Thermal X-Ray Emission and Cosmic-Ray Production in Young Supernova Remnants

2000 ◽  
Vol 543 (1) ◽  
pp. L57-L60 ◽  
Author(s):  
Anne Decourchelle ◽  
Donald C. Ellison ◽  
Jean Ballet
Keyword(s):  
Author(s):  
Ken Makino ◽  
Yutaka Fujita ◽  
Kumiko K Nobukawa ◽  
Hironori Matsumoto ◽  
Yutaka Ohira

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.


2005 ◽  
Vol 632 (2) ◽  
pp. 920-931 ◽  
Author(s):  
Donald C. Ellison ◽  
Gamil Cassam‐Chenai
Keyword(s):  

1965 ◽  
Vol 23 ◽  
pp. 195-225
Author(s):  
R. J. Gould ◽  
G. R. Burbidge

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.


1998 ◽  
Vol 188 ◽  
pp. 117-120
Author(s):  
R. Petre ◽  
J. Keohane ◽  
U. Hwang ◽  
G. Allen ◽  
E. Gotthelf

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.


2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Hiromasa Suzuki ◽  
Aya Bamba ◽  
Ryo Yamazaki ◽  
Yutaka Ohira

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.


2013 ◽  
Vol 9 (S296) ◽  
pp. 315-319
Author(s):  
Marco Miceli ◽  
F. Bocchino ◽  
A. Decourchelle ◽  
G. Maurin ◽  
J. Vink ◽  
...  

AbstractSupernova remnant shocks are strong candidates for being the source of energetic cosmic rays and hadron acceleration is expected to increase the shock compression ratio, providing higher post-shock densities. We exploited the deep observations of the XMM-Newton Large Program on SN 1006 to verify this prediction. Spatially resolved spectral analysis led us to detect X-ray emission from the shocked ambient medium in SN 1006 and to find that its density significantly increases in regions where particle acceleration is efficient. Our results provide evidence for the effects of acceleration of cosmic ray hadrons on the post-shock plasma in supernova remnants.


2000 ◽  
Vol 195 ◽  
pp. 69-76
Author(s):  
R. Petre ◽  
G. E. Allen ◽  
U. Hwang ◽  
J. W. Keohane ◽  
E. V. Gotthelf

X-ray observations over the past several years have led to the discovery of nonthermal X-ray emission arising in the shells of many young supernova remnants, including SN 1006, Cas A, and Tycho. This emission is thought to be synchrotron emission from electrons that have been shock accelerated to hundreds of TeV, and thus represents strong evidence that cosmic rays are accelerated in SNR shocks. The X-ray observations are corroborated by detection of TeV gamma rays from two of these remnants. A systematic investigation of young, shell-like remnants suggests that the nonthermal X-ray emission from shock-accelerated electrons is a common, if not ubiquitous, feature. We review the status of the X-ray observations and describe how they can be used to provide insight into the shock acceleration process.


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