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Fermi-LAT observations revealed that each GeV phase-folded light-curve (aka. phaseogram) of the Crab, Geminga, Dragonfly and Vela pulsars consists of two pulses (P1 & P2) and a "Bridge" between them. There is clearly a "bump" at the Bridge…

High Energy Astrophysical Phenomena · Physics 2025-08-28 Paul K. H. Yeung , Dmitry Khangulyan , Takayuki Saito

The second pulsar catalogue of the Fermi Large Area Telescope (LAT) will contain in excess of 100 gamma-ray pulsars. The light curves (LCs) of these pulsars exhibit a variety of shapes, and also different relative phase lags with respect to…

High Energy Astrophysical Phenomena · Physics 2015-01-22 M. Breed , C. Venter , A. K. Harding , T. J. Johnson

The bipolarity of Supernova 1987A can be understood through its very early light curve observed from the CTIO 0.4-m telescope and IUE FES, and following speckle observations of the `Mystery Spot' by two groups. These indicate a highly…

High Energy Astrophysical Phenomena · Physics 2015-03-20 John Middleditch

Modifications to polar-gap models for pulsars are discussed for the case where the surface magnetic field, $B_\S$, of the neutron star is strong. For $B\ga4\times10^8\rm\,T$, the curvature $\gamma$-quanta emitted tangentially to the curved…

Astrophysics · Physics 2015-06-24 V. V. Usov , D. B. Melrose

The vast majority of pulsars detected by the Fermi Large Area Telescope (LAT) display exponentially cutoff spectra with cutoffs falling in a narrow band around a few GeV. Early spectral modelling predicted spectral cutoffs at energies of up…

High Energy Astrophysical Phenomena · Physics 2016-07-25 M. Breed , C. Venter , A. K. Harding

We propose a novel beam model for radio pulsars based on the scenario that the broadband and coherent emission from secondary relativistic particles, as they move along a flux tube in a dipolar magnetic field, forms a radially extended…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Hong Guang Wang , Fei Peng Pi , Xiao Ping Zheng , Chun Lan Deng , Sai Qin Wen , Feng Ye , Kai Ying Guan , Yi Liu , Li Qing Xu

We report the hard X-ray properties of the young Crab-like LMC pulsar PSR B0540-69, using archival RXTE PCA (2 - 60 keV) and RXTE HEXTE (15 - 250 keV) data. Making use of the very long effective exposure of 684 ks, we derived a very…

Astrophysics · Physics 2011-05-23 J. de Plaa , L. Kuiper , W. Hermsen

We present a multicomponent model to explain the features of the pulsed emission and spectrum of the Crab Pulsar, on the basis of X and gamma-ray observations performed with BeppoSAX, INTEGRAL and CGRO. This model explains the evolution of…

Astrophysics · Physics 2007-05-23 R. Campana , E. Massaro , G. Cusumano , T. Mineo

We modify polar cap cascade picture to include the ICS of the higher generation pairs. In such a ``full-cascade'' scenario, not only the perpendicular portion of the energy of the pairs goes to high energy radiation via SR, but the parallel…

Astrophysics · Physics 2009-10-31 Bing Zhang , Alice K. Harding

We present a modified scenario of gamma-ray emission from pulsars within the framework of polar cap models. Our model incorporates possible acceleration of electron-positron pairs created in magnetospheres, and their subsequent contribution…

Astrophysics · Physics 2009-10-30 B. Rudak , J. Dyks

The magnetosphere of a rotating pulsar naturally develops a current sheet beyond the light cylinder (LC). Magnetic reconnection in this current sheet inevitably dissipates a nontrivial fraction of the pulsar spin-down power within a few LC…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Dmitri A. Uzdensky , Anatoly Spitkovsky

New polarimetric observations of the Crab pulsar at frequencies between 1.4 and 8.4 GHz are presented. Additional pulse components discovered in earlier observations (Moffett & Hankins 1996, astro-ph/9604163) are found to have high levels…

Astrophysics · Physics 2009-10-31 D. A. Moffett , T. H. Hankins

Observing simultaneously pulsed radio and gamma-ray emission from these stars helps to constrain the geometry and radiation mechanisms within their magnetosphere and to localize the multiple photon production sites. In this paper, we fit…

High Energy Astrophysical Phenomena · Physics 2021-10-20 J. Pétri , D. Mitra

Some giant pulses and fast radio bursts exhibit notable circular polarization, which remains unexplained and carries significant implications for their emission mechanisms. In this study, we identify multiple nanoshot pairs uniformly spaced…

Plasma Physics · Physics 2024-10-02 Hui-Chun Wu

Context{The high energy emission regions of rotation powered pulsars are studied using folded light curve (FLCs) and phase resolved spectra (PRS).} aims{This work uses the NICER observatory to obtain the highest resolution FLC and PRS of…

High Energy Astrophysical Phenomena · Physics 2021-06-04 M. Vivekanand

We report on gamma-ray observations of the Crab Pulsar and Nebula using 8 months of survey data with the Fermi Large Area Telescope (LAT). The high quality light curve obtained using the ephemeris provided by the Nancay and Jodrell Bank…

High Energy Astrophysical Phenomena · Physics 2012-08-27 The Fermi LAT collaboration , the Fermi Pulsar Timing Consortium , : , A. A. Abdo

(Abridged) We present high-resolution Chandra X-ray observations of PSR B0833-45, the 89 ms pulsar associated with the Vela supernova remnant. We have acquired two observations separated by one month to search for changes in the pulsar and…

Astrophysics · Physics 2009-10-31 D. J. Helfand , E. V. Gotthelf , J. P. Halpern

Despite the fact that pulsars have been observed for almost half a century, many questions have remained unanswered. We use the analysis of X-ray observations in order to study the polar cap region of radio pulsars. The size of the hot…

High Energy Astrophysical Phenomena · Physics 2013-04-19 Andrzej Szary

Using all available multi-component radio pulse profiles for pulsars with medium to long periods and good polarisation data, we have constructed a two-dimensional image of the mean radio beamshape. This shows a peak near the centre of the…

Astrophysics · Physics 2009-10-31 J. L. Han , R. N. Manchester

The Crab nebula and its pulsar have been observed for about 3 hours with the high-speed photo-polarimeter OPTIMA in January 2002 at the Calar Alto 3.5m telescope. The Crab pulsar intensity and polarization are determined at all phases of…

Astrophysics · Physics 2009-01-14 G. Kanbach , A. Slowikowska , S. Kellner , H. Steinle