scholarly journals X-ray and Gamma-ray Observations of Pulsars

1981 ◽  
Vol 95 ◽  
pp. 241-250 ◽  
Author(s):  
R. Buccheri
Keyword(s):  
Gamma Ray ◽  
Theoretical Models ◽  
Radio Pulsars ◽  
X Ray ◽  
Special Regard ◽  
Energy Domain ◽  
Similarities And Differences

Measurements of pulsars in the energy domain above ~ 1 keV have provided in the last few years new and interesting results. This paper presents a review of the observational features of PSR 0531+21 and PSR 0833–45 (the Crab and Vela pulsars). Searches for pulsed emission from old radio pulsars in the same energy domain are also reviewed and results assessed. The comparison of the observed features with each other and with the corresponding features observed at lower energies reveals similarities and differences capable to constrain theoretical models with special regard to the geometry of the emission mechanisms.

X-ray and gamma-ray upper limits for pulsed emission from radio pulsars

1982 ◽  
Vol 260 ◽  
pp. 553 ◽  
Author(s):  
F. K. Knight ◽  
J. L. Matteson ◽  
L. E. Peterson ◽  
R. E. Rothschild
Keyword(s):  
Gamma Ray ◽  
Radio Pulsars ◽  
X Ray ◽  
Upper Limits

A comparison of optical and X-ray novae

1979 ◽  
Vol 366 (1726) ◽  
pp. 357-365
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
Theoretical Models ◽  
Dwarf Novae ◽  
X Ray ◽  
Classical Novae ◽  
Binary Structure ◽  
Nuclear Burning ◽  
Similarities And Differences

The similarities and differences between optical novae and transient X-ray novae are discussed. Both classes almost certainly require a semi­-detached binary structure. Present theoretical models of classical novae account for the outburst in terms of a nuclear burning runaway in the accreted material on the white dwarf within a semi-detached binary system. In the case of the dwarf novae and the transient X-ray sources, unstable accretion events are the generally accepted model. Mechanisms that could generate unstable accretion events are described.

scholarly journals Searching for X-ray counterparts of Fermi Gamma-ray pulsars in Suzaku observations

2011 ◽  
Vol 7 (S279) ◽  
pp. 317-318 ◽  
Author(s):  
Yu Aoki ◽  
Takahiro Enomoto ◽  
Yoichi Yatsu ◽  
Nobuyuki Kawai ◽  
Takeshi Nakamori ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Thermal Emission ◽  
Flux Ratio ◽  
Radio Pulsars ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
Absorbed Power ◽  
Pulsar Wind ◽  
Error Circle

AbstractWe report the Suzaku follow-up observations of the Gamma-ray pulsars, 1FGL J0614,13328, J1044.55737, J1741.82101, and J1813.31246, which were discovered by the Fermi Gamma-ray observatory. Analysing Suzaku/XIS data, we detected X-ray counterparts of these pulsars in the Fermi error circle and interpreted their spectra with absorbed power-law functions. These results indicate that the origin of these X-ray sources is non-thermal emission from the pulsars or from Pulsar Wind Nebulae (PWNe) surrounding them. Moreover we found that J1741.82101 exhibits a peculiar profile: spin-down luminosity vs flux ratio between X- and gamma-rays is unusually large compared to usual radio pulsars.

scholarly journals Emission of particles and photons in the pulsar polar cap

2000 ◽  
Vol 177 ◽  
pp. 473-478
Author(s):  
A. I. Tsygan
Keyword(s):  
Gamma Ray ◽  
Radio Pulsars ◽  
Polar Cap ◽  
X Ray ◽  
Polar Caps ◽  
Electron Positron ◽  
Inertial Frames ◽  
General Relativistic ◽  
Star Surface ◽  
General Relativistic Effect

AbstractWe study emission of particles and photons from a pulsar polar cap. The Goldreich-Julian model for the regime of free emission of charged particles from the neutron star surface is used. In this case the electric field is generated due to the general relativistic effect of dragging of inertial frames. The spectra and shapes of gamma-ray pulses, the parameters of the electron-positron plasma and the intensity of X-ray emission from hot spots in the polar region of radio pulsars are discussed. The effect of non-dipole magnetic field on X-ray emission of polar caps is considered. It is shown that the increase of magnetic line curvature leads to much smaller temperatures and X-ray luminosities of the polar caps as compared with the purely dipole field.

scholarly journals Experimental Measurement of Nanolayers via Electromagnetic, Near Infrared, and Gamma Radiation

2019 ◽  
Vol 19 (4) ◽  
pp. 144-152
Author(s):  
Pavel Fiala ◽  
Karel Bartušek ◽  
Jarmila Dědková ◽  
Radim Kadlec ◽  
Přemysl Dohnal
Keyword(s):  
Electromagnetic Wave ◽  
Near Infrared ◽  
Electromagnetic Wave Propagation ◽  
Gamma Ray ◽  
Theoretical Models ◽  
Layered Material ◽  
Periodic Systems ◽  
Electromagnetic Spectrum ◽  
X Ray ◽  
Shielding Effects

Abstract We discuss and compare the results obtained from experimental measurements of a two-layer, Ni and TiO2 nanometric structure deposited on siliceous glass. Utilizing previous theoretical models of multilayers or periodic systems and their verifications, the paper focuses on measurement in the NIR, visible, UV, X-ray, and gamma bands of the electromagnetic spectrum; the wavelength of the incident electromagnetic wave is respected. The proposed evaluation comprises a brief description of a Snell’s law-based semi-analytic model of electromagnetic wave propagation through a layered material. We also demonstrate the expected anti-reflective and shielding effects in the X-ray and gamma-ray bands, respectively.

The X-ray emission from gamma-ray burst sources - Constraints on theoretical models

1987 ◽  
Vol 313 ◽  
pp. 711 ◽  
Author(s):  
James N. Imamura ◽  
Richard I. Epstein
Keyword(s):  
Gamma Ray ◽  
Theoretical Models ◽  
Gamma Ray Burst ◽  
X Ray

scholarly journals Spectral characterization of the non-thermal X-ray emission of gamma-ray pulsars

2019 ◽  
Vol 492 (1) ◽  
pp. 1025-1043 ◽  
Author(s):  
Francesco Coti Zelati ◽  
Diego F Torres ◽  
Jian Li ◽  
Daniele Viganò
Keyword(s):  
Gamma Ray ◽  
Theoretical Models ◽  
Spectral Shape ◽  
Spectral Characterization ◽  
Large Area ◽  
Large Sample ◽  
X Ray ◽  
Spectral Distributions ◽  
Selection Of

ABSTRACT We report on a detailed spectral characterization of the non-thermal X-ray emission for a large sample of gamma-ray pulsars in the second Fermi Large Area Telescope catalogue. We outline the criteria adopted for the selection of our sample, its completeness, and critically describe different approaches to estimate the spectral shape and flux of pulsars. We perform a systematic modelling of the pulsars’ X-ray spectra using archival observations with XMM–Newton, Chandra, and NuSTAR and extract the corresponding non-thermal X-ray spectral distributions. This set of data is made available online and is useful to confront with predictions of theoretical models.

scholarly journals Neutron Star Powered Accelerators

2000 ◽  
Vol 195 ◽  
pp. 463-471
Author(s):  
M. Ruderman
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Surrounding Medium ◽  
Radio Pulsars ◽  
X Ray ◽  
Energetic Radiation ◽  
Γ Ray ◽  
Star Binary

Neutron stars can be the underlying source of energetic particle acceleration in several ways. The huge gravitational-collapse energy released in their birth, or the violent fusion at the end of the life of a neutron-star binary, is the energy source for an accelerator in the surrounding medium far from the star. This would be the case for: (a) cosmic rays from supernova explosions with neutron-star remnants; (b) energetic radiation from “plerions” around young neutron stars (e.g., the Crab Nebula, see Pacini 2000); and (c) “afterglow” and γ-rays of cosmic Gamma-Ray Burst (GRB) sources with possible neutron-star central engines. Particles can also be energetically accelerated if a neutron star's gravitational pull sustains an accretion disk fed by a companion. Examples are accretion-powered X-ray pulsars and low-mass X-ray binaries. A third family of “neutron-star powered” accelerators consists of those which do not depend on the surrounding environment. These are the accelerators which must exist in the magnetospheres of many solitary, spinning-down, magnetized neutron stars (“spinsters”) when they are observed as radio pulsars or γ-ray pulsars. (There are probably ~ 103 dead radio pulsars for each one in our Galaxy that is still active; the ratio for γ-ray pulsars may well exceed 105.)

scholarly journals ASCA observations of Galactic rotation-powered pulsars

2000 ◽  
Vol 177 ◽  
pp. 351-352 ◽  
Author(s):  
M. J. Pivovaroff ◽  
V. M. Kaspi ◽  
E. V. Gotthelf
Keyword(s):  
Supernova Remnant ◽  
Gamma Ray ◽  
Position Error ◽  
Galactic Rotation ◽  
Radio Pulsars ◽  
Error Ellipse ◽  
X Ray ◽  
Upper Limit ◽  
Synchrotron Nebula ◽  
Galactic Radio

AbstractWe have examined several archivalASCAobservations of Galactic radio pulsars, including PSRs B1046–58 and B1610–50. X-ray emission is detected from PSR B1046–58 with a significance of ∼5σ. We find no evidence for pulsations. We argue that the emission is from a spatially unresolved synchrotron nebula powered by the pulsar. The location of the X-ray counterpart within the 95% position error ellipse of the gamma-ray source 3EG J1048–5840 strengthens the claim of Kaspi et al. (2000) that PSR B1046–58 emitϒ-rays. X-ray emission from PSR B1610–50 is not detected. We use the X-ray luminosity upper limit to constrain the pulsar’s velocity ≲ 200km s−1, arguing against an association with the nearby supernova remnant Kes 32. Our results for these radio pulsars contradict previous reports of detections of large (tens of arc minutes) associated synchrotron nebulae.

scholarly journals The Gamma-Ray Sky

1981 ◽  
Vol 94 ◽  
pp. 279-307 ◽  
Author(s):  
L. Scarsi ◽  
R. Buccheri ◽  
G. Gerardi ◽  
B. Sacco
Keyword(s):  
Energy Range ◽  
Gamma Ray ◽  
Energy Detector ◽  
Characteristic Parameters ◽  
X Ray ◽  
Gamma Ray Astronomy ◽  
Observational Technique ◽  
Wide Domain ◽  
Energy Domain

When we talk of Gamma-Ray Astronomy we refer in general to celestial photons covering the energy domain from a fraction of MeV up to the highest detected energies at hundreds or thousands of GeV. The six to seven decades altogether spanning the overall energy range constitute a very wide domain to be compared with those of the optical (less than one decade) or of the neighbouring X-Ray Astronomy (about two decades). The observational technique varies widely with changing energy; detector performances and characteristic parameters are not, in general, comparable.

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