scholarly journals Study on the escape timescale of high-energy particles from supernova remnants through thermal X-ray properties

2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Hiromasa Suzuki ◽  
Aya Bamba ◽  
Ryo Yamazaki ◽  
Yutaka Ohira
Keyword(s):  
Power Law ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Spectral Shape ◽  
X Ray ◽  
Galactic Cosmic Ray ◽  
High Energy Particles ◽  
Accelerated Particles

Abstract In the current decade, GeV/TeV gamma-ray observations of several supernova remnants (SNRs) have implied that accelerated particles are escaping from their acceleration sites. However, when and how they escape from the SNR vicinities are yet to be understood. Recent studies have suggested that the particle escape might develop with thermal plasma ages of the SNRs. We present a systematic study on the time evolution of particle escape using thermal X-ray properties and gamma-ray spectra using 38 SNRs associated with GeV/TeV gamma-ray emissions. We conducted spectral fittings on the gamma-ray spectra using exponential cutoff power-law and broken power-law models to estimate the exponential cutoff or the break energies, both of which are indicators of particle escape. Plots of the gamma-ray cutoff/break energies over the plasma ages show similar tendencies to those predicted by analytical/numerical calculations of particle escape under conditions in which a shock is interacting with thin interstellar medium or clouds. The particle escape timescale is estimated as ∼100 kyr from the decreasing trends of the total energy of the confined protons with the plasma age. The large dispersions of the cutoff/break energies in the data may suggest an intrinsic variety of particle escape environments. This might be the cause of the complicated Galactic cosmic ray spectral shape measured on Earth.

Particle acceleration at forward and reverse shocks in SNRs

2018 ◽  
Vol 27 (10) ◽  
pp. 1844023 ◽  
Author(s):  
Vladimir Zirakashvili
Keyword(s):  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Field Amplification ◽  
Streaming Instability ◽  
Cosmic Ray Acceleration ◽  
Astrophysical Neutrinos ◽  
Astrophysical Shocks ◽  
Accelerated Particles

Cosmic ray acceleration by astrophysical shocks in supernova remnants is briefly reviewed. Results of numerical modeling taking into account the magnetic field amplification by streaming instability and the shock modification are presented. Nonthermal emission produced by accelerated particles in old supernova remnants is compared with available data of modern radio, X-ray and gamma-ray astronomies. It is also shown that high-energy neutrinos produced in young supernova remnants of Type IIn extragalactic supernova can explain the recent IceCube detection of astrophysical neutrinos.

scholarly journals Constraining the cosmic ray spectrum in the vicinity of the supernova remnant W28: from sub-GeV to multi-TeV energies

2020 ◽  
Vol 635 ◽  
pp. A40
Author(s):  
V. H. M. Phan ◽  
S. Gabici ◽  
G. Morlino ◽  
R. Terrier ◽  
J. Vink ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Molecular Clouds ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Ionization Rate ◽  
High Energy ◽  
Radio Waves ◽  
X Ray

Context. Supernova remnants interacting with molecular clouds are ideal laboratories to study the acceleration of particles at shock waves and their transport and interactions in the surrounding interstellar medium. Aims. Here, we focus on the supernova remnant W28, which over the years has been observed in all energy domains from radio waves to very-high-energy gamma rays. The bright gamma-ray emission detected from molecular clouds located in its vicinity revealed the presence of accelerated GeV and TeV particles in the region. An enhanced ionization rate has also been measured by means of millimeter observations, but such observations alone cannot tell us whether the enhancement is due to low-energy (MeV) cosmic rays (either protons or electrons) or the X-ray photons emitted by the shocked gas. The goal of this study is to determine the origin of the enhanced ionization rate and to infer from multiwavelength observations the spectrum of cosmic rays accelerated at the supernova remnant shock in an unprecedented range spanning from MeV to multi-TeV particle energies. Methods. We developed a model to describe the transport of X-ray photons into the molecular cloud, and we fitted the radio, millimeter, and gamma-ray data to derive the spectrum of the radiating particles. Results. The contribution from X-ray photons to the enhanced ionization rate is negligible, and therefore the ionization must be due to cosmic rays. Even though we cannot exclude a contribution to the ionization rate coming from cosmic-ray electrons, we show that a scenario where cosmic-ray protons explain both the gamma-ray flux and the enhanced ionization rate provides the most natural fit to multiwavelength data. This strongly suggests that the intensity of CR protons is enhanced in the region for particle energies in a very broad range covering almost six orders of magnitude: from ≲100 MeV up to several tens of TeV.

scholarly journals Gamma-Ray and Neutrino Signals from Accretion Disk Coronae of Active Galactic Nuclei

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 36
Author(s):  
Yoshiyuki Inoue ◽  
Dmitry Khangulyan ◽  
Akihiro Doi
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Thermal Activity ◽  
X Ray ◽  
Cascade Models ◽  
Coronal Activity ◽  
Ngc 1068 ◽  
High Energy Particles

To explain the X-ray spectra of active galactic nuclei (AGN), non-thermal activity in AGN coronae such as pair cascade models has been extensively discussed in the past literature. Although X-ray and gamma-ray observations in the 1990s disfavored such pair cascade models, recent millimeter-wave observations of nearby Seyferts have established the existence of weak non-thermal coronal activity. In addition, the IceCube collaboration reported NGC 1068, a nearby Seyfert, as the hottest spot in their 10 yr survey. These pieces of evidence are enough to investigate the non-thermal perspective of AGN coronae in depth again. This article summarizes our current observational understanding of AGN coronae and describes how AGN coronae generate high-energy particles. We also provide ways to test the AGN corona model with radio, X-ray, MeV gamma ray, and high-energy neutrino observations.

scholarly journals Fermi-LAT and WMAP observations of the supernova remnant Puppis A

2013 ◽  
Vol 9 (S296) ◽  
pp. 295-299
Author(s):  
Marie-Hélène Grondin ◽  
John W. Hewitt ◽  
Marianne Lemoine-Goumard ◽  
Thierry Reposeur ◽  
Keyword(s):  
Supernova Remnants ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
High Energy ◽  
Radio Spectrum ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Large Area ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Γ Ray

AbstractThe supernova remnant (SNR) Puppis A (aka G260.4-3.4) is a middle-aged supernova remnant, which displays increasing X-ray surface brightness from West to East corresponding to an increasing density of the ambient interstellar medium at the Eastern and Northern shell. The dense IR photon field and the high ambient density around the remnant make it an ideal case to study in γ-rays. Gamma-ray studies based on three years of observations with the Large Area Telescope (LAT) aboard Fermi have revealed the high energy gamma-ray emission from SNR Puppis A. The γ-ray emission from the remnant is spatially extended, and nicely matches the radio and X-ray morphologies. Its γ-ray spectrum is well described by a simple power law with an index of ~2.1, and it is among the faintest supernova remnants yet detected at GeV energies. To constrain the relativistic electron population, seven years of Wilkinson Microwave Anisotropy Probe (WMAP) data were also analyzed, and enabled to extend the radio spectrum up to 93 GHz. The results obtained in the radio and γ-ray domains are described in detail, as well as the possible origins of the high energy γ-ray emission (Bremsstrahlung, Inverse Compton scattering by electrons or decay of neutral pions produced by proton interactions).

scholarly journals Interaction between molecular clouds and MeV–TeV cosmic-ray protons escaped from supernova remnants

2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Ken Makino ◽  
Yutaka Fujita ◽  
Kumiko K Nobukawa ◽  
Hironori Matsumoto ◽  
Yutaka Ohira
Keyword(s):  
Gamma Rays ◽  
Molecular Clouds ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Iron Line ◽  
X Ray ◽  
Line Intensities ◽  
Neutral Gas ◽  
Additional Support

Abstract Recent discovery of the X-ray neutral iron line (Fe  i Kα at 6.40 keV) around several supernova remnants (SNRs) show that MeV cosmic-ray (CR) protons are distributed around the SNRs and are interacting with neutral gas there. We propose that these MeV CRs are the ones that have been accelerated at the SNRs together with GeV–TeV CRs. In our analytical model, the MeV CRs are still confined in the SNR when the SNR collides with molecular clouds. After the collision, the MeV CRs leak into the clouds and produce the neutral iron line emissions. On the other hand, GeV–TeV CRs had already escaped from the SNRs and emitted gamma-rays through interaction with molecular clouds surrounding the SNRs. We apply this model to the SNRs W 28 and W 44 and show that it can reproduce the observations of the iron line intensities and the gamma-ray spectra. This could be additional support of the hadronic scenario for the gamma-ray emissions from these SNRs.

scholarly journals DIVISION D COMMISSION 44: SPACE AND HIGH-ENERGY ASTROPHYSICS

2015 ◽  
Vol 11 (T29A) ◽  
pp. 219-244
Author(s):  
Christine Jones ◽  
Noah Brosch ◽  
Günther Hasinger ◽  
Matthew G. Baring ◽  
Martin Adrian Barstow ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
High Energy Astrophysics ◽  
X Ray ◽  
Neutrino Detectors ◽  
Gamma Ray Astronomy ◽  
The Hague ◽  
Almost All ◽  
Modern Astronomy

Division XI, the predecessor to Division D until 2012, was formed in 1994 at the IAU General Assembly in The Hague by merging Commission 44 Astronomy from Space and Commission 48 High Energy Astrophysics. Historically, space astrophysics started with the high energy wavelengths (far UV, X-ray, and gamma-ray astronomy) which are only accessible from space. However, in modern astronomy, to study high energy astrophysical processes, almost all wavelengths are used (including gamma-ray, X-ray, UV, optical, infrared, submillimeter and radio). In addition other ground-based facilities, including gravitational wave antennas, neutrino detectors and high-energy cosmic ray arrays are joining in this era of multi-messenger astrophysics, as well as space missions with the primary goals to discover and study exoplanets, are under the umbrella of Division XI.

Radiation Hard Devices Based on SiC

2006 ◽  
Vol 527-529 ◽  
pp. 1473-1476 ◽  
Author(s):  
Evgenia V. Kalinina ◽  
Anatoly M. Strel'chuk ◽  
Alexander A. Lebedev ◽  
Nikita B. Strokan ◽  
Alexander M. Ivanov ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Signal Amplitude ◽  
High Energy ◽  
Pair Creation ◽  
Transistor Structure ◽  
Electron Hole ◽  
X Ray ◽  
Electron Hole Pair ◽  
Radiation Hard ◽  
High Energy Particles

The effect of irradiation with protons, electrons, neutrons, x-ray radiation and gamma-ray photons as well as with different ions on properties of starting SiC material and devices based on it was studied. The rectifying properties of the diode structures, which degraded as a result of irradiation with high energy particles, were recovered at higher operation temperatures. The transistor structure SiC-based detectors were realized with the signal amplification by a factor of tens under irradiation. The energy resolution of 0.34 %, commensurable with Si-detectors, has been achieved for SiC detectors and is correct for all classes of short range ions. The maximum signal amplitude corresponds, in SiC, to a mean electron-hole pair creation energy of 7.7 eV.

scholarly journals High energy cosmic photons and neutrinos

1965 ◽  
Vol 23 ◽  
pp. 195-225
Author(s):  
R. J. Gould ◽  
G. R. Burbidge
Keyword(s):  
Supernova Remnants ◽  
Crab Nebula ◽  
Meson Production ◽  
Cosmic Ray ◽  
High Energy ◽  
Relativistic Electrons ◽  
X Ray ◽  
Hard Radiation ◽  
The Galaxy ◽  
The Crab Nebula

This review concentrates primarily on the problem of interpreting the recent X-ray and γ-ray observations of celestial sources. The expected fluxes of hard radiation from various processes are estimated (when possible) and are compared with the observations. We compute the synchrotron, bremsstrahlung, and (inverse) Compton spectra originating from relativistic electrons produced (via meson production) in the galaxy and intergalactic medium by cosmic ray nuclear collisions; the spectra from π°-decay are also computed. Neutron stars, stellar coronae, and supernova remnants are reviewed as possible X-ray sources. Special consideration is given to the processes in the Crab Nebula. Extragalactic objects as discrete sources of energetic photons are considered on the basis of energy requirements; special emphasis is given to the strong radio sources and the possibility of the emission of hard radiation during their formation. The problem of the detection of cosmic neutrinos is reviewed.As yet, no definite process can be identified with any of the observed fluxes of hard radiation, although a number of relevant conclusions can be drawn on the basis of the available preliminary observational results. In particular, some cosmogonical theories can be tested.

scholarly journals Search for Nonthermal X-Rays from Supernova Remnant Shells

1998 ◽  
Vol 188 ◽  
pp. 117-120
Author(s):  
R. Petre ◽  
J. Keohane ◽  
U. Hwang ◽  
G. Allen ◽  
E. Gotthelf
Keyword(s):  
Radio Emission ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Cosmic Ray ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Nonthermal Radio ◽  
Cosmic Ray Acceleration ◽  
Nonthermal Radio Emission

The suggestion that the shocks of supernova remnants (SNR's) are cosmic ray acceleration sites dates back more than 40 years. While observations of nonthermal radio emission from SNR shells indicate the ubiquity of GeV cosmic ray production, there is still theoretical debate about whether SNR shocks accelerate particles up to the well-known “knee” in the primary cosmic ray spectrum at ~3,000 TeV. Recent X-ray observations of SN1006 and other SNR's may have provided the missing observational link between SNR shocks and high energy cosmic ray acceleration. We discuss these observations and their interpretation, and summarize our ongoing efforts to find evidence from X-ray observations of cosmic ray acceleration in the shells of other SNR's.

scholarly journals Less noticeable shallow decay phase in early X-ray afterglows of GeV/TeV-detected gamma-ray bursts

2020 ◽  
Vol 494 (4) ◽  
pp. 5259-5269 ◽  
Author(s):  
Ryo Yamazaki ◽  
Yuri Sato ◽  
Takanori Sakamoto ◽  
Motoko Serino
Keyword(s):  
Power Law ◽  
Gamma Ray ◽  
High Energy ◽  
Decay Phase ◽  
Power Law Model ◽  
X Ray ◽  
High Energy Gamma ◽  
Very High Energy ◽  
Energy Gamma ◽  
Very High

ABSTRACT The nature of the shallow decay phase in the X-ray afterglow of the gamma-ray burst (GRB) is not yet clarified. We analyse the data of early X-ray afterglows of 26 GRBs triggered by Burst Alert Telescope onboard Neil Gehrels Swift Observatory and subsequently detected by Fermi Large Area Telescope (LAT) and/or Imaging Atmospheric Cherenkov Telescopes. It is found that nine events (including two out of three very-high-energy gamma-ray events) have no shallow decay phase and that their X-ray afterglow light curves are well described by single power-law model except for the jet break at later epoch. The rest are fitted by double power-law model and have a break in the early epoch (around ks), however, eight events (including a very-high-energy gamma-ray event) have the pre-break decay index larger than 0.7. We also analyse the data of well-sampled X-ray afterglows of GRBs without LAT detection and compare their decay properties with those of high-energy and very-high-energy gamma-ray events. It is found that for the GeV/TeV bursts, the fraction of events whose X-ray afterglows are described by single power law is significantly larger than those for non-GeV/TeV GRBs. Even if the GeV/TeV GRBs have shallow decay phase, their decay slope tends to be steeper than non-GeV/TeV bursts, that is, they have less noticeable shallow decay phase in the early X-ray afterglow. A possible interpretation along with the energy injection model is briefly discussed.

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