scholarly journals XMM-Newton and Geminga

2004 ◽  
Vol 218 ◽  
pp. 215-218
Author(s):  
Patrizia Caraveo ◽  
Andrea De Luca ◽  
Sandro Mereghetti ◽  
Alberto Pellizzoni ◽  
Giovanni Bignami ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Surrounding Medium ◽  
Matter Density ◽  
Bow Shock ◽  
Synchrotron Emission ◽  
Electron Synchrotron ◽  
X Ray ◽  
Injection Energy ◽  
Pulsar Wind ◽  
Supersonic Motion

A deep XMM-Newton/EPIC observation of the field of the Geminga pulsar unveiled the presence of two elongated parallel X-ray tails trailing the neutron star. They are aligned with the object's supersonic motion, extend for ∼ 2′, and have a nonthermal spectrum produced by electron-synchrotron emission in the bow shock between the pulsar wind and the surrounding medium. Such a first ever X-ray detection of a pulsar bow shock allows us to gauge the pulsar electron injection energy and the shock magnetic field while constraining the angle of Geminga's motion and the local matter density.

scholarly journals Chandra Observations of the Guitar Nebula

2003 ◽  
Vol 214 ◽  
pp. 135-136 ◽  
Author(s):  
Diane S. Wong ◽  
James M. Cordes ◽  
Shami Chatterjee ◽  
Ellen G. Zweibel ◽  
John P. Finley ◽  
...  
Keyword(s):  
Proper Motion ◽  
Hot Spot ◽  
Optical Emission ◽  
Position Angle ◽  
Bow Shock ◽  
Radio Pulsar ◽  
X Ray ◽  
Multi Wavelength ◽  
Pulsar Wind

As part of a multi-wavelength study, we report on a 50 ks Chandra/ACIS observation of the Guitar Nebula, a bow shock nebula associated with the radio pulsar B2224+65. We see a “hot spot” at the tip of the bow shock. We also notice a “jet” of X-ray emission at position angle (PA) −69°. However, the proper motion of the pulsar and the axis of optical emission is at PA 52°.1. We discuss the resulting interpretations of the relativistic pulsar wind and the surrounding ISM.

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 Hot gas heating via magnetic arms in spiral galaxies

2020 ◽  
Vol 640 ◽  
pp. A109
Author(s):  
M. Weżgowiec ◽  
M. Ehle ◽  
M. Soida ◽  
R.-J. Dettmar ◽  
R. Beck ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Radio Emission ◽  
Magnetic Reconnection ◽  
Spiral Galaxy ◽  
Surrounding Medium ◽  
Spiral Arms ◽  
X Ray ◽  
Hot Gas ◽  
Gas Heating

Context. Reconnection heating has been considered as a potential source of the heating of the interstellar medium. In some galaxies, significant polarised radio emission has been found between the spiral arms. This emission has a form of “magnetic arms” that resembles the spiral structure of the galaxy. Reconnection effects could convert some of the energy of the turbulent magnetic field into the thermal energy of the surrounding medium, leaving more ordered magnetic fields, as is observed in the magnetic arms. Aims. Sensitive radio and X-ray data for the grand-design spiral galaxy M 83 are used for a detailed analysis of the possible interactions of magnetic fields with hot gas, including a search for signatures of gas heating by magnetic reconnection effects. Methods. Magnetic field strengths and energies derived from the radio emission are compared with the parameters of the hot gas calculated from the model fits to sensitive X-ray spectra of the hot gas emission. Results. The available X-ray data allowed us to distinguish two thermal components in the halo of M 83. We found slightly higher average temperatures of the hot gas in the interarm regions, which results in higher energies per particle and is accompanied by a decrease in the energy density of the magnetic fields. Conclusions. The observed differences in the energy budget between the spiral arms and the interarm regions suggest that, similar to the case of another spiral galaxy NGC 6946, we may be observing hints for gas heating by magnetic reconnection effects in the interarm regions. These effects, which act more efficiently on the turbulent component of the magnetic field, are expected to be stronger in the spiral arms. However, with the present data it is only possible to trace them in the interarm regions, where the star formation and the resulting turbulence is low.

scholarly journals Modelling multiwavelength emissions from PSR B1259–63/LS 2883: Effects of the stellar disc on shock radiations

2019 ◽  
Vol 627 ◽  
pp. A87 ◽  
Author(s):  
A. M. Chen ◽  
J. Takata ◽  
S. X. Yi ◽  
Y. W. Yu ◽  
K. S. Cheng
Keyword(s):  
Magnetic Field ◽  
Gamma Ray ◽  
Thermal Emission ◽  
Orbital Plane ◽  
Light Curves ◽  
Double Peak ◽  
Stellar Disc ◽  
X Ray ◽  
Pulsar Wind ◽  
Star Binary

PSR B1259–63/LS 2883 is an elliptical pulsar/Be star binary that emits broadband emissions from radio to TeV γ-rays. The massive star possesses an equatorial disc that is inclined with the orbital plane of the pulsar. Non-thermal emission from the system is believed to be produced by pulsar wind shock and double-peak profiles in the X-ray, and TeV γ-ray light curves are related to the phases of the pulsar passing through the disc region of the star. In this paper, we investigate the interactions between the pulsar wind and stellar outflows, especially with the presence of the disc, and present a multiwavelength modelling of the emission from this system. We show that the double-peak profiles of X-ray and TeV γ-ray light curves are caused by the enhancements of the magnetic field and soft photons at the shock during the disc passages. As the pulsar is passing through the equatorial disc, the additional pressure of the disc pushes the shock surface closer to the pulsar, which causes the enhancement of magnetic field in the shock, and thus increases the synchrotron luminosity. The TeV γ-rays due to the inverse-Compton (IC) scattering of shocked electrons with seed photons from the star are expected to peak around periastron, which is inconsistent with observations. However, the shock heating of the stellar disc could provide additional seed photons for IC scattering during the disc passages, and thus produces the double-peak profiles as observed in the TeV γ-ray light curve. Our model can possibly be examined and applied to other similar gamma-ray binaries, such as PSR J2032+4127/MT91 213, HESS J0632+057, and LS I+61°303.

scholarly journals CONSTRAINTS ON X-RAY POLARIZATION OF SYNCHROTRON JETS FROM STELLAR-MASS BLACK HOLES

2012 ◽  
Vol 08 ◽  
pp. 102-107
Author(s):  
D. M. RUSSELL
Keyword(s):  
Magnetic Field ◽  
Black Holes ◽  
Black Hole ◽  
Synchrotron Emission ◽  
Relativistic Jets ◽  
X Ray ◽  
Linearly Polarized ◽  
Hard State ◽  
X Ray Binaries ◽  
The Magnetic Field

For most black hole X-ray binaries, the fraction of X-ray flux originating in the synchrotron jets is generally thought to be low in the hard state. However in one intriguing case, the infrared – X-ray correlations, evolution of broadband spectra and timing signatures suggest that synchrotron emission from a jet likely dominated both the infrared and X-ray flux on the hard state decline of an outburst of XTE J1550–564 at a luminosity of ~ (2 × 10-4 – 2 × 10-3) L Edd . Synchrotron emission from the relativistic jets launched close to black holes can be highly linearly polarized, depending on the configuration of the magnetic field. It has recently been shown that the polarimetric signature of their jets is detected in the infrared and is highly variable. This reveals the magnetic geometry in a region of the compact jet near its base, close to the black hole. From these results, it is predicted that in some cases, high (possibly up to 10%), variable levels of X-ray polarization from synchrotron emission originating in jets will be detected from accreting black holes by future spaceborne X-ray polarimeters.

scholarly journals A search for variability of hard X-ray emission from the Vela pulsar wind nebula

2021 ◽  
Vol 2103 (1) ◽  
pp. 012006
Author(s):  
A M Krassilchtchikov ◽  
M S Pshirkov ◽  
A M Bykov
Keyword(s):  
Magnetic Field ◽  
Gamma Ray ◽  
Next Generation ◽  
Short Term ◽  
X Ray ◽  
Term Evolution ◽  
Flux Variability ◽  
Vela Pulsar ◽  
Pulsar Wind ◽  
Significant Flux

Abstract Observations of hard X-ray emission from the Vela pulsar wind nebula (PWN) with the ISGRI camera aboard INTEGRAL gamma-ray observatory have been analysed with the aim to search for possible flux variability on scales from weeks to years, which could be caused by short-term evolution of pulsar wind structures similar to those governing sharp flares and flux depressions observed in the sub-GeV emission of the Crab PWN. No statistically significant flux depressions or flares have been found in none of the considered energy ranges: 20-50 keV, 50-100 keV, and 100-200 keV, however some hints of flux instability can be seen in the former two bands. If the variability of the pulsar wind termination surface or instabilities of turbulent magnetic field in the nebula predicted by a number of PWN models indeed influence the synchrotron spectrum of such objects, the variability of the 1-30 MeV emission from the Vela PWN could be checked with the next generation of gamma-ray facilities, like eASTROGAM or HERMES.

scholarly journals On the Nature of Radio Eclipsing

2000 ◽  
Vol 177 ◽  
pp. 533-534
Author(s):  
Ya. N. Istomin
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Electric Current ◽  
Plasma Waves ◽  
Bow Shock ◽  
Companion Star ◽  
Atmosphere Density ◽  
Pulsar Wind ◽  
Transverse Electromagnetic ◽  
The Magnetic Field

AbstractIt is shown that the phenomena of radio eclipsing can be explained by the linear mechanism of transformation of the transverse electromagnetic wave, propagating in the pulsar wind, into the plasma waves in the region of interaction of wind with a companion star atmosphere. The coefficient of the passingηdepends on the wave frequencyωby the exponential mannerη= exp{–const ·ω−1}. The estimated scale for the pulsar wind and star’s atmosphere density gradients are of the order of 100 meters. Such gradient can be obtained in the bow shock forming when the pulsar wind enters into the companion star atmosphere. Annihilation of the part of the wind’s positrons with the star’s electrons produces the electric current. This current generates the magnetic field from which the pulsar wind’s particles are reflected. The magnitude of the magnetic field in this shock of about several Gauss.

scholarly journals Multiband nonthermal radiative properties of pulsar wind nebulae

2018 ◽  
Vol 609 ◽  
pp. A110 ◽  
Author(s):  
Bo-Tao Zhu ◽  
Li Zhang ◽  
Jun Fang
Keyword(s):  
Magnetic Field ◽  
Gamma Ray ◽  
High Energy ◽  
Maximum Energy ◽  
Energy Electron ◽  
Radiative Properties ◽  
Spectral Energy ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
Pulsar Wind

Aims. The nonthermal radiative properties of 18 pulsar wind nebulae (PWNe) are studied in the 1D leptonic model. Methods. The dynamical and radiative evolution of a PWN in a nonradiative supernova remnant are self-consistently investigated in this model. The leptons (electrons/positrons) are injected with a broken power-law form, and nonthermal emission from a PWN is mainly produced by time-dependent relativistic leptons through synchrotron radiation and inverse Compton process. Results. Observed spectral energy distributions (SEDs) of all 18 PWNe are reproduced well, where the indexes of low-energy electron components lie in the range of 1.0–1.8 and those of high-energy electron components in the range of 2.1–3.1. Our results show that FX/Fγ > 10 for young PWNe; 1 <FX/Fγ ≤ 10 for evolved PWNe, except for G292.0+1.8; and FX/Fγ ≤ 1 for mature/old PWNe, except for CTA 1. Moreover, most PWNe are particle-dominated. Statistical analysis for the sample of 14 PWNe further indicate that (1) not all pulsar parameters have correlations with electron injection parameters, but electron maximum energy and PWN magnetic field correlate with the magnetic field at the light cylinder, the potential difference at the polar cap, and the spin-down power; (2) the spin-down power positively correlates with radio, X-ray, bolometric, and synchrotron luminosities, but does not correlate with gamma-ray luminosity; (3) the spin-down power positively correlates with radio, X-ray, and γ-band surface brightness; and (4) the PWN radius and the PWN age negatively correlate with X-ray luminosity, the ratio of X-ray to gamma-ray luminosities, and the synchrotron luminosity.

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 The braking index of PSR B0540−69 and the associated pulsar wind nebula emission after spin-down rate transition

2020 ◽  
Vol 494 (2) ◽  
pp. 1865-1870 ◽  
Author(s):  
L J Wang ◽  
M Y Ge ◽  
J S Wang ◽  
S S Weng ◽  
H Tong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Energy Density ◽  
Observational Evidence ◽  
The Other ◽  
High Quality ◽  
X Ray ◽  
Dipole Magnetic Field ◽  
Pulsar Wind ◽  
The Magnetic Field ◽  
High Cadence

ABSTRACT In 2011 December, PSR B054−69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by $\sim 36{{\ \rm per\ cent}}$. About 1000 d after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by $32\pm 8{{\ \rm per\ cent}}$. After the SRT, the braking index n of PSR B0540−69 changes from n = 2.12 to 0.03 and then keeps this value for about five years before rising to n = 0.9 in the following years. We find that most of the current models have difficulties in explaining the measured braking index. One exceptive model of the braking index evolution is the increasing dipole magnetic field of PSR B0540−69. We suggest that the field increase may result from some instabilities within the pulsar core that enhance the poloidal component at the price of toroidal component of the magnetic field. The increasing dipole magnetic field will result in the X-ray brightening of the PWN. We fit the PWN X-ray light curve by two models: one assumes a constant magnetic field within the PWN during the brightening and the other assumes an enhanced magnetic field proportional to the energy density of the PWN. It appears that the two models fit the data well, though the later model seems to fit the data a bit better. This provides marginal observational evidence that magnetic field in the PWN is generated by the termination shock. Future high-quality and high-cadence data are required to draw a solid conclusion.

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