Radio Point Source Contamination in Galaxy Clusters
radio astronomy, scientific research, Cosmic Microwave Background
The NRAO (National Radio Astronomy Observatory), in Green Bank, West Virginia is the World's Largest Fully Steerable Radio Telescope. Green Bank is what we call in the astronomy community a "dead zone." It is literally in the middle of a "radio free zone" in order to minimize radio frequency interference (RFI). That means no cell phones, no cable TV, not even microwaves!
My work at the NRAO focused on the Cosmic Microwave Background (CMB), which is the radiation emitted after the Big Bang. By studying the CMB, we can learn about the origin of our universe. I worked with renowned CMB scientist Dr. Brian Mason and served as his research assistant. My contribution in the project involved accessing data (that Dr. Mason had obtained from a telescope called the Cosmic Background Imager which is in the Andes mountains in Chile) and performing analysis on this data coding mainly in C.
Observations of the Cosmic Microwave Background (CMB) with the Cosmic Background Imager (CBI) have revealed radio foreground signals that limit the accuracy of measurements of the anisotropic properties of the CMB such as the Sunyaev-Zeldovich Effect. By comparing CBI data to NVSS (and PMN) data, accurate counts of the number of radio sources in low redshift galaxy clusters were made. It was determined that at 30 GHz there are 1.4±0.3 sources brighter than 30mJy in the sky per deg² in fields containing galaxy clusters. Comparing these results to the number of radio sources at random in the sky at 30 GHz (Mason et al.) a 1.38σ difference was found. We therefore do not detect a strong difference in the number of radio sources at 30 GHz in galaxy cluster fields.
Download my paper on cosmic microwave background here.