04/07/2026
By Anthony DeVasto

The Kennedy College of Sciences, Department of Physics & Applied Physics, invites you to attend a Master’s Thesis defense by Anthony DeVasto on “Investigating High Mass X-Ray Binary Systems Through Spectral Modeling And Light Curve Analysis.”

Candidate Name: Anthony DeVasto
Degree: Master’s
Defense Date: Thursday, April 9, 2026
Time: 4 to 5:30 p.m.
Location: 136 D, Olney Science Center, North Campus

Thesis/Dissertation Title: Investigating High Mass X-Ray Binary Systems Through Spectral Modeling And Light Curve Analysis

Committee:

  • Advisor: Silas Laycock Ph.D., Department of Physics & Applied Physics, University of Massachusetts Lowell
  • Ofer Cohen Ph.D., Department of Physics & Applied Physics, University of Massachusetts Lowell
  • Hugo Ribeiro Ph.D., Department of Physics & Applied Physics, University of Massachusetts Lowell

Brief Abstract:
High Mass X-ray Binary (HMXB) systems consist of a compact object, a neutron star or a black hole, orbiting a massive stellar companion. This study focuses on IC 10 X-1 (~750 kpc away) and NGC 300 X-1 (~2,000 kpc away), both likely black hole and Wolf-Rayet binaries. In these systems, mass transfer occurs via Roche-Lobe Overflow (RLO) or by capturing the companion’s stellar wind, with these systems thought to be wind-fed. This accretion produces thermal emission which is Comptonized into X-ray photons observed by space-based observatories. Although HMXB systems are well studied, significant uncertainties remain in fundamental binary properties, such as black hole mass, spin, and accretion disk luminosity due to strong parameter degeneracies.

In this study, we estimate the black hole masses of IC 10 X-1 and NGC 300 X-1 using data from the Chandra and XMM-Newton observatories. By generating phase-resolved light curves from 15 observations of IC 10 X-1, featuring one October 2025 observation, and 9 observations of NGC 300 X-1, we estimate flux, characterize spectral states, and identify eclipse regions.

We fit the non-eclipse spectra according to a tbabs*(slimbh+powerlaw) model and explore the parameter space through Markov Chain Monte Carlo (MCMC) methods. In modeling black hole mass, spin, and disk luminosity, we find physically reasonable but unconstrained fits. We remedy this by fixing the black hole spin, and discover well-constrained estimates of black hole mass and accretion disk luminosity consistent with the current literature. We conclude our study by visualizing each system’s potential and Roche-Lobe geometry.