Uncovering the LISA-Detectable Double White Dwarf Population
We are harnessing time-domain surveys such as ZTF, TESS, and ATLAS to discover and characterize compact binary systems that emit gravitational waves in the millihertz band. Our discoveries have doubled the known sample of double white dwarfs detectable by LISA, allowing us to investigate how gravitational radiation, mass transfer, and tidal effects drive binary evolution. This work is critical to understanding the progenitors of explosive events like Type Ia supernovae and refining our models of stellar evolution.
Probing Compact Objects in Globular Clusters
Dense stellar environments, such as globular clusters, provide unique laboratories for studying neutron stars and other compact remnants. Our targeted surveys—using instruments like the Hubble Space Telescope—aim to uncover hidden populations of spider pulsars and related systems in clusters like 47 Tuc. By mapping these exotic objects, we gain insights into the mass distribution and dynamical interactions that govern neutron star formation and evolution in high-density regions.
A JWST image of the outskirts of the globular cluster Terzan 5 taken as part of one of our research programs:
A movie generated from image subtraction applied to our globular cluster data, with a Chandra error circle shown in green, encompassing a variable star:
Exploring Black Hole Triples and Tertiary Dynamics
Our research extends to complex multiple-star systems, where the presence of tertiary companions can dramatically influence the evolution of black hole binaries. By identifying systems such as V404 Cygni with an additional companion, we are uncovering how these extra bodies trigger orbital changes and mergers. This work not only refines our understanding of black hole formation—whether through direct collapse or other channels—but also offers new tests for models of gravitational interactions in multi-body systems.
An artist’s depiction of V404 Cygni, a black hole low mass X-ray binary in a hierarchical triple (image credit, Jorge Lugo):
Developing High Temporal Resolution OIR Instrumentation
Capturing the fleeting signals of rapid astrophysical phenomena requires state-of-the-art optical and infrared instrumentation. Many events of interest—such as short-period eclipses, rapid accretion changes, and pulsar timing—occur on millisecond timescales, demanding instruments with sub-millisecond timing precision and extremely low noise. Our team has pioneered high-speed imagers like the “Lightspeed” camera, which uses advanced qCMOS sensors to achieve unprecedented time resolution. After successful initial deployments, we are planning next-generation instruments, including a multi-band ultra-fast imager for major telescopes. These instruments will not only enhance our ability to study compact binary evolution in exquisite detail but also open new windows on phenomena such as gravitational-wave induced orbital decay and fast radio bursts.
Installing the Lightspeed prototype camera in the Prime Focus cage of the 200 inch Hale Telescope at Palomar:
