UC Santa Cruz

Pulsars are small, dense, rotating stars that appear to flash as they sweep the sky with beams of radiation. This light originates from high energy particles following curved paths as they flow into interstellar space. Where these particles originate, and how they are accelerated to the necessary energies, is still an open question. The answer may change as the pulsar goes through its evolutionary process.

Theorists have focused on four accelerating regions: the polar cap, slot gap, outer gap, and current sheet. Testing these models requires detecting pulsars and measuring their spectra and spin characteristics. It is to this task that I devote myself in this thesis, focusing in particular on the millisecond and soft gamma-ray pulsar populations.

Millisecond pulsars are the oldest known pulsars, and are defined by their millisecond periods. I characterized the Fermi-LAT spectrum of PSR J0218+4232 as part of a larger work on searching for very high energy emission with MAGIC. While MAGIC was not able to detect the source, the Fermi-LAT spectrum was useful in providing insight as to why this was the case.

Soft gamma-ray pulsars are brightest at MeV energies, and are challenging to study due to the lack of an instrument sensitive in this energy region. I characterize the spin characteristics of the soft pulsars PSR J1813-1749 and PSR J1846-0258 with NICER, and attempt to detect them with the Fermi-LAT to characterize a portion of their MeV spectra. While the spin characterization will aid in detecting these sources with future MeV telescopes, there was not a strong enough LAT detection to extract spectral information. Examining PSR J2022+3842 with NICER did lead to a detection of pulsations with Fermi-LAT, which improved upon the prior detection, as well as provided spectral information for emission modeling.