Two Candidate Pulsar TeV Halos Identified from Property-Similarity Studies

TL;DR

This study identifies and analyzes potential TeV halos around three pulsars using gamma-ray data, suggesting these halos are common features linked to middle-aged pulsars and are proportional in luminosity to pulsar spin-down energy.

Contribution

The paper presents the first identification of candidate TeV halos associated with pulsars from LHAASO data, expanding understanding of pulsar-related TeV gamma-ray phenomena.

Findings

TeV halos likely associated with the three pulsars.

No residual GeV emissions detected after pulsar emission removal.

TeV halo luminosity is proportional to pulsar spin-down energy.

Abstract

TeV halos have been suggested as a common phenomenon associated with middle-aged pulsars. Based on our recent work on PSR~J0631+1036, which is the only known source positionally coincident with a hard TeV gamma-ray source and likely powers the latter as a TeV halo, we select 3 candidate TeV halos from the first Large High Altitude Air Shower Observatory (LHAASO) catalog of gamma-ray sources. The corresponding pulsars, given by the positional coincidences and property similarities, are PSR J1958+2846, PSR J2028+3332, and PSR J1849$-$0001. We analyze the GeV $\gamma$-ray data obtained with the Large Area Telescope (LAT) onboard {\it the Fermi Gamma-ray Space Telescope} for the first two pulsars, as the last is gamma-ray quiet. We remove the pulsed emissions of the pulsars from the source regions from timing analysis, and determine that there are no residual GeV emissions in the regions as any possible counterparts to the TeV sources. Considering the previous observational results for the source regions and comparing the two pulsars to Geminga (and Monogem), the LHAASO-detected TeV sources are likely the pulsars' respective TeV halos. We find that the candidate and identified TeV halos, including that of PSR~J1849$-$0001, have luminosites at 50 TeV (estimated from the differential fluxes) approximately proportional to the spin-down energy $\dot{E}$ of the pulsars, and the ratios of the former to the latter are $\sim 6\times 10^{-4}$.