Hunting for Fast Radio Transients in the Local Universe and Pulsars Toward the Center of the Milky Way Galaxy

Citation

Pearlman, Aaron Benjamin (2021) Hunting for Fast Radio Transients in the Local Universe and Pulsars Toward the Center of the Milky Way Galaxy. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ts6a-c751. https://resolver.caltech.edu/CaltechThesis:06082021-172928280

Abstract

The dynamic radio sky is full of fast radio transients that produce emission on timescales ranging from nanoseconds to seconds. The two classes of fast radio transients studied in this thesis are pulsars and fast radio bursts (FRBs). Pulsars are highly magnetized, rotating neutron stars that produce pulses of electromagnetic radiation as a result of charged particles being accelerated along magnetic field lines. FRBs are short-duration, transient radio pulses with extragalactic origins, but the nature of their progenitors still remains a mystery. The extremely high brightness temperatures of pulsars and FRBs indicate that their emission is produced by coherent radiation mechanisms.

Although the focus of this thesis is centered around pulsars and FRBs, I cover a broad range of topics, including (1) the emission behavior of radio magnetars, rotation-powered radio pulsars, and repeating FRBs, (2) the development of novel, state-of-the-art algorithms for pulsar searching, (3) a new, sensitive search for pulsars toward the Galactic Center (GC), and (4) the X-ray behavior of wind-accreting high-mass X-ray binaries (HMXBs) displaying superorbital modulation. In this thesis, I explore the emission properties of several radio magnetars in the radio and X-ray bands using the NASA Deep Space Network (DSN) radio telescopes and the NICER X-ray telescope. I also study the emission behavior of two repeating FRBs, FRB 121102 and FRB 180916.J0158+65 (also referred to as FRB 20121102A and FRB 20180916B, respectively), at high radio frequencies using the DSN's 70 m radio telescopes. In particular, I show that there is a phenomenological link between the radio pulses observed from radio magnetars and repeating FRB sources. I also describe two novel pulsar search algorithms that have been developed to coherently search for accelerated pulsars in Keplerian orbits. In addition, I describe a new, ongoing survey of the GC region that is being carried out at high radio frequencies to search for GC pulsars using the 70 m DSN radio telescope (DSS-43) in Tidbinbilla, Australia. Lastly, I present the results of a pulsar timing analysis of the wind-accreting HMXB, IGR J16493-4348, which displays a 20.06 day superorbital period of unknown origin.

Thesis Files