scholarly journals Near‐Infrared, Kilosecond Variability of the Wisps and Jet in the Crab Pulsar Wind Nebula

2005 ◽  
Vol 633 (2) ◽  
pp. 931-940 ◽  
Author(s):  
A. Melatos ◽  
D. Scheltus ◽  
M. T. Whiting ◽  
S. S. Eikenberry ◽  
R. W. Romani ◽  
...  
Keyword(s):  
Near Infrared ◽  
Crab Pulsar ◽  
Pulsar Wind

scholarly journals Theory of Pulsar Winds

2004 ◽  
Vol 218 ◽  
pp. 143-150
Author(s):  
A. Melatos
Keyword(s):  
Linear Accelerator ◽  
Recent Progress ◽  
Near Infrared ◽  
Poynting Flux ◽  
Open Questions ◽  
Field Geometry ◽  
Parametric Instabilities ◽  
Pulsar Wind ◽  
Pulsar Winds ◽  
The Magnetic Field

Recent progress in the theory of pulsar wind electrodynamics is reviewed, with emphasis on the following open questions, (i) Is the bipolar, jet-torus geometry imprinted by collimation or injection? (ii) what is the magnetic field geometry as a function of latitude, and is it stable? (iii) How rapidly does the postshock flow fluctuate, e.g. in the near infrared? (iv) The σ paradox: is Poynting flux converted gradually to kinetic energy flux as the wind expands, as in a linear accelerator, or is the conversion lossy, due to reconnection or parametric instabilities in a wave-like outflow?

scholarly journals The σ Problem of the Crab Pulsar Wind

2004 ◽  
Vol 218 ◽  
pp. 171-174
Author(s):  
J. G. Kirk ◽  
O. Skjæraasen
Keyword(s):  
Dissipation Rate ◽  
A Priori ◽  
Termination Shock ◽  
Crab Pulsar ◽  
Complete Conversion ◽  
Poynting Flux ◽  
Dissipation Rates ◽  
Pulsar Wind

The conversion of the Crab pulsar wind from one dominated by Poynting flux close to the star to one dominated by particle-borne energy at the termination shock is considered. The idea put forth by Coroniti (1990) and criticized by Lyubarsky & Kirk (2001) that reconnection in a striped wind is responsible, is generalized to include faster prescriptions for the a priori unknown dissipation rate. Strong acceleration of the wind is confirmed, and the higher dissipation rates imply complete conversion of Poynting flux into particle-borne flux within the unshocked wind.

scholarly journals The optical and NIR spectrum of the Crab pulsar with X-shooter

2019 ◽  
Vol 629 ◽  
pp. A140
Author(s):  
J. Sollerman ◽  
J. Selsing ◽  
P. M. Vreeswijk ◽  
P. Lundqvist ◽  
A. Nyholm
Keyword(s):  
Spectral Index ◽  
Near Infrared ◽  
Maximum Velocity ◽  
Noise Spectrum ◽  
Emission Lines ◽  
High Signal ◽  
Electromagnetic Spectrum ◽  
Crab Pulsar ◽  
Very Large Telescope ◽  
Nir Emission

Context. Pulsars are well studied all over the electromagnetic spectrum, and the Crab pulsar may be the most studied object in the sky. Nevertheless, a high-quality optical to near-infrared (NIR) spectrum of the Crab or any other pulsar has not been published to date. Aims. Obtaining a properly flux-calibrated spectrum enables us to measure the spectral index of the pulsar emission, without many of the caveats from previous studies. This was the main aim of this project, but in addition we could also detect absorption and emission features from the pulsar and nebula over an unprecedentedly wide wavelength range. Methods. A spectrum was obtained with the X-shooter spectrograph on the Very Large Telescope. Special care was given to the flux-calibration of these data. Results. A high signal-to-noise spectrum of the Crab pulsar was obtained from 300 nm to 2400 nm. The spectral index fit to this spectrum is flat with αν = 0.16 ± 0.07. For the emission lines we measured a maximum velocity of ∼1600 km s−1, whereas the absorption lines from the material between us and the pulsar is unresolved at the ∼50 km s−1 resolution. A number of diffuse interstellar bands and a few NIR emission lines that have previously not been reported from the Crab are highlighted.

scholarly journals The Crab pulsar and its pulsar-wind nebula in the optical and infrared

2009 ◽  
Vol 508 (1) ◽  
pp. 221-228 ◽  
Author(s):  
A. Tziamtzis ◽  
P. Lundqvist ◽  
A. A. Djupvik
Keyword(s):  
Crab Pulsar ◽  
Pulsar Wind

Magnetohydrodynamic Acceleration of the Crab Pulsar Wind

2002 ◽  
Vol 573 (1) ◽  
pp. L31-L34 ◽  
Author(s):  
I. Okamoto
Keyword(s):  
Crab Pulsar ◽  
Pulsar Wind

scholarly journals Ultra-high-energy Gamma-Ray Radiation from the Crab Pulsar Wind Nebula

2022 ◽  
Vol 924 (2) ◽  
pp. 42
Author(s):  
Lin Nie ◽  
Yang Liu ◽  
Zejun Jiang ◽  
Xiongfei Geng
Keyword(s):  
Gamma Ray ◽  
Crab Nebula ◽  
High Energy ◽  
Model Parameters ◽  
Wave Band ◽  
Crab Pulsar ◽  
High Energy Gamma ◽  
Energy Gamma ◽  
Pulsar Wind ◽  
The Crab Nebula

Abstract It has been long debated whether the high-energy gamma-ray radiation from the Crab Nebula stems from leptonic or hadronic processes. In this work, we investigate the multiband nonthermal radiation from the Crab pulsar wind nebula with the leptonic and leptonic–hadronic hybrid models, respectively. Then we use the Markov Chain Monte Carlo sampling technology and method of sampling trace to study the stability and reasonability of the model parameters according to the recently observed results and obtain the best-fitting values of parameters. Finally, we calculate different radiative components generated by the electrons and protons in the Crab Nebula. The modeling results indicate that the pure leptonic origin model with the one-zone only can partly agree with some segments of the data from various experiments (including the PeV gamma-ray emission reported by the LHAASO and the other radiation ranging from the radio to very-high-energy gamma-ray wave band), and the contribution of hadronic interaction is hardly constrained. However, we find that the hadronic process may also contribute, especially in the energy range exceeding the PeV. In addition, it can be inferred that the higher energy signals from the Crab Nebula could be observed in the future.

scholarly journals A search for near infrared counterparts of three pulsar wind nebulae

2011 ◽  
Vol 534 ◽  
pp. A48 ◽  
Author(s):  
P. A. Curran ◽  
S. Chaty ◽  
J. A. Zurita Heras ◽  
A. Coleiro
Keyword(s):  
Near Infrared ◽  
Pulsar Wind Nebulae ◽  
Pulsar Wind
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