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Title: High-energy emission of the first millisecond pulsar

Abstract

We report on X-ray and gamma-ray observations of the millisecond pulsar (MSP) 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 MSPs with high magnetic fields at the light cylinder. We discuss a possible physical scenario that could give rise to these features.

Authors:
; ; ;  [1];  [2]
  1. Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong (China)
  2. Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada)
Publication Date:
OSTI Identifier:
22356735
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; GAMMA RADIATION; LIMITING VALUES; MAGNETIC FIELDS; PHOTONS; PULSARS; SPECTRA; STARS; TELESCOPES; VISIBLE RADIATION; X RADIATION

Citation Formats

Ng, C.-Y., Takata, J., Leung, G. C. K., Cheng, K. S., and Philippopoulos, P., E-mail: ncy@bohr.physics.hku.hk. High-energy emission of the first millisecond pulsar. United States: N. p., 2014. Web. doi:10.1088/0004-637X/787/2/167.
Ng, C.-Y., Takata, J., Leung, G. C. K., Cheng, K. S., & Philippopoulos, P., E-mail: ncy@bohr.physics.hku.hk. High-energy emission of the first millisecond pulsar. United States. doi:10.1088/0004-637X/787/2/167.
Ng, C.-Y., Takata, J., Leung, G. C. K., Cheng, K. S., and Philippopoulos, P., E-mail: ncy@bohr.physics.hku.hk. 2014. "High-energy emission of the first millisecond pulsar". United States. doi:10.1088/0004-637X/787/2/167.
@article{osti_22356735,
title = {High-energy emission of the first millisecond pulsar},
author = {Ng, C.-Y. and Takata, J. and Leung, G. C. K. and Cheng, K. S. and Philippopoulos, P., E-mail: ncy@bohr.physics.hku.hk},
abstractNote = {We report on X-ray and gamma-ray observations of the millisecond pulsar (MSP) 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 MSPs with high magnetic fields at the light cylinder. We discuss a possible physical scenario that could give rise to these features.},
doi = {10.1088/0004-637X/787/2/167},
journal = {Astrophysical Journal},
number = 2,
volume = 787,
place = {United States},
year = 2014,
month = 6
}
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