Understanding the most powerful objects in the universe

Quasar 3C-273. Photo by Hubble Space Telescope

Usually when people observe hot gas coming out of something, they are watching a politician deliver a speech. Astronomers have found objects that do the same thing but in a far more spectacular fashion.

Quasars contain a supermassive black hole, with a disk of gas orbiting around the black hole and are most commonly found near the center of galaxies. As the gas orbits the black hole, it becomes charged and energy is released in the form of electromagnetic radiation.

Astronomer Paul Smith of the Steward Observatory at the University of Arizona has dedicated nearly a decade to observing these extraordinary objects. Using the 2.3m Bok telescope at Kitt Peak National Observatory, Smith has spent many nights viewing quasars.

“This plays into my love of working at a telescope and obtaining accurate information with specialized instruments,” Smith said.

According to Smith, other than the Steward Observatory telescopes at Kitt Peak, few places in the world can provide this amount of information about the polarization of quasars. The enjoyment of doing something that no one else is doing plays a large role as well. Most quasars are billions of light years away, so by studying them, scientists can gather information about the early stages of the universe.

Astronomers have observed more than 200,000 quasars. According to Smith, roughly 10 to 20 percent of those have two jets of particles being shot out in opposite directions of each other — traveling at or near the speed of light. According to Smith, the problems these jets pose to astrophysicists is unknown. That adds excitement to this project as Smith and other astronomers attempt to understand the powerful objects.

2.3m Bok Telescope Tower. Photo by TJ Gibbs/Arizona Sonora News

Of those quasars with jets, some jets are pointed directly at the Earth, which are known as blazars. Quasars are many light years away, so they don’t pose any harm, but the phenomenon of looking right into the jet is much different than looking at a jet aimed away from Earth.

To help understand quasars, Smith is studying their polarization with a spectropolarimeter, or SPOL. The device, used to measure optical properties of polarized light, was created in 1990 by Gary Schmidt and H.S Stockman.

Telescope control panel. Photo by TJ Gibbs/Arizona Sonora News. The instrument is quite old by today’s standards and operates with a 1995 computer. “It isn’t because modern computers can’t run it, it’s because it is written in language that was popular in the 1980’s,” Smith said. It would require many hours to rewrite the language for modern computers. The instrument is also portable which is not nearly as common with modern telescope instruments. According to Smith due to the increasing size of telescopes, instruments had to increase in size as well. “All together the components of SPOL weigh about 150 to 200 pounds. Modern instruments can weigh tons,” Smith said.

Focusing on polarization allows Smith to understand the magnetic fields of these objects. The jets are collimated, which means a magnetic field is present. The direction of the magnetic field can give insight into the geometry of the source of the light, Smith said.

He is also partnering his research with the NASA Fermi Gamma-ray telescope. Smith uses the data from Fermi, along with his own observations, to attempt to predict the behavior — as well as notate any anomalies in the behavior of specific quasars. Data from the observations Smith has performed can be found here.

Gamma ray radiation is the most energetic form of radiation. It is much more energetic than visible light, and takes extraordinary phenomena such as a quasar to generate this sort of radiation.

Smith is unsure if he will continue his research beyond November 2018.

“I am not sure if I will win another grant to be able to continue this project. My advancing age doesn’t help either,” said Smith, who will be 61 .

According to Smith, he isn’t certain that continuing past the decade would provide more meaningful information that hasn’t already been collected. He plans to dive into the data and see what he can learn from it, as well as write some science papers.

The Fermi telescope will continue to observe these objects. According to Smith, there are no plans to shut it down, nor are there any telescopes being made to replace it.

TJ Gibbs is a reporter for Arizona Sonora News, a service from the School of Journalism with the University of Arizona. Contact him at tjgibbs@email.arizona.edu


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