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gamma-ray emission in dissipative pulsar magnetospheres: from theory to fermi observationsWe compute the patterns of gamma-ray emission due to curvature radiation in dissipative pulsar magnetospheres. Our ultimate goal is to construct macrophysical models that are able to reproduce the observed gamma-ray light curve phenomenology recently published in the Second Fermi Pulsar Catalog. We apply specific forms of Ohm's law on the open field lines using a broad range for the macroscopic conductivity values that result in solutions ranging, from near-vacuum to near-force-free. Using these solutions, we generate model gamma-ray light curves by calculating realistic trajectories and Lorentz factors of radiating particles under the influence of both the accelerating electric fields and curvature radiation reaction. We further constrain our models using the observed dependence of the phase lags between the radio and gamma-ray emission on the gamma-ray peak separation. We perform a statistical comparison of our model radio-lag versus peak-separation diagram and the one obtained for the Fermi standard pulsars. We find that for models of uniform conductivity over the entire open magnetic field line region, agreement with observations favors higher values of this parameter. We find, however, significant improvement in fitting the data with models that employ a hybrid form of conductivity, specifically, infinite conductivity interior to the light cylinder and high but finite conductivity on the outside. In these models the gamma-ray emission is produced in regions near the equatorial current sheet but modulated by the local physical properties. These models have radio lags near the observed values and statistically best reproduce the observed light curve phenomenology. Additionally, they also produce GeV photon cut-off energies.
Document ID
20170003460
Document Type
Reprint (Version printed in journal)
Authors
Kalapotharakos, Konstantinos
(Maryland Univ. College Park, MD, United States)
Harding, Alice K.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Kazanas, Demosthenes
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
April 14, 2017
Publication Date
September 11, 2014
Publication Information
Publication: The Astrophysical Journal
Volume: 793
Issue: 2
ISSN: 2041-8205
Subject Category
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN41594
Funding Number(s)
CONTRACT_GRANT: NNG17PT01A
Distribution Limits
Public
Copyright
Other
Keywords
stars
neutron
general
pulsars
Gamma rays
stars