Astrophysics Brown Bag Lunch Talk 11/22/2021: Speakers: Emily Kuhn (Yale University) And Laura Rogers (Cambridge University)
Monday November 22, 2021 12:00 pm
Monday, November 22, 2021
12:00 – 12:30pm
Emily Kuhn, Yale University
Drone Calibration for 21cm Experiments
Abstract: Drone calibration is a new and exciting technique for generating 2D telescope beam maps that will address the challenges of calibrating stationary 21cm telescopes such as HIRAX and CHIME. At Yale, we have built a robust drone calibration system from the ground up, consisting of a stable broadband noise source, a GPS- locked timing board, an omnidirectional transmitter antenna, and a precision differential GPS to fly on a quadcopter drone.This system has produced the first beam maps of several UHF and L-Band telescopes, most recently mapping the CHIME outrigger dishes at Green Bank Radio Observatory (GBO). In this talk, I will describe the drone system design, recount the status of calibration measurements, report preliminary results from recent GBO flights, and discuss upcoming plans, particularly in the context of HIRAX.
Bio: Emily is a 6th year graduate student at Yale and a NASA Space Technology Research Fellow. Her dissertation research focuses on developing instrumentation for the HIRAX radio telescope, which has looked like anything from DIY-ing a 600L cryostat out of attic insulation to rescuing a 20lb drone from a forest in the rain. Outside of research, Emily enjoys sharing science with the public, adventuring outdoors, playing the flute, and spoiling her pets.
12:30 – 1:00pm
Laura Rogers, Cambridge University
Using polluted white dwarfs to understand the bulk composition ofexo-planetary material
Abstract: Exoplanets are ubiquitous across the Milky Way, but finding out what the interiors of these planets are made from is challenging. At least 30% of white dwarfs are observed with signatures of swallowed exoplanets in their atmospheres. From these ‘polluted’ white dwarfs we infer the bulk composition of the parent body that was accreted. With over 1000 known polluted white dwarfs we can make powerful conclusions about exoplanetary composition and their geology. We present the first results from a new large survey studying some of the heaviest polluted white dwarfs. The composition of the planetary material that has ‘polluted’ the white dwarf is inferred from the spectra. What can the composition tell us about exoplanetary material and geological processes in exoplanetary systems?
Bio: I am a final year PhD student at the Insitute of Astronomy, University of Cambridge, UK. I primarily work on observations of polluted white dwarf systems- white dwarfs which have signatures of accreted exoplanetary material in their atmopshere. I use these white dwarfs to investigate the bulk composition of exoplanetary material and link this back to our solar system.