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Article: A model of unpulsed very high energy gamma rays from the crab nebula and pulsar

TitleA model of unpulsed very high energy gamma rays from the crab nebula and pulsar
Authors
KeywordsGamma Rays: General
Nebulae: Crab Nebula
Pulsars
Issue Date1991
PublisherInstitute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/2041-8205
Citation
Astrophysical Journal Letters, 1991, v. 379 n. 2, p. 653-658 How to Cite?
AbstractThe angular resolution of gamma-ray detectors does not allow one to separate the nebula from the pulsar in the Crab. It is generally assumed that the steady emission of gamma rays comes from the nebula. Using the "outer magnetospheric gap" model, we propose an alternative mechanism in which the steady emission of gamma rays could come from a compact region, a couple of light cylinder radii beyond the pulsar. In that region, the magnetic field has been transformed from a dipole field to a swirling field. In the model, two mono-energetic beams of gap primary e+(e-) if Ω · Bs > 0 (<0) with a Lorentz factor ∼ 4 × 107 are streaming out from the outer gaps through the light cylinder. The gap primary e+(e-) beam from the first outer gap can produce ∼10 TeV primary very high energy (VHE) gamma rays through inverse Compton scattering with the IR photons from the second gap, and vice versa. The primary VHE gamma rays are sufficiently energetic to produce secondary e± pairs by collision with the same pulsed IR photons. Since the mean free path of these conversion processes is comparable to the local radius of curvature, the pitch angles of the secondary pairs are large enough to result in isotropic secondary VHE gamma rays with Eγ ∼ TeV. Comparisons between the model spectra and the observed data are discussed in the text.
Persistent Identifierhttp://hdl.handle.net/10722/174850
ISSN
2015 Impact Factor: 5.487
2015 SCImago Journal Rankings: 3.369

 

DC FieldValueLanguage
dc.contributor.authorKwok, PWen_US
dc.contributor.authorCheng, KSen_US
dc.contributor.authorLau, MMen_US
dc.date.accessioned2012-11-26T08:47:48Z-
dc.date.available2012-11-26T08:47:48Z-
dc.date.issued1991en_US
dc.identifier.citationAstrophysical Journal Letters, 1991, v. 379 n. 2, p. 653-658en_US
dc.identifier.issn2041-8205en_US
dc.identifier.urihttp://hdl.handle.net/10722/174850-
dc.description.abstractThe angular resolution of gamma-ray detectors does not allow one to separate the nebula from the pulsar in the Crab. It is generally assumed that the steady emission of gamma rays comes from the nebula. Using the "outer magnetospheric gap" model, we propose an alternative mechanism in which the steady emission of gamma rays could come from a compact region, a couple of light cylinder radii beyond the pulsar. In that region, the magnetic field has been transformed from a dipole field to a swirling field. In the model, two mono-energetic beams of gap primary e+(e-) if Ω · Bs > 0 (<0) with a Lorentz factor ∼ 4 × 107 are streaming out from the outer gaps through the light cylinder. The gap primary e+(e-) beam from the first outer gap can produce ∼10 TeV primary very high energy (VHE) gamma rays through inverse Compton scattering with the IR photons from the second gap, and vice versa. The primary VHE gamma rays are sufficiently energetic to produce secondary e± pairs by collision with the same pulsed IR photons. Since the mean free path of these conversion processes is comparable to the local radius of curvature, the pitch angles of the secondary pairs are large enough to result in isotropic secondary VHE gamma rays with Eγ ∼ TeV. Comparisons between the model spectra and the observed data are discussed in the text.en_US
dc.languageengen_US
dc.publisherInstitute of Physics Publishing Ltd. The Journal's web site is located at http://iopscience.iop.org/2041-8205en_US
dc.relation.ispartofAstrophysical Journal Lettersen_US
dc.subjectGamma Rays: Generalen_US
dc.subjectNebulae: Crab Nebulaen_US
dc.subjectPulsarsen_US
dc.titleA model of unpulsed very high energy gamma rays from the crab nebula and pulsaren_US
dc.typeArticleen_US
dc.identifier.emailCheng, KS: hrspksc@hkucc.hku.hken_US
dc.identifier.authorityCheng, KS=rp00675en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.scopuseid_2-s2.0-0039810510en_US
dc.identifier.volume379en_US
dc.identifier.issue2en_US
dc.identifier.spage653en_US
dc.identifier.epage658en_US
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridKwok, PW=43961154400en_US
dc.identifier.scopusauthoridCheng, KS=9745798500en_US
dc.identifier.scopusauthoridLau, MM=16441454100en_US

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