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dc.contributor.authorAbdo, A.A.en_US
dc.contributor.authorVenter, C.en_US
dc.contributor.authorAckermann, M.en_US
dc.contributor.authorAjello, M.en_US
dc.contributor.authorBaldini, L.en_US
dc.date.accessioned2012-02-29T09:52:01Z
dc.date.available2012-02-29T09:52:01Z
dc.date.issued2010en_US
dc.identifier.citationAbdo, A.A. et al. 2010. Fermi-LAT observations of the Geminga pulsar. Astrophysical journal, 720:272-283. [https://doi.org/10.1088/0004-637X/720/1/272]en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.issn1538-4357 (Online)en_US
dc.identifier.urihttp://hdl.handle.net/10394/6154
dc.identifier.urihttps://doi.org/10.1088/0004-637X/720/1/272
dc.identifier.urihttp://iopscience.iop.org/article/10.1088/0004-637X/720/1/272/pdf
dc.description.abstractWe report on the Fermi-LAT observations of the Geminga pulsar, the second brightest non-variable GeV source in the γ-ray sky and the first example of a radio-quiet γ-ray pulsar. The observations cover one year, from the launch of the Fermi satellite through 2009 June 15. A data sample of over 60,000 photons enabled us to build a timing solution based solely on γ-rays. Timing analysis shows two prominent peaks, separated by Δphgr = 0.497 ± 0.004 in phase, which narrow with increasing energy. Pulsed γ-rays are observed beyond 18 GeV, precluding emission below 2.7 stellar radii because of magnetic absorption. The phase-averaged spectrum was fitted with a power law with exponential cutoff of spectral index Γ = (1.30 ± 0.01 ± 0.04), cutoff energy E 0 = (2.46 ± 0.04 ± 0.17) GeV, and an integral photon flux above 0.1 GeV of (4.14 ± 0.02 ± 0.32) × 10–6 cm–2 s–1. The first uncertainties are statistical and the second ones are systematic. The phase-resolved spectroscopy shows a clear evolution of the spectral parameters, with the spectral index reaching a minimum value just before the leading peak and the cutoff energy having maxima around the peaks. The phase-resolved spectroscopy reveals that pulsar emission is present at all rotational phases. The spectral shape, broad pulse profile, and maximum photon energy favor the outer magnetospheric emission scenarios
dc.publisherIOP Publishingen_US
dc.subjectGamma rays: stars
dc.subjectPulsars: general
dc.subjectPulsars: individual (PSR J0633+1746, Geminga)
dc.titleFermi-LAT observations of the Geminga pulsaren_US
dc.contributor.researchID12006653 - Venter, Christo


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