Signal-to-noise cutoffs for simulations in the data analysis system for HETDEX

The universe we live in is continually expanding, and we have known for almost 15 years that the expansion rate is actually increasing. The source of this acceleration was termed ”Dark Energy” by astronomers, and it is thought to comprise over 70% of the matter-energy in the universe. An important project to learn more about Dark Energy will be the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). HETDEX will survey over 1 million very distant galaxies, looking for their speed away from us and for their exact distance from us. A crucial part of this survey is the detection algorithms that will actually acknowledge a lightsource on the telescope chip. An important factor to consider in detections is signal-to-noise (s/n) cutoff. Signal-to-noise ratio is a measure of how likely a detection is a real lightsource rather than just background noise. Finding the right cutoff is an important task in computing the expansion rate of the universe, because the number of true and false detections affect the accuracy of that measurement. This project has been to evaluate how the accuracy on this measure changes with s/n cutoff for simulated data of several set brightnesses. The standard cutoff is s/n=5, and this project indicates some potential in lowering that requirement, although more analysis will be required between s/n 4 and 5, and at additional brightness levels.