January 14, 2021
Animated gif showing DIM image of Cen A, plus the identification of shells

Animated gif showing DIM image of Cen A, plus the identification of shells. In yellow are shells identified by Malin, D., Quin, P.J, Graham, J.A., 1983 Astrophysical Journal, 272, L5 (done with the CTIO 4m telescope). In red are shells identified by DIM.

Academics are familiar with the process of presenting their own discoveries at professional conferences. Catholic University Professor Duilia de Mello is quite adept at it — she discovered supernova SN1997D, blue blobs (“nurseries'' of orphan stars outside of galaxies), and was part of the team that discovered the true size of the largest spiral galaxy NCG 6872.

This winter, de Mello will present work she is collaborating on with amateur astrophotographers in Brazil at the American Astronomical Society’s 237th Meeting in January.

De Mello teaches astronomy at Catholic University as a professor of physics, serves as the Vice Provost for Global Strategies, and is a research associate at NASA's Goddard Space Flight Center. A native of Brazil, she often returns there to speak to young people (especially women) about participating in STEM education and careers. 

In her latest project, de Mello is working with amateur astronomers — Marcelo Wagner Silva Domingues, a civil servant; Cristovao Jacques Lage de Faria, engineer and entrepreneur; Joao Antonio Mattei, engineering and CEO of a construction company; Eduardo de Jesus Oliveira, professor of pharmaceutical sciences at Federal University dos Vales do Jequitinhonha e Mucuri; and Sergio Jose Goncalves da Silva, a telecommunications engineer. They are collaborating to capture Deep Images of Mergers (DIM) to illustrate the final stages of galaxy evolution by revealing optical shells or ripples around early-type galaxies. 

Using their own personal equipment (telescopes and cameras), the team of five is capturing deep space images over 30 or more hours in their own homes. This number of dedicated hours is usually not easily obtained on professional telescopes.  De Mello is working to ensure that the data being collected by different instruments is still scientifically useful.  

Using very specific imaging methods, the team is working to capture images of the faint shells that form around galaxies to search for any correlation with the hydrogen gas normally distanced from a galaxy after an interaction or merger. Galaxies they are examining include Centaurus A, Arp 230, and NGC 1052. 

“We have the right technology and methodology,” de Mello says. Centaurus A is a bright galaxy in the southern hemisphere, 13 million light years away, and  known to have shells and external HI gas. It was used as a proof of concept of the project. They were able to see faint shells really far from the central galaxy, assuring that they could move the project forward. On Arp 230, the team has started to collect dozens of hours of data and has observed shells as far away as the ones discovered on images using the Hubble telescope.

De Mello hopes this project will demonstrate to the larger astronomy community that collaboration between scientists and amateurs can be both “fruitful and exciting.” This project is a proof of concept to show that data sets can be combined and translated into meaningful scientific information. 

“In deep images taken with these relatively small telescopes we are able to see a large field of view and expand our search for faint shells at large distances,” she says in her abstract. “After combining all images to the same scale, the first results of the stacked images with dozens of hours of exposure reveal a large number of shells confirming the feasibility of the project and the importance of deep images when analyzing mergers.” The next step now is to extend the collaboration to more amateurs who would like to join the project and observe dozens of other mergers.

MEDIA: To schedule an interview with de Mello, contact the Office of Marketing and Communications at communications@cua.edu or 202-319-5600.

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