scholarly journals THE THEORY OF PULSAR WIND NEBULAE

2014 ◽  
Vol 28 ◽  
pp. 1460160 ◽  
Author(s):  
ELENA AMATO
Keyword(s):  
Thermal Emission ◽  
Detailed Comparison ◽  
Current Status ◽  
X Rays ◽  
Pulsar Wind Nebulae ◽  
Theoretical Understanding ◽  
Recent Developments ◽  
Multi Wavelength ◽  
Pulsar Wind ◽  
Pulsar Winds

I will review the current status of our theoretical understanding of Pulsar Winds and associated nebulae (PWNe). In recent years, axisymmetric models of pulsar winds with a latitude dependent energy flux have proved very successful at explaining the morphology of PWNe as seen in the X-rays. This success has prompted developments aimed at using multi-wavelength observations of these nebulae as a diagnostics of the hidden physics of the pulsar wind and of the mechanism(s) through which particles are accelerated in these sources. I will discuss these most recent developments in terms of the information that we infer from detailed comparison of simulated non-thermal emission with current observations.

scholarly journals Introducing the HD+B model for pulsar wind nebulae: a hybrid hydrodynamics/radiative approach

2020 ◽  
Vol 494 (3) ◽  
pp. 4357-4370
Author(s):  
B Olmi ◽  
D F Torres
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Theoretical Modelling ◽  
X Rays ◽  
Pulsar Wind Nebulae ◽  
New Approach ◽  
Energy Gamma ◽  
Radiative Model ◽  
Pulsar Wind

ABSTRACT Identification and characterization of a rapidly increasing number of pulsar wind nebulae is, and will continue to be, a challenge of high-energy gamma-ray astrophysics. Given that such systems constitute -by far- the most numerous expected population in the TeV regime, such characterization is important not only to learn about the sources per se from an individual and population perspective, but also to be able to connect them with observations at other frequencies, especially in radio and X-rays. Also, we need to remove the emission from nebulae in highly confused regions of the sky for revealing other underlying emitters. In this paper, we present a new approach for theoretical modelling of pulsar wind nebulae: a hybrid hydrodynamic-radiative model able to reproduce morphological features and spectra of the sources, with relatively limited numerical cost.

scholarly journals Pulsar wind nebulae created by fast-moving pulsars

2017 ◽  
Vol 83 (5) ◽  
Author(s):  
O. Kargaltsev ◽  
G. G. Pavlov ◽  
N. Klingler ◽  
B. Rangelov
Keyword(s):  
Hubble Space Telescope ◽  
Ambient Medium ◽  
Pulsar Wind Nebulae ◽  
The Past ◽  
Recent Developments ◽  
Pulsar Velocity ◽  
Bow Shocks ◽  
Observational Status ◽  
Pulsar Wind ◽  
Made In

We review multiwavelength properties of pulsar wind nebulae created by supersonically moving pulsars and the effects of pulsar motion on the pulsar wind nebulae morphologies and the ambient medium. Supersonic pulsar wind nebulae are characterized by bow-shaped shocks around the pulsar and/or cometary tails filled with the shocked pulsar wind. In the past several years significant advances in supersonic pulsar wind nebula studies have been made in deep observations with the Chandra and XMM-Newton X-ray observatories and the Hubble Space Telescope. In particular, these observations have revealed very diverse supersonic pulsar wind nebula morphologies in the pulsar vicinity, different spectral behaviours of long pulsar tails, the presence of puzzling outflows misaligned with the pulsar velocity and far-UV bow shocks. Here we review the current observational status focusing on recent developments and their implications.

scholarly journals Kinetic ‘jets’ from fast-moving pulsars

2019 ◽  
Vol 485 (2) ◽  
pp. 2041-2053 ◽  
Author(s):  
Maxim V Barkov ◽  
Maxim Lyutikov ◽  
Noel Klingler ◽  
Pol Bordas
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Interstellar Medium ◽  
Fast Moving ◽  
Thermal Emission ◽  
Pulsar Wind Nebulae ◽  
Ambient Magnetic Field ◽  
Ram Pressure ◽  
Pulsar Wind ◽  
Ism Magnetic Fields

AbstractSome fast-moving pulsars, such as the Guitar and the Lighthouse, exhibit asymmetric non-thermal emission features that extend well beyond their ram pressure confined pulsar wind nebulae (PWNe). Based on our 3D relativistic simulations, we analytically explain these features as kinetically streaming pulsar wind particles that escaped into the interstellar medium (ISM) due to reconnection between the PWN and ISM magnetic fields. The structure of the reconnecting magnetic fields at the incoming and outgoing regions produces highly asymmetric magnetic bottles therefore and result in asymmetric extended features. For the features to become visible, the ISM magnetic field should be sufficiently high, BISM > 10 $\mu$G. We also discuss archival observations of PWNe displaying evidence of kinetic jets: the Dragonfly PWN (PSR J2021 + 3651), G327.1–1.1, and MSH 11–62, the latter two of which exhibit symmetric ‘snail eyes’ morphologies. We suggest that in those cases the pulsar is moving along the ambient magnetic field in a frisbee-type configuration.

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 Pulsar Wind Nebulae

1996 ◽  
Vol 160 ◽  
pp. 393-399 ◽  
Author(s):  
James M. Cordes
Keyword(s):  
Neutron Stars ◽  
Radial Velocity ◽  
Velocity Component ◽  
Pulsar Wind Nebulae ◽  
Radial Velocity Component ◽  
Ram Pressure ◽  
Pulsar Wind ◽  
Pulsar Winds

AbstractI discuss pulsar wind nebulae for which ram pressure from the neutron star’s motion is a key element of the morphology. These PWN are tools for determining the pulsar distance, radial velocity component, and interaction of pulsar winds with surrounding media. The Guitar Nebula pulsar (B2224+65) also represents a ‘smoking gun’ for velocity kicks from asymmetric supernovae or other rocket effects. The detectability of wind nebulae from pulsars and from as-yet unknown neutron stars is discussed.

scholarly journals The H.E.S.S. view of the Milky Way in TeV light

2011 ◽  
Vol 7 (S284) ◽  
pp. 365-370
Author(s):  
Christoph Deil
Keyword(s):  
Energy Range ◽  
Supernova Remnants ◽  
Milky Way ◽  
Gamma Ray ◽  
Thermal Emission ◽  
Large Field ◽  
Large Area ◽  
Pulsar Wind Nebulae ◽  
Cherenkov Telescopes ◽  
Multi Wavelength

AbstractSince 2003 the H.E.S.S. collaboration has been operating an array of four imaging Cherenkov telescopes in the Khomas Highlands of Namibia. H.E.S.S. can detect gamma rays in the energy range 100 GeV to 100 TeV, has a large field of view (5 degree), good angular resolution (0.1 degree), energy resolution (15%) and sensitivity (a 1% Crab flux point source is detected at 5 sigma significance in 25 h). About half of the available observing time has been spent on the Milky Way, either in scan mode or on individual sources, resulting in the detection of more than 60 Galactic TeV sources. In this talk the two most numerous source classes will be discussed, pulsar wind nebulae and supernova remnants. For the identification and understanding of the TeV emission seen by H.E.S.S. additional measurements of non-thermal emission, mainly in the radio, X-ray and lower-energy gamma-ray bands, are critical. Since August 2008 the Fermi Large Area Telescope has been scanning the whole sky in the energy range from 20 MeV to more than 300 GeV and has detected about 200 Galactic sources as well as diffuse emission from the Milky Way. This talk will give an overview of Galactic H.E.S.S. observations in the multi-wavelength context, with a focus on Fermi.

scholarly journals CONSTRAINING THE PULSAR POWER IN GAMMA-RAY BINARIES THROUGH THERMAL X-RAY EMISSION

2012 ◽  
Vol 08 ◽  
pp. 132-137
Author(s):  
VÍCTOR ZABALZA ◽  
VALENTÍ BOSCH-RAMON ◽  
JOSEP MARIA PAREDES
Keyword(s):  
Stellar Wind ◽  
Binary Systems ◽  
Massive Star ◽  
Gamma Ray ◽  
Thermal Emission ◽  
Mass Loss Rate ◽  
X Rays ◽  
Orbital Inclination ◽  
X Ray ◽  
Pulsar Wind

Gamma-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds collide producing non-thermal emission, most likely from the shocked pulsar wind. Thermal X-rays are expected from the shocked stellar wind, with a spectrum akin to the one observed in massive star binaries. The goal of this work is, through the study of the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries, constrain the pulsar spin-down luminosity and the stellar wind properties. A semi-analytic model is developed to compute the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries. The model results are compared with XMM-Newton observations of LS 5039, a candidate pulsar gamma-ray binary with a strong stellar wind. Exploring the range of possible values for the stellar mass-loss rate and orbital inclination, we obtain an upper limit on the pulsar spin-down luminosity of 6 × 1036 erg s-1. We conclude that, to explain the non-thermal luminosity of LS 5039 in the pulsar wind scenario, a non-thermal to spin-down luminosity ratio very close to unity may be required.

scholarly journals PeV Emission of the Crab Nebula: Constraints on the Proton Content in Pulsar Wind and Implications

2021 ◽  
Vol 922 (2) ◽  
pp. 221
Author(s):  
Ruo-Yu Liu ◽  
Xiang-Yu Wang
Keyword(s):  
Energy Content ◽  
Crab Nebula ◽  
Cosmic Ray ◽  
Ultrahigh Energy ◽  
Pulsar Wind Nebulae ◽  
Air Shower ◽  
Pulsar Wind ◽  
The Crab Nebula ◽  
Pulsar Winds ◽  
Cosmic Ray Flux

Abstract Recently, two photons from the Crab Nebula with energy of approximately 1 PeV were detected by the Large High Altitude Air Shower Observatory (LHAASO), opening an ultrahigh-energy window for studying pulsar wind nebulae (PWNe). Remarkably, the LHAASO spectrum at the highest-energy end shows a possible hardening, which could indicate the presence of a new component. A two-component scenario with a main electron component and a secondary proton component has been proposed to explain the whole spectrum of the Crab Nebula, requiring a proton energy of 1046–1047 erg remaining in the present Crab Nebula. In this paper, we study the energy content of relativistic protons in pulsar winds using the LHAASO data of the Crab Nebula, considering the effect of diffusive escape of relativistic protons. Depending on the extent of the escape of relativistic protons, the total energy of protons lost in the pulsar wind could be 10–100 times larger than that remaining in the nebula presently. We find that the current LHAASO data allow up to (10–50)% of the spindown energy of pulsars being converted into relativistic protons. The escaping protons from PWNe could make a considerable contribution to the cosmic-ray flux of 10–100 PeV. We also discuss the leptonic scenario for the possible spectral hardening at PeV energies.

scholarly journals A multi-wavelength view of the pulsar environments

2017 ◽  
Vol 13 (S337) ◽  
pp. 241-246
Author(s):  
Roberta Zanin
Keyword(s):  
Gamma Ray ◽  
Population Studies ◽  
State Of The Art ◽  
Theoretical Models ◽  
Rotational Energy ◽  
Pulsar Wind Nebulae ◽  
Morphological Measurement ◽  
Multi Wavelength ◽  
Push Forward ◽  
Pulsar Wind

AbstractSometimes the explosion of a supernova can generate a pulsar, most of whose rotational energy is carried away by an energetic wind of particles and magnetic fields expanding into its surroundings and eventually forming extended nebulae, i.e. the pulsar wind nebulae. The experimental advances reached in the last decades, from radio frequencies up to the highest gamma-ray energies, with instruments like VLA, VLBA, Chandra, NuStar, Fermi-LAT and H.E.S.S. among the others, led to the discovery of hundreds of this kind of sources allowing for population studies. In addition, this variety of high-precision spectral and morphological measurement provided an unprecedented opportunity to test and push forward the state-of-the-art theoretical models. In this contribution, we will review the latest, and most significant theoretical and experimental results.

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