The first coherent census of optical variability in X-ray binaries with Gemini

Abstract

X-ray binary systems (XRBs) consist of a compact object, such as a black hole or neutron star, that accretes matter from its companion star, ejecting a portion of the accreted matter into relativistic jets. It has been shown that time-domain observations, measuring how observed emission changes over time, can be used to address key open questions in compact object research. In particular, pairing time-domain methods with multi-wavelength observations probing different regions within an XRB, can provide further insight into the accretion and jet launching mechanisms of these systems. To this end, the Gemini Optical FAST timing of X-Ray Binaries (GOFAST–XRB) project is a Gemini Large and Long Program that aims to track matter as it propagates from inflow (probed by X-ray light) to outflow (probed by optical light), and characterize how this depends on the nature of different compact objects. This program uses observations in the optical and X-ray wavelengths from Gemini's `Alopeke and Zorro instruments and several X-ray telescopes, such as the Neutron star Interior Composition Explorer (NICER), Hard X-ray Modulation Telescope (HXMT), and Einstein Probe (EP). In this thesis, I develop the foundational optical data processing pipeline for the GOFAST–XRB program. This pipeline extracts the intensity of the sampled XRBs on rapid sub-second timescales (known as lightcurves) from the raw Gemini telescope data, and quantifies how these measurements vary over different timescales. My work represents a novel use for the Gemini `Alopeke and Zorro instruments, directly enabling a new observation and data analysis mode; rapid time-series observations. In the future, my pipeline can be incorporated in the Gemini observatory software packages and made available for use by the broader astronomical community.