Phase-resolved spectroscopy of Geminga shows rotating hot spot(s).
Isolated neutron stars are seen in x-rays through their nonthermal and/or surface thermal emissions. X-ray Multimirror Mission-Newton observations of the Geminga pulsar show a 43-electron volt spectrum from the whole neutron star surface, as well as a power-law component above 2 kiloelectron volts. In addition, we have detected a hot (170 electron volts) thermal emission from an approximately 60-meter-radius spot on the pulsar's surface. Such a thermal emission, only visible at selected phase intervals, may be coming from polar hot spot(s), long thought to exist as a result of heating from magnetospheric accelerated particles. It may provide the missing link between the x-ray and gamma-ray emission of the pulsar.
Caraveo
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PA
Istituto di Astrofisica Spaziale e Fisica Cosmica, Consiglio Nazionale delle Ricerche, Via Bassini, 15-20133 Milano, Italy. pat@mi.iasf.cnr.it
De Luca
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Mereghetti
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S
Pellizzoni
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A
Bignami
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GF