X-ray and gamma-ray studies of particle acceleration in supernova remnants

2012 ◽  
Author(s):  
Takaaki Tanaka ◽  
Fermi LAT Collaboration
2013 ◽  
Vol 9 (S296) ◽  
pp. 295-299
Author(s):  
Marie-Hélène Grondin ◽  
John W. Hewitt ◽  
Marianne Lemoine-Goumard ◽  
Thierry Reposeur ◽  

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).


2019 ◽  
Vol 485 (3) ◽  
pp. 4287-4310 ◽  
Author(s):  
Samuel W Jones ◽  
Heiko Möller ◽  
Chris L Fryer ◽  
Christopher J Fontes ◽  
Reto Trappitsch ◽  
...  

Abstract We investigate 60Fe in massive stars and core-collapse supernovae focussing on uncertainties that influence its production in 15, 20, and 25 M$\odot$ stars at solar metallicity. We find that the 60Fe yield is a monotonic increasing function of the uncertain 59Fe(n, γ)60Fe cross-section and that a factor of 10 reduction in the reaction rate results in a factor of 8–10 reduction in the 60Fe yield, while a factor of 10 increase in the rate increases the yield by a factor of 4–7. We find that none of the 189 simulations we have performed are consistent with a core-collapse supernova triggering the formation of the Solar system, and that only models using 59Fe(n, γ)60Fe cross-section that is less than or equal to that from NON-SMOKER can reproduce the observed 60Fe/26Al line flux ratio in the diffuse interstellar medium. We examine the prospects of detecting old core-collapse supernova remnants (SNRs) in the Milky Way from their gamma-ray emission from the decay of 60Fe, finding that the next generation of gamma-ray missions could be able to discover up to ∼100 such old SNRs as well as measure the 60Fe yields of a handful of known Galactic SNRs. We also predict the X-ray spectrum that is produced by atomic transitions in 60Co following its ionization by internal conversion and give theoretical X-ray line fluxes as a function of remnant age as well as the Doppler and fine-structure line broadening effects. The X-ray emission presents an interesting prospect for addressing the missing SNR problem with future X-ray missions.


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.


Author(s):  
J. A. Hinton ◽  
R. L. C. Starling

Cosmic explosions dissipate energy into their surroundings on a very wide range of time scales: producing shock waves and associated particle acceleration. The historical culprits for the acceleration of the bulk of Galactic cosmic rays are supernova remnants: explosions on approximately 10 4 year time scales. Increasingly, however, time-variable emission points to rapid and efficient particle acceleration in a range of different astrophysical systems. Gamma-ray bursts have the shortest time scales, with inferred bulk Lorentz factors of approximately 1000 and photons emitted beyond 100 GeV, but active galaxies, pulsar wind nebulae and colliding stellar winds are all now associated with time-variable emission at approximately teraelectron volt energies. Cosmic photons and neutrinos at these energies offer a powerful probe of the underlying physical mechanisms of cosmic explosions, and a tool for exploring fundamental physics with these systems. Here, we discuss the motivations for high-energy observations of transients, the current experimental situation, and the prospects for the next decade, with particular reference to the major next-generation high-energy observatory, the Cherenkov Telescope Array.


2009 ◽  
Author(s):  
Jacco Vink ◽  
Jéro^me Rodriguez ◽  
Phillippe Ferrando

2000 ◽  
Vol 177 ◽  
pp. 703-706
Author(s):  
B. M. Gaensler

AbstractI consider the state of play regarding associations of supernova remnants (SNRs) with anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs). The three AXP/SNR associations are convincing, and are consistent with AXPs being young, low-velocity neutron stars. The three SGR/SNR associations are far more likely to be chance superpositions, and rely on SGRs being high velocity (>1000 km s−1) objects. These results imply either that AXPs evolve into SGRs, or that SGRs and AXPs represent different populations of object.


2018 ◽  
Vol 612 ◽  
pp. A14 ◽  
Author(s):  
◽  
M. L. Ahnen ◽  
S. Ansoldi ◽  
L. A. Antonelli ◽  
C. Arcaro ◽  
...  

Context. The large jet kinetic power and non-thermal processes occurring in the microquasar SS 433 make this source a good candidate for a very high-energy (VHE) gamma-ray emitter. Gamma-ray fluxes above the sensitivity limits of current Cherenkov telescopes have been predicted for both the central X-ray binary system and the interaction regions of SS 433 jets with the surrounding W50 nebula. Non-thermal emission at lower energies has been previously reported, indicating that efficient particle acceleration is taking place in the system.Aim. We explore the capability of SS 433 to emit VHE gamma rays during periods in which the expected flux attenuation due to periodic eclipses (Porb~ 13.1 days) and precession of the circumstellar disk (Ppre ~ 162 days) periodically covering the central binary system is expected to be at its minimum. The eastern and western SS 433/W50 interaction regions are also examined using the whole data set available. We aim to constrain some theoretical models previously developed for this system with our observations.Methods. We made use of dedicated observations from the Major Atmospheric Gamma Imaging Cherenkov telescopes (MAGIC) and High Energy Spectroscopic System (H.E.S.S.) of SS 433 taken from 2006 to 2011. These observation were combined for the first time and accounted for a total effective observation time of 16.5 h, which were scheduled considering the expected phases of minimum absorption of the putative VHE emission. Gamma-ray attenuation does not affect the jet/medium interaction regions. In this case, the analysis of a larger data set amounting to ~40–80 h, depending on the region, was employed.Results. No evidence of VHE gamma-ray emission either from the central binary system or from the eastern/western interaction regions was found. Upper limits were computed for the combined data set. Differential fluxes from the central system are found to be ≲ 10−12–10−13 TeV−1 cm−2 s−1 in an energy interval ranging from ~few × 100 GeV to ~few TeV. Integral flux limits down to ~ 10−12–10−13 ph cm−2 s−1 and ~ 10−13–10−14 ph cm−2 s−1 are obtainedat 300 and 800 GeV, respectively. Our results are used to place constraints on the particle acceleration fraction at the inner jetregions and on the physics of the jet/medium interactions.Conclusions. Our findings suggest that the fraction of the jet kinetic power that is transferred to relativistic protons must be relatively small in SS 433, qp ≤ 2.5 × 10−5, to explain the lack of TeV and neutrino emission from the central system. At the SS 433/W50 interface, the presence of magnetic fields ≳10 μG is derived assuming a synchrotron origin for the observed X-ray emission. This also implies the presence of high-energy electrons with Ee− up to 50 TeV, preventing an efficient production of gamma-ray fluxes in these interaction regions.


2001 ◽  
Vol 559 (2) ◽  
pp. 963-972 ◽  
Author(s):  
B. M. Gaensler ◽  
P. O. Slane ◽  
E. V. Gotthelf ◽  
G. Vasisht
Keyword(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.


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