scholarly journals Numerical simulations of mass loading in the tails of bow-shock pulsar-wind nebulae

2018 ◽  
Vol 481 (3) ◽  
pp. 3394-3400 ◽  
Author(s):  
B Olmi ◽  
N Bucciantini ◽  
G Morlino
Keyword(s):  
Numerical Simulations ◽  
Bow Shock ◽  
Mass Loading ◽  
Pulsar Wind Nebulae ◽  
Pulsar Wind

scholarly journals Mass loading of bow shock pulsar wind nebulae

2015 ◽  
Vol 454 (4) ◽  
pp. 3886-3901 ◽  
Author(s):  
G. Morlino ◽  
M. Lyutikov ◽  
M. Vorster
Keyword(s):  
Bow Shock ◽  
Mass Loading ◽  
Pulsar Wind Nebulae ◽  
Pulsar Wind

scholarly journals Probing the origin of the off-pulse emission from the pulsars B0525+21 and B2045−16

2019 ◽  
Vol 627 ◽  
pp. L2 ◽  
Author(s):  
B. Marcote ◽  
Y. Maan ◽  
Z. Paragi ◽  
A. Keimpema
Keyword(s):  
High Resolution ◽  
Radio Emission ◽  
Bow Shock ◽  
Noise Levels ◽  
Pulsar Wind Nebulae ◽  
Pulse Emission ◽  
Upper Limits ◽  
Pulsar Wind ◽  
Very High ◽  
Extended Emission

Pulsars typically exhibit radio emission in the form of narrow pulses originated from confined regions of their magnetospheres. A potential presence of magnetospherically originated emission outside this region, the so-called off-pulse emission, would challenge the existing theories. Detection of significant off-pulse emission has been reported so far from only two pulsars: B0525+21 and B2045−16 at 325 and 610 MHz, respectively. However, the nature of this newly uncovered off-pulse emission remains unclear. To probe its origin we conducted very-high-resolution radio observations of B0525+21 and B2045−16 with the European VLBI Network (EVN) at 1.39 GHz. Whereas the pulsed emission is detected at a level consistent with previous observations, we report an absence of any off-pulse emission above 42 and 96 μJy beam−1 (three times the rms noise levels) for B0525+21 and B2045−16, respectively. Our stringent upper limits imply the off-pulse emission to be less than 0.4 and 0.3% of the period-averaged pulsed flux density, i.e., much fainter than the previously suggested values of 1−10%. Since the EVN data are most sensitive to extremely compact angular scales, our results suggest a non-magnetospheric origin for the previously reported off-pulse emission. The presence of extended emission that is resolved out to these milliarcsecond scales still remains plausible. In this case, we constrain the emission to arise from structures with sizes of ∼(0.61−19) × 103 au for B0525+21 and ∼(0.48−8.3) × 103 au for B2045−16. These constraints might indicate that the two pulsars are accompanied by compact bow-shock pulsar wind nebulae. Future observations probing intermediate angular scales (∼0.1−5 arcsec) will help to clarify the actual origin of the off-pulse emission.

scholarly journals Jet-like structures from PSR J1135–6055

2020 ◽  
Vol 644 ◽  
pp. L4
Author(s):  
P. Bordas ◽  
X. Zhang
Keyword(s):  
High Energy ◽  
Bow Shock ◽  
Morphological Properties ◽  
Physical Origin ◽  
Pulsar Wind Nebulae ◽  
Jet Formation ◽  
X Ray ◽  
Pulsar Wind ◽  
Alternative Scenarios ◽  
High Energy Particles

Pulsar wind nebulae (PWNe) produced from supersonic runaway pulsars can render extended X-ray structures in the form of tails and prominent jets. In this Letter, we report on the analysis of ∼130 ks observations of the PWN around PSR J1135–6055 that were obtained with the Chandra satellite. The system displays bipolar jet-like structures of uncertain origin, a compact nebula around the pulsar likely formed by the bow shock ahead of it, and a trailing tail produced by the pulsar fast proper motion. The spectral and morphological properties of these structures reveal strong similarities with the PWNe in other runaway pulsars, such as PSR J1509–5850 and Geminga. We discuss their physical origin considering both canonical PWN and jet formation models as well as alternative scenarios that can also yield extended jet-like features following the escape of high-energy particles into the ambient magnetic field.

scholarly journals On the origin of jet-like features in bow shock pulsar wind nebulae

2019 ◽  
Vol 490 (3) ◽  
pp. 3608-3615 ◽  
Author(s):  
B Olmi ◽  
N Bucciantini
Keyword(s):  
Supernova Remnant ◽  
High Energy ◽  
Field Structure ◽  
Bow Shock ◽  
Pulsar Wind Nebulae ◽  
Magnetic Field Structure ◽  
X Ray ◽  
Class A ◽  
Pulsar Wind ◽  
High Energy Particles

ABSTRACT Bow shock pulsar wind nebulae are a large class of non-thermal synchrotron sources associated to old pulsars that have emerged from their parent supernova remnant and are directly interacting with the interstellar medium. Within this class a few objects show extended X-ray features, generally referred as ‘jets’, that defies all the expectations from the canonical MHD models, being strongly misaligned respect to the pulsar direction of motion. It has been suggested that these jets might originate from high energy particles that escape from the system. Here we investigate this possibility, computing particle trajectories on top of a 3D relativistic MHD model of the flow and magnetic field structure, and we show not only that beamed escape is possible, but that it can easily be asymmetric and charge separated, which as we will discuss are important aspects to explain known objects.

scholarly journals Full-3D relativistic MHD simulations of bow shock pulsar wind nebulae: emission and polarization

2019 ◽  
Vol 488 (4) ◽  
pp. 5690-5701 ◽  
Author(s):  
B Olmi ◽  
N Bucciantini
Keyword(s):  
Three Dimensional ◽  
Polarized Light ◽  
Bow Shock ◽  
Synchrotron Emission ◽  
Pulsar Wind Nebulae ◽  
Emission Pattern ◽  
Mhd Simulations ◽  
Pulsar Wind ◽  
Relativistic Magnetohydrodynamics ◽  
The Magnetic Field

ABSTRACT Bow shock pulsar wind nebulae are observed with a variety of complex morphologies at different wavelengths, most likely due to differences in the magnetic field strength and pulsar wind geometry. Here we present a detailed analysis, showing how these differences affect the observational properties in these systems, focusing on non-thermal synchrotron emission. By adopting different prescriptions for the local emissivity, on top of the magnetic and flow patterns taken from three-dimensional (3D) high-resolution numerical simulations in relativistic magnetohydrodynamics (MHD), and considering various viewing angles, we try to characterize the main features of the emission and polarization, to verify if and how these can be used to get information, or to put constraints, on known objects. We found, for example, that conditions leading to a strong development of the turbulence in the bow shock tail produce substantial differences in the emission pattern, especially in polarized light.

scholarly journals Modelling the bow shock Pulsar Wind Nebulae propagating through a non-uniform ISM

2019 ◽  
Vol 484 (2) ◽  
pp. 1475-1486 ◽  
Author(s):  
O D Toropina ◽  
M M Romanova ◽  
R V E Lovelace
Keyword(s):  
Bow Shock ◽  
Pulsar Wind Nebulae ◽  
Pulsar Wind
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