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OH(1720 MHz) masers are excellent signposts of interaction between supernova remnants(SNRs) and molecular clouds. Using the GBT and VLA we have surveyed 75 SNRs and six candidates for maser emission. Four new interacting SNRs are detected…

Astrophysics of Galaxies · Physics 2009-11-13 John W. Hewitt , Farhad Yusef-Zadeh

Galactic cosmic rays (CRs) are accelerated at the forward shocks of supernova remnants (SNRs) via diffusive shock acceleration (DSA), an efficient acceleration mechanism that predicts power-law energy distributions of CRs. However,…

High Energy Astrophysical Phenomena · Physics 2021-11-24 Rebecca Diesing , Damiano Caprioli

Recent observations of the supernova remnant W44 by the \emph{Fermi} spacecraft observatory strongly support the idea that the bulk of galactic cosmic rays is accelerated in such remnants by a Fermi mechanism, also known as diffusive shock…

High Energy Astrophysical Phenomena · Physics 2011-03-04 M. A. Malkov , P. H. Diamond , R. Z. Sagdeev

The origin of the bulk of cosmic rays (CRs) observed at Earth is the topic of a century long investigation, paved with successes and failures. From the energetic point of view, supernova remnants (SNRs) remain the most plausible sources of…

High Energy Astrophysical Phenomena · Physics 2016-12-09 Pasquale Blasi

The Supernova Remnant (SNR) HESS J1731-347 displays strong non-thermal TeV gamma-ray and X-ray emission, thus the object is at present time accelerating particles to very high energies. A distinctive feature of this young SNR is the nearby…

High Energy Astrophysical Phenomena · Physics 2016-06-22 Y. Cui , G. Pühlhofer , A. Santangelo

Supernova remnants (SNRs) have been considered as the dominant contributors to Galactic cosmic rays. However, the relation between high-energy particles trapped in SNRs and cosmic rays observed at the Earth remains obscure. In this paper,…

High Energy Astrophysical Phenomena · Physics 2019-03-27 Houdun Zeng , Yuliang Xin , Siming Liu

The EGRET results for gamma-ray intensities in and near the Galactic Plane have been analysed in some detail. Attention has been concentrated on energies above 1 GeV and the individual intensities in a $4^\circ$ longitude bin have been…

Astrophysics · Physics 2009-11-11 A. D. Erlykin , A. W. Wolfendale

Supernova remnants (SNRs) are the outcome of supernovae (SNe, either core-collapse or thermonuclear). The remnant results from the interaction between the stellar ejecta and the ambient medium around the progenitor star. Young SNRs are…

High Energy Astrophysical Phenomena · Physics 2020-02-18 Gilles Ferrand

The proof of cosmic ray (CR) origin in supernova remnants (SNR) must hinge on full consistency of the CR acceleration theory with the observations; direct proof is impossible because of the orbit stochasticity of CR particles. Recent…

Astrophysics of Galaxies · Physics 2016-10-11 M. A. Malkov , P. H. Diamond , R. Z. Sagdeev

We report the extended GeV $\gamma$-ray emission around the high Galactic latitude supernova remnant (SNR) DA 530 with the PASS 8 data recorded by the Fermi Large Area Telescope (Fermi-LAT). The $\gamma$-ray spectrum in the energy range of…

High Energy Astrophysical Phenomena · Physics 2023-09-13 Yuliang Xin , Xiaolei Guo

Aims. Two-dimensional MHD simulations are used to model the emission properties of TeV-bright shell-type supernova remnants (SNRs) and to explore their nature. Methods. In the leptonic scenario for the TeV emission, the $\gamma$-ray…

High Energy Astrophysical Phenomena · Physics 2014-12-17 Chuyuan Yang , Siming Liu , Jun Fang , Hui Li

The emission mechanism for hard $\gamma$-ray spectra from supernova remnants (SNRs) is still a matter of debate. Recent multi-wavelength observations of TeV source HESS J1912+101 show that it is associated with an SNR with an age of $\sim…

High Energy Astrophysical Phenomena · Physics 2021-04-07 Houdun Zeng , Yuliang Xin , Shuinai Zhang , Siming Liu

We model the transport of cosmic ray nuclei in the Galaxy by means of a new numerical code. Differently from previous numerical models we account for a generic spatial distribution of the diffusion coefficient. We found that in the case of…

Astrophysics · Physics 2016-05-19 C. Evoli , D. Gaggero , D. Grasso , L. Maccione

A considerable fraction of Galactic supernova remnants (SNRs) characterize flat spectral indices ($\alpha<0.5$). There are several explanations of the flat radio spectra of SNRs in the present literature. The most of models involve a…

Astrophysics of Galaxies · Physics 2015-06-15 D. Onic

It is difficult to distinguish hadronic process from the leptonic one in $\gamma$-ray observation, which is however crucial in revealing the origin of cosmic rays. As an endeavor in the regard, we focus in this work on the complex…

High Energy Astrophysical Phenomena · Physics 2022-06-08 Xiao Zhang , Yang Chen , Fa-xiang Zheng , Qian-cheng Liu , Ping Zhou , Bing Liu

We present a detailed analysis of $\gamma$-ray emission from the middle-aged supernova remnant (SNR) S147 (G180.0$-$1.7) using approximately 16.5 years of Fermi-LAT data. Spatially, a new extended $\gamma$-ray component distinct from the…

High Energy Astrophysical Phenomena · Physics 2026-01-29 Huan Yang , Bing Liu , Houdun Zeng , Xiaoyuan Huang

Supernova Remnants (SNRs) are believed to be the main source of Galactic cosmic rays (CR). The strong SNR shocks provide ideal acceleration sites for particles of at least 10^14 eV/nucleon. Radio continuum studies of SNRs carried out with…

High Energy Astrophysical Phenomena · Physics 2011-11-08 G. Dubner

It is widely believed that supernova remnants are the best candidate sources for the observed cosmic ray flux up to the knee, i.e. up to ~PeV energies. Indeed, the gamma-ray spectra of some supernova remnants can be well explained by…

High Energy Astrophysical Phenomena · Physics 2015-09-02 Nils Nierstenhoefer , Philipp Graeser , Florian Schuppan , Julia Becker Tjus

Star-forming and starburst galaxies are considered as one of the viable candidate sources of the high-energy cosmic neutrino background detected in IceCube. We revisit contributions of supernova remnants (SNRs) and hypernova remnants (HNRs)…

High Energy Astrophysical Phenomena · Physics 2016-09-27 Di Xiao , Peter Mészáros , Kohta Murase , Zi-gao Dai

Supernova remnants (SNRs) have long been hypothesized as the main source of Galactic Cosmic Rays up to PeV energies. Some of them have indeed been shown to accelerate protons to TeV energies and above. But which of them are indeed efficient…

High Energy Astrophysical Phenomena · Physics 2019-07-22 Henrike Fleischhack