Mock Observations of the Sunyaev-Zel’dovich Effect in Massive Galaxy Clusters and a Six-Layer Integral Antireflective Structure for Silicon Optics

Citation

Macioce, Theodore Kenneth (2023) Mock Observations of the Sunyaev-Zel’dovich Effect in Massive Galaxy Clusters and a Six-Layer Integral Antireflective Structure for Silicon Optics. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/w1ds-j507. https://resolver.caltech.edu/CaltechTHESIS:05052023-033943351

Abstract

Part 1: Measuring the kinematic Sunyaev-Zel’dovich (kSZ) effect is a promising observational tool to constrain both cosmic growth and galaxy cluster formation. As millimeter-wave telescopes gain sensitivity and angular resolution over multiple frequency bands, high signal-to-noise imaging of the kSZ effect in large samples of galaxy clusters will become increasingly feasible. However, maximizing the science reach of these upcoming data will require more sophisticated analysis methods to characterize and remove contamination from a range of unwanted signals, such as the emission from dusty star forming galaxies. Current predictions of kSZ-derived constraints do not account for these effects in sufficient detail. Moreover, they typically rely on Fisher matrix analyses, which cannot fully capture the degeneracies among the physical parameters describing the cluster. We present a mock observation and analysis pipeline to determine the science reach of kSZ galaxy cluster observations that employs more detailed noise models and more sophisticated analysis methods. From our mock observations, we derive new forecasts of the constraining power of next-generation telescopes on cluster peculiar velocities for several instrument configurations from the 10-m, 30-m, and 50-m classes. These forecasts will inform the designs of next-generation telescopes targeting kSZ observations and will indicate the optimal instrumentation for both cosmological and cluster-scale constraints. The software pipeline we develop will also be directly usable as an analysis tool once observations from such telescopes become available.

Part 2: Silicon optics can greatly benefit future millimeter and submillimeter astronomical instruments thanks to silicon’s useful properties such as low loss, high refractive index, and high strength. However, silicon’s high index (n = 3.4) necessitates antireflection (AR) treatment, which has proven a major challenge, especially for the multilayer treatments required for wide spectral bandwidths. We present our approach to this challenge, in which we develop a wide-bandwidth integral AR structure for silicon optics that uses a novel fabrication technique that combines deep reactive ion etching (DRIE) and wafer bonding. We have previously demonstrated a two-layer AR structure for windows over a 1.6:1 bandwidth and are currently fabricating a four-layer coating for a 4:1 bandwidth. Here, we focus on a design for a six-layer structure optimized to give -20 dB reflection between 80 and 420 GHz (5.25:1 bandwidth), which will be useful for future multicolor SZ observations.

Thesis Files