A VERITAS view of HESS J1857+026 within a multi-wavelength analysis

TL;DR

This study uses VERITAS observations to analyze the extended VHE gamma-ray emission of HESS J1857+026, aiming to understand its emission mechanisms within a multi-wavelength context, and explores a leptonic PWN scenario.

Contribution

It provides detailed spectral and morphological characterization of HESS J1857+026 in the VHE band and investigates its emission mechanism through a leptonic PWN model.

Findings

Confirmed the extended nature of HESS J1857+026

Characterized the spectral and morphological features in VHE gamma rays

Explored electron transport processes in a leptonic PWN scenario

Abstract

HESS J1857+026 remains a mysterious gamma-ray emitter since its discovery in 2008. Despite the disclosure of a nearby pulsar and multiple studies in the high-energy (HE, E > 100 MeV) and very-high-energy (VHE, E > 100 GeV) regimes, there have been no confirmed counterparts (e.g., an SNR shell or other extended structure) in X-ray or other wavelengths. We present the result of our study of the VHE emission of HESS~J1857+026 with VERITAS as part of a multi-wavelength investigation to uncover its emission mechanisms. Our result confirms the extended nature of the source and we characterize its spectral and morphological features in the VHE band. Using the morphology of the source revealed in our analysis, we also explore the underlying transport process of a possible electron population in a leptonic PWN scenario for the gamma-ray emission.