currently has about 350 hours of access to the multimillion-dollar facility spread out over three years.

With that time, Brotherton is observing around 400 distant quasars using near-infrared spectroscopy. A quasar is a supermassive black hole (SMBH), the center of a distant galaxy that is consuming gas. Through this process, a hot, swirling disk forms that feeds the SMBH. One of these disks can outshine the entire galaxy the SMBH exists within and is called a quasar.

Quasars not only are the most massive individual objects in existence, but they are among the most luminous objects to have ever existed in the universe.

Scientists have identified about a million quasars throughout the universe and have studied hundreds of thousands of those with optical spectra. Because of the expansion of the university and Hubble law, light from the most distant objects gets “red-shifted,” though. That means the optical part of the spectrum shifts toward the infrared, making the observations more difficult. The infrared technology is not as advanced, and Brotherton’s project is one of the most ambitious yet in terms of scope.

“We’ve gotten vast quantities of data using one technique, and we know almost nothing about quasar properties using this other technique,” he says. “This is a step in remedying that. Nobody has systematically been gathering infrared spectra for large numbers of these objects. What we’re really doing is jumping ahead to get a large sample with uniform data and selection.”

Those data are valuable because quasars are an integral part of the evolution of galaxies as a whole. How they grew, how they influence galaxies and how they continue in present day are all topics Brotherton hopes to gain a greater understanding of with his research.

“Today, quasars barely exist,” he says. “The supermassive black holes are still around, but they are not being fed or fueled the way they used to be. When these quasars were really around and common and having a huge influence on the universe, was a long time ago.”

Now, with the NSF grant, Brotherton will be able to finish his allotted time on the Gemini telescope and have funding for several years of data analysis and paper writing with graduate student help.