Towards a Phase-Resolved Study of Bright Fermi LAT Pulsars

Pulsars are rotating neutron stars that emit electromagnetic radiation across the electromagnetic spectrum. The Third Pulsar Catalog (3PC) of the Fermi Large Area Telescope (LAT) contains more than 300 𝛾-ray pulsars and pulsar candidates. However, to date phase-resolved spectroscopy has been performed on only a few of them, which is not sufficient to reveal new trends that could improve our understanding of the 𝛾-ray pulsar emission mechanism and geometry. Our objective is to conduct a systematic study using phase-resolved spectroscopy on two pulsar samples that appear in the recently released 3PC (young and millisecond pulsars) in order to identify novel trends, such as a relationship between the phase-resolved spectrum’s hardness (slope and cutoff energy) and the light curve peak brightness, hints of which have been found in prior preliminary studies. We focused on the brightest pulsars with a range of light curve profile shapes, spin-down power ranges, and radio pulse characteristics for these pulsars, we specifically analyze only the two brightest peaks in their light curves. In this paper, we discuss our source selection, phase selection, and spectral pipeline adjustments that we have made.