June 17, 2019
The first of two grants that Sigma Xi awarded to Haylee Archer helped to spark her interest in observational astronomy. She is shown above with the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile.
Grant awarded: $975 in fall 2015
Education level at the time of the grant: undergraduate student at the University of North Dakota
How the funds were used: travel to and from Kitt Peak National Observatory in Tucson, Arizona, and lodging
Project goal: The project’s objective is to quantify the impact of the high-density galaxy cluster environment on the star formation rate (SFR) of dwarf (low-mass) galaxies that gravity is pulling toward the cluster center—a process known as infalling. Dwarf galaxies traveling through the hot intracluster medium are subjected to compression shocks, called ram pressure, that either compress the gas in galaxies and trigger star formation or strip gas from individual galaxies and truncate or quench star formation. Characterizing this process in terms of its effect on the SFR of infalling galaxies will provide valuable insights into the impact of the cluster environment on the galaxy population. Galaxy clusters are the largest gravitationally bound structures in the universe. Learning how the cluster environment affects galaxy evolution provides more understanding of how the universe works at some of the largest scales.
Project results: Evidence was found at all radii for quenching star formation toward the cluster center. Results suggest that both galaxy harassment (high-speed flyby interactions) and ram pressure stripping help to quench star formation in the low-density cluster outskirts, while ram pressure stripping plays a more important role than galaxy harassment in quenching star formation toward the high-density cluster center. It was also found that dwarf galaxies are more susceptible than the giant systems to ram pressure stripping. It was determined that ram pressure and galaxy harassment have similar effects on the SFR for both elliptical and spiral galaxies.
Where is she now? Archer was inducted into Sigma Xi in 2016. She is finishing her master’s degree in science teacher education at Northern Arizona University in Flagstaff, Arizona.
How the grant helped her: Sigma Xi’s Grants in Aid of Research (GIAR) program funded Archer’s first professional observing experience, which sparked her passion for observational astronomy. GIAR also funded her with $2,271 in 2017 for travel to Chile for another observing run at Cerro Tololo Inter-American Observatory.
“What I like most about observational astronomy is that we are looking at things millions or billions of light years away,” she said. “I’m continuously fascinated by the capabilities of humans to observe and study things at the largest and smallest scales in the universe.”