Three Clemson University astrophysicists have been awarded more than $1 million combined through the NASA Astrophysics Data Analysis Program to study active galactic nuclei, their obscuring material, and variability and periodicity.
Pablo Penil del Campo and Nuria Torres-Alba are postdoctoral fellows and Stefano Marchesi is an adjunct professor in the Department of Physics and Astronomy.
The grants, which are highly competitive, support investigations focused on the analysis of publicly available archival data from NASA space astrophysics missions.
Four Blazers
Penil will study quasi-periodic oscillations in blazars, a type of galaxy powered by supermassive black holes. Blazars appear bright in all forms of light, including gamma rays — the light with the highest level of energy — when one of the jets of matter happens to point almost directly toward Earth.
In this study, he will use observations from NASA missions spanning more than 30 years to study four blazars that show signs of periodic, long-term (2-4 year) emissions in their gamma-ray band. Theoretical models have been proposed to explain the physical mechanisms responsible for these possible periodicities, including the presence of a binary system of supermassive black holes. In this project, Penil will use NASA archival data to search for similar periodic behavior in X-ray and ultraviolet optical bands.
“We aim to provide a detailed and complete picture of how and why these blazars vary over time,” Penil said.
Potentially, the results of the study may uncover evidence of the existence of a binary supermassive black hole at the center of one of these blazars, which would offer valuable insights into the galaxy’s evolution.
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