Allen Lawrence, wrapping up a long career as an electrical engineer, was serious about moving his astronomy hobby beyond the 20-inch telescope he’d hauled to star parties under the dark skies of Texas and Arizona.
So in 2011 – in his late 60s, after 30 years of operating his own consulting firm around Green Bay, Wisconsin – he enrolled in some courses at the University of Wisconsin-Madison. It wasn’t long before he went around Sterling Hall asking about joining a research team.
Jay Gallagher, now the W. W. Morgan & Rupple Bascom Emeritus Professor of Astronomy at Wisconsin, offered Lawrence the chance to study one of two galaxy systems. Lawrence picked a nearby system studied since the 1960s and featuring the interaction of two galaxies, a larger one known as NGC 4490 (nicknamed the “Cocoon Galaxy” because of its shape) and a smaller one known as NGC 4485. The system is about 20% the size of the Milky Way, located in the Northern Hemisphere and about 30 million light years from Earth.
After taking a look at some infrared images from NASA’s Wide-field Infrared Survey Explorer, Lawrence said it looked like the larger galaxy had a rare double nucleus. One nucleus could be seen in visible wavelengths, the other nucleus was hidden in dust and could only be seen in infrared and radio wavelengths.
Well – after years of study, including earning an Iowa State University master’s degree in 2018 and continuing to work with Iowa State astronomers – Lawrence, at 77, is the first author of a paper revealing the NGC 4490 galaxy does, indeed, have a double nucleus. The paper is now online and has been accepted for publication by the Astrophysical Journal.
Some astronomers may have seen one nucleus with their optical telescopes. And others may have seen the other with their radio telescopes. But he said the two groups never compared notes to observe and describe the double nucleus.
Co-authors of the paper are Iowa State’s Charles Kerton, who researches star formation, said, “This project demonstrates that using multiple wavelengths from space- and ground-based observations together can really help us understand a particular object.”
Source: “77-year-old amateur astronomer helps reveal rare galaxy double nucleus” Iowa State UniversityNews Service, 5 February 2020 <https://www.news.iastate.edu/news/2020/02/05/galaxy>.