A group of 86 scientists from 13 countries recently carried out high-time resolution optical monitoring of a distant active galaxy. Mike Joner was a professor of physics and astronomy at the time.
Dr. Joner and Gilvan Apolonio used the telescope at the West Mountain Observatory to obtain over 200 observations. The Whole Earth Blazar Telescope is a collaboration of scientists around the world. During times of high variability, the WEBT network allows objects to be monitored from different locations.
Astronomers used the WEBT observations made in the summer of 2020 to discover a sudden change in the central jet of the BL Lac. There are twists in the jet's magnetic field that cause the cycles of brightness to change. The study was published in Nature.
The optical variations of the blazar BL Lac were monitored by the West Mountain Observatory. During the height of the Pandemic, Joner and Apolonio worked different groups of nights at the observatory. Since there were no other trained student observers in the area, there was a need for an atypical work schedule.
The analysis of the high-cadence optical observations was important to understand the high-energy observations from the space-based Fermi Gamma-Ray Telescope.
You need to combine the data from space observatories with the ground-based data. Joner said that the billion-dollar space telescopes that are used on projects like this often need to compare results. The correlation of what was seen in the high energy observations with the ground based light curves helped confirm the rapid periodic oscillations that were observed in the high energy data from space.
Joner is an expert in astrophysical research, but he still marvels at the level of detail scientists are capturing through such observations. He's thankful for the opportunity to explore the far reaches of the universe with his students.
The central jet of a blazar is not very large. The variations of the jet are clear. He said that the variability of the jet is easy to see even though it is combined with the light from hundreds of billions of stars.
It's noteworthy that in this age of giant telescopes and space-based research, it's still necessary to rely on modest sized and well-equipped facilities.
A co-author of the paper was a graduate student from Boston University.
More information: S. G. Jorstad et al, Rapid quasi-periodic oscillations in the relativistic jet of BL Lacertae, Nature (2022). DOI: 10.1038/s41586-022-05038-9 Journal information: Nature
All Rights Reserved © 2024
