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We study the pulsar energy-dependent $\gamma$-ray light curves and spectra from curvature radiation in the dissipative magnetospheres. The dissipative magnetospheres with the combined force-free (FFE) and Aristotelian (AE) are computed by a…

High Energy Astrophysical Phenomena · Physics 2024-03-12 Gang Cao , Xiongbang Yang

We explore the emission properties of a dissipative pulsar magnetosphere model introduced by Kalapotharakos et al. (2014), comparing its high energy light curves and spectra, due to curvature radiation, with data collected by the Fermi LAT.…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Gabriele Brambilla , Constantinos Kalapotharakos , Alice K. Harding , Demosthenes Kazanas

Based on the Fermi observational data we reveal meaningful constraints for the dependence of the macroscopic conductivity $(\sigma)$ of dissipative pulsar magnetosphere models on the corresponding spin-down rate, $\dot{\mathcal{E}}$. Our…

High Energy Astrophysical Phenomena · Physics 2017-06-28 Constantinos Kalapotharakos , Alice K. Harding , Demosthenes Kazanas , Gabriele Brambilla

We explore the multiwavelength radiation properties of the light curves and energy spectra in the dissipative magnetospheres of pulsars. The dissipative magnetospheres are simulated by the pseudo-spectral method with the combined force-free…

High Energy Astrophysical Phenomena · Physics 2024-03-12 Xiongbang Yang , Gang Cao

Pulsars emit pulsed emission across the entire electromagnetic spectrum and their light curve phenomenology is strongly dependent on energy. This is also true for the gamma-ray waveband. Continued detections by Fermi Large Area Telescope in…

High Energy Astrophysical Phenomena · Physics 2018-11-29 Monica Barnard , Christo Venter , Alice K. Harding , Constantinos Kalapotharakos

In recent years, surprise discoveries of pulsed emission from the Crab and Vela pulsars above 100 GeV have drawn renewed attention to this largely unexplored region of the energy range. In this paper, we discuss example light curves due to…

High Energy Astrophysical Phenomena · Physics 2018-08-22 Christo Venter , Monica Barnard , Alice K. Harding , Constantinos Kalapotharakos

The Fermi Large Area Telescope has revolutionised the $\gamma$-ray pulsar field, increasing the population to over 250 detected pulsars. The majority display spectra with exponential cutoffs in a narrow range around a few GeV. Models…

High Energy Astrophysical Phenomena · Physics 2021-03-22 M. Barnard

The high-quality Fermi LAT observations of gamma-ray pulsars have opened a new window to understanding the generation mechanisms of high-energy emission from these systems. The high statistics allow for careful modeling of the light curve…

High Energy Astrophysical Phenomena · Physics 2011-11-03 Megan E. DeCesar , Alice K. Harding , M. Coleman Miller , Ioannis Contopoulos , Constantinos Kalapotharakos , Damien Parent

$\gamma$-ray spectra of pulsars have been mostly studied in a phenomenological way, by fitting them to a cut-off power-law function. Here, we analyze a model where pulsed emission comes from synchro-curvature processes in a gap. We…

High Energy Astrophysical Phenomena · Physics 2015-06-24 Daniele Viganò , Diego F. Torres

We investigate the strong electric current sheet that develops at the tip of the pulsar closed line region through time dependent three-dimensional numerical simulations of a rotating magnetic dipole. We show that curvature radiation from…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Ioannis Contopoulos , Constantinos Kalapotharakos

Recent kinetic simulations sparked a debate regarding the emission mechanism responsible for pulsed GeV $\gamma$-ray emission from pulsars. Some models invoke curvature radiation, while other models assume synchrotron radiation in the…

High Energy Astrophysical Phenomena · Physics 2022-02-16 Monica Barnard , Christo Venter , Alice K. Harding , Constantinos Kalapotharakos , Tyrel J. Johnson

We report on analysis of timing and spectroscopy of the Vela pulsar using eleven months of observations with the Large Area Telescope on the Fermi Gamma-Ray Space Telescope. The intrinsic brightness of Vela at GeV energies combined with the…

High Energy Astrophysical Phenomena · Physics 2015-05-18 A. A. Abdo

We reanalyze the Fermi spectra of the Geminga and Vela pulsars. We find that the spectrum of Geminga above the break is exceptionally well approximated by a simple power law without the exponential cut-off, making Geminga's spectrum similar…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Maxim Lyutikov

My thesis deals with a fundamental question of high energy gamma-ray astronomy. Namely, I studied the cut-off shape of the Crab pulsar spectrum to distinguish between the leading scenarios for the pulsar models. Pulsars are celestial…

High Energy Astrophysical Phenomena · Physics 2011-05-18 Takayuki Saito

We compute the patterns of $\gamma$-ray emission due to curvature radiation in dissipative pulsar magnetospheres. Our ultimate goal is to construct macrophysical models that are able to reproduce the observed $\gamma$-ray light-curve…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Constantinos Kalapotharakos , Alice K. Harding , Demosthenes Kazanas

Current models of gamma-ray lightcurves in pulsars suffer from large uncertainties on the precise location of particle acceleration and radiation. Here, we present an attempt to alleviate these difficulties by solving for the…

High Energy Astrophysical Phenomena · Physics 2016-02-17 Benoît Cerutti , Alexander A. Philippov , Anatoly Spitkovsky

The pulsar light curves and energy spectra are explored in dissipative pulsar magnetospheres with the Aristotelian electrodynamics (AE), where particle acceleration is fully balanced with radiation reaction. The AE magnetospheres with…

High Energy Astrophysical Phenomena · Physics 2022-02-09 Gang Cao , Xiongbang Yang

We demonstrate a method for quantitatively comparing gamma-ray pulsar light curves with magnetosphere beaming models. With the Fermi LAT providing many pulsar discoveries and high quality pulsar light curves for the brighter objects, such…

High Energy Astrophysical Phenomena · Physics 2015-03-13 Roger W. Romani , Kyle P. Watters

Context. More than one hundred GeV pulsars have been detected up to now by the LAT telescope on the Fermi gamma-ray observatory, showing peak energies around a few GeV. Current modelling proposes that the high energy emission comes from…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Ioanna Arka , Guillaume Dubus

Beam radii for cone-dominant pulsars follow a power-law relation with frequency, $\vartheta = (\nu/\nu_0)^k+\vartheta_0$, which has not yet well explained in previous works. We study this frequency dependence of beam radius (FDB) for…

High Energy Astrophysical Phenomena · Physics 2015-06-15 P. F. Wang , J. L. Han , C. Wang
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