Astronomy PhD Student · Harvard University

Samuel Feyan

I am a theoretical astrophysicist studying compact objects and their accretion dynamics. My work examines how gas behaves around black holes, including unstable mass transfer and misaligned accretion disks. I use general relativistic magnetohydrodynamic simulations, radiative transfer, stellar-evolution and binary population models to connect physical models with observable electromagnetic signatures.

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Samuel Feyan · Harvard University

Research

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Unstable mass transfer and precursor emission

Under the direction of Morgan MacLeod and Daichi Tsuna, I model unstable mass transfer between an evolving star and a compact-object companion to understand the electromagnetic emission that may precede their eventual merger. This work leverages stellar evolution models, binary population models, and semi-analytic models of mass transfer rates and light curves for the Vera Rubin Observatory.

Unstable mass transfer A donor star transfers gas into the outer edge of a thin accretion disk surrounding a black hole.
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Misaligned accretion disks around supermassive black holes

Under Michael Johnson, I analyze general relativistic magnetohydrodynamic simulations of misaligned accretion disks to determine how disk misalignment changes the fluid and emissivity structures surrounding black holes. From these simulations, I use radiative transfer models to produce synthetic images at frequencies relevant to the Event Horizon Telescope and the Black Hole Explorer.

Misaligned black-hole accretion disk A black hole sits on a vertical spin axis while surrounded by a geometrically thick, inclined accretion flow.

Contact

I welcome anyone interested in discussing research or collaborating on a related project to get in touch.

Institution
Harvard University
Location
Cambridge, Massachusetts
Research profiles