Research

My research seeks to understand the growth, structure, and physical processes governing supermassive black holes (SMBHs) and their galactic environments over cosmic time. I am also interested in using astrophysical sources as probes of physics beyond the Standard Model. I approach these areas by combining observational data, computational modeling, and statistical inference, with an emphasis on strong gravitational lensing and high-energy astrophysics.

Strong gravitational lensing of AGN

Since joining the CfA, I have been undertaking a multiwavelength study of gravitationally lensed AGN using archival X-ray (Chandra) and optical (Gaia and/or HST) observations. By leveraging strong gravitational lenses as natural high-resolution telescopes, we can uniquely reveal sub-kiloparsec (sub-kpc) inner structure in cosmologically distant AGN – a frontier otherwise inaccessible to direct imaging with current and even future facilities.

Sub-kpc structures may arise from offsets between different emission regions (e.g. due to X-ray outflows or radio jets) or may be attributable to the existence of compact AGN pairs at large redshifts. Both scenarios have important implications for SMBH growth, AGN physics, and SMBH-galaxy co-evolution. My current work measures these offsets with milliarcsecond precision.

Fundamental physics

My Ph.D. at the University of Cambridge used high-resolution X-ray spectroscopy of AGN to probe nonstandard physics and the extreme, energetic environments around active SMBHs. In particular, I focused on:

• Ultralight axions: well-motivated particles and compelling dark matter candidates, which could imprint spectral signatures in the spectrum of X-ray emission of AGN residing at the centers of galaxy clusters
• Black hole spin: one of two fundamental parameter of astrophysical black holes (along with the black hole mass). Moreover, the observed mass vs. spin demographics of SMBH populations help us unlock the cosmic growth histories of SMBHs and probe their accretion physics.

My Ph.D. research set some of the most sensitive constraints to date on the interaction between ultralight axions and photons, and provided the only well-defined spin constraint for a very massive black hole studied with X-ray reflection spectroscopy to date. These frontiers demonstrate the power of AGN as laboratories for fundamental physics and extreme-gravity astrophysics.

An online version of my Ph.D. thesis is available here.

Looking ahead

Across the research directions I have pursued, my long-term goals is to build a coherent research program that uses multiwavelength observations, strong gravitational lensing, and spectroscopy to address fundamental questions about how SMBHs grow over cosmic time, what their accretion physics is, and physics beyond the Standard Model. Upcoming facilities such as Euclid, Rubin, Roman, NewAthena, and other next-generation X-ray and radio observatories will significantly expand the reach of my current research.