High-Energy Emission of the First Millisecond Pulsar

Abstract

We report on X-ray and gamma-ray observations of the millisecond pulsar B1937+21 taken with the Chandra X-ray Observatory, XMM-Newton, and the Fermi Large Area Telescope. The pulsar X-ray emission shows a purely non-thermal spectrum with a hard photon index of 0.9+/-0.1, and is nearly 100% pulsed. We found no evidence of varying pulse profile with energy as previously claimed. We also analyzed 5.5 yr of Fermi survey data and obtained much improved constraints on the pulsar's timing and spectral properties in gamma-rays. The pulsed spectrum is adequately fitted by a simple power-law with a photon index of 2.38+/-0.07. Both the gamma-ray and X-ray pulse profiles show similar two-peak structure and generally align with the radio peaks. We found that the aligned profiles and the hard spectrum in X-rays seem to be common properties among millisecond pulsars with high magnetic fields at the light cylinder. We discuss a possible physical scenario that could give rise to these features.

10 pages, 4 figures, accepted for publication in ApJ

References in corpus (6)

• On Pulsar Distance Measurements and their Uncertainties
• Chandra X-Ray Observations of Nineteen Millisecond Pulsars in the Globular Cluster 47 Tucanae
• Pulsar Timing for the Fermi Gamma-ray Space Telescope
• Pulse Profiles, Spectra and Polarization Characteristics of Non-Thermal Emissions from the Crab-Like Pulsars
• Studying Millisecond Pulsars in X-rays
• Turn-over in pulsar spectra around 1 GHz

Cited by in corpus (6)

• Diffuse gamma-ray emission from galactic pulsars
• A broadband radio study of the average profile and giant pulses from PSR B1821-24A
• High-Precision X-ray Timing of Three Millisecond Pulsars with NICER: Stability Estimates and Comparison with Radio
• R-modes and neutron star recycling scenario
• X-ray bounds on the r-mode amplitude in millisecond pulsars
• Differences between radio-loud and radio-quiet gamma-ray pulsars as revealed by Fermi