Recent pulsar results from VERITAS on Geminga and the missing link binary pulsar PSR J1023+0038

TL;DR

This paper reports recent VERITAS observations of Geminga and PSR J1023+0038, setting upper limits on their very high-energy gamma-ray flux and discussing implications for pulsar emission models.

Contribution

It provides new VHE gamma-ray flux upper limits for Geminga and PSR J1023+0038, informing theoretical models and future observational strategies.

Findings

No VHE gamma-ray detection; upper flux limits established.

Results constrain models of pulsar gamma-ray emission.

Discussion of future VERITAS pulsar observation plans.

Abstract

In recent years, the Fermi-LAT gamma-ray telescope has detected a population of over 160 gamma-ray pulsars, which has enabled the detailed study of electromagnetic radiation from pulsars at energies above 100 MeV. Further, since the surprising detection of the Crab pulsar in very high-energy (VHE; E > 100 GeV) gamma rays by the MAGIC and VERITAS collaborations, there has been an ongoing effort in the astrophysics community to detect new pulsars in the VHE band. However, the Crab remains the only pulsar so far detected in VHE gamma rays, raising the question of whether or not the Crab is unique and also making it more difficult to constrain model predictions that attempt to explain the emission. Presented here are recent VERITAS results from observational campaigns on the brightest northern-hemisphere high-energy gamma-ray pulsar Geminga and the missing link binary pulsar PSR J1023+0038, which have both resulted in upper limits on a possible VHE flux. These limits are placed into context with the current theoretical framework attempting to explain the origin of the gamma-ray emission from pulsars. Additionally, future plans for pulsar observations with VERITAS are be briefly discussed.