Drone Beammapping Methods for 21cm Cosmology Experiments

Will Tyndall (Yale University)

Nov 22, 2023 3:30 PM
Location: Bell Room
Seminar Event

Extracting cosmological 21cm emission from the radio foregrounds which dominate requires precision calibration, including sub-percent measurements of the complex instrument beam. 21cm cosmology experiments are typically driven to be compact transit interferometers with poor point-source sensitivity, and have found it difficult to constrain the beam shape to this precision with sky data alone. A technique that has been developed and demonstrated by multiple groups to address this is to transmit a calibrated radiofrequency signal from a drone into the telescope to measure the beam pattern. I will present ongoing improvements to drone calibration techniques performed by the Newburgh group at Yale University, including a new drone and digital noise source, and improvements to our data reduction and analysis pipeline from the past year. I will also present measurements of the complex beam pattern of a 3m dish acquired in the near-field and the methods and instrumentation used to recover the phase of the antenna under test. We will compute the far-field beam pattern of the 3m dish using a near-field to far-field transformation to demonstrate the feasibility of this technique that can be used to calibrate large diameter telescopes.




Upcoming Seminars

TSI Seminars take place weekly during the Fall and Winter terms. TSI seminars are intended to be accessible to scientists from the entire breadth of backgrounds at TSI, including, Physics, Planetary Science, Geology, Atmospheric Science, and Astrobiology. Our seminar series is partially funded by the Centre de recherche en astrophysique du Québec (CRAQ).