Joint Astrophysics Colloquium

Mapping Matter in Strong Gravity:
Spectral-Timing of Black Holes and Neutron Stars

Abigail Stevens

Michigan State University

One of the best laboratories to study strong-field gravity is the inner 100s of kilometers around black holes and neutron stars in binary systems with low-mass stars like our Sun. The light curves of low-mass X-ray binaries show variability on timescales from milliseconds to months - the shorter (sub-second) variability is particularly interesting because it probes the inner region of the accretion disk and compact object. My research looks at X-ray quasi-periodic oscillations (QPOs) from black holes and neutron stars (as well as coherent X-ray pulsations from neutron stars) by fitting the phase-resolved energy spectra of these signals to constrain their physical origin and track their evolution in time. In this talk, I will present state-of-the-art ‘spectral-timing’ analysis of QPOs from different classes of sources and different accretion states, and I will discuss how this sets the stage for future research.