Master Thesis Defense by Arthur Matthew Kadela

Title: Optimizing UV Arm for Photon Counting: Nordic Optical Telescope Transient Explorer

Abstract: The use of electron multiplying charged coupled devices (EMCCD’s) for high-speed, short-exposure imaging has been used for decades to correct atmospheric turbulence, and improve image resolution. Development of increasingly sensitive, low noise EMCCD’s, and Skipper CCD’s, has opened the possibility for medium sized telescopes to perform faint object spectroscopy, up to the sky background limit, with greater fidelity. By reducing the amount of readout noise higher resolution can be achieved, and a better final scientific result can be obtained. To optimize the UV-arm of a new instrument, the Nordic Optical Telescope, Transient Explorer (NTE), various modes of operation, exposure times, and minimal noise settings are considered. Simulations were setup to resemble a low flux, echelle spectrum, falling onto a 1k x 1k (1024 x 1024 pixel) detector. Clock induced charge (CIC) is identified as the leading contributor to noise, and simulations were run using various levels of CIC. An ideal range of object magnitudes is constructed, and various operation modes are explored. Current work on including photon counting (PC) data into a major spectroscopic reduction pipeline is presented and criticized. Improvements to simulations are also mentioned. Finally, it is shown that improvements in total system efficiency, in the UV, and the use of PC, lead to shorter integration times, when compared to current instruments available at the NOT.

Supervisor:

• Johan Peter Uldall Fynbo, University of Copenhagen, Niels Bohr Institute

Censor:

• Frank Grundahl, Aarhus University