scholarly journals Magnetic turbulence in supernova remnants: perspective for IXPE polarimeter

2021 ◽  
Vol 2103 (1) ◽  
pp. 012016
Author(s):  
A M Bykov ◽  
Y A Uvarov
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Observation Time ◽  
Polarization Degree ◽  
Pixel Detector ◽  
Energy Bands ◽  
Magnetic Field Generation ◽  
X Ray ◽  
Magnetic Turbulence ◽  
New Family

Abstract Supernova remnants (SNRs) are well known sources of the non-thermal radiation, particle acceleration and magnetic field generation and amplification. Synchrotron radiation of the accelerated electrons in the magnetic field is an important emission mechanism in SNRs that can dominate in radio and X-ray energy bands. Turbulent magnetic field yields to formation of the special inhomogeneous (clumpy) structure in the SNR synchrotron X-ray images. This structure could differ significantly on the SNR polarization maps for different types of the magnetic turbulence. A new family of the gas pixel detector X-ray polarimeters that are supposed to have good sensitivity and angular resolution should be well suited for SNR polarimetry. IXPE (NASA) will be the first polarimeter of this kind. Lately a model IXPE synchrotron polarization images of Tycho SNR were simulated in the 3 — 8 keV energy band. It was shown that IXPE observation time of ~ 1 Ms should be enough to distinguish characteristic features that are specific for some types of the magnetic turbulence. We perform simulations of Tycho SNR polarization maps for a wider set of energy bands in order to determine the most suitable energy range for study of the SNR turbulent magnetic field using IXPE. The dependence of the polarization degree on the photon energy is accurately considered in the simulations. IXPE background influence on the observations of Tycho SNR is also discussed here together with possible ways of data processing and interpretation reducing this effect.

scholarly journals A New View on Young Pulsars in Supernova Remnants: Slow, Radio-quiet & X-ray Bright

2000 ◽  
Vol 177 ◽  
pp. 699-702 ◽  
Author(s):  
E. V. Gotthelf ◽  
G. Vasisht
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Simple Explanation ◽  
Crab Pulsar ◽  
Radio Pulsars ◽  
Substantial Fraction ◽  
Subsequent Evolution ◽  
X Ray ◽  
Field Decay

AbstractWe propose a simple explanation for the apparent dearth of radio pulsars associated with young supernova remnants (SNRs). Recent X-ray observations of young remnants have revealed slowly rotating (P∼ 10s) central pulsars with pulsed emission above 2 keV, lacking in detectable radio emission. Some of these objects apparently have enormous magnetic fields, evolving in a manner distinct from the Crab pulsar. We argue that these X-ray pulsars can account for a substantial fraction of the long sought after neutron stars in SNRs and that Crab-like pulsars are perhaps the rarer, but more highly visible example of these stellar embers. Magnetic field decay likely accounts for their high X-ray luminosity, which cannot be explained as rotational energy loss, as for the Crab-like pulsars. We suggest that the natal magnetic field strength of these objects control their subsequent evolution. There are currently almost a dozen slow X-ray pulsars associated with young SNRs. Remarkably, these objects, taken together, represent at least half of the confirmed pulsars in supernova remnants. This being the case, these pulsars must be the progenitors of a vast population of previously unrecognized neutron stars.

scholarly journals Modeling the Radio and X-ray Emission of SN 1993J and SN 2002ap

2005 ◽  
Vol 192 ◽  
pp. 59-69
Author(s):  
Claes Fransson ◽  
Claes-Ingvar Björnsson
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Loss Rate ◽  
Relativistic Particle ◽  
Mass Loss Rate ◽  
Light Curves ◽  
Magnetic Field Generation ◽  
Absorption Mechanism ◽  
X Ray ◽  
Physical Mechanisms

SummaryModeling of radio and X-ray observations of supernovae interacting with their circumstellar media are discussed, with special application to SN 1993J and SN 2002ap. We emphasize the importance of including all relevant physical mechanisms, especially for the modeling of the radio light curves. The different conclusions for the absorption mechanism (free-free or synchrotron self-absorption), as well as departures from an ρ ∝ r−2 CSM, as inferred by some authors, are discussed in detail. We conclude that the evidence for a variation in the mass loss rate with time is very weak. The results regarding the efficiencies of magnetic field generation and relativistic particle acceleration are summarized.

scholarly journals Powering central compact objects with a tangled crustal magnetic field

2020 ◽  
Vol 495 (2) ◽  
pp. 1692-1699 ◽  
Author(s):  
Konstantinos N Gourgouliatos ◽  
Rainer Hollerbach ◽  
Andrei P Igoshev
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Initial Conditions ◽  
Supernova Explosion ◽  
Compact Objects ◽  
Dipole Field ◽  
Ohmic Dissipation ◽  
X Ray ◽  
Axisymmetric Structure ◽  
Central Compact Objects

ABSTRACT Central Compact Objects (CCOs) are X-ray sources with luminosity ranging between 1032 and 1034 erg s−1, located at the centres of supernova remnants. Some of them have been confirmed to be neutron stars. Timing observations have allowed the estimation of their dipole magnetic field, placing them in the range ∼1010–1011 G. The decay of their weak dipole fields, mediated by the Hall effect and Ohmic dissipation, cannot provide sufficient thermal energy to power their X-ray luminosity, as opposed to magnetars whose X-ray luminosities are comparable. Motivated by the question of producing high X-ray power through magnetic field decay while maintaining a weak dipole field, we explore the evolution of a crustal magnetic field that does not consist of an ordered axisymmetric structure, but rather comprises a tangled configuration. This can be the outcome of a non-self-excited dynamo, buried inside the crust by fallback material following the supernova explosion. We find that such initial conditions lead to the emergence of the magnetic field from the surface of the star and the formation of a dipolar magnetic field component. An internal tangled magnetic field of the order of 1014 G can provide sufficient Ohmic heating to the crust and power CCOs, while the dipole field it forms is approximately 1010 G, as observed in CCOs.

Intermittency of magnetic field turbulence: Astrophysical applications of in-situ observations

2015 ◽  
Vol 81 (4) ◽  
Author(s):  
Lev M. Zelenyi ◽  
Andrei M. Bykov ◽  
Yury A. Uvarov ◽  
Anton V. Artemyev
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Supernova Remnants ◽  
Random Media ◽  
Chemical Elements ◽  
High Energy ◽  
Statistical Characteristics ◽  
Physical Parameters ◽  
Magnetic Turbulence

We briefly review some aspects of magnetic turbulence intermittency observed in space plasmas. Deviation of statistical characteristics of a system (e.g. its high statistical momenta) from the Gaussian can manifest itself as domination of rare large intensity peaks often associated with the intermittency in the system's dynamics. Thirty years ago, Zeldovich stressed the importance of the non-Gaussian appearance of the sharp values of vector and scalar physical parameters in random media as a factor of magnetic field amplification in cosmic structures. Magnetic turbulence is governing the behavior of collisionless plasmas in space and especially the physics of shocks and magnetic reconnections. Clear evidence of intermittent magnetic turbulence was found in recent in-situ spacecraft measurements of magnetic fields in the near-Earth and interplanetary plasma environments. We discuss the potentially promising approaches of incorporating the knowledge gained from spacecraft in-situ measurements into modern models describing plasma dynamics and radiation in various astrophysical systems. As an example, we discuss supernova remnants (SNRs) which are known to be the sources of energy, momentum, chemical elements, and high-energy cosmic rays (CRs) in galaxies. Supernova shocks accelerate charged particles to very high energies and may strongly amplify turbulent magnetic fields via instabilities driven by CRs. Relativistic electrons accelerated in SNRs radiate polarized synchrotron emission in a broad range of frequencies spanning from the radio to gamma-rays. We discuss the effects of intermittency of magnetic turbulence on the images of polarized synchrotron X-ray emission of young SNRs and emission spectra of pulsar wind nebula.

scholarly journals Broad-band X-ray characteristics of the transient pulsar GRO J2058+42

2020 ◽  
Vol 497 (1) ◽  
pp. 1059-1065
Author(s):  
Sanhita Kabiraj ◽  
Biswajit Paul
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Broad Band ◽  
High Energy ◽  
Energy Bands ◽  
X Ray ◽  
Energy Cutoff ◽  
Cyclotron Line ◽  
Energy Dependent

ABSTRACT The Be X-ray binary GRO J2058+42 recently went through a Type-II outburst during 2019 March–April lasting for about 50 d. This outburst was detected with the operating all sky X-ray monitors like the Fermi-GBM, Swift-BAT, and MAXI-GSC. Two Nuclear Spectroscopic Telescope Array(NuSTAR) observations were also made, one during the rise and other during the decay of the outburst. It gave us the unique opportunity to analyse the broad-band characteristics of the pulsar for the first time and accretion torque characteristics of the pulsar over a range of X-ray luminosity. The pulse profiles are strongly energy-dependent, with at least four different pulse components at low energy (< 20 keV), which evolves to a single-peaked profile at high energy (> 30 keV). In each of the narrow energy bands, the pulse profiles are nearly identical in the two NuSTAR observations. The spectra from both the observations are fitted well to a power-law with a Fermi–Dirac-type high-energy cutoff. We ruled out presence of a cyclotron line in the pulse phase averaged X-ray spectrum in the NuSTAR band with an optical depth greater than 0.15. An iron emission line is detected in both the NuSTAR spectra with an equivalent width of about 125 eV. We looked at the dependence of the spin-up rate on the luminosity and estimated the magnetic field strength from that, which came out to be much higher compared to other known BeXRB pulsars. Lastly, we discussed the inadequacy of the torque–luminosity relation for determination of magnetic field strength of neutron stars.

scholarly journals Modeling of the spatially resolved nonthermal emission from the Vela Jr. supernova remnant

2018 ◽  
Vol 618 ◽  
pp. A155 ◽  
Author(s):  
Iurii Sushch ◽  
Robert Brose ◽  
Martin Pohl
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Supernova Remnants ◽  
High Energy ◽  
Radial Dependence ◽  
Electromagnetic Spectrum ◽  
X Ray ◽  
Spatially Resolved ◽  
Magnetic Field Profile ◽  
Broadband Emission

Vela Jr. (RX J0852.0−4622) is one of just a few known supernova remnants (SNRs) with a resolved shell across the whole electromagnetic spectrum from radio to very-high-energy (>100 GeV; VHE) gamma-rays. Its proximity and large size allow for detailed spatially resolved observations of the source, making Vela Jr. one of the primary sources used for the study of particle acceleration and emission mechanisms in SNRs. High-resolution X-ray observations reveal a steepening of the spectrum toward the interior of the remnant. In this study we aim for a self-consistent radiation model of Vela Jr. which at the same time would explain the broadband emission from the source and its intensity distribution. We solve the full particle transport equation combined with the high-resolution one-dimensional (1D) hydrodynamic simulations (using Pluto code) and subsequently calculate the radiation from the remnant. The equations are solved in the test particle regime. We test two models for the magnetic field profile downstream of the shock: damped magnetic field, which accounts for the damping of strong magnetic turbulence downstream, and transported magnetic field. Neither of these scenarios can fully explain the observed radial dependence of the X-ray spectrum under spherical symmetry. We show, however, that the softening of the spectrum and the X-ray intensity profile can be explained under the assumption that the emission is enhanced within a cone.

scholarly journals Detection of X-ray flares from AX J1714.1−3912, the unidentified source near RX J1713.7−3946

2018 ◽  
Vol 612 ◽  
pp. A32 ◽  
Author(s):  
Marco Miceli ◽  
Aya Bamba
Keyword(s):  
Supernova Remnants ◽  
Time Variability ◽  
X Rays ◽  
Energy Bands ◽  
X Ray ◽  
Nonthermal Emission ◽  
Photon Index ◽  
Unidentified Source

Context. Molecular clouds are predicted to emit nonthermal X-rays when they are close to particle-accelerating supernova remnants (SNRs), and the hard X-ray source AX J1714.1−3912, near the SNR RX J1713.7−3946, has long been considered a candidate for diffuse nonthermal emission associated with cosmic rays diffusing from the remnant to a closeby molecular cloud. Aim. We aim at ascertaining the nature of this source by analyzing two dedicated X-ray observations performed with Suzaku and Chandra. Methods. We extracted images from the data in various energy bands, spectra, and light curves and studied the long-term evolution of the X-ray emission on the basis of the ~4.5 yr time separation between the two observations. Results. We found that there is no diffuse emission associated with AX J1714.1−3912, which is instead the point-like source CXOU J171343.9−391205. We discovered rapid time variability (timescale ~ 103 s), together with a high intrinsic absorption and a hard nonthermal spectrum (power law with photon index Γ ~ 1.4). We also found that the X-ray flux of the source drops down by 1–2 orders of magnitude on a timescale of a few years. Conclusions. Our results suggest a possible association between AX J1714.1−3912 and a previously unknown supergiant fast X-ray transient, although further follow-up observations are necessary to prove this association definitively.

scholarly journals X-ray Images of Supernova Remnants

1988 ◽  
Vol 101 ◽  
pp. 115-118
Author(s):  
Frederick D. Seward
Keyword(s):  
High Resolution ◽  
Magnetic Tape ◽  
Supernova Remnants ◽  
Energy Bands ◽  
X Ray

Einstein observations of supernova remnants have been reviewed and analyzed. Images of 44 galactic remnants have been reprocessed, merged when necessary, and collected into a catalog. Some bright remnants were viewed with both moderate and high resolution instruments (IPC with 1’ resolution and HRI with 4” resolution). Some IPC images of nearby remnants have been separated into 2 energy bands, 0.2–0.6 keV and 0.6–4.5 keV; whereas most images cover the band 0.2–4.5 keV. The catalog consists of 72 images of the 44 remnants.These images will be published in the form illustrated here. Contour levels are spaced geometrically as indicated below the figures and show the faintest observable features. The pictures are more linear and generally show only the brighter regions. Images are available now, however, in FITS format, on magnetic tape and may be obtained by writing to the author.

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