TY - JOUR
T1 - Synchrotron self-absorption in pulsar magnetospheres
T2 - Implications for optical emission
AU - O'Connor, P.
AU - Golden, A.
AU - Shearer, A.
N1 - Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2005/9/20
Y1 - 2005/9/20
N2 - Nonthermal optical emission from pulsars has been observed definitively from five objects. The model that most accurately predicts the luminosity of such emissions is that of Pacini and Salvati, a model based on synchrotron radiation originating at a constant fraction of the light cylinder. We parameterize optical emission in a similar way, obtaining the solution to the radiative transfer equation that yields expressions for the expected monochromatic luminosity and synchrotron self-absorption frequency. If due to synchrotron self-absorption, we investigate whether the rollover at IR wavelengths observed for the Crab pulsar is a process likely to be common to all the synchrotron active pulsars. Although the low-frequency turnover in the Crab pulsar spectrum may be due to a low-energy cutoff in the underlying emitting particle population or to particles emitting below their critical frequency, a test of the current self-absorption model is provided by PSR B0540-69 and the 16 ms "Crab-like" pulsar J0537-69. Our model, scaled relative to the Crab pulsar, predicts that PSR B0540-69 should exhibit a rollover between the L and I bands and that PSR J0537-69 may be self-absorbed at optical wavelengths with mv ∼ 24 (dependent on the spectral index, a, where F v ∼ v-α). Our model is applicable to frequency regions well outside the optical and is limited to "young," "fast" (<100 ms) pulsars.
AB - Nonthermal optical emission from pulsars has been observed definitively from five objects. The model that most accurately predicts the luminosity of such emissions is that of Pacini and Salvati, a model based on synchrotron radiation originating at a constant fraction of the light cylinder. We parameterize optical emission in a similar way, obtaining the solution to the radiative transfer equation that yields expressions for the expected monochromatic luminosity and synchrotron self-absorption frequency. If due to synchrotron self-absorption, we investigate whether the rollover at IR wavelengths observed for the Crab pulsar is a process likely to be common to all the synchrotron active pulsars. Although the low-frequency turnover in the Crab pulsar spectrum may be due to a low-energy cutoff in the underlying emitting particle population or to particles emitting below their critical frequency, a test of the current self-absorption model is provided by PSR B0540-69 and the 16 ms "Crab-like" pulsar J0537-69. Our model, scaled relative to the Crab pulsar, predicts that PSR B0540-69 should exhibit a rollover between the L and I bands and that PSR J0537-69 may be self-absorbed at optical wavelengths with mv ∼ 24 (dependent on the spectral index, a, where F v ∼ v-α). Our model is applicable to frequency regions well outside the optical and is limited to "young," "fast" (<100 ms) pulsars.
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U2 - 10.1086/432461
DO - 10.1086/432461
M3 - Article
AN - SCOPUS:27744543016
SN - 0004-637X
VL - 631
SP - 471
EP - 479
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1 I
ER -