10/01/2025
By Lynne Schaufenbil
Abstract: Galaxy clusters are the largest gravitationally bound objects in the universe. Their study probes the evolution of large-scale structure in the universe and is sensitive to cosmological parameters. I will discuss a new methodology to study the thermal and kinematic properties of galaxy clusters with cosmic microwave background (CMB) observations. The hot electrons and the bulk motion of clusters modify CMB photons as they pass through the clusters, leading to the so-called thermal and kinematic Sunyaev–Zeldovich (SZ) effects, respectively. My approach relies on using CMB temperature maps from multiple instruments at different frequencies to simultaneously fit for both the tSZ and kSZ effects, while accounting for relativistic corrections and modelling foregrounds such as dust emission. I will demonstrate the success of this approach by applying it to the Abell 399–401 galaxy cluster pair and filament system using data from the Atacama Cosmology Telescope and the Planck satellite. I will also discuss the flight performance and results from the SuperBIT balloon-borne mission, a 0.5-meter near-ultraviolet to near-infrared telescope that completed a 45-night superpressure flight in 2023. SuperBIT achieved diffraction-limited imaging from a balloon platform and mapped the distribution of 30 merging galaxy clusters using weak gravitational lensing. Looking ahead, I will discuss emerging trends in space and discuss the potential for developing a future where individual institutions can develop and launch low-cost space missions for astronomy.
Bio: Ajay S. Gill received his Ph.D. in Astronomy and Astrophysics from the University of Toronto and is currently a Postdoctoral Research Associate at MIT AeroAstro. His research interests span cosmology, space systems, instrumentation, and suborbital missions.
If you are interested in joining us please contact Lynne_Schaufenbil@uml.edu