The Ultra-High-Energy Source MGRO J1908+06

TL;DR

This paper analyzes the ultra-high-energy gamma-ray source MGRO J1908+06, revealing complex spectral features and discussing potential particle origins, with implications for multi-wavelength and multi-messenger astrophysics.

Contribution

It provides the first detailed spectral and morphological analysis of MGRO J1908+06 at energies above 100 TeV, highlighting the need for a two-population model.

Findings

Emission extends past 100 TeV

Spectral energy distribution requires two particle populations

Both leptonic and hadronic models fit the high-energy data

Abstract

The TeV gamma-ray source MGRO J1908+06 is one of the highest-energy sources known, with observed emission by the High Altitude Water Cherenkov (HAWC) Observatory extending well past 100 TeV. The source exhibits both energy-dependent morphology and a spatially-dependent spectral index. The emission is likely to be dominantly leptonic, and associated with the radio-quiet PSR J1907+0602. However, one-population models do not describe the data well; a second particle population is needed to explain the shape of the spectral energy distribution at the highest energies. This component can be well-described by either leptonic or hadronic hypotheses. We discuss this feature and implications for detection by multi-wavelength and multi-messenger experiments.