scholarly journals Secondary-electron radiation accompanying hadronic GeV–TeV gamma-rays from supernova remnants

2020 ◽  
Vol 492 (3) ◽  
pp. 4246-4253 ◽  
Author(s):  
Yan Huang ◽  
Zhuo Li ◽  
Wei Wang ◽  
Xiaohong Zhao
Keyword(s):  
Synchrotron Radiation ◽  
Gamma Rays ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Far Infrared ◽  
Hadronic Interactions ◽  
Electrons And Positrons ◽  
Tev Gamma Rays ◽  
The Magnetic Field

ABSTRACT The synchrotron radiation from secondary electrons and positrons (SEPs) generated by hadronic interactions in the shock of supernova remnant (SNR) could be a distinct evidence of cosmic ray (CR) production in SNR shocks. Here, we provide a method where the observed gamma-ray flux from SNRs, created by pion decays, is directly used to derive the SEP distribution and hence the synchrotron spectrum. We apply the method to three gamma-ray bright SNRs. In the young SNR RX J1713.7−3946, if the observed GeV−TeV gamma-rays are of hadronic origin and the magnetic field in the SNR shock is B ≳ 0.5 mG, the SEPs may produce a spectral bump at 10−5–10−2 eV, exceeding the predicted synchrotron component of the leptonic model, and a soft spectral tail at ≳100 keV, distinct from the hard spectral slope in the leptonic model. In the middle-aged SNRs IC443 and W44, if the observed gamma-rays are of hadronic origin, the SEP synchrotron radiation with B ∼ 400–500 μG can well account for the observed radio flux and spectral slopes, supporting the hadronic origin of gamma-rays. Future microwave to far-infrared and hard X-ray (>100keV) observations are encouraged to constraining the SEP radiation and the gamma-ray origin in SNRs.

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 Linking supernovae and supernova remnants. Time-dependent injection in SN1987A and gamma-ray spectrum of IC443

2017 ◽  
Vol 12 (S331) ◽  
pp. 268-273
Author(s):  
O. Petruk ◽  
S. Orlando ◽  
M. Miceli
Keyword(s):  
Gamma Rays ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Supernova Explosion ◽  
Cosmic Ray ◽  
Proton Spectrum ◽  
Stationary Equation ◽  
Particle Injection ◽  
Particle Momentum ◽  
Number Of Particles

AbstractAcceleration times of particles responsible for the gamma-rays in supernova remnants (SNRs) are comparable with SNR age. If the number of particles starting acceleration was varying during early times after the supernova explosion then this variation should be reflected in the shape of the gamma-ray spectrum. In order to analyse this effect, we consider the time variation of the radio spectral index in SN1987A and solution of the non-stationary equation for particle acceleration. We reconstruct evolution of the particle injection in SN1987A, apply it to derive the particle momentum distribution in IC443 and model its gamma-ray spectrum. We show that: i) observed break in the proton spectrum around 50 GeV in IC443 is a consequence of the variation of the cosmic ray injection; ii) shape of the hadronic gamma-ray spectrum in SNRs critically depends on the temporal variation of the cosmic ray injection in the immediate post explosion phases.

scholarly journals Gamma-rays from reaccelerated particles at supernova remnant shocks

2019 ◽  
Vol 489 (1) ◽  
pp. 108-115 ◽  
Author(s):  
P Cristofari ◽  
P Blasi
Keyword(s):  
Gamma Rays ◽  
Supernova Remnants ◽  
Large Scale ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Shock Acceleration ◽  
X Rays ◽  
Diffusive Shock Acceleration ◽  
Particle In Cell ◽  
Large Scale Magnetic Field

ABSTRACT Diffusive shock acceleration is considered as the main mechanism for particle energization in supernova remnants, as well as in other classes of sources. The existence of some remnants that show a bilateral morphology in the X-rays and gamma-rays suggests that this process occurs with an efficiency that depends upon the inclination angle between the shock normal and the large-scale magnetic field in which the shock propagates. This interpretation is additionally supported by recent particle-in-cell simulations that show how ions are not injected if the shock is more oblique than ∼45°. These shocks provide an excellent test bench for the process of reacceleration at the same shock: non-thermal seed particles that are reached by the shock front are automatically injected and accelerated. This process was recently discussed as a possible reason for some anomalous behaviour of the spectra of secondary cosmic ray nuclei. Here, we discuss how gamma-ray observations of selected supernova remnants can provide us with precious information about this process and lead us to a better assessment of particle diffusive shock reacceleration for other observables in cosmic ray physics.

scholarly journals Supernova remnants and the origin of cosmic rays

2013 ◽  
Vol 9 (S296) ◽  
pp. 305-314
Author(s):  
Jacco Vink
Keyword(s):  
Synchrotron Radiation ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Long Time ◽  
Gamma Ray Emission

AbstractSupernova remnants have long been considered to be the dominant sources of Galactic cosmic rays. For a long time the prime evidence consisted of radio synchrotron radiation from supernova remnants, indicating the presence of electrons with energies of several GeV. However, in order to explain the cosmic ray energy density and spectrum in the Galaxy supernova remnant should use 10% of the explosion energy to accelerate particles, and about 99% of the accelerated particles should be protons and other atomic nuclei.Over the last decade a lot of progress has been made in providing evidence that supernova remnant can accelerate protons to very high energies. The evidence consists of, among others, X-ray synchrotron radiation from narrow regions close to supernova remnant shock fronts, indicating the presence of 10-100 TeV electrons, and providing evidence for amplified magnetic fields, gamma-ray emission from both young and mature supernova remnants. The high magnetic fields indicate that the condition for accelerating protons to >1015 eV are there, whereas the gamma-ray emission from some mature remnants indicate that protons have been accelerated.

scholarly journals Star-forming galaxies dominate the diffuse, isotropic γ-ray background

2020 ◽  
Author(s):  
Matt Roth ◽  
Mark Krumholz ◽  
Roland Crocker ◽  
Silvia Celli
Keyword(s):  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Far Infrared ◽  
Small Sample ◽  
Physical Models ◽  
Dark Matter Annihilation ◽  
Star Forming ◽  
Γ Ray ◽  
The Many

Abstract The Fermi Gamma Ray Space Telescope has revealed a diffuse, isotropic γ-ray background at energies ranging from 0.1 GeV to 1 TeV [1] whose astrophysical sources remain uncertain. Previous efforts to understand the origin of this background have been hampered by the lack of physical models capable of predicting the γ-ray emission produced by the many candidate sources, which include star-forming galaxies (SFGs) [2–6], active galactic nuclei (particularly blazars [7–9]), millisecond pulsars[7], and dark matter annihilation [10]. In the absence of predictive models, estimates of the contribution from potential sources have relied on a highly-uncertain process of empirically scaling the emission from a small sample of local, resolved sources by their estimated cosmological abundances. Here we present the first calculation of the contribution of SFGs to the γ-ray background that is based on a physical model for the γ-ray emission produced when cosmic ray ions accelerated in supernova remnants interact with the interstellar medium [11]. We validate the model by showing that it reproduces the γ-ray spectra, source count distribution and far infrared-γ-ray correlation observed for nearby, resolved SFGs. When we apply the model to the observed cosmological SFG population, we recover an excellent match to the γ-ray background from 1 GeV to 1 TeV. Our result shows that SFGs alone can explain the full diffuse γ-ray background over this energy range, and strongly suggests that emission in excess of our model at energies <1 GeV originates from cosmic ray electrons produced in the same galaxies.

scholarly journals Cosmic ray origin: Supernova remnants through the electromagnetic spectrum

2019 ◽  
Vol 208 ◽  
pp. 04006
Author(s):  
V. G. Sinitsyna ◽  
S.S. Borisov ◽  
R. M. Mirzafatikhov ◽  
V. Y. Sinitsyna
Keyword(s):  
Experimental Data ◽  
Gamma Rays ◽  
Supernova Remnants ◽  
Cosmic Ray ◽  
High Energy ◽  
Electromagnetic Spectrum ◽  
Tev Gamma Rays ◽  
Cas A ◽  
Tycho’S Snr ◽  
Observation Results

Supernova Remnants have long been considered as unique candidates for cosmic-ray sources. Recent observations of several SNRs in X-rays and TeV gamma-rays will help in solving the problem of the origin of cosmic rays and are key to understanding the mechanism of particle acceleration at a propagating shock wave. The observation results of Galactic shell-type supernova remnants at different evolution stages Cas A, Tycho's SNR, γCygni SNR, IC 443 and G166.0+4.3 by the SHALON mirror Cherenkov telescope are presented. For each SNR the SHALON observation results are given with its spectral energy distribution compared with other experimental data and images by SHALON together with data from X-ray by Chandra and radio-data by Canadian Galactic Plane Survey DRAO (CGPS). The comparison of the source's morphology in different energy bands could reveal its essential features as a forward and reverse shock or the location of swept out dense molecular cloud. The experimental data presented here have confirmed the prediction of the theory about the hadronic generation mechanism of very high energy 800 GeV-100 TeV gamma-rays in Tycho's SNR, Cas A and IC 443. Also the collected experimental data help to make clear the origin of TeV gamma-ray emission in the SNRs like γCygni SNR and G166.0+4.3.

scholarly journals An interacting molecular cloud scenario for production of gamma-rays and neutrinos from MAGIC J1835-069, and MAGIC J1837-073

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Prabir Banik ◽  
Arunava Bhadra
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Molecular Cloud ◽  
Gamma Ray ◽  
Galactic Plane ◽  
Cosmic Ray ◽  
Maximum Energy ◽  
Hadronic Interactions ◽  
Extended Sources ◽  
First Time

AbstractRecently the MAGIC telescope observed three TeV gamma-ray extended sources in the galactic plane in the neighborhood of radio SNR G24.7+0.6. Among them, the PWN HESS J1837-069 was detected earlier by the HESS observatory during its first galactic plane survey. The other two sources, MAGIC J1835-069 and MAGIC J1837-073 are detected for the first time at such high energies. Here we shall show that the observed gamma-rays from the SNR G24.7+0.6 and the HESS J1837-069 can be explained in terms of hadronic interactions of the PWN/SNR accelerated cosmic rays with the ambient matter. We shall further demonstrate that the observed gamma-rays from the MAGIC J1837-073 can be interpreted through hadronic interactions of runaway cosmic-rays from PWN HESS J1837-069 with the molecular cloud at the location of MAGIC J1837-073. No such association has been found between MAGIC J1835-069 and SNR G24.7+0.6 or PWN HESS J1837-069. We have examined the maximum energy attainable by cosmic-ray particles in the SNR G24.7+0.6/ PWN HESS J1837-069 and the possibility of their detection with future gamma-ray telescopes. The study of TeV neutrino emissions from the stated sources suggests that the HESS J1837-069 should be detected by IceCube Gen-2 neutrino telescope in a few years of observation.

scholarly journals TeV Gamma Rays from Ultrahigh Energy Cosmic Ray Interactions in the Cores of Active Galactic Nuclei: Lessons from Centaurus A

2010 ◽  
Vol 27 (4) ◽  
pp. 482-489 ◽  
Author(s):  
M. Kachelrieß ◽  
S. Ostapchenko ◽  
R. Tomàs
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Rays ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
Far Infrared ◽  
High Energy ◽  
Ultrahigh Energy ◽  
Very High Energy ◽  
Tev Gamma Rays ◽  
Centaurus A

AbstractTeV gamma rays have been observed from blazars as well as from radio galaxies like M 87 and Centaurus A. In leptonic models, gamma rays above the pair production threshold can escape from the ultrarelativistic jet, because large Lorentz factors reduce the background photon densities compared to those required for isotropic emission. Here we discuss an alternative scenario, where very high energy photons are generated as secondaries from ultrahigh energy cosmic rays interactions in the cores of active galactic nuclei. We show that TeV gamma-rays can escape from the core despite large infrared and ultraviolet backgrounds. For the special case of Centaurus A, we study whether the various existing observations from the far infrared to the ultrahigh energy range can be reconciled within this picture.

scholarly journals Constraining the coherence scale of the interstellar magnetic field using TeV gamma-ray observations of supernova remnants

2020 ◽  
Vol 496 (2) ◽  
pp. 2448-2461 ◽  
Author(s):  
Matteo Pais ◽  
Christoph Pfrommer ◽  
Kristian Ehlert ◽  
Maria Werhahn ◽  
Georg Winner
Keyword(s):  
Magnetic Field ◽  
Interstellar Medium ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Galactic Cosmic Rays ◽  
Shock Acceleration ◽  
Interstellar Gas ◽  
Narrow Angle ◽  
Magnetohydrodynamic Simulations ◽  
Tev Gamma Rays

ABSTRACT Galactic cosmic rays (CRs) are believed to be accelerated at supernova remnant (SNR) shocks. In the hadronic scenario, the TeV gamma-ray emission from SNRs originates from decaying pions that are produced in collisions of the interstellar gas and CRs. Using CR-magnetohydrodynamic simulations, we show that magnetic obliquity-dependent shock acceleration is able to reproduce the observed TeV gamma-ray morphology of SNRs such as Vela Jr and SN1006 solely by varying the magnetic morphology. This implies that gamma-ray bright regions result from quasi-parallel shocks (i.e. when the shock propagates at a narrow angle to the upstream magnetic field), which are known to efficiently accelerate CR protons, and that gamma-ray dark regions point to quasi-perpendicular shock configurations. Comparison of the simulated gamma-ray morphology to observations allows us to constrain the magnetic coherence scale λB around Vela Jr and SN1006 to $\lambda _B \simeq 13_{-4.3}^{+13}$ pc and $\lambda _B \gt 200_{-40}^{+50}$ pc, respectively, where the ambient magnetic field of SN1006 is consistent with being largely homogeneous. We find consistent pure hadronic and mixed hadronic-leptonic models that both reproduce the multifrequency spectra from the radio to TeV gamma-rays and match the observed gamma-ray morphology. Finally, to capture the propagation of an SNR shock in a clumpy interstellar medium, we study the interaction of a shock with a dense cloud with numerical simulations and analytics. We construct an analytical gamma-ray model for a core collapse SNR propagating through a structured interstellar medium, and show that the gamma-ray luminosity is only biased by 30 per cent for realistic parameters.

scholarly journals Radio jets and gamma-ray emission in radio-silent narrow-line Seyfert 1 galaxies

2018 ◽  
Vol 614 ◽  
pp. L1 ◽  
Author(s):  
A. Lähteenmäki ◽  
E. Järvelä ◽  
V. Ramakrishnan ◽  
M. Tornikoski ◽  
J. Tammi ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Spiral Galaxies ◽  
Narrow Line ◽  
Radio Jets ◽  
Relativistic Jet ◽  
Gamma Ray Emission

We have detected six narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz that were previously classified as radio silent and two that were classified as radio quiet. These detections reveal the presumption that NLS1 galaxies labelled radio quiet or radio silent and hosted by spiral galaxies are unable to launch jets to be incorrect. The detections are a plausible indicator of the presence of a powerful, most likely relativistic jet because this intensity of emission at 37 GHz cannot be explained by, for example, radiation from supernova remnants. Additionally, one of the detected NLS1 galaxies is a newly discovered source of gamma rays and three others are candidates for future detections.

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