Radio and Gamma-ray Pulsed Emission from Millisecond Pulsars

TL;DR

This paper uses a 3D annular gap model to simulate radio and gamma-ray emissions from millisecond pulsars, explaining observed pulse profiles and phase lags, and challenging existing pulsar emission models.

Contribution

It introduces a self-consistent 3D annular gap model that explains multi-wavelength pulsar emissions, including complex pulse profiles and phase separations.

Findings

Gamma-ray and radio emissions originate from the same magnetic pole.

The annular gap model can account for radio interpulses with large phase separation.

The model challenges the necessity of an orthogonal rotator assumption.

Abstract

Pulsed gamma-ray emission from millisecond pulsars (MSPs) has been detected by the sensitive Fermi, which sheds light on studies of the emission region and mechanism. In particular, the specific patterns of radio and gamma-ray emission from PSR J0101-6422 challenge the popular pulsar models, e.g. outer gap and two-pole caustic (TPC) models. Using the three dimension (3D) annular gap model, we have jointly simulated radio and gamma-ray light curves for three representative MSPs (PSR J0034-0534, PSR J0101-6422 and PSR J0437-4715) with distinct radio phase lags and present the best simulated results for these MSPs, particularly for PSR J0101-6422 with complex radio and gamma-ray pulse profiles and for PSR J0437-4715 with a radio interpulse. It is found that both the gamma-ray and radio emission originate from the annular gap region located in only one magnetic pole, and the radio emission region is not primarily lower than the gamma-ray region in most cases. In addition, the annular gap model with a small magnetic inclination angle instead of "orthogonal rotator" can account for MSPs' radio interpulse with a large phase separation from the main pulse. The annular gap model is a self-consistent model not only for young pulsars but also MSPs, and multi-wavelength light curves can be fundamentally explained by this model.