Ph. D. Research: Radio Transients from Millisecond to Hour-long Timescales

Radio transients are astrophysical events that either appear and disappear, or display variations in their radio emissions. The intrinsic variability time scales can be diverse, ranging from fast radio bursts (millisecond duration extragalactic pulses of as-yet unknown physical origin) and millisecond pulsars (dense, magnetized neutron stars that have spun up to millisecond rotational periods through accretion from a binary companion) at millisecond time scales to minute-hour long interactions of magnetized exoplanets with their host stars.

Transient detection in radio data presents a fascinating challenge due to the variability of astrophysical phenomena, the abundance of extraneous interference sources (e.g., radio waves used for telecommunications, satellite transmissions, etc.), and the enormous data volumes output by modern surveys. The central goal of my research is to enable rapid radio transient discovery through the development of a broad net of computational tools and processing pipelines.

Research Summary
Research themes: Radio Transients from Millisecond to Hour-long Time Scales

Past Projects

Pulse splitting for FRB 121102 ignoring scattering

Induced Polarization from Birefringent Pulse Splitting in Magneto-ionic Media

In this work, Jim Cordes and I show that pulses propagating through regions with large Faraday rotation measures (RMs) can be split into circularly polarized components with measurable differences in arrival times. Incorporating pulse scatter broadening, we discuss, in particular, birefringent pulse splitting effects for FRB 121102 and the Galactic Center magnetar J1745—2900. Both lines of sight have RM ~ 105 rad m—2 that yield millisecond splittings at frequencies well below 1 GHz.

DS events

Wavelet-based Characterization of Small-scale Solar Emission Features at Low Radio Frequencies

Mentored by Divya Oberoi, I developed an automated wavelet-based approach to characterize the spectro-temporal properties of a new class of weak, short-lived (1—2 s), narrow-band (4—5 MHz) solar emission features revealed in Murchison Widefield Array data. We detect numerous features even during quiet solar conditions. At the time of publishing our results, these features were the weakest reported solar radio events with typical energies of 1015—1018 erg. These features ride on a broadband background continuum, likely hinting at them being weak variants of conventional type-I bursts.