There is an active galaxy called BL Lacertae located approximately one billion light-years away, and it features a strange twist at its core.
Exploring the universe is of great importance not only because of human curiosity and our need to see what is out there but because by studying distant stars and galaxies, we can learn more about us and how galaxies such as the milky way came into existence and what their future holds.
With state-of-the-art observatories like the James Webb Space Telescope, we are closer than ever to unraveling some of the greatest mysteries of astrophysics but also coming across new ones. But James Webb isn’t the only observatory that astronomers rely on when exploring the vastness of deep space. The BL Lacertae (BL Lac) galaxy has recently been studied by 86 scientists from 13 countries with high-resolution optical monitoring.
Whole Earth Blazar Telescope (WEBT)
Using the 0.9-meter reflecting telescope at the BYU West Mountain Observatory, Dr. Mike Joner and BYU undergraduate student Gilvan Apolonio captured over 200 observations of the galaxy. As part of a collaborative project called the Whole Earth Blazar Telescope (WEBT), their measurements were combined with observations made by scientists across the globe. When there is high variability in an object, the WEBT network allows monitoring from different locations around the clock.
Scientists have found that the BL Lac central jet shows surprisingly rapid brightness changes based on WEBT observations made in the summer of 2020. A twist in the jet’s magnetic field may be causing these cycles of brightness changes. West Mountain Observatory, a ground-based telescope at BYU, was among 37 worldwide that monitored the optical variations of BL Lac, an active galaxy about 1 billion light years away. While working at the observatory in the spring and summer of 2020, Joner and Apolonio alternated working different groups of nights. It was necessary to work an atypical schedule since observations were required every clear night, and no other trained student observers existed in Provo.
To understand the high-energy observations from Fermi Gamma-Ray Telescope, it was crucial to analyze high-cadence optical observations. Combining data from high-energy space observatories with information from optical ground-based monitoring stations is essential. Space telescopes costing billions of dollars are often used for projects like these, Joner explained. Comparing the high-energy observations and the ground-based light curves confirmed that high-energy observations showed rapid periodic oscillations.
Despite his established expertise in astrophysical research, Joner is still amazed by the amount of detail scientists can obtain from such observations. “It is striking to see the variations in a blazar’s central jet so clearly on a galactic scale, even though it is combined with the light of hundreds of billions of stars in its host galaxy,” he said. The jet’s variability is easily seen despite being accompanied by light from hundreds of billions of stars.
BYU’s well-equipped and modestly sized facilities, like those available at BYU, can still be relied on to explore the unknown reaches of the universe in our age of giant telescopes and space-based research, reads a statement. The study was published in Nature.