Undergraduate Columbia Astronomy Students Intern at Chile’s Universidad Católica

September 14, 2018

Yasmeen Asali and John Staunton, two Columbia University undergraduates from the Astronomy Department, spent two months in Chile in a practicum at Universidad Católica’s Astrophysics Institute (UC) as part of an ongoing exchange program between both institutions funded by the President's Global Innovation Fund (PGIF).

The collaborative program, run by Marcel Agueros at Columbia and Gaspar Galaz at UC, had benefited five graduate students from both universities. This time, thanks to the efforts of Frits Paerels, Director of Undergraduate Studies at the Astronomy Department, and the support of the Santiago Center, the series incorporated the participation of undergraduate students: “Chile holds a place of primary importance in astronomy because it has superb locations for observation and access to the most advanced facilities”, said Paerels. “For our students to be able to go to there is a unique and career-changing opportunity which will attract the best students to Columbia”, he added.

Yasmeen, a second year astrophysics major, worked under the supervision of Andreas Reisenegger and Germán Gómez-Vargas on indirect dark matter detection using the Cherenkov Telescope Array (CTA), a next generation high-energy gamma-ray telescope projected to be complete in 2025 and composed of arrays in the northern and southern hemisphere (on the island of La Palma, Spain, and in Paranal, Chile, respectively). They analyzed simulated CTA data of the galactic center in search of gamma-ray signals produced by dark matter annihilation. “The galactic center is ideal for this search because the high dark matter density allows for a higher probability of annihilation, and thus a stronger signal”, she explained. “Emission from known sources in the galactic center is subtracted from the simulated data, leaving a residual image that is compared to models of the expected gamma-ray output from dark matter annihilation”. She worked on methods of fitting projected signals to the data in order to determine an efficient analysis method that can be used to quickly place constraints on dark matter models as soon as the telescopes are operating.

“Yasmeen demonstrated tremendous motivation on the project with a strong commitment to finish it on time… she worked on setting up a tutorial on data analysis for dark matter searches with the CTA, which will be a starting point for future students in our team”, explained Gómez-Vargas. “She not only created the tutorial on a well-documented Jupiter Python notebook, but she was also deep into the CTA observation strategies and the theory behind dark matter”.

Yasmeen actively participated in the ANSWERS group meetings doing regular reports and interacting with other group members working on different topics. “I foresee a bright future in science for Yasmeen; she is motivated, proactive, eager to learn, and has fully developed soft skills”, said Gómez-Vargas

John, a physics major, worked under the leadership of Ezequiel Treister, an expert in Active Galactic Nuclei (AGNs) studying the properties of dual AGNs, galaxy mergers with two active black holes at the center of their respective galaxies with the goal of understanding the connection between X-ray emissions outside the nucleus and the merger stage. “For example”, said John,”we showed that shock-heated gas appears outside the nucleus during the intermediate stage”. The data used to study these properties came from the Chandra X-ray observatory, an advanced telescope with high spatial resolution with the capability of seeing X-ray emissions from hot gas, thereby allowing him to build on skills gained throughout the year with Paerels. He also worked on a side project aimed at finding the X-ray luminosity of a newly discovered galaxy that has been deformed due to ram pressure in the galaxy cluster Abell 2670.

According to Treister, John was not only able to carry out the analysis of the Chandra archival data for the nearby galaxies undergoing major galaxy mergers but he went much farther doing a very deep and careful study of the extended X-ray emission in these systems… “to the point that beyond his most remote expectations, Staunton produced a draft of a paper that was already circulated among members of our research group, received very positive feedback and will be soon submitted to the Astrophysical Journal”, he explained. “I’ve never seen an undergraduate student before that was able to produce a high quality paper like this one in only a couple of months, starting the project from scratch”.

In addition to projects, John found time to expand his interest in physics and astrophysics alike by presenting two papers at weekly seminars held at UC: “This experience and the setting on which it occurred helped foster an irreplaceable love for physics and astrophysics alike”, he said after completing his internship.