research

Gravitational waves and supermassive black holes

Pulsar timing arrays (PTAs) consist of a set of regularly monitored millisecond pulsars with extremely stable rotational periods. The arrival time of pulses can be altered by the passage of gravitational waves (GWs) between them and the Earth, thus serving as a galaxy-wide GW detector. First evidence for low-frequency (~nHz) gravitational waves has recently been reported across multiple PTA collaborations, opening a new observational window into the Universe; I am currently interested in understading what we are seeing through this new window.
The dominant sources of nanohertz gravitational waves are expected to be mergers of the most massive black holes in the Universe. My research is shedding light on their properties and how the gravitational-wave based information fits in with our existing body of electromagnetic observations.

Line-intensity mapping

LIM is an observational technique that targets atomic or molecular spectral lines. I'm interested in its potential to survey both the large-scale matter distribution and the astrophysical conditions of the interstellar and intergalactic medium across vast volumes of the Universe. I have worked on a variety of projects exploring how it can be used to learn about inflation, reionization, and dark matter, as well as developed a formalism to combine summary statistics of LIM data.

Dark matter

Axions and axion-like particles are among the compelling dark-matter candidates. In a recent work, we showed that a high-significance excess in the cosmic optical background measured by NASA’s New Horizons spacecraft can be explained by an axion-like particle in a region of parameter space that was previously unconstrained. Motivated by this result, we then studied a similar parameter space through the attenuation of γ-rays from blazars.