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Sample records for supernova remnant shock

  1. Fermi acceleration at supernova remnant shocks

    CERN Document Server

    Caprioli, Damiano

    2012-01-01

    We investigate the physics of particle acceleration at non-relativistic shocks exploiting two different and complementary approaches, namely a semi-analytic modeling of cosmic-ray modified shocks and large hybrid (kinetic protons/fluid electrons) simulations. The former technique allows us to extract some information from the multi-wavelength observations of supernova remnants, especially in the gamma-ray band, while the latter returns fundamental insights into the details of particle injection and magnetic field amplification via plasma instabilities. In particular, we present the results of large hybrid simulations of non-relativistic shocks, discussing the properties of the transition from the thermal to the non-thermal component, the spectrum of which turns out to be the power-law predicted by first-order Fermi acceleration. Along with a rather effective magnetic field amplification, we find that more than 20% of the bulk energy is converted in non-thermal particles, altering significantly the dynamics of...

  2. Particle acceleration by shocks in supernova remnants

    CERN Document Server

    Bell, A R

    2013-01-01

    Particle acceleration occurs on a range of scales from AU in the heliosphere to Mpc in clusters of galaxies and to energies ranging from MeV to EeV. A number of acceleration processes have been proposed, but diffusive shock acceleration (DSA) is widely invoked as the predominant mechanism. DSA operates on all these scales and probably to the highest energies. DSA is simple, robust and predicts a universal spectrum. However there are still many unknowns regarding particle acceleration. This paper focuses on the particular question of whether supernova remnants (SNR) can produce the Galactic CR spectrum up to the knee at a few PeV. The answer depends in large part on the detailed physics of diffusive shock acceleration.

  3. Cosmic Ray Spectrum in Supernova Remnant Shocks

    CERN Document Server

    Kang, Hyesung

    2010-01-01

    We perform kinetic simulations of diffusive shock acceleration (DSA) in Type Ia supernova remnants (SNRs) expanding into a uniform interstellar medium (ISM). Bohm-like diffusion assumed, and simple models for Alfvenic drift and dissipation are adopted. Phenomenological models for thermal leakage injection are considered as well. We find that the preshock gas temperature is the primary parameter that governs the cosmic ray (CR) acceleration efficiency and energy spectrum, while the CR injection rate is a secondary parameter. For SNRs in the warm ISM, if the injection fraction is larger than 10^{-4}, the DSA is efficient enough to convert more than 20 % of the SN explosion energy into CRs and the accelerated CR spectrum exhibits a concave curvature flattening to E^{-1.6}. Such a flat source spectrum near the knee energy, however, may not be reconciled with the CR spectrum observed at Earth. On the other hand, SNRs in the hot ISM, with an injection fraction smaller than 10^{-4}, are inefficient accelerators with...

  4. Particle Acceleration at Shocks: Insights from Supernova Remnant Shocks

    Indian Academy of Sciences (India)

    T. W. Jones

    2011-12-01

    I review some basic properties of diffusive shock acceleration (DSA) in the context of young supernova remnants (SNRs). I also point out some key differences with cosmological, cluster-related shocks. DSA seems to be very efficient in strong, young SNR shocks. Provided the magnetic fields exceed some hundreds of Gauss (possibly amplified by CR related dynamics), these shocks can accelerate cosmic ray hadrons to PeV energies in the time available to them. Electron energies, limited by radiative losses, are likely limited to the TeV range. Injection of fresh particles at these shocks is poorly understood, but hadrons are much more easily injected than the more highly magnetized electrons. That seems supported by observational data, as well. So, while CR protons in young SNRs may play very major roles in the SNR evolution, the CR electron populations have minimal such impact, despite their observational importance.

  5. New insights on hadron acceleration at supernova remnant shocks

    CERN Document Server

    Caprioli, Damiano

    2013-01-01

    We outline the main features of nuclei acceleration at supernova remnant forward shocks, stressing the crucial role played by self-amplified magnetic fields in determining the energy spectrum observed in this class of sources. In particular, we show how the standard predictions of the non-linear theory of diffusive shock acceleration has to be completed with an additional ingredient, which we propose to be the enhanced velocity of the magnetic irregularities particles scatter against, to reconcile the theory of efficient particle acceleration with recent observations of gamma-ray bright supernova remnants.

  6. Mechanism for strong shock electron heating in supernova remnants

    International Nuclear Information System (INIS)

    It is shown that collisionless shock waves propagating away from a supernova may be directly responsible for the 10 keV X-ray emission seen in supernova remnants. A sequence of plasma instabilities (Buneman and ion acoustic) between the reflected and/or transmitted ions and the background electrons at the foot of the shock front can give rise to rapid anomalous heating of electrons. Hybrid simulations of a perpendicular collisionless shock are presented to demonstrate that this heating can arise within a self-consistently computed shock structure. 15 references

  7. Grain Destruction in a Supernova Remnant Shock Wave

    Science.gov (United States)

    Raymond, John C.; Ghavamian, Parviz; Williams, Brian J.; Blair, William P.; Borkowski, Kazimierz J.; Gaetz, Terrance J.; Sankrit, Ravi

    2014-01-01

    Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants, gradually enriching the gas phase with refractory elements. We have measured emission in C IV (lambda)1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the shock agrees approximately with predictions from model calculations that match the Spitzer 24 micron and the X-ray intensity profiles. Thus these observations confirm the overall picture of dust destruction in SNR shocks and the sputtering rates used in models. However, there is a discrepancy in that the CIV intensity 10'' behind the shock is too high compared to the intensities at the shock and 25'' behind it. Variations in the density, hydrogen neutral fraction and the dust properties over parsec scales in the pre- shock medium limit our ability to test dust destruction models in detail.

  8. Nonlinear Particle Acceleration at Reverse Shocks in Supernova Remnants

    CERN Document Server

    Ellison, D C; Ballet, J; Ellison, Donald C.; Decourchelle, Anne; Ballet, Jean

    2004-01-01

    Without amplification, magnetic fields in expanding ejecta of young supernova remnants (SNRs) will be orders of magnitude below those required to shock accelerate thermal electrons, or ions, to relativistic energies or to produce radio synchrotron emission at the reverse shock. The reported observations of such emission give support to the idea that diffusive shock acceleration (DSA) can amplify magnetic fields by large factors. Furthermore, the uncertain character of the amplification process leaves open the possibility that ejecta fields, while large enough to support radio emission and DSA, may be much lower than typical interstellar medium values. We show that DSA in such low reverse shock fields is extremely nonlinear and efficient in the production of cosmic-ray (CR) ions, although CRs greatly in excess of mc^2 are not produced. These nonlinear effects, which occur at the forward shock as well, are manifested most importantly in shock compression ratios much greater than four and cause the interaction r...

  9. Grain destruction in a supernova remnant shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, John C.; Gaetz, Terrance J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ghavamian, Parviz [Department of Physics, Astronomy and Geosciences, Towson University, Towson, MD 21252 (United States); Williams, Brian J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Borkowski, Kazimierz J. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Sankrit, Ravi, E-mail: jraymond@cfa.harvard.edu [SOFIA Science Center, NASA Ames Research Center, M/S 232-12, Moffett Field, CA 94035 (United States)

    2013-12-01

    Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants (SNRs), gradually enriching the gas phase with refractory elements. We have measured emission in C IV ?1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the shock agrees approximately with predictions from model calculations that match the Spitzer 24 ?m and the X-ray intensity profiles. Thus, these observations confirm the overall picture of dust destruction in SNR shocks and the sputtering rates used in models. However, there is a discrepancy in that the C IV intensity 10'' behind the shock is too high compared with the intensities at the shock and 25'' behind it. Variations in the density, hydrogen neutral fraction, and the dust properties over parsec scales in the pre-shock medium limit our ability to test dust destruction models in detail.

  10. Cosmic ray acceleration at perpendicular shocks in supernova remnants

    CERN Document Server

    Ferrand, Gilles; Shalchi, Andreas; Safi-Harb, Samar; Edmon, Paul; Mendygral, Peter

    2014-01-01

    Supernova remnants (SNRs) are believed to accelerate particles up to high energies through the mechanism of diffusive shock acceleration (DSA). Except for direct plasma simulations, all modeling efforts must rely on a given form of the diffusion coefficient, a key parameter that embodies the interactions of energetic charged particles with the magnetic turbulence. The so-called Bohm limit is commonly employed. In this paper we revisit the question of acceleration at perpendicular shocks, by employing a realistic model of perpendicular diffusion. Our coefficient reduces to a power-law in momentum for low momenta (of index $\\alpha$), but becomes independent of the particle momentum at high momenta (reaching a constant value $\\kappa_{\\infty}$ above some characteristic momentum $p_{\\rm c}$). We first provide simple analytical expressions of the maximum momentum that can be reached at a given time with this coefficient. Then we perform time-dependent numerical simulations to investigate the shape of the particle d...

  11. Supernova Remnant Shock - Molecular Cloud Interactions: Masers as tracers of hadronic particle acceleration

    CERN Document Server

    Frail, Dale A

    2011-01-01

    We review the class of galactic supernova remnants which show strong interactions with molecular clouds, revealed through shock-excited hydroxyl masers. These remnants are preferentially found among the known GeV and TeV detections of supernova remnants. It has been argued that the masers trace out the sites of hadronic particle acceleration. We discuss what is known about the physical conditions of these shocked regions and we introduce a potential new maser tracer for identifying the sites of cosmic ray acceleration. This review includes a reasonably complete bibliography for researchers new to the topic of shock-excited masers and supernova remnants.

  12. Cosmic ray acceleration at perpendicular shocks in supernova remnants

    Energy Technology Data Exchange (ETDEWEB)

    Ferrand, Gilles; Danos, Rebecca J.; Shalchi, Andreas; Safi-Harb, Samar [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Edmon, Paul [Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States); Mendygral, Peter, E-mail: gferrand@physics.umanitoba.ca [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2014-09-10

    Supernova remnants (SNRs) are believed to accelerate particles up to high energies through the mechanism of diffusive shock acceleration (DSA). Except for direct plasma simulations, all modeling efforts must rely on a given form of the diffusion coefficient, a key parameter that embodies the interactions of energetic charged particles with magnetic turbulence. The so-called Bohm limit is commonly employed. In this paper, we revisit the question of acceleration at perpendicular shocks, by employing a realistic model of perpendicular diffusion. Our coefficient reduces to a power law in momentum for low momenta (of index ?), but becomes independent of the particle momentum at high momenta (reaching a constant value ?{sub ?} above some characteristic momentum p {sub c}). We first provide simple analytical expressions of the maximum momentum that can be reached at a given time with this coefficient. Then we perform time-dependent numerical simulations to investigate the shape of the particle distribution that can be obtained when the particle pressure back-reacts on the flow. We observe that for a given index ? and injection level, the shock modifications are similar for different possible values of p {sub c}, whereas the particle spectra differ markedly. Of particular interest, low values of p {sub c} tend to remove the concavity once thought to be typical of non-linear DSA, and result in steep spectra, as required by recent high-energy observations of Galactic SNRs.

  13. MAGNETIC AMPLIFICATION BY MAGNETIZED COSMIC RAYS IN SUPERNOVA REMNANT SHOCKS

    International Nuclear Information System (INIS)

    X-ray observations of synchrotron rims in supernova remnant (SNR) shocks show evidence of efficient electron acceleration and strong magnetic field amplification (a factor of ?100 between the upstream and downstream medium). This amplification may be due to plasma instabilities driven by shock-accelerated particles or cosmic rays (CRs), as they propagate ahead of the shocks. One candidate process is the cosmic ray current-driven (CRCD) instability caused by the electric current of 'unmagnetized' CRs (i.e., CRs whose Larmor radii are much larger than the length scale of the CRCD modes) propagating parallel to the upstream magnetic field. Particle-in-cell (PIC) simulations have shown that the back-reaction of the amplified field on CRs would limit the amplification factor of this instability to less than ?10 in galactic SNRs (not including the additional field compression at the shock). In this paper, we study the possibility of further amplification driven near shocks by 'magnetized' CRs, whose Larmor radii are smaller than the length scale of the field that was previously amplified by the CRCD instability. We find that additional amplification can occur due to a new instability, driven by the CR current perpendicular to the field, which we term the perpendicular current-driven instability (PCDI). We derive the growth rate of this instability and, using PIC simulations, study its non-linear evolution. We show that the maximum amplification of PCDI is determined by the disruption of CR current, which happens when CR Larmor radii in the amplified field become comparable to the length scale of the instability. We find that, in regions close to the shock, PCDI grows on scales smaller than the scales of the CRCD instability, and, therefore, it results in larger amplification of the field (amplification factor up to ?45). One possible observational signature of PCDI is the characteristic dependence of the amplified field on the shock velocity, B 2 ? v 2sh, which contrasts with the one corresponding to the CRCD instability acting alone, B 2 ? v 3sh. Our results strengthen the idea of CRs driving a significant part of the magnetic field amplification observed in SNR shocks.

  14. Postshock turbulence and diffusive shock acceleration in young supernova remnants

    OpenAIRE

    Marcowith, A; Casse, F.

    2010-01-01

    Thin X-ray filaments are observed in the vicinity of young supernova remnants (SNR) blast waves. Identifying processes involved in the creation of such filaments would provide a direct insight of particle acceleration occurring within SNR, in particular regarding the cosmic ray yield issue. Aims. The present article investigates magnetic amplification in the upstream medium of SNR blast wave through both resonant and non-resonant regimes of the streaming instability. It aims at a better under...

  15. On the plasma temperature in supernova remnants with cosmic-ray modified shocks

    CERN Document Server

    O'Connor-Drury, L; Malyshev, D; Gabici, S

    2008-01-01

    Context: Multiwavelength observations of supernova remnants can be explained within the framework of the diffusive shock acceleration theory, which allows effective conversion of the explosion energy into cosmic rays. Although the models of nonlinear shocks describe reasonably well the nonthermal component of emission, certain issues, including the heating of the thermal plasma and the related X-ray emission, remain still open. Aims: To discuss how the evolution and structure of supernova remnants is affected by strong particle acceleration at the forward shock. Methods: Analytical estimates combined with detailed discussion of the physical processes. Results: The overall dynamics is shown to be relatively insensitive to the amount of particle acceleration, but the post-shock gas temperature can be reduced to a relatively small multiple, even as small as six times, the ambient temperature with a very weak dependence on the shock speed. This is in marked contrast to pure gas models where the temperature is ins...

  16. 3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration

    CERN Document Server

    Lee, Shiu-Hang; Ellison, Donald C

    2008-01-01

    We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occuring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to devel...

  17. APEX observations of supernova remnants - I. Non-stationary MHD-shocks in W44

    CERN Document Server

    Anderl, S; Güsten, R

    2014-01-01

    Aims. The interaction of supernova remnants (SNRs) with molecular clouds gives rise to strong molecular emission in the far-IR and sub-mm wavelength regimes. The application of MHD shock models in the interpretation of this line emission can yield valuable information on the energetic and chemical impact of supernova remnants. Methods. New mapping observations with the APEX telescope in CO (3-2), (4-3), (6-5), (7-6) and 13CO (3-2) towards two regions in the supernova remnant W44 are presented. Integrated intensities are extracted on five different positions, corresponding to local maxima of CO emission. The integrated intensities are compared to the outputs of a grid of models, which combine an MHD shock code with a radiative transfer module based on the large velocity gradient approximation. Results. All extracted spectra show ambient and line-of-sight components as well as blue- and red-shifted wings indicating the presence of shocked gas. Basing the shock model fits only on the highest-lying transitions th...

  18. The Role of Diffusive Shock Acceleration on Non-Equilibrium Ionization in Supernova Remnants

    CERN Document Server

    Patnaude, Daniel J; Slane, Patrick

    2009-01-01

    We present results of semi-analytic calculations which show clear evidence for changes in the non-equilibrium ionization behind a supernova remnant forward shock undergoing efficient diffusive shock acceleration (DSA). The efficient acceleration of particles (i.e., cosmic rays) lowers the shock temperature and raises the density of the shocked gas, thus altering the ionization state of the plasma in comparison to the test particle approximation where cosmic rays gain an insignificant fraction of the shock energy. The differences between the test particle and efficient acceleration cases are substantial and occur for both slow and fast temperature equilibration rates: in cases of higher acceleration efficiency, particular ion states are more populated at lower electron temperatures. We also present results which show that, in the efficient shock acceleration case, higher ionization fractions are reached noticeably closer to the shock front than in the test-particle case, clearly indicating that DSA may enhance...

  19. Molecule and dust reprocessing by the reverse shock in the supernova remnant Cas A

    Science.gov (United States)

    Biscaro, C.; Cherchneff, I.

    Dust and molecules are observed in various supernovae (SNe) and their remnants, but their formation and evolution in these hostile, shocked environments are still unclear. In some remnants, such as the 330 years-old SN remnant Cas A, the reverse shock (RS) is currently reprocessing the material formed after the SN explosion. Recently, transitions of warm CO have been detected with the Spitzer, AKARI and Herschel telescopes in Cas A ([9], [12]). In particular, CO lines were detected with Herschel in a small O-rich clump, and a high CO column density and temperature, compatible with shocked gas, were derived from line modelling ([12]). These observations thus show that a fair quantity of CO reforms after the passage of the RS. The Cas A remnant results from the explosion of a 19 M star as a Type IIb supernova ([6]), characterised by a lowdensity ejecta. We first model the SN ejecta chemistry to identify the molecules and dust clusters that form after the explosion and are reprocessed by the RS. We find that Cas A progenitor could have formed large quantities of molecules and dust only in a dense ejecta involving clumps. We then model the impact of the RS on an oxygen-rich ejecta clump, considering various RS speeds and investigating the post-shock chemistry. We consider the destruction of molecules and dust clusters by the shock and their reformation using a chemical kinetic model. The impact of UV photons coming from the hot post-shock region on the ionization fraction of the post-shock gas is included. We also model the sputtering (thermal and non-thermal) of the dust by the RS. We found that the reverse shock destroys the molecules and clusters present in the O-rich clump. CO reforms in the post shock gas with abundances that concur with the latest Herschel observations, confirming a post-shock origin for the submm CO lines. We then derive a dust size distribution for the ejecta of the Cas A progenitor, and investigate the effect of different RS velocities on this dust size distribution. Our results show that medium- and large-sized grains can survive the RS and that small dust clusters do not efficiently reform in the shocked gas. This result indicates that the dust formed in the SN ejecta and destroyed by the RS is unable to reform from the gas phase in the SN remnant.

  20. Particle Spectra from Acceleration at Forward and Reverse Shocks of Young Type Ia Supernova Remnants

    CERN Document Server

    Telezhinsky, Igor; Pohl, Martin

    2011-01-01

    We study cosmic-ray acceleration in young Type Ia Supernova Remnants (SNRs) by means of test-particle diffusive shock acceleration theory and 1-D hydrodynamical simulations of their evolution. In addition to acceleration at the forward shock, we explore the particle acceleration at the reverse shock in the presence of a possible substantial magnetic field, and consequently the impact of this acceleration on the particle spectra in the remnant. We investigate the time evolution of the spectra for various time-dependent profiles of the magnetic field in the shocked region of the remnant. We test a possible influence on particle spectra of the Alfv\\'enic drift of scattering centers in the precursor regions of the shocks. In addition, we study the radiation spectra and morphology in a broad band from radio to gamma-rays. It is demonstrated that the reverse shock contribution to the cosmic-ray particle population of young Type Ia SNRs may be significant, modifying the spatial distribution of particles and noticeab...

  1. Electron heating, magnetic field amplification, and cosmic-ray precursor length at supernova remnant shocks

    International Nuclear Information System (INIS)

    We investigate the observability, by direct and indirect means, of a shock precursor arising from magnetic field amplification by cosmic rays. We estimate the depth of such a precursor under conditions of nonresonant amplification, which can provide magnetic field strengths comparable to those inferred for supernova remnants. Magnetic field generation occurs as the streaming cosmic rays induce a plasma return current, and it may be quenched by either nonresonant or resonant channels. In the case of nonresonant saturation, the cosmic rays become magnetized and amplification saturates at higher magnetic fields. The precursor can extend out to 1017-1018 cm and is potentially detectable. If resonant saturation occurs, the cosmic rays are scattered by turbulence and the precursor length will likely be much smaller. The dependence of precursor length on shock velocity has implications for electron heating. In the case of resonant saturation, this dependence is similar to that in the more familiar resonantly generated shock precursor, which when expressed in terms of the cosmic-ray diffusion coefficient kappav and shock velocity vs is kappav/vs . In the nonresonantly saturated case, the precursor length declines less quickly with increasing vs . Where precursor length proportional to 1/vs gives constant electron heating, this increased precursor length could be expected to lead to higher electron temperatures for nonresonant amplification. This should be expected at faster supernova remnant shocks than studied by previous works. Existing results and new data analysis of SN 1006 and Cas A suggest some observational support for this idea.

  2. Time-dependent Diffusive Shock Acceleration in Slow Supernova Remnant Shocks

    Science.gov (United States)

    Tang, Xiaping; Chevalier, Roger A.

    2015-02-01

    Recent gamma-ray observations show that middle-aged supernova remnants (SNRs) interacting with molecular clouds can be sources of both GeV and TeV emission. Models involving reacceleration of preexisting cosmic rays (CRs) in the ambient medium and direct interaction between SNR and molecular clouds have been proposed to explain the observed gamma-ray emission. For the reacceleration process, standard diffusive shock acceleration (DSA) theory in the test particle limit produces a steady-state particle spectrum that is too flat compared to observations, which suggests that the high-energy part of the observed spectrum has not yet reached a steady state. We derive a time-dependent DSA solution in the test particle limit for situations involving reacceleration of preexisting CRs in the preshock medium. Simple estimates with our time-dependent DSA solution plus a molecular cloud interaction model can reproduce the overall shape of the spectra of IC 443 and W44 from GeV to TeV energies through pure ?0-decay emission. We allow for a power-law momentum dependence of the diffusion coefficient, finding that a power-law index of 0.5 is favored.

  3. Dust Destruction by the Reverse Shock in the Cassiopeia A Supernova Remnant

    CERN Document Server

    Micelotta, Elisabetta R; Slavin, Jonathan D

    2016-01-01

    Core collapse supernovae (CCSNe) are important sources of interstellar dust, potentially capable of producing one solar mass of dust in their explosively expelled ejecta. However, unlike other dust sources, the dust has to survive the passage of the reverse shock, generated by the interaction of the supernova blast wave with its surrounding medium. Knowledge of the net amount of dust produced by CCSNe is crucial for understanding the origin and evolution of dust in the local and high-redshift universe. Our aim is to identify the dust destruction mechanisms in the ejecta, and derive the net amount of dust that survives the passage of the reverse shock. We use analytical models for the evolution of a supernova blast wave and of the reverse shock, with special application to the clumpy ejecta of the remnant of Cassiopeia A. We assume that the dust resides in cool oxygen-rich clumps that are uniformly distributed within the remnant and surrounded by a hot X-ray emitting plasma, and that the dust consists of silic...

  4. Postshock turbulence and diffusive shock acceleration in young supernova remnants

    CERN Document Server

    Marcowith, A

    2010-01-01

    The present article investigates magnetic amplification in the upstream medium of SNR blast wave through both resonant and non-resonant regimes of the streaming instability. It aims at a better understanding of the diffusive shock acceleration (DSA) efficiency considering various relaxation processes of the magnetic fluctuations in the downstream medium. Multi-wavelength radiative signatures coming from the SNR shock wave are used in order to put to the test the different downstream turbulence relaxation models. We confirm the result of Parizot et al (2006) that the maximum CR energies should not go well beyond PeV energies in young SNRs where X-ray filaments are observed. In order to match observational data, we derive an upper limit on the magnetic field amplitude insuring that stochastic particle reacceleration remain inefficient. Considering then, various magnetic relaxation processes, we present two necessary conditions to achieve efficient acceleration and X-ray filaments in SNRs: 1/the turbulence must ...

  5. Electron heating, magnetic field amplification, and cosmic-ray precursor length at supernova remnant shocks

    Energy Technology Data Exchange (ETDEWEB)

    Laming, J. Martin [Space Science Division, Naval Research Laboratory, Code 7684, Washington, DC 20375 (United States); Hwang, Una [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Ghavamian, Parviz [Department of Physics, Astronomy and Geosciences, Towson University, Towson, MD 21252 (United States); Rakowski, Cara, E-mail: laming@nrl.navy.mil, E-mail: Una.Hwang-1@nasa.gov, E-mail: pghavamian@towson.edu

    2014-07-20

    We investigate the observability, by direct and indirect means, of a shock precursor arising from magnetic field amplification by cosmic rays. We estimate the depth of such a precursor under conditions of nonresonant amplification, which can provide magnetic field strengths comparable to those inferred for supernova remnants. Magnetic field generation occurs as the streaming cosmic rays induce a plasma return current, and it may be quenched by either nonresonant or resonant channels. In the case of nonresonant saturation, the cosmic rays become magnetized and amplification saturates at higher magnetic fields. The precursor can extend out to 10{sup 17}-10{sup 18} cm and is potentially detectable. If resonant saturation occurs, the cosmic rays are scattered by turbulence and the precursor length will likely be much smaller. The dependence of precursor length on shock velocity has implications for electron heating. In the case of resonant saturation, this dependence is similar to that in the more familiar resonantly generated shock precursor, which when expressed in terms of the cosmic-ray diffusion coefficient kappav and shock velocity v{sub s} is kappav/v{sub s} . In the nonresonantly saturated case, the precursor length declines less quickly with increasing v{sub s} . Where precursor length proportional to 1/v{sub s} gives constant electron heating, this increased precursor length could be expected to lead to higher electron temperatures for nonresonant amplification. This should be expected at faster supernova remnant shocks than studied by previous works. Existing results and new data analysis of SN 1006 and Cas A suggest some observational support for this idea.

  6. Balmer line diagnostic of electron heating at collisionless shocks in supernova remnants

    International Nuclear Information System (INIS)

    The mechanism and extent of electron heating at collisionless shocks has recently been under intense investigation. H? Balmer line emission is excited immediately behind the shock front and provides the best diagnostic for the electron to proton temperature ratio at supernova remnant shocks. Two components of emission are produced, a narrow component from electron and proton impact excitation of cold neutrals, and a broad component produced through charge exchange between the cold neutrals and the shock heated protons. Thus the broad and narrow component fluxes reflect the competition between electron and proton impact ionization, electron and proton impact excitation and charge exchange. This diagnostic has led to the discovery of an approximate inverse square relationship between the electron to proton temperature ratio and the shock velocity. In turn, this implies a constant level of electron heating, independent of shock speed above ? 450 km/s. In this talk I will present the observational evidence to date. Time permitting, I will introduce how lower-hybrid waves in an extended cosmic ray precursor could explain such a relationship, and how this and other parameters in the H? profile might relate to properties of cosmic rays and magnetic field amplification ahead of the shock. (author)

  7. APEX observations of supernova remnants. I. Non-stationary magnetohydrodynamic shocks in W44

    Science.gov (United States)

    Anderl, S.; Gusdorf, A.; Güsten, R.

    2014-09-01

    Context. When supernova blast waves interact with nearby molecular clouds, they send slower shocks into these clouds. The resulting interaction regions provide excellent environments for the use of MHD shock models to constrain the physical and chemical conditions in these regions. Aims: The interaction of supernova remnants (SNRs) with molecular clouds gives rise to strong molecular emission in the far-IR and sub-mm wavelength regimes. The application of MHD shock models in the interpretation of this line emission can yield valuable information on the energetic and chemical impact of SNRs. Methods: New mapping observations with the APEX telescope in 12CO (3-2), (4-3), (6-5), (7-6), and 13CO (3-2) towards two regions in the SNR W44 are presented. Integrated intensities are extracted on five different positions, corresponding to local maxima of CO emission. The integrated intensities are compared to the outputs of a grid of models, which combine an MHD shock code with a radiative transfer module based on the large velocity gradient approximation. Results: All extracted spectra show ambient and line-of-sight components as well as blue- and red-shifted wings indicating the presence of shocked gas. Basing the shock model fits only on the highest-lying transitions that unambiguously trace the shock-heated gas, we find that the observed CO line emission is compatible with non-stationary shocks and a pre-shock density of 104 cm-3. The ages of the modelled shocks scatter between values of ~1000 and ~3000 years. The shock velocities in W44F are found to lie between 20 km s-1 and 25 km s-1, while in W44E fast shocks (30-35 km s-1) as well as slower shocks (~20 km s-1) are compatible with the observed spectral line energy diagrams. The pre-shock magnetic field strength components perpendicular to the line of sight in both regions have values between 100 ?G and 200 ?G. Our best-fitting models allow us to predict the full ladder of CO transitions, the shocked gas mass in one beam as well as the momentum and energy injection. The velocity-integrated CO maps shown in Figs. 3 and 4 are available as FITS files at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/569/A81Appendix A is available in electronic form at http://www.aanda.org

  8. Reverse and Forward Shock X-ray Emission in an Evolutionary Model of Supernova Remnants undergoing Efficient Diffusive Shock Acceleration

    CERN Document Server

    Lee, Shiu-Hang; Ellison, Donald C; Nagataki, Shigehiro; Slane, Patrick O

    2014-01-01

    We present new models for the forward and reverse shock thermal X-ray emission from core-collapse and Type Ia supernova remnants (SNRs) which include the efficient production of cosmic rays via non-linear diffusive shock acceleration (DSA). Our CR-hydro-NEI code takes into account non-equilibrium ionization (NEI), hydrodynamic effects of efficient CR production on the SNR evolution, and collisional temperature equilibration among heavy ions and electrons in both the shocked supernova (SN) ejecta and the shocked circumstellar material. While X-ray emission is emphasized here, our code self-consistently determines both thermal and non-thermal broadband emission from radio to TeV energies. We include Doppler broadening of the spectral lines by thermal motions of the ions and by the remnant expansion. We study, in general terms, the roles which the ambient environment, progenitor models, temperature equilibration, and processes related to DSA have on the thermal and non-thermal spectra. The study of X-ray line em...

  9. Post-adiabatic supernova remnants in an interstellar magnetic field: parallel and perpendicular shocks

    Science.gov (United States)

    Petruk, O.; Kuzyo, T.; Beshley, V.

    2016-03-01

    Gamma-rays from hadronic collisions are expected from supernova remnants (SNRs) located near molecular clouds. The temperature of the shock interacting with the dense environment quickly reaches 105 K. Radiative losses of plasma become essential in the evolution of SNRs. They decrease the thermal pressure and essentially increase the density behind the shock. The presence of an ambient magnetic field may alter the behaviour of the post-adiabatic SNRs considerably compared with the hydrodynamic scenario. In the present article, magnetohydrodynamic simulations of radiative shocks in a magnetic field are performed. High plasma compression due to radiative losses also results in a prominent increase in the strength of the tangential component of magnetic field behind the shock and a decrease of the parallel one. If the strength of the tangential field before the shock is higher than about 3 ?G, it prevents formation of a very dense thin shell. The higher the strength of the tangential magnetic field, the larger the thickness and the lower the maximum density in the radiative shell. The parallel magnetic field does not affect the distribution of the hydrodynamic parameters behind the shock. There are almost independent channels of energy transformations: radiative losses are due to thermal energy, magnetic energy increases come from reducing the kinetic energy. The large density and high strength of the perpendicular magnetic field in the radiative shells of SNRs should result in a considerable increase of the hadronic gamma-ray flux compared with the leptonic one.

  10. Time-dependent Diffusive Shock Acceleration in Slow Supernova Remnant Shocks

    CERN Document Server

    Tang, Xiaping

    2014-01-01

    Recent gamma ray observations show that middle aged supernova remnants interacting with molecular clouds can be sources of both GeV and TeV emission. Models involving re-acceleration of pre-existing cosmic rays in the ambient medium and direct interaction between supernova remnant and molecular clouds have been proposed to explain the observed gamma ray emission. For the re-acceleration process, standard DSA theory in the test particle limit produces a steady state particle spectrum that is too flat compared to observations, which suggests that the high energy part of the observed spectrum has not yet reached a steady state. We derive a time dependent DSA solution in the test particle limit for situations involving re-acceleration of pre-existing cosmic rays in the preshock medium. Simple estimates with our time dependent DSA solution plus a molecular cloud interaction model can reproduce the overall shape of the spectra of IC 443 and W44 from GeV to TeV energies through pure $\\pi^0$-decay emission. We allow ...

  11. Post-adiabatic supernova remnants in the interstellar magnetic field. Parallel and perpendicular shocks

    CERN Document Server

    Petruk, O; Beshley, V

    2015-01-01

    Gamma-rays from hadronic collisions are expected from supernova remnants (SNRs) located near molecular clouds. The temperature on the shock interacting with the dense environment quickly reaches $10^5$ K. The radiative losses of plasma become essential in the evolution of SNRs. They decrease the thermal pressure and essentially increase the density behind the shock. The presence of ambient magnetic field may considerably alter the behavior of the post-adiabatic SNRs comparing to hydrodynamic scenario. In the present paper, the magneto-hydrodynamic simulations of radiative shocks in magnetic field are performed. High plasma compression due to the radiative losses results also in the prominent increase of the strength of the tangential component of magnetic field behind the shock and the decrease of the parallel one. If the strength of the tangential field before the shock is higher than about $3\\mathrm{\\mu G}$ it prevents formation of the very dense thin shell. The higher the strength of the tangential magneti...

  12. Infrared analysis of supernova remnants

    International Nuclear Information System (INIS)

    Infrared observations of supernova remnants obtained with the infrared astronomical satellite provide new insights into the dynamics and energetics of the remnants, and into their interaction with the ambient interstellar medium. In most remnants the infrared emission arises from dust that is collisonally heated by the x-ray emitting gas. The infrared observations can therefore be used as a diagnostic for the physical conditions of the shocked gas. In particular, it is shown that all the prominent x-ray remnants in the galaxy and in the LMC cool mainly by dust grain collisions instead of atomic processes

  13. Turbulence and particle acceleration in collisionless supernovae remnant shocks: II- Cosmic-ray transport

    CERN Document Server

    Marcowith, A; Pelletier, G; Marcowith, Alexandre; Lemoine, Martin; Pelletier, Guy

    2006-01-01

    Supernovae remnant shock waves could be at the origin of cosmic rays up to energies in excess of the knee ($E\\simeq3\\cdot 10^{15} $eV) if the magnetic field is efficiently amplified by the streaming of accelerated particles in the shock precursor. This paper follows up on a previous paper \\citep{pell05} which derived the properties of the MHD turbulence so generated, in particular its anisotropic character, its amplitude and its spectrum. In the present paper, we calculate the diffusion coefficients, also accounting for compression through the shock, and show that the predicted three-dimensional turbulence spectrum $k_\\perp S_{3\\rm d}(k_\\parallel,k_\\perp)\\propto k_\\parallel^{-1}k_\\perp^{-\\alpha}$ (with $k_\\parallel$ and $k_\\perp$ the wavenumber components along and perpendicular to the shock normal) generally leads to Bohm diffusion in the parallel direction. However, if the anisotropy is constrained by a relation of the form $k_\\parallel \\propto k_\\perp^{2/3}$, which arises when the turbulent energy cascade ...

  14. A Generalized Model of Nonlinear Diffusive Shock Acceleration Coupled to an Evolving Supernova Remnant

    CERN Document Server

    Lee, Shiu-Hang; Nagataki, Shigehiro

    2012-01-01

    To better model the efficient production of cosmic rays (CRs) in supernova remnants (SNRs) with the associated coupling between CR production and SNR dynamics, we have generalized an existing cr-hydro-NEI code (i.e., Ellison et al. 2012) to include the following processes: (1) an explicit calculation of the upstream precursor structure including the position dependent flow speed, density, temperature, and magnetic field strength; (2) a momentum and space dependent CR diffusion coefficient; (3) an explicit calculation of magnetic field amplification (MFA); (4) calculation of the maximum CR momentum using the amplified magnetic field; (5) a finite Alfven speed for the particle scattering centers; and (6) the ability to accelerate a superthermal seed population of CRs as well as the ambient thermal plasma. While a great deal of work has been done modeling SNRs, most work has concentrated on either the continuum emission from relativistic electrons or ions, or the thermal emission from the shock heated plasma. Ou...

  15. Reverse and forward shock X-ray emission in an evolutionary model of supernova remnants undergoing efficient diffusive shock acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Shiu-Hang [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Patnaude, Daniel J.; Slane, Patrick O. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ellison, Donald C. [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States); Nagataki, Shigehiro, E-mail: slee@astro.isas.jaxa.jp, E-mail: shiu-hang.lee@riken.jp, E-mail: shigehiro.nagataki@riken.jp, E-mail: slane@cfa.harvard.edu, E-mail: dpatnaude@cfa.harvard.edu, E-mail: don_ellison@ncsu.edu [RIKEN, Astrophysical Big Bang Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2014-08-20

    We present new models for the forward and reverse shock thermal X-ray emission from core-collapse and Type Ia supernova remnants (SNRs) that include the efficient production of cosmic rays (CR) via nonlinear diffusive shock acceleration (DSA). Our CR-hydro-NEI code takes into account non-equilibrium ionization, hydrodynamic effects of efficient CR production on the SNR evolution, and collisional temperature equilibration among heavy ions and electrons in both the shocked supernova (SN) ejecta and the shocked circumstellar material. While X-ray emission is emphasized here, our code self-consistently determines both thermal and non-thermal broadband emission from radio to TeV energies. We include Doppler broadening of the spectral lines by thermal motions of the ions and by the remnant expansion. We study, in general terms, the roles that the ambient environment, progenitor models, temperature equilibration, and processes related to DSA have on the thermal and non-thermal spectra. The study of X-ray line emission from young SNRs is a powerful tool for determining specific SN elemental contributions and for providing critical information that helps to understand the type and energetics of the explosion, the composition of the ambient medium in which the SN exploded, and the ionization and dynamics of the hot plasma in the shocked SN ejecta and interstellar medium. With the approaching launch of the next-generation X-ray satellite Astro-H, observations of spectral lines with unprecedented high resolution will become a reality. Our self-consistent calculations of the X-ray spectra from various progenitors will help interpret future observations of SNRs.

  16. Non-relativistic perpendicular shocks modeling young supernova remnants: nonstationary dynamics and particle acceleration at forward and reverse shocks

    CERN Document Server

    Wieland, Volkmar; Niemiec, Jacek; Rafighi, Iman; Nishikawa, Ken-Ichi

    2016-01-01

    For parameters that are applicable to the conditions at young supernova remnants, we present results of 2D3V particle-in-cell simulations of a non-relativistic plasma shock with a large-scale perpendicular magnetic field inclined at 45-deg angle to the simulation plane to approximate 3D physics. We developed an improved clean setup that uses the collision of two plasma slabs with different density and velocity, leading to the development of two distinctive shocks and a contact discontinuity. The shock formation is mediated by Weibel-type filamentation instabilities that generate magnetic turbulence. Cyclic reformation is observed in both shocks with similar period, for which we note global variations on account of shock rippling and local variations arising from turbulent current filaments. The shock rippling occurs on spatial and temporal scales given by gyro-motions of shock-reflected ions. The drift motion of electrons and ions is not a gradient drift, but commensurates with E x B drift. We observe a stabl...

  17. Broad Balmer line emission and cosmic ray acceleration efficiency in supernova remnant shocks

    CERN Document Server

    Morlino, G; Bandiera, R; Amato, E

    2013-01-01

    Balmer emission may be a powerful diagnostic tool to test the paradigm of cosmic ray (CR) acceleration in young supernova remnant (SNR) shocks. The width of the broad Balmer line is a direct indicator of the downstream plasma temperature. In case of efficient particle acceleration an appreciable fraction of the total kinetic energy of the plasma is channeled into CRs, therefore the downstream temperature decreases and so does the broad Balmer line width. This width also depends on the level of thermal equilibration between ions and neutral hydrogen atoms in the downstream. Since in general in young SNR shocks only a few charge exchange (CE) reactions occur before ionization, equilibration between ions and neutrals is not reached, and a kinetic description of the neutrals is required in order to properly compute Balmer emission. We provide a method for the calculation of Balmer emission using a self-consistent description of the shock structure in the presence of neutrals and CRs. We use a recently developed s...

  18. Shock processing of interstellar dust and polycyclic aromatic hydrocarbons in the supernova remnant N132D

    CERN Document Server

    Tappe, A; Reach, W T

    2006-01-01

    We observed the oxygen-rich Large Magellanic Cloud (LMC) supernova remnant N132D (SNR 0525-69.6), using all instruments onboard the Spitzer Space Telescope, IRS, IRAC, and MIPS (Infrared Spectrograph, Infrared Array Camera, Multiband Imaging Photometer for Spitzer). The 5-40 micron IRS spectra toward the southeastern shell of the remnant show a steeply rising continuum with [NeIII] and [OIV] as well as PAH emission. We also present the spectrum of a fast moving ejecta knot, previously detected at optical wavelengths, which is dominated by strong [NeIII] and [OIV] emission lines. We interpret the continuum as thermal emission from swept-up, shock-heated dust grains in the expanding shell of N132D, which is clearly visible in the MIPS 24 micron image. A 15-20 micron emission hump appears superposed on the dust continuum, and we attribute this to PAH C-C-C bending modes. We also detect the well-known 11.3 micron PAH C-H bending feature, and find the integrated strength of the 15-20 micron hump about a factor of ...

  19. Broad Balmer line emission and cosmic ray acceleration efficiency in supernova remnant shocks

    Science.gov (United States)

    Morlino, G.; Blasi, P.; Bandiera, R.; Amato, E.

    2013-10-01

    Context. Balmer emission may be a powerful diagnostic tool for testing the paradigm of cosmic ray (CR) acceleration in young supernova remnant (SNR) shocks. The width of the broad Balmer line is a direct indicator of the downstream plasma temperature. In the case of efficient particle acceleration, an appreciable fraction of the total kinetic energy of the plasma is channeled into CRs, therefore the downstream temperature decreases and so does the broad Balmer line width. This width also depends on the level of thermal equilibration between ions and neutral hydrogen atoms in the downstream. Since generally only a few charge exchange (CE) reactions occur before ionization in young SNR shocks, equilibration between ions and neutrals is not reached, and a kinetic description of the neutrals is required to properly compute Balmer emission. Aims: We provide a method for calculating Balmer emission using a self-consistent description of the shock structure in the presence of neutrals and CRs, which also accounts for the non-Maxwellian distribution of neutrals. Methods: We use a recently developed semi-analytical approach, where neutral particles, ionized plasma, accelerated particles, and magnetic fields are all coupled together through the mass, momentum, and energy flux-conservation equations. The distribution of neutrals is obtained from the full Boltzmann equation in velocity space, coupled to Maxwellian ions through ionization and CE processes. The computation is also an improvement over previous work thanks to a better approximation of the atomic interaction rates. Results: We find that for shock speeds ?2500 km s-1, the distribution of broad neutrals never approaches a Maxwellian and its moments differ from those of the ionized component. These differences lead to a smaller FWHM than predicted in previous calculations, where thermalization was assumed. Conclusions: The method presented here provides a realistic estimate of particle acceleration efficiency in Balmer-dominated shocks.

  20. Supernova remnants and the ISM

    International Nuclear Information System (INIS)

    Supernova remnants can reaccelerate cosmic rays and modify their distribution during the cosmic ray propagation in the galaxy. Cosmic ray observations (in particular the boron-to-carbon data) strongly limit the permitted amount of reacceleration, which is used to set an upper limit on the expansion of supernova remnants, and a lower limit on the effective density of the ISM swept up by supernova shocks. The constraint depends on the theory of cosmic ray propagation: the standard Leaky Box model requires a high effective density, > 1 -3, and is probably inconsistent with the present picture of the ISM. Modifying the Leaky Box model to include a moderate amount of weak-shock reacceleration, a self consistent solution is found, where the effective density in this solution is ? 0.1 cm-3

  1. GALACTIC AND EXTRAGALACTIC SUPERNOVA REMNANTS AS SITES OF PARTICLE ACCELERATION

    Directory of Open Access Journals (Sweden)

    Manami Sasaki

    2013-12-01

    Full Text Available Supernova remnants, owing to their strong shock waves, are likely sources of Galactic cosmic rays. Studies of supernova remnants in X-rays and gamma rays provide us with new insights into the acceleration of particles to high energies. This paper reviews the basic physics of supernova remnant shocks and associated particle acceleration and radiation processes. In addition, the study of supernova remnant populations in nearby galaxies and the implications for Galactic cosmic ray distribution are discussed.

  2. Analytical solutions for energy spectra of electrons accelerated by nonrelativistic shock-waves in shell type supernova remnants

    OpenAIRE

    Zirakashvili, V. N.; Aharonian, F.

    2006-01-01

    %context {Recent observations of hard X-rays and very high energy gamma-rays from a number of young shell type supernova remnants indicate the importance of detailed quantitative studies of energy spectra of relativistic electrons formed via diffusive shock acceleration accompanied by intense nonthermal emission through synchrotron radiation and inverse Compton scattering.} %aim {The aim of this work was derivation of exact asymptotic solutions of the kinetic equation which ...

  3. Hydromagnetic turbulence amplification in the vicinity of shock wave front and maximum energies of accelerated particles in supernova remnants

    International Nuclear Information System (INIS)

    A self-consistent mechanism of the diffusive shock acceleration with particles generating the m. h. d. waves is considered. Spectral and spatial characteristics of the turbulence, diffusion coefficient and the particle distribution function are calculated. From comparison of the characteristic particle acceleration time with the supernova remnants lifitimes the particle limitative energies, which can be achieved within the context of the considered mechanism Emax? 102-103 GeV are determined

  4. Radio emission from Supernova Remnants

    CERN Document Server

    Dubner, Gloria

    2015-01-01

    The explosion of a supernova releases almost instantaneously about 10^51 ergs of mechanic energy, changing irreversibly the physical and chemical properties of large regions in the galaxies. The stellar ejecta, the nebula resulting from the powerful shock waves, and sometimes a compact stellar remnant, constitute a supernova remnant (SNR). They can radiate their energy across the whole electromagnetic spectrum, but the great majority are radio sources. Almost 70 years after the first detection of radio emission coming from a SNR, great progress has been achieved in the comprehension of their physical characteristics and evolution. We review the present knowledge of different aspects of radio remnants, focusing on sources of the Milky Way and the Magellanic Clouds, where the SNRs can be spatially resolved. We present a brief overview of theoretical background, analyze morphology and polarization properties, and review and critical discuss different methods applied to determine the radio spectrum and distances....

  5. Progenitors of Recombining Supernova Remnants

    OpenAIRE

    Moriya, Takashi J.

    2012-01-01

    Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with the ionization temperature higher than the electron temperature, is recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the t...

  6. Production of Magnetic Turbulence by Cosmic Rays Drifting Upstream of Supernova Remnant Shocks

    Science.gov (United States)

    Stroman, Thomas; Niemiec, Jacek; Pohl, Martin; Nishikawa, Ken-ichi

    2008-01-01

    I will present results of our recent two- and three-dimensional Particle-In-Cell simulations of magnetic-turbulence production by cosmic-ray ions drifting upstream of supernova remnant shocks. These studies' aim is twofold: test recent predictions of strong amplification in short wavelength, non-resonant wave modes, and study the subsequent evolution of the magnetic turbulence, including its backreaction on cosmic-ray trajectories. We confirm that the drifting cosmic rays give rise to a turbulent magnetic field, but show that an oblique filamentary mode grows more rapidly than the non-resonant parallel modes found in analytical theory. The field perturbations grow more slowly than estimated using a quasi-linear analytical approach for the parallel plane-wave mode, and saturate in amplitude at deltaB/B approximately equal to 1. The backreaction of the magnetic turbulence on the particles leads to an alignment of the bulk-flow velocities of the cosmic rays and the background medium. This is an essential characteristic of cosmic ray-modified shocks: the upstream flow speed is continuously changed by the cosmic rays. The reduction of relative drift between cosmic rays and background medium accounts for the saturation of the instability at only moderate magnetic-field amplitudes. It is possible that the prolonged magnetic field growth observed in recent MHD simulations results from a cosmic-ray current assumed to be constant and thus immune to the backreaction from the turbulent field. We speculate that the parallel plane-wave mode found in analytical treatments very quickly leads co filamentation, which we observe in our PIC modeling and is also apparent in the MHD simulations.

  7. Shocked Gas from the supernova remnant G357.7+0.3

    Science.gov (United States)

    Rho, Jeonghee; Hewitt, John; Reach, William T.; Bieging, John H.; Andersen, Morten; Güsten, Rolf

    2016-01-01

    We present detection of hydrogen molecular hydrogen (H2) in mid-infrared using the Spitzer IRS. The supernova remnant (SNR) G357.7+0.3 is one of relatively unknown and under-studied SNRs. We performed an IRS spectral mapping centered on the northwestern shell of G357.7+0.3. The observations covered an area of 75arcsec x 60arcsec with short-low (SL) and 170arcsec x 55arcsec with long-low (LL). All rotational H2 lines within the IRS wavelength range are detected except S(6) line. Interestingly, G357.7+0.3 shows lack of ionic lines compared with those in other SNRs observed. Only ionic line detected is [Si II] at 34.8micron. The detection of H2 line is an evidence that G357.7+0.3 is interacting with dense molecular clouds. This is the first evidence showing that G357.7+0.3 is an interacting SNR with clouds. We generated a H2 excitation diagram. A two-temperature fit yields a low temperature of 197 K with a column density 2.3E21/cm2 and and a high temperature of 663 K with a column density of 2.7E19/cm2. We preformed high-J CO and OH observations with The German REceiver for Astronomy at Terahertz Frequencies (GREAT) on board of Stratospheric Observatory for Infrared Astronomy (SOFIA), but no lines are detected. We provide the upper limits of the lines. We also present millimeter observations of the SNR. The observations were made with the Arizona-MPIfR Heinrich Hertz Submillimeter Telescope (HHT), Arizona 12 Meter Telescope, and Atacama Pathfinder Experiment (APEX) Telescope. We discuss physical conditions of shocked gas in G357.7+0.3.

  8. TWO-DIMENSIONAL PARTICLE-IN-CELL SIMULATIONS OF THE NONRESONANT, COSMIC-RAY-DRIVEN INSTABILITY IN SUPERNOVA REMNANT SHOCKS

    International Nuclear Information System (INIS)

    In supernova remnants, the nonlinear amplification of magnetic fields upstream of collisionless shocks is essential for the acceleration of cosmic rays to the energy of the 'knee' at 1015.5 eV. A nonresonant instability driven by the cosmic ray current is thought to be responsible for this effect. We perform two-dimensional, particle-in-cell simulations of this instability. We observe an initial growth of circularly polarized nonpropagating magnetic waves as predicted in linear theory. It is demonstrated that in some cases the magnetic energy density in the growing waves can grow to at least 10 times its initial value. We find no evidence of competing modes, nor of significant modification by thermal effects. At late times, we observe saturation of the instability in the simulation, but the mechanism responsible is an artifact of the periodic boundary conditions and has no counterpart in the supernova-shock scenario.

  9. Environmental impact of Supernova Remnants

    CERN Document Server

    Dubner, Gloria

    2015-01-01

    The explosion of a supernovae (SN) represents the sudden injection of about 10^51 ergs of thermal and mechanical energy in a small region of space, causing the formation of powerful shock waves that propagate through the interstellar medium at speeds of several thousands of km/s. These waves sweep, compress and heat the interstellar material that they encounter, forming the supernova remnants. Their evolution over thousands of years change forever, irreversibly, not only the physical but also the chemical properties of a vast region of space that can span hundreds of parsecs. This contribution briefly analyzes the impact of these explosions, discussing the relevance of some phenomena usually associated with SNe and their remnants in the light of recent theoretical and observational results.

  10. SPECTRA OF MAGNETIC FLUCTUATIONS AND RELATIVISTIC PARTICLES PRODUCED BY A NONRESONANT WAVE INSTABILITY IN SUPERNOVA REMNANT SHOCKS

    International Nuclear Information System (INIS)

    We model strong forward shocks in young supernova remnants with efficient particle acceleration where a nonresonant instability driven by the cosmic ray current amplifies magnetic turbulence in the shock precursor. Particle injection, magnetic field amplification (MFA), and the nonlinear feedback of particles and fields on the bulk flow are derived consistently. The shock structure depends critically on the efficiency of turbulence cascading. If cascading is suppressed, MFA is strong, the shock precursor is stratified, and the turbulence spectrum contains several discrete peaks. These peaks, as well as the amount of MFA, should influence synchrotron X-rays, allowing observational tests of cascading and other assumptions intrinsic to the nonlinear model of nonresonant wave growth.

  11. Spectra of magnetic fluctuations and relativistic particles produced by a nonresonant wave instability in supernova remnant shocks

    CERN Document Server

    Vladimirov, Andrey E; Ellison, Donald C

    2009-01-01

    We model strong forward shocks in young supernova remnants with efficient particle acceleration where a nonresonant instability driven by the cosmic ray current amplifies magnetic turbulence in the shock precursor. Particle injection, magnetic field amplification (MFA) and the nonlinear feedback of particles and fields on the bulk flow are derived consistently. The shock structure depends critically on the efficiency of turbulence cascading. If cascading is suppressed, MFA is strong, the shock precursor is stratified, and the turbulence spectrum contains several discrete peaks. These peaks, as well as the amount of MFA, should influence synchrotron X-rays, allowing observational tests of cascading and other assumptions intrinsic to the nonlinear model of nonresonant wave growth.

  12. Cosmic Ray Acceleration in Supernova Remnants

    International Nuclear Information System (INIS)

    This paper describes some recent developments in our understanding of cosmic ray acceleration in supernova remnant shocks. It is pointed out that while good agreement now exists as to steady nonlinear modifications to the shock structure, there is also growing evidence that the mesoscopic scales may not in fact be steady and that significant instabilities associated with magnetic field amplification may be a feature of strong collisionless plasma shocks. There is strong observational evidence for such magnetic field amplification, and it appears to solve a number of long-standing issues concerned with acceleration of cosmic rays in supernova remnants

  13. Radio to Gamma-Ray Emission from Shell-Type Supernova Remnants: Predictions from Non-Linear Shock Acceleration Models

    Science.gov (United States)

    Baring, Matthew G.; Ellison, Donald C.; Reynolds, Stephen P.; Grenier, Isabelle A.; Goret, Philippe

    1998-01-01

    Supernova remnants (SNRs) are widely believed to be the principal source of galactic cosmic rays, produced by diffusive shock acceleration in the environs of the remnant's expanding blast wave. Such energetic particles can produce gamma-rays and lower energy photons via interactions with the ambient plasma. The recently reported observation of TeV gamma-rays from SN1006 by the CANGAROO Collaboration, combined with the fact that several unidentified EGRET sources have been associated with known radio/optical/X-ray-emitting remnants, provides powerful motivation for studying gamma-ray emission from SNRs. In this paper, we present results from a Monte Carlo simulation of non-linear shock structure and acceleration coupled with photon emission in shell-like SNRs. These non-linearities are a by-product of the dynamical influence of the accelerated cosmic rays on the shocked plasma and result in distributions of cosmic rays which deviate from pure power-laws. Such deviations are crucial to acceleration efficiency considerations and impact photon intensities and spectral shapes at all energies, producing GeV/TeV intensity ratios that are quite different from test particle predictions.

  14. New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant

    CERN Document Server

    Yamaguchi, Hiroya; Badenes, Carles; Hughes, John P; Brickhouse, Nancy S; Foster, Adam R; Patnaude, Daniel J; Petre, Robert; Slane, Patrick O; Smith, Randall K

    2013-01-01

    Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here we present the first clear evidence for efficient collisionless electron heating at the reverse shock of Tycho's supernova remnant (SNR), revealed by Fe-K diagnostics using high-quality X-ray data obtained by the Suzaku satellite. We detect K-beta (3p->1s) fluorescence emission from low-ionization Fe ejecta excited by energetic thermal electrons at the reverse shock front, which peaks at a smaller radius than Fe K-alpha (2p->1s) emission dominated by a relatively highly-ionized component. Comparison with our hydrodynamical simulations implies instantaneous electron heating to a temperature 1000 times higher than expected from Coulomb collisions alone. The unique environment of the reverse shock, which is propagating w...

  15. Cosmic-ray acceleration in supernova remnants

    CERN Document Server

    Tatischeff, Vincent

    2008-01-01

    Galactic cosmic rays are widely believed to be accelerated in expanding shock waves initiated by supernova explosions. The theory of diffusive shock acceleration of cosmic rays is now well established, but two fundamental questions remain partly unanswered: what is the acceleration efficiency, i.e. the fraction of the total supernova energy converted to cosmic-ray energy, and what is the maximum kinetic energy achieved by particles accelerated in supernova explosions? Recent observations of supernova remnants, in X-rays with the Chandra and XMM-Newton satellites and in very-high-energy gamma rays with several ground-based atmospheric Cerenkov telescopes, have provided new pieces of information concerning these two questions. After a review of these observations and their current interpretations, I show that complementary information on the diffusive shock acceleration process can be obtained by studying the radio emission from extragalactic supernovae. As an illustration, a nonlinear model of diffusive shock ...

  16. Spectral modeling of supernova remnants

    Science.gov (United States)

    Fontes, C. J.; Eriksen, K. A.; Colgan, J.; Zhang, H. L.; Hughes, J. P.

    2014-03-01

    We report on recent efforts to generate high quality, self-consistent atomic physics models for L-shell ion stages for iron and the use of these data in collisional-radiative modeling of X-ray spectra of supernova remnants. As a specific example, we present comparisons between observed and theoretical X-ray spectra produced by Tycho's supernova remnant.

  17. TURBULENCE AND MAGNETIC FIELD AMPLIFICATION IN SUPERNOVA REMNANTS: INTERACTIONS BETWEEN A STRONG SHOCK WAVE AND MULTIPHASE INTERSTELLAR MEDIUM

    International Nuclear Information System (INIS)

    We examine magnetohydrodynamic simulations of the propagation of a strong shock wave through the interstellar two-phase medium composed of small-scale cloudlets and diffuse warm neutral medium in two-dimensional geometry. The preshock two-phase medium is provided as a natural consequence of the thermal instability that is expected to be ubiquitous in the interstellar medium. We show that the shock-compressed shell becomes turbulent owing to the preshock density inhomogeneity, and magnetic field amplification takes place in the shell. The maximum field strength is determined by the condition that plasma ? ? 1, which gives the field strength on the order of 1 mG in the case of shock velocity ?103 km s-1. The strongly magnetized region shows filamentary and knotlike structures in two-dimensional simulations. The spatial scale of the regions with a magnetic field of ?1 mG in our simulation is roughly 0.05 pc, which is comparable to the spatial scale of the X-ray hot spots recently discovered in supernova remnants where the magnetic field strength is indicated to be amplified up to the order of 1 mG. This result may also suggest that the turbulent region with a locally strong magnetic field is expected to be spread out in the region with frequent supernova explosions, such as in the Galactic center and starburst galaxies.

  18. New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant

    Science.gov (United States)

    Yamaguchi, Hiroya; Eriksen, Kristoffer A.; Badenes, Carles; Hughes, John P.; Brickhouse, Nancy S.; Foster, Adam R.; Patnaude, Daniel J.; Petre, Robert; Slane, Patrick O.; Smith, Randall K.

    2013-01-01

    Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here, we present the first clear evidence for efficient collisionless electron heating at the reverse shock of Tycho's supernova remnant (SNR), revealed by Fe K diagnostics using high-quality X-ray data obtained by the Suzaku satellite. We detect K beta (3p yields 1s) fluorescence emission from low-ionization Fe ejecta excited by energetic thermal electrons at the reverse shock front, which peaks at a smaller radius than Fe K alpha (2p yields 1s) emission dominated by a relatively highly ionized component. Comparisons with our hydrodynamical simulations imply instantaneous electron heating to a temperature 1000 times higher than expected from Coulomb collisions alone. The unique environment of the reverse shock, which is propagating with a high Mach number into rarefied ejecta with a low magnetic field strength, puts strong constraints on the physical mechanism responsible for this heating and favors a cross-shock potential created by charge deflection at the shock front. Our sensitive observation also reveals that the reverse shock radius of this SNR is about 10% smaller than the previous measurement using the Fe K alpha morphology from the Chandra observations. Since strong Fe K beta fluorescence is expected only from low-ionization plasma where Fe ions still have many 3p electrons, this feature is key to diagnosing the plasma state and distribution of the immediate postshock ejecta in a young SNR.

  19. Cosmic ray acceleration in young supernova remnants

    OpenAIRE

    Schure, K.M.; Bell, A. R.

    2013-01-01

    We investigate the appearance of magnetic field amplification resulting from a cosmic ray escape current in the context of supernova remnant shock waves. The current is inversely proportional to the maximum energy of cosmic rays, and is a strong function of the shock velocity. Depending on the evolution of the shock wave, which is drastically different for different circumstellar environments, the maximum energy of cosmic rays as required to generate enough current to trigger the non-resonant...

  20. Radio emission from supernova remnants

    Science.gov (United States)

    Dubner, Gloria; Giacani, Elsa

    2015-09-01

    The explosion of a supernova releases almost instantaneously about 10^{51} ergs of mechanic energy, changing irreversibly the physical and chemical properties of large regions in the galaxies. The stellar ejecta, the nebula resulting from the powerful shock waves, and sometimes a compact stellar remnant, constitute a supernova remnant (SNR). They can radiate their energy across the whole electromagnetic spectrum, but the great majority are radio sources. Almost 70 years after the first detection of radio emission coming from an SNR, great progress has been achieved in the comprehension of their physical characteristics and evolution. We review the present knowledge of different aspects of radio remnants, focusing on sources of the Milky Way and the Magellanic Clouds, where the SNRs can be spatially resolved. We present a brief overview of theoretical background, analyze morphology and polarization properties, and review and critically discuss different methods applied to determine the radio spectrum and distances. The consequences of the interaction between the SNR shocks and the surrounding medium are examined, including the question of whether SNRs can trigger the formation of new stars. Cases of multispectral comparison are presented. A section is devoted to reviewing recent results of radio SNRs in the Magellanic Clouds, with particular emphasis on the radio properties of SN 1987A, an ideal laboratory to investigate dynamical evolution of an SNR in near real time. The review concludes with a summary of issues on radio SNRs that deserve further study, and analysis of the prospects for future research with the latest-generation radio telescopes.

  1. Turbulence and Magnetic Field Amplification in Supernova Remnants: Interactions Between A Strong Shock Wave and Multi-Phase Interstellar Medium

    CERN Document Server

    Inoue, Tsuyoshi; Inutsuka, Shu-ichiro

    2009-01-01

    We examine MHD simulations of the propagation of a strong shock wave through the interstellar two-phase medium composed of small-scale cloudlets and diffuse warm neutral medium in two-dimensional geometry. The pre-shock two-phase medium is provided as a natural consequence of the thermal instability that is expected to be ubiquitous in the interstellar medium. We show that the shock-compressed shell becomes turbulent owing to the preshock density inhomogeneity and magnetic field amplification takes place in the shell. The maximum field strength is determined by the condition that plasma beta ~ 1, which gives the field strength on the order of 1 mG in the case of shock velocity ~ 1,000 km/s. The strongly magnetized region shows filamentary and knot-like structures in two-dimensional simulations. The spatial scale of the regions with magnetic field of 1 mG in our simulation is roughly 0.05 pc which is comparable to the spatial scale of the X-ray hot spots recently discovered in supernova remnants where the magn...

  2. AKARI Near-infrared Spectral Observations of Shocked H2 Gas of the Supernova Remnant IC 443

    CERN Document Server

    Shinn, Jong-Ho; Seon, Kwang-Il; Lee, Ho-Gyu

    2011-01-01

    We present near-infrared (2.5 - 5.0 um) spectra of shocked H2 gas in the supernova remnant IC 443, obtained with the satellite AKARI. Three shocked clumps-known as B, C, and G-and one background region were observed, and only H2 emission lines were detected. Except the clump B, the extinctioncorrected level population shows the ortho-to-para ratio of ~ 3.0. From the level population of the clumps C and G-both AKARI's only and the one extended with previous mid-infrared observations-we found that the v = 0 levels are more populated than the v > 0 levels at a fixed level energy, which cannot be reproduced by any combination of H2 gas in Local Thermodynamic Equilibrium. The populations are described by the two-density power-law thermal admixture model, revised to include the collisions with H atoms. We attributed the lower (n(H2)=10^(2.8-3.8) cm-3) and higher (n(H2)=10^(5.4-5.8) cm-3) density gases to the shocked H2 gas behind C-type and J-type shocks, respectively, based on several arguments including the obtai...

  3. First Simulations of Core- Collapse Supernovae to Supernova Remnants with SNSPH

    CERN Document Server

    Ellinger, Carola I; Fryer, Christopher L; Young, Patrick A; Park, Sangwook

    2013-01-01

    We present the first 3-dimensional simulations following the evolution of supernova shocks from their inception in the stellar core through the development of a supernova remnant into the Sedov phase. Our set of simulations use two different progenitors and two different conditions for the structure of the circumstellar environment. These calculations demonstrate the role that supernova instabilities (the instabilities that develop as the shock drive through the star) play in defining the structure and long-term development of instabilities in supernova remnants. We also present a first investigation of the mixing between stellar and interstellar matter as the supernova evolves into a young supernova remnant.

  4. LOCALIZED SiO EMISSION TRIGGERED BY THE PASSAGE OF THE W51C SUPERNOVA REMNANT SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, G. [Institut de Radioastronomie Millimétrique, 300 Rue de la Piscine, F-38406 Saint Martin d' Hères (France); Vaupré, S.; Ceccarelli, C.; Hily-Blant, P.; Dubus, G. [UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d" Astrophysique de Grenoble (IPAG) UMR 5274, F-38041 Grenoble (France); Montmerle, T. [UPMC-CNRS, UMR 7095, Institute d' Astrophysique de Paris, 98 bis boulevard Arago, F-75014 Paris (France); Gabici, S. [APC, AstroParticule et Cosmologie, Université Paris Diderot, CNRS, CEA, Observatoire de Paris, Sorbonne Paris, F-75205 Paris (France)

    2014-05-10

    The region toward W51C is a convincing example of interaction between a supernova remnant (SNR) and a surrounding molecular cloud. Large electron abundances have been reported toward the position W51C-E located in this interaction region, and it was proposed that the enhanced ionization fraction was due to cosmic ray particles freshly accelerated by the SNR shock. We present Plateau de Bure Interferometer observations of the H{sup 13}CO{sup +}(1-0) and DCO{sup +}(2-1) emission lines centered at position W51C-E. These observations confirm the previous scenario of cosmic-ray-induced ionization at this location. In addition, SiO(2-1) emission has been successfully mapped in the close vicinity of W51C-E, with a spatial resolution of 7''. The morphology and kinematics of the SiO emission are analyzed and strongly suggest that this emission is produced by the passage of the SNR primary shock. Put in conjunction with the enhanced ionization fraction in this region, we give a consistent picture in which the W51C-E position is located downstream of the shock, where a large reservoir of freshly accelerated particles is available.

  5. ANTIPROTONS PRODUCED IN SUPERNOVA REMNANTS

    Energy Technology Data Exchange (ETDEWEB)

    Berezhko, E. G.; Ksenofontov, L. T., E-mail: ksenofon@ikfia.sbras.ru [Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Avenue, 677891 Yakutsk (Russian Federation)

    2014-08-20

    We present the energy spectrum of an antiproton cosmic ray (CR) component calculated on the basis of the nonlinear kinetic model of CR production in supernova remnants (SNRs). The model includes the reacceleration of antiprotons already existing in the interstellar medium as well as the creation of antiprotons in nuclear collisions of accelerated protons with gas nuclei and their subsequent acceleration by SNR shocks. It is shown that the production of antiprotons in SNRs produces a considerable effect in their resultant energy spectrum, making it essentially flatter above 10 GeV so that the spectrum at TeV energies increases by a factor of 5. The calculated antiproton spectrum is consistent with the PAMELA data, which correspond to energies below 100 GeV. As a consistency check, we have also calculated within the same model the energy spectra of secondary nuclei and show that the measured boron-to-carbon ratio is consistent with the significant SNR contribution.

  6. Infrared Studies of Molecular Shocks in the Supernova Remnant HB 21: II. Thermal Admixture of Shocked H$_2$ Gas in the South

    CERN Document Server

    Shinn, Jong-Ho; Burton, Michael G; Lee, Ho-Gyu; Moon, Dae-Sik

    2009-01-01

    We present near- and mid-infrared observations on the shock-cloud interaction region in the southern part of the supernova remnant HB 21, performed with the InfraRed Camera (IRC) aboard AKARI satellite and the Wide InfraRed Camera (WIRC) at the Palomar 5 m telescope. The IRC 4 um (N4), 7 um (S7), and 11 um (S11) band images and the WIRC H2 v=1->0 S(1) 2.12 um image show similar diffuse features, around a shocked CO cloud. We analyzed the emission through comparison with the H2 line emission of several shock models. The IRC colors are well explained by the thermal admixture model of H2 gas--whose infinitesimal H2 column density has a power-law relation with the temperature $T$, $dN\\sim T^{-b}dT$--with n(H2) $\\sim3.9\\times10^4$ cm^{-2}, $b\\sim4.2$, and N(H2;T>100K) $\\sim2.8\\times10^{21}$ cm^{-2}. We interpreted these parameters with several different pictures of the shock-cloud interactions--multiple planar C-shocks, bow shocks, and shocked clumps--and discuss their weaknesses and strengths. The observed H2 v=1...

  7. X-ray haloes around supernova remnants

    International Nuclear Information System (INIS)

    Recent observations of the Cas-A supernova remnant have shown X-ray emissions not only from the interior, but also from a fainter 'halo' extending beyond what is normally regarded as the outer boundary, or shock front. The authors suggest that this may be due to the diffusion of energetic, charged particles out of the remnant giving rise to precursor structure of the type predicted by the theory of diffusive shock acceleration. If this is the case we are seeing thermal emission from ambient gas heated by compression and wave dissipation. (author)

  8. X-Ray Emission from Multi-Phase Shock in the Large Magellanic Cloud Supernova Remnant N49

    CERN Document Server

    Park, S; Garmire, G P; Nousek, J A; Hughes, J P; Williams, R M; Park, Sangwook; Burrows, David N.; Garmire, Gordon P.; Nousek, John A.; Hughes, John P.; Williams, Rosa Murphy

    2003-01-01

    The supernova remnant (SNR) N49 in the Large Magellanic Cloud has been observed with the Advanced CCD Imaging Spectrometer (ACIS) on board the {\\it Chandra X-Ray Observatory}. The superb angular resolution of the {\\it Chandra}/ACIS images resolves a point source, the likely X-ray counterpart of soft gamma-ray repeater SGR 0526$-$66, and the diffuse filaments and knots across the SNR. These filamentary features represent the blast wave sweeping through the ambient interstellar medium and nearby dense molecular clouds. We detect metal-rich ejecta beyond the main blast wave shock boundary in the southwest of the SNR, which appear to be explosion fragments or ``bullets'' ejected from the progenitor star. The detection of strong H-like Si line emission in the eastern side of the SNR requires multi-phase shocks in order to describe the observed X-ray spectrum, whereas such a multi-phase plasma is not evident in the western side. This complex spectral structure of N49 suggests that the postshock regions toward the e...

  9. Infrared Spectroscopy of Molecular Supernova Remnants

    CERN Document Server

    Reach, W T; Reach, William T.; Rho, Jeonghee

    2000-01-01

    We present Infrared Space Observatory spectroscopy of sites in the supernova remnants W28, W44, and 3C391, where blast waves are impacting molecular clouds. Atomic fine-structure lines were detected from C, N, O, Si, P, and Fe. The S(3) and S(9) lines of H2 were detected for all three remnants. The observations require both shocks into gas with moderate (~ 100 /cm3) and high (~10,000 /cm3) pre-shock densities, with the moderate density shocks producing the ionic lines and the high density shock producing the molecular lines. No single shock model can account for all of the observed lines, even at the order of magnitude level. We find that the principal coolants of radiative supernova shocks in moderate-density gas are the far-infrared continuum from dust grains surviving the shock, followed by collisionally-excited [O I] 63.2 and [Si II] 34.8 micron lines. The principal coolant of the high-density shocks is collisionally-excited H2 rotational and ro-vibrational line emission. We systematically examine the gro...

  10. INFRARED STUDIES OF MOLECULAR SHOCKS IN THE SUPERNOVA REMNANT HB21. I. THERMAL ADMIXTURE OF SHOCKED H2 GAS IN THE NORTH

    International Nuclear Information System (INIS)

    We present near- and mid-infrared observations on the shock-cloud interaction region in the northern part of the supernova remnant HB21, performed with the infrared camera (IRC) aboard the AKARI satellite and the wide-field infrared camera (WIRC) at the Palomar 5 m telescope. The IRC 7 ?m (S7), 11 ?m (S11), and 15 ?m (L15) band images and the WIRC H2 ? = 1 ? 0 S(1) 2.12 ?m image show similar shock-cloud interaction features. We chose three representative regions, and analyzed their IRC emissions through comparison with H2 line emissions of several shock models. The IRC colors are well explained by the thermal admixture model of H2 gas-whose infinitesimal H2 column density has a power-law relation with the temperature T, d N ? T -b dT-with n(H2)?103 cm-3, b ? 3, and N(H2; T > 100 K) ?3x1020 cm-2. The derived b value may be understood by a bow shock picture, whose shape is cycloidal (cuspy) rather than paraboloidal. However, this picture raises another issue that the bow shocks must reside within ?0.01 pc size scale, smaller than the theoretically expected. Instead, we conjectured a shocked clumpy interstellar medium picture, which may avoid the size-scale issue while explaining the similar model parameters. The observed H2 ? = 1 ? 0 S(1) intensities are a factor of ?17-33 greater than the prediction from the power-law admixture model. This excess may be attributed to either an extra component of hot H2 gas or to the effects of collisions with hydrogen atoms, omitted in our power-law admixture model, both of which would increase the population in the ? = 1 level of H2.

  11. Shocked forbidden O I 63 micron line emission from the supernova remnant IC 443

    Science.gov (United States)

    Burton, Michael G.; Hollenbach, D. J.; Haas, M. R.; Erickson, E. F.

    1990-01-01

    Observations of the fine-structure emission from the forbidden O I 63 micron line in the SNR IC 443 are presented. It is shown that the emission correlates well with the distribution of line emission from shock-excited molecular hydrogen, which leads to the conclusion that the line is shock-excited. X-ray heating as well as UV-heating from a photodissociation region is ruled out as a possible excitation mechanism for the emission. It is shown that the forbidden O I 63 micron line is an important contributor to the total emission in the IRAS 60 micron band, estimated as approximately 40-75 percent of the total band flux. An attempt to shock model the line emission from IC 443 is made; however, to match the observational evidence, it has to be assumed that the shock is J-type, and that the oxygen chemistry is suppressed so that oxygen remains in atomic form and does not get converted into H2O. However, no theoretical rationale for these assumptions can be provided.

  12. X-Ray Emission from Multi-Phase Shock in the Large Magellanic Cloud Supernova Remnant N49

    OpenAIRE

    Park, Sangwook; Burrows, David N.; Garmire, Gordon P; Nousek, John A.; Hughes, John P.; Williams, Rosa Murphy

    2002-01-01

    The supernova remnant (SNR) N49 in the Large Magellanic Cloud has been observed with the Advanced CCD Imaging Spectrometer (ACIS) on board the {\\it Chandra X-Ray Observatory}. The superb angular resolution of the {\\it Chandra}/ACIS images resolves a point source, the likely X-ray counterpart of soft gamma-ray repeater SGR 0526$-$66, and the diffuse filaments and knots across the SNR. These filamentary features represent the blast wave sweeping through the ambient interstella...

  13. Molecular clouds near supernova remnants

    International Nuclear Information System (INIS)

    The physical properties of molecular clouds near supernova remnants were investigated. Various properties of the structure and kinematics of these clouds are used to establish their physical association with well-known remmnants. An infrared survey of the most massive clouds revealed embedded objects, probably stars whose formation was induced by the supernova blast wave. In order to understand the relationship between these and other molecular clouds, a control group of clouds was also observed. Excitation models for dense regions of all the clouds are constructed to evaluate molecular abundances in these regions. Those clouds that have embedded stars have lower molecular abundances than the clouds that do not. A cloud near the W28 supernova remnant also has low abundances. Molecular abundances are used to measure an important parameter, the electron density, which is not directly observable. In some clouds extensive deuterium fractionation is observed which confirms electron density measurements in those clouds. Where large deuterium fractionation is observed, the ionization rate in the cloud interior can also be measured. The electron density and ionization rate in the cloud near W28 are higher than in most clouds. The molecular abundances and electron densities are functions of the chemical and dynamical state of evolution of the cloud. Those clouds with lowest abundances are probably the youngest clouds. As low-abundance clouds, some clouds near supernova remnants may have been recently swept from the local interstellar material. Supernova remnants provide sites for star formation in ambient clouds by compressing them, and they sweep new clouds from more diffuse local matter

  14. Production of Magnetic Turbulence by Cosmic Rays Drifting Upstream of Supernova Remnant Shocks

    CERN Document Server

    Niemiec, Jacek; Stroman, Thomas; Nishikawa, and Ken-Ichi

    2008-01-01

    We present results of 2D and 3D PIC simulations of magnetic turbulence production by isotropic cosmic-ray ions drifting upstream of SNR shocks. The studies aim at testing recent predictions of a strong amplification of short wavelength non-resonant wave modes and at studying the evolution of the magnetic turbulence and its backreaction on cosmic rays. We confirm the generation of the turbulent magnetic field due to the drift of cosmic rays in the upstream plasma, but show that an oblique filamentary mode grows more rapidly than the non resonant parallel modes found in analytical theory. The growth rate of the field perturbations is much slower than is estimated using a quasi-linear approach, and the amplitude of the turbulence saturates at about dB/B~1. The backreaction of the turbulence on the particles leads to an alignment of the bulk-flow velocities of the cosmic rays and the background medium, which is an essential characteristic of cosmic-ray modified shocks. It accounts for the saturation of the instab...

  15. Future GLAST observations of Supernova remnants and Pulsar Wind Nebulae

    OpenAIRE

    GLAST Collaboration; Funk, S

    2007-01-01

    Shell-type Supernova remnants (SNRs) have long been known to harbour a population of ultra-relativistic particles, accelerated in the Supernova shock wave by the mechanism of diffusive shock acceleration. Experimental evidence for the existence of electrons up to energies of ~100 TeV was first provided by the detection of hard X-ray synchrotron emission as e.g. in the shell of the young SNR SN1006. Furthermore using theoretical arguments shell-type Supernova remnants have lo...

  16. Supernova Remnant in 3-D

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Click on the image for the movie For the first time, a multiwavelength three-dimensional reconstruction of a supernova remnant has been created. This stunning visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several telescopes: X-ray data from NASA's Chandra X-ray Observatory, infrared data from NASA's Spitzer Space Telescope and optical data from the National Optical Astronomy Observatory 4-meter telescope at Kitt Peak, Ariz., and the Michigan-Dartmouth-MIT 2.4-meter telescope, also at Kitt Peak. In this visualization, the green region is mostly iron observed in X-rays. The yellow region is a combination of argon and silicon seen in X-rays, optical, and infrared including jets of silicon plus outer debris seen in the optical. The red region is cold debris seen in the infrared. Finally, the blue reveals the outer blast wave, most prominently detected in X-rays. Most of the material shown in this visualization is debris from the explosion that has been heated by a shock moving inwards. The red material interior to the yellow/orange ring has not yet encountered the inward moving shock and so has not yet been heated. These unshocked debris were known to exist because they absorb background radio light, but they were only recently discovered in infrared emission with Spitzer. The blue region is composed of gas surrounding the explosion that was heated when it was struck by the outgoing blast wave, as clearly seen in Chandra images. To create this visualization, scientists took advantage of both a previously known phenomenon the Doppler effect and a new technology that bridges astronomy and medicine. When elements created inside a supernova, such as iron, silicon and argon, are heated they emit light at certain wavelengths. Material moving towards the observer will have shorter wavelengths and material moving away will have longer wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through. The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave. This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron. High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these structures, but their orientation and position with resp

  17. Neutron Stars in Supernova Remnants and Beyond

    CERN Document Server

    Gvaramadze, V V

    2002-01-01

    We discuss a concept of off-centred cavity supernova explosion as applied to neutron star/supernova remnant associations and show how this concept could be used to preclude the anti-humane decapitating the Duck (G5.4-1.2 + G5.27-0.9) and dismembering the Swan (Cygnus Loop), as well as to search for a stellar remnant associated with the supernova remnant RCW86.

  18. The blast wave of Tycho's supernova remnant

    CERN Document Server

    Cassam-Chenai, G; Ballet, J; Decourchelle, A; Cassam-Chenai, Gamil; Hughes, John P.; Ballet, Jean; Decourchelle, Anne

    2007-01-01

    We use the Chandra X-ray Observatory to study the region in the Tycho supernova remnant between the blast wave and the shocked ejecta interface or contact discontinuity. This zone contains all the history of the shock-heated gas and cosmic-ray acceleration in the remnant. We present for the first time evidence for significant spatial variations of the X-ray synchrotron emission in the form of spectral steepening from a photon index of 2.6 right at the blast wave to a value of 3.0 several arcseconds behind. We interpret this result along with the profiles of radio and X-ray intensity using a self-similar hydrodynamical model including cosmic ray backreaction that accounts for the observed ratio of radii between the blast wave and contact discontinuity. Two different assumptions were made about the post-shock magnetic field evolution: one where the magnetic field (amplified at the shock) is simply carried by the plasma flow and remains relatively high in the post-shock region [synchrotron losses limited rim cas...

  19. Low Frequency Insights Into Supernova Remnants

    CERN Document Server

    Dyer, K K; Borkowski, K J; Dyer, Kristy K.; Reynolds, Stephen P; Borkowski, Kazik J.

    2000-01-01

    Low frequency observations at 330 and 74 MHz can provide new insights into supernova remnants (SNR). We can test theoretical predictions for spectral index variations. Nonlinear models of shock acceleration predict that the spectra from young SNR should be slightly concave rather than power laws -- flattening toward higher energies. However, few SNR are bright and compact enough to be studied at millimeter wavelengths, restricting studies to the small range from 6 to 20 cm (a factor of 1.7 in electron energies). Observations at 330 MHz increase the electron energy baseline to a factor of 4, while providing sensitivity to larger spatial scales that are resolved out by centimeter-wavelength interferometers. Such observations can also separate thermal from nonthermal emission and detect excess free-free absorption associated with cool gas in remnants. Wide field images also provide an efficient census of both thermal and nonthermal sources over a large region.

  20. Multi-Wavelength Observations of Supernova Remnants

    Science.gov (United States)

    Williams, B.

    2012-01-01

    Supernova remnants (SNRs) provide a laboratory for studying various astrophysical processes, including particle acceleration, thermal and non thermal emission processes across the spectrum, distribution of heavy elements, the physics of strong shock waves, and the progenitor systems and environments of supernovae. Long studied in radio and X-rays, the past decade has seen a dramatic increase in the detection and subsequent study of SNRs in the infrared and gamma-ray regimes. Understanding the evolution of SNRs and their interaction with the interstellar medium requires a multi-wavelength approach. I will review the various physical processes observed in SNRs and how these processes are intertwined. In particular, I will focus on X-ray and infrared observations, which probe two very different but intrinsically connected phases of the ISM: gas and dust. I will discuss results from multi-wavelength studies of several SNRs at various stages of evolution, including Kepler, RCW 86, and the Cygnus Loop.

  1. The molecular emission from old supernova remnants

    CERN Document Server

    Gusdorf, Antoine; Anderl, Sibylle; Hezareh, Talayeh

    2014-01-01

    Supernovae constitute a critical source of energy input to the interstellar medium (ISM). In this short review, we focus on their latest phase of evolution, the supernova remnants (SNRs). We present observations of three old SNRs that have reached the phase where they interact with the ambient ISM: W28, IC443, and 3C391. We show that such objects make up clean laboratories to constrain the physical and chemical processes at work in molecular shock environments. Our studies subsequently allow us to quantify the impact of SNRs on their environment in terms of mass, momentum, and energy dissipation. In turn, their contribution to the energy balance of galaxies can be assessed. Their potential to trigger a further generation of star formation can also be investigated. Finally, our studies provide strong support for the interpretation of gamma-ray emission in SNRs, a crucial step to answer questions related to cosmic rays population and acceleration.

  2. Asymmetric supernova remnants generated by Galactic, massive runaway stars

    Science.gov (United States)

    Meyer, D. M.-A.; Langer, N.; Mackey, J.; Velázquez, P. F.; Gusdorf, A.

    2015-07-01

    After the death of a runaway massive star, its supernova shock wave interacts with the bow shocks produced by its defunct progenitor, and may lose energy, momentum and its spherical symmetry before expanding into the local interstellar medium (ISM). We investigate whether the initial mass and space velocity of these progenitors can be associated with asymmetric supernova remnants. We run hydrodynamical models of supernovae exploding in the pre-shaped medium of moving Galactic core-collapse progenitors. We find that bow shocks that accumulate more than about 1.5 M? generate asymmetric remnants. The shock wave first collides with these bow shocks 160-750 yr after the supernova, and the collision lasts until 830-4900 yr. The shock wave is then located 1.35-5 pc from the centre of the explosion, and it expands freely into the ISM, whereas in the opposite direction it is channelled into the region of undisturbed wind material. This applies to an initially 20 M? progenitor moving with velocity 20 km s-1 and to our initially 40 M? progenitor. These remnants generate mixing of ISM gas, stellar wind and supernova ejecta that is particularly important upstream from the centre of the explosion. Their light curves are dominated by emission from optically thin cooling and by X-ray emission of the shocked ISM gas. We find that these remnants are likely to be observed in the [O III] ? 5007 spectral line emission or in the soft energy-band of X-rays. Finally, we discuss our results in the context of observed Galactic supernova remnants such as 3C 391 and the Cygnus Loop.

  3. Einstein Observations of Galactic supernova remnants

    Science.gov (United States)

    Seward, Frederick D.

    1990-01-01

    This paper summarizes the observations of Galactic supernova remnants with the imaging detectors of the Einstein Observatory. X-ray surface brightness contours of 47 remnants are shown together with gray-scale pictures. Count rates for these remnants have been derived and are listed for the HRI, IPC, and MPC detectors.

  4. A simple model for electron plasma heating in supernova remnants

    CERN Document Server

    Malyshev, D; Drury, L O'C; Aharonian, F A

    2010-01-01

    Context: Multiwavelength observations of supernova remnants can be explained within the framework of diffusive shock acceleration theory, which allows effective conversion of the explosion energy into cosmic rays. Although the models of nonlinear shocks describe reasonably well the nonthermal component of emission, certain issues, including the heating of the thermal electron plasma and the related X-ray emission, still remain open. Methods: Numerical solution of the equations of the Chevalier model for supernova remnant evolution, coupled with Coulomb scattering heating of the electrons. Results: The electron temperature and the X-ray thermal Bremsstrahlung emission from supernova remnants have been calculated as functions of the relevant parameters. Since only the Coulomb mechanism was considered for electron heating, the values obtained for the electron temperatures should be treated as lower limits. Results from this work can be useful to constrain model parameters for observed SNRs.

  5. Cosmic ray acceleration in young supernova remnants

    CERN Document Server

    Schure, K M

    2013-01-01

    We investigate the appearance of magnetic field amplification resulting from a cosmic ray escape current in the context of supernova remnant shock waves. The current is inversely proportional to the maximum energy of cosmic rays, and is a strong function of the shock velocity. Depending on the evolution of the shock wave, which is drastically different for different circumstellar environments, the maximum energy of cosmic rays as required to generate enough current to trigger the non-resonant hybrid instability that confines the cosmic rays follows a different evolution and reaches different values. We find that the best candidates to accelerate cosmic rays to ~few PeV energies are young remnants in a dense environment, such as a red supergiant wind, as may be applicable to Cassiopeia A. We also find that for a typical background magnetic field strength of 5 microG the instability is quenched in about 1000 years, making SN1006 just at the border of candidates for cosmic ray acceleration to high energies.

  6. Cosmic ray acceleration in young supernova remnants

    Science.gov (United States)

    Schure, K. M.; Bell, A. R.

    2013-10-01

    We investigate the appearance of magnetic field amplification resulting from a cosmic ray escape current in the context of supernova remnant shock waves. The current is inversely proportional to the maximum energy of cosmic rays, and is a strong function of the shock velocity. Depending on the evolution of the shock wave, which is drastically different for different circumstellar environments, the maximum energy of cosmic rays as required to generate enough current to trigger the non-resonant hybrid instability that confines the cosmic rays follows a different evolution and reaches different values. We find that the best candidates to accelerate cosmic rays to ˜ few PeV energies are young remnants in a dense environment, such as a red supergiant wind, as may be applicable to Cassiopeia A. We also find that for a typical background magnetic field strength of 5 ?G the instability is quenched in about 1000 years, making SN1006 just at the border of candidates for cosmic ray acceleration to high energies.

  7. Hot interstellar tunnels. I. Simulation of interacting supernova remnants

    International Nuclear Information System (INIS)

    Reexamining a suggestion of Cox and Smith, we find that intersecting supernova remnants can indeed generate and maintain hot interstellar regions with napproximately-less-than10-2 cm-3 and Tapprox.106 K. These regions are likely to occupy at least 30% of the volume of a spiral arm near the midplane of the gaseous disk if the local supernova rate there is greater than 1.5 x 10-7 Myr-1 pc-3. Their presence in the interstellar medium is supported by observations of the soft X-ray background. The theory required to build a numerical simulation of interacting supernova remnants is developed. The hot cavities within a population of remnants will become connected for a variety of assumed conditions in the outer shells of old remnants. Extensive hot cavity regions or tunnels are built and enlarged by supernovae occurring in relatively dense gas which produce connections, but tunnels are kept hot primarily by supernovae occurring within the tunnels. The latter supernovae initiate fast shock waves which apparently reheat tunnels faster than they are destroyed by thermal conduction in a galactic magnetic field or by radiative cooling. However, the dispersal of these rejuvenating shocks over a wide volume is inhibited by motions of cooler interstellar gas in the interval between shocks. These motions disrupt the contiguity of the component cavities of a tunnel and may cause its death.The Monte Carlo simulations indicate that a quasi-equilibrium is reached within 107 years of the first supernova in a spiral arm. This equilibrium is characterized by a constant average filling fraction for cavities in the interstellar volume. Aspects of the equilibrium are discussed for a range of supernova rates. Two predictions of Cox and Smith are not confirmed within this range: critical growth of hot regions to encompass the entire medium, and the efficient quenching of a remnant's expansion by interaction with other cavities

  8. Synthetic Observation of Turbulent Supernova Remnants

    Science.gov (United States)

    Shimoda, Jiro; Inoue, Tsuyoshi; Ohira, Yutaka; Yamazaki, Ryo

    It is known that observations of polarized radio synchrotron emissions from young supernova remnants show radially oriented distributions of magnetic field. By using synthetic polarization observations of the results of three-dimensional magnetohydrodynamics simulations, we find that the radially oriented distribution of magnetic field can be reproduced by turbulent dynamo mechanism induced by the Richtmyer-Meshkov instability. In the simulation, we consider propagation of a supernova blast wave shock in realistic inhomogeneous interstellar medium. Interaction between the density inhomogeneity and the shock wave induces the so-called Richtmyer-Meshkov instability that generates shear of radial-component velocity in the downstream of the blast wave. In such medium, magnetic field lines are stretched by the shear motion that leads to amplification of radial-component magnetic field. Thus, the downstream magnetic field is oriented parallel to the shock normal. We conclude that the observed polarized synchrotron emission is successfully explained by the dynamo effect induced by the Richtmyer-Meshkov instability.

  9. Magnetic field in supernova remnant SN 1987A

    OpenAIRE

    Berezhko, E. G.; Ksenofontov, L. T.

    2006-01-01

    A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants is employed to investigate the properties of the remnant SN 1987A. It is shown that a large downstream magnetic field ~10 mG is required to fit the existing observational data. Such a strong field together with the strong shock modification due to CR backreaction provides the steep and concave radioemission spectrum and considerable synchrotron cooling of high energy electrons which diminish the...

  10. Energy of Tycho's Supernova Remnant is increasing with time

    OpenAIRE

    Barenblatt, Grigory Isaakovich

    2008-01-01

    It is shown, using the Zeldovich integral relations, that the energy of Tycho's Supernova Remnant is strongly growing with time, approximately as t1/3. This growth can be attributed to the exothermic reactions going inside the remnant. The use of the assumption of the adiabaticity of the motion inside of the shock front, and no losses or gain of energy at the front, seems therefore unjustified.

  11. Cosmic ray production in Historical Supernova Remnants

    Science.gov (United States)

    Sinitsyna, V. G.; Y Sinitsyna, V.

    2013-02-01

    We present the results of observations of two types of Galactic supernova remnants with the SHALON mirror Cherenkov telescope of Tien-Shan high-mountain Observatory: the shell-type supernova remnants Tycho, Cas A and IC 443; plerions Crab Nebula, 3c58(SN1181) and Geminga (probably plerion). The experimental data 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 supernova remnant. The data obtained suggest that the very high energy gamma-ray emission in the objects being discussed is different in origin.

  12. On the radio spectra of supernova remnants

    CERN Document Server

    Uroševi?, Dejan

    2014-01-01

    The theoretical fundamentals of formation of the supernova remnant (SNR) continuum radio spectra are presented in this review. Mainly based on the Fermi 1 theory - also known as diffuse shock acceleration (DSA) - the different shapes (linear or curved in log-log scale) of SNR radio spectra are predicted for both young and evolved SNRs. On the other hand, some particular forms of spectra of older SNRs can be predicted by including the additional processes such as Fermi 2 acceleration mechanism or thermal bremsstrahlung radiation. Also, all of these theoretically predicted forms of radio spectra are compared with real spectra obtained from observations. Finally this review can represent some kind of "atlas" with initial patterns for the different kinds of SNR radio spectra - it should be helpful for radio astronomers in their interpretation of the observed radio spectra.

  13. Strong evidences of hadron acceleration in Tycho's Supernova Remnant

    OpenAIRE

    Morlino, G.; Caprioli, D.

    2011-01-01

    Very recent gamma-ray observations of G120.1+1.4 (Tycho's) supernova remnant (SNR) by Fermi-LAT and VERITAS provided new fundamental pieces of information for understanding particle acceleration and non-thermal emission in SNRs. We want to outline a coherent description of Tycho's properties in terms of SNR evolution, shock hydrodynamics and multi-wavelength emission by accounting for particle acceleration at the forward shock via first order Fermi mechanism. We adopt here a quick and reliabl...

  14. An infrared survey of galactic supernova remnants

    International Nuclear Information System (INIS)

    Presented are preliminary results from a survey of supernova remnants (SNRs) in the data base collected by the Infrared Astronomical Satellite (IRAS). About one-third of the known galactic SNRs are visible in the IRAS data. Confusion with other sources in the galactic plane prohibits the detection of many remnants. The objects that are detected have similar spectral characteristics and temperatures, except that the three youngest remnants known, Tycho, Kepler, and Cassiopeia A, are distinctly warmer

  15. Asymmetric supernova remnants generated by Galactic, massive runaway stars

    CERN Document Server

    Meyer, D M -A; Mackey, J; Velazquez, P F; Gusdorf, A

    2015-01-01

    After the death of a runaway massive star, its supernova shock wave interacts with the bow shocks produced by its defunct progenitor, and may lose energy, momentum, and its spherical symmetry before expanding into the local interstellar medium (ISM). We investigate whether the initial mass and space velocity of these progenitors can be associated with asymmetric supernova remnants. We run hydrodynamical models of supernovae exploding in the pre-shaped medium of moving Galactic core-collapse progenitors. We find that bow shocks that accumulate more than about 1.5 Mo generate asymmetric remnants. The shock wave first collides with these bow shocks 160-750 yr after the supernova, and the collision lasts until 830-4900 yr. The shock wave is then located 1.35-5 pc from the center of the explosion, and it expands freely into the ISM, whereas in the opposite direction it is channelled into the region of undisturbed wind material. This applies to an initially 20 Mo progenitor moving with velocity 20 km/s and to our i...

  16. Chandra Observations of Tycho’s Supernova Remnant

    Indian Academy of Sciences (India)

    U. Hwang; R. Petre; A. E. Szymkowiak; S. S. Holt

    2002-03-01

    We present a new Chandra observation of Tycho’s supernova remnant with the Advanced CCD Imaging Spectrometer. Multicolor X-ray imaging reveals new details of the outer shock and ejecta. At energies between 4 and 6 keV, the outline of the outer shock is clearly revealed in X-rays for the first time. The distribution of the emission from lines of Si and Fe are confirmed to have a different morphology from each other, and the Si ejecta are shown to extend to the blast shock at several locations. Characteristic spectra of the outer shock and ejecta are also presented.

  17. Origin of Radially Aligned Magnetic Fields in Young Supernova Remnants

    CERN Document Server

    Inoue, Tsuyoshi; Ohira, Yutaka; Yamazaki, Ryo

    2013-01-01

    It has been suggested by radio observations of polarized synchrotron emissions that downstream magnetic field in some young supernova remnants are oriented radially. We study magnetic field distribution of turbulent supernova remnant driven by the Richtmyer-Meshkov instability -- in other words, the effect of rippled shock -- by using three-dimensional magnetohydrodynamics simulations. We find that the induced turbulence has radially biased anisotropic velocity dispersion that leads to a selective amplification of the radial component of the magnetic field. The Richtmyer-Meshkov instability is induced by the interaction between the shock and upstream density fluctuations. Future high-resolution polarization observation can distinguish the following candidates responsible for the upstream density fluctuations: (i) inhomogeneity caused by the cascade of large-scale turbulence in the ISM so-called the big-power-law-in-the-sky, (ii) structures generated by the Drury instability in the cosmic-ray modified shock, a...

  18. X-ray images of supernova remnants

    International Nuclear Information System (INIS)

    Einstein observations of supernova remnants have been review and analyzed. Images of 44 galactic remnants have been reprocessed, merged when necessary, and collected. Some bright remnants were viewed with both moderate and high resolution instruments (IPC with 1 ft. resolution and HRI with 4 in. resolution). Some IPC images of nearby remnants have been separated into 2 energy bands, 0.2-0.6 keV and 0.6-4.5 keV; whereas most images cover the band 0.2-4.5 keV. These images are illustrated in this paper

  19. X-ray High Resolution and Imaging Spectroscopy of Supernova Remnants

    CERN Document Server

    Vink, J

    2006-01-01

    The launch of Chandra and XMM-Newton has led to important new findings concerning the X-ray emission from supernova remnants. These findings are a result of the high spatial resolution with which imaging spectroscopy is now possible, but also some useful results have come out of the grating spectrometers of both X-ray observatories, despite the extended nature of supernova remnants. The findings discussed here are the evidence for slow equilibration of electron and ion temperatures near fast supernova remnant shocks, the magnetic field amplification near remnant shocks due to cosmic ray acceleration, a result that has come out of studying narrow filaments of X-ray synchrotron emission, and finally the recent findings concerning Fe-rich ejecta in Type Ia remnants and the presence of a jet/counter jet system in the Type Ib supernova remnant Cas A.

  20. Interaction of a Pulsar Wind with the Expanding Supernova Remnant

    CERN Document Server

    Jun, B I

    1997-01-01

    Recent HST observations of the Crab Nebula show filamentary structures that appear to originate from the Rayleigh-Taylor (R-T) instability operating on the supernova ejecta accelerated by the pulsar-driven wind. In order to understand the origin and formation of the filaments in the Crab Nebula, we study the interaction of a pulsar wind with the uniformly expanding supernova remnant by means of numerical simulation. By performing two-dimensional numerical simulations, we find three independent instabilities in the interaction region between the pulsar wind and the expanding supernova remnant. The most important instability develops as the shock driven by the pulsar bubble becomes accelerated ($r \\propto t^{6/5}$). The instability produces pronounced filamentary structures that resemble the observed filaments in the Crab Nebula. Our numerical simulations can reproduce important observational features of the Crab Nebula. The high density heads in the R-T finger tips are produced because of the compressibility o...

  1. Luminous stars in galactic supernova remnants

    International Nuclear Information System (INIS)

    A discussion of reasons to expect luminous stars in the vicinity of supernova remnants is followed by a list of them from the Luminous Stars in the Northern- and Southern-Milky Way catalogs inside the areas of 24 SNR in An Optical Atlas of Galactic Supernova Remnants and in distances that are consistent with the SNR distances. This is supplemented by remarks on stars and other data of seven more optical counterparts of possible SNR that are not in the Atlas, including new spectroscopic data of S 104 and S 188. (31 references, 3 tables) (U.S.)

  2. Recent VERITAS results on galactic supernova remnants

    Science.gov (United States)

    Pohl, Martin

    The VERITAS array of atmospheric Cherenkov telescope has observed TeV-band emission from a number of galactic supernova remnants, including both pulsar-wind nebula and shell-type remnants. We present an overview of recent results with emphasis on IC443, Cas A, and G106.3+2.7/Boomerang, and discuss them in the context of measurements at lower photon energy and theoretical expectations.

  3. New evidence for strong nonthermal effects in Tycho's supernova remnant

    OpenAIRE

    Voelk, H J; Berezhko, E. G.; Ksenofontov, L. T.

    2005-01-01

    For the case of Tycho's supernova remnant (SNR) we present the relation between the blast wave and contact discontinuity radii calculated within the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is demonstrated that these radii are confirmed by recently published Chandra measurements which show that the observed contact discontinuity radius is so close to the shock radius that it can only be explained by efficient CR acceleration which in turn makes th...

  4. Radio polarimetry signatures of strong magnetic turbulence in Supernova Remnants

    OpenAIRE

    Stroman, Wendy; Pohl, Martin

    2009-01-01

    We discuss the emission and transport of polarized radio-band synchrotron radiation near the forward shocks of young shell-type supernova remnants, for which X-ray data indicate a strong amplification of turbulent magnetic field. Modeling the magnetic turbulence through the superposition of waves, we calculate the degree of polarization and the magnetic polarization direction which is at $90^\\circ$ to the conventional electric polarization direction. We find that isotropic strong turbulence w...

  5. Supernova Remnants, Cosmic Rays, and GLAST

    International Nuclear Information System (INIS)

    The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the 'knee' energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the 'knee' energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

  6. Reacceleration of electrons in supernova remnants

    CERN Document Server

    Pohl, M; Telezhinsky, I

    2014-01-01

    The radio spectra of many shell-type supernova remnants show deviations from those expected on theoretical grounds. In this paper we determine the effect of stochastic reacceleration on the spectra of electrons in the GeV band and at lower energies, and we investigate whether or not reacceleration can explain the observed variation of radio spectral indices. We explicitely calculate the momentum diffusion coefficient for 3 types of turbulence expected downstream of the forward shock: fast-mode waves, small-scale non-resonant modes, and large-scale modes arising from turbulent dynamo activity. Noting that low-energy particles are efficiently coupled to the quasi-thermal plasma, a simplified cosmic-ray transport equation can be formulated and is numerically solved. Only fast-mode waves can provide momentum diffusion fast enough to significantly modify the spectra of particles. Using a synchrotron emissivity that accurately reflects a highly turbulent magnetic field, we calculate the radio spectral index and fin...

  7. Nonthermal Radiation from Type Ia Supernova Remnants

    CERN Document Server

    Edmon, Paul P; Jones, T W; Ma, Renyi

    2011-01-01

    We present calculations of expected continuum emissions from Sedov-Taylor phase Type Ia supernova remnants (SNRs), using the energy spectra of cosmic ray (CR) electrons and protons from nonlinear diffusive shock acceleration (DSA) simulations. A new, general-purpose radiative process code, Cosmicp, was employed to calculate the radiation expected from CR electrons and protons and their secondary products. These radio, X-ray and gamma-ray emissions are generally consistent with current observations of Type Ia SNRs. The emissions from electrons in these models dominate the radio through X-ray bands. For warm ISM cases (n_{ISM}=0.3 cm^{-3}), thermal bremsstrahlung becomes the dominant component in the UV to X-rays at late times. Decays of \\pi^0 s from p-p collisions mostly dominate the gamma-ray range, although for a hot, low density ISM case (n_{ISM}=0.003 cm^{-3}), the pion decay contribution is reduced sufficiently to reveal the inverse Compton contribution to TeV gamma-rays. In addition, we present simple sc...

  8. Neutron Star/Supernova Remnant Associations

    OpenAIRE

    Kaspi, V.M.

    1999-01-01

    The evidence for associations between neutron stars and supernova remnants is reviewed. After summarizing the situation for young radio pulsars, I consider the evidence from associations that young neutron stars can have properties very different from those of radio pulsars. This, though still controversial, shakes our simple perception of the Crab pulsar as prototypical of the young neutron star population.

  9. Gamma-Ray Emission From Crushed Clouds in Supernova Remnants

    Energy Technology Data Exchange (ETDEWEB)

    Uchiyama, Yasunobu; Blandford, Roger D.; Funk, Stefan; /SLAC; Tajima, Hiroyasu; /Nagoya U., Solar-Terrestrial Environ. Lab.; Tanaka, Takaaki; /KIPAC, Menlo Park

    2010-10-27

    It is shown that the radio and gamma-ray emission observed from newly-found 'GeV-bright' supernova remnants (SNRs) can be explained by a model, in which a shocked cloud and shock-accelerated cosmic rays (CRs) frozen in it are simultaneously compressed by the supernova blastwave as a result of formation of a radiative cloud shock. Simple reacceleration of pre-existing CRs is generally sufficient to power the observed gamma-ray emission through the decays of {pi}{sup 0}-mesons produced in hadronic interactions between high-energy protons (nuclei) and gas in the compressed-cloud layer. This model provides a natural account of the observed synchrotron radiation in SNRs W51C, W44 and IC 443 with flat radio spectral index, which can be ascribed to a combination of secondary and reaccelerated electrons and positrons.

  10. Near-Infrared Spectroscopy of Young Galactic Supernova Remnants

    CERN Document Server

    Koo, Bon-Chul

    2015-01-01

    Young Galactic supernova remnants (SNRs) are where we can observe closely the supernova (SN) ejecta and its interaction with circumstellar/interstellar medium. Therefore, they provide an opportunity to explore the explosion and the final stage of the evolution of massive stars. Near-infrared (NIR) emission lines in SNRs mostly originate from shocked dense material. In shocked SN ejecta, forbidden lines from heavy ions are prominent, while in shocked circumstellar/interstellar medium, [Fe II] and H2 lines are prominent. [Fe II] lines are strong in both media, and therefore [Fe II] line images provide a good starting point for the NIR study of SNRs. There are about twenty SNRs detected in [Fe II] lines, some of which have been studied in NIR spectroscopy. We will review the NIR [Fe II] observations of SNRs and introduce our recent NIR spectroscopic study of the young core-collapse SNR Cas A where we detected strong [P II] lines.

  11. Far Ultraviolet Spectral Images of the Vela Supernova Remnant

    CERN Document Server

    Nishikida, K; Feuerstein, W M; Jin, H; Korpela, E J; Lee, D H; Min, K W; Sankrit, R; Seon, K I; Shinn, J H; Yuk, I S

    2006-01-01

    We present far-ultraviolet (FUV) spectral-imaging observations of the Vela supernova remnant (SNR), obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR) instrument, also known as FIMS. The Vela SNR extends 8 degrees in the FUV and its global spectra are dominated by shock-induced emission lines. We find that the global FUV line luminosities can exceed the 0.1-2.5 keV soft X-ray luminosity by an order of magnitude. The global O VI:C III ratio shows that the Vela SNR has a relatively large fraction of slower shocks compared with the Cygnus Loop.

  12. Efficient Cosmic Ray Ion Production in Young Supernova Remnants

    CERN Document Server

    Ellison, D C; Ellison, Donald C.; Cassam-Chenai, Gamil

    2005-01-01

    The strong shocks in young supernova remnants (SNRs) should accelerate cosmic rays (CRs) and no doubt exists that relativistic electrons are produced in SNRs. However, direct evidence that SNRs produce CR nuclei depends on seeing an unambiguous pion-decay feature and this has not yet been obtained. Nevertheless, the lack of an observed pion-decay feature does not necessarily mean that CR ions are not abundantly produced since ions do not radiate efficiently. If CR ions are produced efficiently by diffusive shock acceleration (DSA), their presence will modify the hydrodynamics of the SNR and produce morphological effects which can be clearly seen in radiation produced by electrons.

  13. Fermi LAT Observations of Supernova Remnants Interacting with Molecular Clouds

    CERN Document Server

    Castro, Daniel

    2010-01-01

    We report the detection of gamma-ray emission coincident with four supernova remnants (SNRs) using data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. G349.7+0.2, CTB 37A, 3C 391 and G8.7-0.1 are supernova remnants known to be interacting with molecular clouds, as evidenced by observations of hydroxyl (OH) maser emission at 1720 MHz in their directions. SNR shocks are expected to be sites of cosmic rays acceleration, and clouds of dense material can provide effective targets for production of gamma-rays from pion-decay. The observations reveal unresolved sources in the direction of G349.7+0.2, CTB 37A and 3C 391, and a possibly extended source coincident with G8.7-0.1, all with significance levels greater than 10 sigma.

  14. Kepler's Supernova Remnant: The view at 400 Years

    OpenAIRE

    Blair, W. P.

    2004-01-01

    October 2004 marks the 400th anniversary of the sighting of SN 1604, now marked by the presence of an expanding nebulosity known as Kepler's supernova remnant. Of the small number of remnants of historical supernovae, Kepler's remnant remains the most enigmatic. The supernova type, and hence the type of star that exploded, is still a matter of debate, and even the distance to the remnant is uncertain by more than a factor of two. As new and improved multiwavength observation...

  15. Magnetic fields in supernova remnants and pulsar-wind nebulae

    CERN Document Server

    Reynolds, S P; Bocchino, F

    2011-01-01

    We review the observations of supernova remnants (SNRs) and pulsar-wind nebulae (PWNe) that give information on the strength and orientation of magnetic fields. Radio polarimetry gives the degree of order of magnetic fields, and the orientation of the ordered component. Many young shell supernova remnants show evidence for synchrotron X-ray emission. The spatial analysis of this emission suggests that magnetic fields are amplified by one to two orders of magnitude in strong shocks. Detection of several remnants in TeV gamma rays implies a lower limit on the magnetic-field strength (or a measurement, if the emission process is inverse-Compton upscattering of cosmic microwave background photons). Upper limits to GeV emission similarly provide lower limits on magnetic-field strengths. In the historical shell remnants, lower limits on B range from 25 to 1000 microGauss. Two remnants show variability of synchrotron X-ray emission with a timescale of years. If this timescale is the electron-acceleration or radiativ...

  16. Extremely fast acceleration of cosmic rays in a supernova remnant.

    Science.gov (United States)

    Uchiyama, Yasunobu; Aharonian, Felix A; Tanaka, Takaaki; Takahashi, Tadayuki; Maeda, Yoshitomo

    2007-10-01

    Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) through magnetohydrodynamic waves generated by cosmic rays. Here we report a discovery of the brightening and decay of X-ray hot spots in the shell of the SNR RX J1713.7-3946 on a one-year timescale. This rapid variability shows that the X-rays are produced by ultrarelativistic electrons through a synchrotron process and that electron acceleration does indeed take place in a strongly magnetized environment, indicating amplification of the magnetic field by a factor of more than 100. The X-ray variability also implies that we have witnessed the ongoing shock-acceleration of electrons in real time. Independently, broadband X-ray spectrometric measurements of RX J1713.7-3946 indicate that electron acceleration proceeds in the most effective ('Bohm-diffusion') regime. Taken together, these two results provide a strong argument for acceleration of protons and nuclei to energies of 1 PeV (10(15) eV) and beyond in young supernova remnants. PMID:17914390

  17. Extremely Fast Acceleration of Cosmic Rays in a Supernova Remnant

    International Nuclear Information System (INIS)

    Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) through magnetohydrodynamic waves generated by cosmic rays. Here we report a discovery of the brightening and decay of X-ray hot spots in the shell of theSNRRXJ1713.723946 on a one-year timescale. This rapid variability shows that the X-rays are produced by ultrarelativistic electrons through a synchrotron process and that electron acceleration does indeed take place in a strongly magnetized environment, indicating amplification of the magnetic field by a factor of more than 100. The X-ray variability also implies that we have witnessed the ongoing shock-acceleration of electrons in real time. Independently, broadband X-ray spectrometric measurements of RXJ1713.723946 indicate that electron acceleration proceeds in the most effective ('Bohm-diffusion') regime. Taken together, these two results provide a strong argument for acceleration of protons and nuclei to energies of 1 PeV (1015 eV) and beyond in young supernova remnants

  18. Expected gamma-ray emission of supernova remnant SN 1987A

    OpenAIRE

    Berezhko, E. G.; Ksenofontov, L. T.; Voelk, H J

    2010-01-01

    A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants is employed to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5--100 yr. It is shown that an efficient production of nuclear CRs leads to a strong modification of the outer supernova remnant shock and to a large downstream magnetic field $B_\\mathrm{d}\\approx 20$ mG. The shock modification and the strong field are required to yield the steep...

  19. X-rays from Supernova Remnants

    OpenAIRE

    Aschenbach, B.

    2002-01-01

    A summary of X-ray observations of supernova remnants is presented including the explosion fragment A of the Vela SNR, Tycho, N132D, RX J0852-4622, the Crab Nebula and the 'bulls eye', and SN 1987A, high-lighting the progress made with Chandra and XMM-Newton and touching upon the questions which arise from these observations and which might inspire future research.

  20. The Formation and Evolution of Mixed Morphology Supernova Remnants

    Science.gov (United States)

    Smith, Randall

    Supernovae inject metals at high velocities into the interstellar medium (ISM), leading to shocks, plasma heating, and dust destruction and creation in addition to host of other processes. Supernova remnants (SNR) themselves are generally categorized as shell-type, center-filled, or ``mixed morphology.'' These categories, which encapsulate both the structure and evolution of the remnant, seem to depend critically on the precursor star and the surrounding ISM. Mixed morphology remnants, in particular, show a radio shell with a central region that emits primarily thermal X-rays. Observations show that these SNR are typically found near or in molecular clouds and, since they usually contain compact objects, arise from high-mass precursors. However, our theoretical understanding of these remnants lags far behind our observational data. There are at least four distinct models for their appearance, usually explaining observations from one or at most a few of the remnants, but there is no general solution. However, there has been a recent breakthrough in mixed morphology remnants. Suzaku observations of three remnants show that a significant fraction of the thermal X-rays are from a non-equilibrium recombining plasma, a surprising result since SNR are expected to generate ionizing, not recombining, plasmas. This new discovery should severely constrains theoretical predictions. We propose a combined semi-analytic and computational approach to understanding how these remnants develop and evolve. A number of observational studies have already cataloged the emission characteristics and sizes of these remnants. Our study will therefore begin with an exploration of simple 1-D spherically symmetric hydrodynamic plasma models that can generate the observed emission in X-ray and other bandpasses as well as the approximate size of a range of mixed morphology remnants. We will expand these studies using both 2-D and 3-D magnetohydrodynamic explosion models combined with a non-equilibrium plasma code to calculate the thermal X-ray emission. These models will be able to capture the turbulence and ejecta mixing that must happen in these remnants that cannot be simulated in 1-D. We will then determine the emission as a function of position in various bandpasses for our models with a range of initial conditions. This will allow us to determining which observables are the key to understanding the origin and evolution of mixed morphology remnants, and their overall impact on the ISM and the Galaxy. This work will address NASA's Strategic Subgoal 3D, to discover the origin, structure, evolution, and destiny of the universe, and search for Earth-like planets.

  1. AZIMUTHAL DENSITY VARIATIONS AROUND THE RIM OF TYCHO's SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    Spitzer images of Tycho's supernova remnant in the mid-infrared reveal limb-brightened emission from the entire periphery of the shell and faint filamentary structures in the interior. As with other young remnants, this emission is produced by dust grains, warmed to ?100 K in the post-shock environment by collisions with energetic electrons and ions. The ratio of the 70 to 24 ?m fluxes is a diagnostic of the dust temperature, which in turn is a sensitive function of the plasma density. We find significant variations in the 70/24 flux ratio around the periphery of Tycho's forward shock, implying order-of-magnitude variations in density. While some of these are likely localized interactions with dense clumps of the interstellar medium (ISM), we find an overall gradient in the ambient density surrounding Tycho, with densities 3-10 times higher in the northeast than in the southwest. This large density gradient is qualitatively consistent with the variations in the proper motion of the shock observed in radio and X-ray studies. Overall, the mean ISM density around Tycho is quite low (?0.1-0.2 cm–3), consistent with the lack of thermal X-ray emission observed at the forward shock. We perform two-dimensional hydrodynamic simulations of a Type Ia supernova expanding into a density gradient in the ISM, and find that the overall round shape of the remnant is still easily achievable, even for explosions into significant gradients. However, this leads to an offset of the center of the explosion from the geometric center of the remnant of up to 20%, although lower values of 10% are preferred. The best match with hydrodynamical simulations is achieved if Tycho is located at a large (3-4 kpc) distance in a medium with a mean preshock density of ?0.2 cm–3. Such preshock densities are obtained for highly (?> 50%) porous ISM grains.

  2. Future GLAST Observations of Supernova Remnants And Pulsar Wind Nebulae

    International Nuclear Information System (INIS)

    Shell-type Supernova remnants (SNRs) have long been known to harbour a population of ultra-relativistic particles, accelerated in the Supernova shock wave by the mechanism of diffusive shock acceleration. Experimental evidence for the existence of electrons up to energies of 100 TeV was first provided by the detection of hard X-ray synchrotron emission as e.g. in the shell of the young SNR SN1006. Furthermore using theoretical arguments shell-type Supernova remnants have long been considered as the main accelerator of protons - Cosmic rays - in the Galaxy; definite proof of this process is however still missing. Pulsar Wind Nebulae (PWN) - diffuse structures surrounding young pulsars - are another class of objects known to be a site of particle acceleration in the Galaxy, again through the detection of hard synchrotron X-rays such as in the Crab Nebula. Gamma-rays above 100 MeV provide a direct access to acceleration processes. The GLAST Large Area telescope (LAT) will be operating in the energy range between 30 MeV and 300 GeV and will provide excellent sensitivity, angular and energy resolution in a previously rather poorly explored energy band. We will describe prospects for the investigation of these Galactic particle accelerators with GLAST

  3. Using optical lines to study particle acceleration at supernova remnants

    International Nuclear Information System (INIS)

    The shocks of several young supernova remnants (SNR) are often associated with very thin optical filaments dominated by Balmer emission resulting from charge-exchange and collisional excitation between neutral Hydrogen from the interstellar medium and shocked protons and electrons. Optical lines are a direct probe of the conditions at the shock, in particular the width of the narrow and broad components reflect the temperature upstream and downstream of the shock, respectively. When the shock accelerate efficiently non-thermal particles, the shock structure changes producing anomalous Balmer lines and it is possible to use their line shape and their spatial profile to check the efficiency of SNR shocks in accelerating cosmic rays. Here we illustrate the kinetic theory of shock acceleration in presence of neutrals with some applications to young SNRs. We show that in three cases (RCW 86, SNR 0509-67.5 and Tycho) anomalous Balmer lines can be explained assuming that a fraction of ? 10% of the total shock kinetic energy is converted into not thermal particles, while in one single case, the northwestern part of SN 1006, there is no evidence of efficient acceleration

  4. Using optical lines to study particle acceleration at supernova remnants

    Energy Technology Data Exchange (ETDEWEB)

    Morlino, Giovanni [APC, AstroParticule et Cosmologie, Université Paris Diderot, CNRS/IN2P3, CEA/Irfu, Observatoire de Paris, Sorbonne Paris Cité, 10, rue Alice Domon et Léonie Duquet, F-75205 Paris Cedex 13 (France); Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907-2036 (United States)

    2014-11-15

    The shocks of several young supernova remnants (SNR) are often associated with very thin optical filaments dominated by Balmer emission resulting from charge-exchange and collisional excitation between neutral Hydrogen from the interstellar medium and shocked protons and electrons. Optical lines are a direct probe of the conditions at the shock, in particular the width of the narrow and broad components reflect the temperature upstream and downstream of the shock, respectively. When the shock accelerate efficiently non-thermal particles, the shock structure changes producing anomalous Balmer lines and it is possible to use their line shape and their spatial profile to check the efficiency of SNR shocks in accelerating cosmic rays. Here we illustrate the kinetic theory of shock acceleration in presence of neutrals with some applications to young SNRs. We show that in three cases (RCW 86, SNR 0509-67.5 and Tycho) anomalous Balmer lines can be explained assuming that a fraction of ∼ 10% of the total shock kinetic energy is converted into not thermal particles, while in one single case, the northwestern part of SN 1006, there is no evidence of efficient acceleration.

  5. Second Epoch Hubble Space Telescope Imaging of Kepler's Supernova Remnant

    Science.gov (United States)

    Sankrit, Ravi; Blair, William P.; Borkowski, Kazimierz J.; Long, Knox S.; Patnaude, Daniel; Raymond, John C.; Reynolds, Stephen P.; Williams, Brian J.

    2015-01-01

    We have obtained new HST/WFC3 images of Kepler's supernova remnant in H-alpha (F656N) and [N II] (F658N) emission line filters. The bright radiative shocks in dense clumps are detected in both filters, while non-radiative shocks are seen as faint filaments only in the H-alpha image. Most of these Balmer filaments lie around the periphery of the remnant where the blast wave encounters partially neutral interstellar gas. We compare the new images with HST/ACS images taken nearly 10 years previously, and find that these filaments tracing the forward shock have moved 0.6"-0.9" between the two epochs. Assuming a distance of 4 kpc to the remnant, these proper motions correspond to shock velocities of 1160-1740 km/s, which are consistent with the published values, 1550-2000 km/s (e.g. Blair et al. 1991, ApJ 366, 484). We also find a few Balmer filaments with highly non-radial proper motions. In one particularly interesting case in the projected interior of the remnant, SE of the center, the shock appears to have wrapped around a sharp density enhancement and moved about 0.3" in the period between the observations.The images allow us to study the evolution of the shock around an ejecta knot, which is punching through the remnant boundary in the northwest. The forward shock, visible as an arcuate Balmer filament, has moved about 1". At the trailing edges, the system of radiative knots formed by Rayleigh-Taylor instabilities have undergone significant changes - some knots have disappeared, new ones have appeared, and many have changed in brightness. Elsewhere in the remnant we find changes in the relative intensities of many small, bright knots over the 10 year baseline, indicating the short radiative lifetimes of these features.This work has been supported in part by grant HST-GO-12885 to the Universities Space Research Association.

  6. Cosmic ray acceleration search in Supernova Remnants

    International Nuclear Information System (INIS)

    Galactic Supernova Remnants (SNRs) are among the best candidates as source of cosmic rays due to energetics, observed rate of explosion and as possible sites where the Fermi mechanisms naturally plays a key role. Evidence of hadronic acceleration processes taking place in SNRs are being collected with the Fermi-LAT, whose sensitivity in the range 100MeV–100GeV is crucial for disentangling possible hadronic contribution from inverse Compton or bremsstrahlung leptonic component. A survey of the detected SNRs will be given, focusing the attention on the role of the environment and the evolution stage of the SNR in the interpretation of the observed ?-ray spectra

  7. VHE Gamma-ray supernova remnants

    OpenAIRE

    Funk, S

    2007-01-01

    Increasing observational evidence gathered especially in X-rays and gamma-rays during the course of the last few years support the notion that Supernova remnants (SNRs) are Galactic particle accelerators up to energies close to the ``knee'' in the energy spectrum of Cosmic rays. This review summarises the current status of VHE gamma-ray observations of SNRs. Shell-type as well as plerionic type SNRs are addressed and prospect for observations of these two source classes with the upcoming GLAS...

  8. Cosmic ray acceleration search in Supernova Remnants

    Energy Technology Data Exchange (ETDEWEB)

    Giordano, Francesco; Di Venere, Leonardo [Dipartimento di Fisica M. Merlin dell' Università e del Politecnico di Bari, I-70126 Bari (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari (Italy)

    2014-11-15

    Galactic Supernova Remnants (SNRs) are among the best candidates as source of cosmic rays due to energetics, observed rate of explosion and as possible sites where the Fermi mechanisms naturally plays a key role. Evidence of hadronic acceleration processes taking place in SNRs are being collected with the Fermi-LAT, whose sensitivity in the range 100MeV–100GeV is crucial for disentangling possible hadronic contribution from inverse Compton or bremsstrahlung leptonic component. A survey of the detected SNRs will be given, focusing the attention on the role of the environment and the evolution stage of the SNR in the interpretation of the observed γ-ray spectra.

  9. Magnetic field in supernova remnant SN 1987A

    CERN Document Server

    Berezhko, E G

    2006-01-01

    A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants is employed to investigate the properties of the remnant SN 1987A. It is shown that a large downstream magnetic field ~10 mG is required to fit the existing observational data. Such a strong field together with the strong shock modification due to CR backreaction provides the steep and concave radioemission spectrum and considerable synchrotron cooling of high energy electrons which diminish their X-ray synchrotron flux below the observed Chandra flux which has to be considered as an upper limit for nonthermal X-ray emission. The expected gamma-ray energy flux at TeV-energies at the current epoch is 2x10^{-13} erg/(cm^2 s).

  10. On the evolution of supernova remnants: Pt. 2

    International Nuclear Information System (INIS)

    Supernova explosions within wind-driven bubbles are studied with 2D hydrodynamical calculations. Two different density distributions for the ejecta are considered: (i) a smooth, unfragmented power-law stratification, and (ii) a fragmented distribution. As in 1D models, the presence of the shell of interstellar swept-up matter causes the rapid evolution of the remnant to the radiative phase. The main 2D effects, for both fragmented and unfragmented ejecta, include: (i) substantial chaotic deviations from a purely radial flow in the remnant interior, (ii) efficient turbulent mixing between the ejecta and the shocked wind, resulting in homogenization of the former wind cavity, and (iii) severe distortion of the wind-driven shell by cooling and Rayleigh-Taylor instabilities. (author)

  11. New Limits on Enhanced Turbulence at Supernova Remnants

    Science.gov (United States)

    Spitler, L.; Spangler, S.

    2004-12-01

    Theories of cosmic ray acceleration by supernova remnants predict the existence of regions of intense magnetohydrodynamic turbulence upstream and downstream of the shock wave. Such regions are observed in the case of shock waves in the interplanetary medium, and the interplanetary turbulence possesses substantial density fluctuations. In the interplanetary medium, such turbulent regions produce enhanced radio propagation effects such as scintillations and angular broadening. In this paper, we report a search for enhanced angular broadening of the radio sources J0547+273 and J0128+631, observed through the supernova remnants S147 and G127.1+0.5, respectively. The observations were made with the Very Long Baseline Array of the National Radio Astronomy Observatory in the Fall of 2002. Observations were made at wavelengths of 6, 13, 18, and 21 cm. These multifrequency observations allow the scattered and intrinsic structures of these sources to be distinguished. For both sources, angular broadening attributable to interstellar turbulence was measured. The scattering sizes correspond to 1 GHz angular diameters (FWHM) of 8.9 milliarcseconds (mas) for J0128+631 and 6.4 mas for J0547+273, with uncertainties of about 1 mas for both sources. The expected ``incidental'' angular broadening due to the interstellar medium along these lines of sight was estimated from an updated version of the model of Lazio and Cordes (ApJ 479, 238, 1998). The incidental angular size estimates are 9.5 mas and 6.5-7.0 mas for J0128+631 and J0547+273, respectively. We therefore find no evidence for an enhancement of scattering, and thus intense turbulence, associated with either supernova remnant. Quantitative limits on the properties of waves and turbulence will be presented. This work was supported by grant ATM03-54782 from the Division of Atmospheric Sciences, National Science Foundation.

  12. Approximate supernova remnant dynamics with cosmic ray production

    International Nuclear Information System (INIS)

    Supernova explosions are the most violent and energetic events in the galaxy and have long been considered probable sources of cosmic rays. Recent shock acceleration models treating the cosmic rays (CR's) as test particles nb a prescribed supernova remnant (SNR) evolution, indeed indicate an approximate power law momentum distribution f sub source (p) approximation p(-a) for the particles ultimately injected into the interstellar medium (ISM). This spectrum extends almost to the momentum p = 1 million GeV/c, where the break in the observed spectrum occurs. The calculated power law index approximately less than 4.2 agrees with that inferred for the galactic CR sources. The absolute CR intensity can however not be well determined in such a test particle approximation

  13. Supernovae. The bubble-like interior of the core-collapse supernova remnant Cassiopeia A.

    Science.gov (United States)

    Milisavljevic, Dan; Fesen, Robert A

    2015-01-30

    The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of these catastrophic explosions remain uncertain, due partly to limited observational constraints on asymmetries deep inside the star. Here we present near-infrared observations of the young supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimensional map of its interior unshocked ejecta. The remnant's interior has a bubble-like morphology that smoothly connects to and helps explain the multiringed structures seen in the remnant's bright reverse-shocked main shell of expanding debris. This internal structure may originate from turbulent mixing processes that encouraged outwardly expanding plumes of radioactive (56)Ni-rich ejecta. If this is true, substantial amounts of its decay product, (56)Fe, may still reside in these interior cavities. PMID:25635094

  14. Tachyonic Cherenkov radiation from supernova remnants

    Science.gov (United States)

    Tomaschitz, Roman

    2015-12-01

    The subexponential decay observed in the ?-ray spectral maps of supernova remnants is explained in terms of tachyonic Cherenkov emission from a relativistic electron population. The tachyonic radiation densities of an electronic spinor current are derived, the total density as well as the transversal and longitudinal polarization components, taking account of electron recoil. Tachyonic flux quantization subject to dispersive and dissipative permeabilities is discussed, the matrix elements of the transversal and longitudinal Poynting vectors of the Maxwell-Proca field are obtained, Cherenkov emission angles and radiation conditions are derived. The spectral energy flux of an ultra-relativistic electron plasma is calculated, a tachyonic Cherenkov fit to the high-energy (1 GeV to 30 TeV) ?-ray spectrum of the Crab Nebula is performed, and estimates of the linear polarization degree are given. The spectral tail shows subexponential Weibull decay, which can be modeled with a frequency-dependent tachyon mass in the dispersion relations. Tachyonic flux densities interpolate between exponential and power-law spectral decay, which is further illustrated by Cherenkov fits to the ?-ray spectra of the supernova remnants IC 443 and W44. Subexponential spectral decay is manifested in double-logarithmic spectral maps as curved Weibull or straight power-law slope.

  15. Radio evolution of young supernova remnants

    International Nuclear Information System (INIS)

    A one dimensional spherically symmetric magnetohydrodynamic code was developed to describe the evolution of the dynamical and radio properties of young supernova remnants. The code contains subroutines which treat the development of Rayleigh-Taylor instabilities wherever they arise in the remnant. Under the assumption of quasi-stationary equilibrium (dynamical changes considered slow in comparison to the time it takes the instability to achieve equilibrium) determined that the velocity of the instability is W approximately (a lambda)/sup 1/2/, where a is the Rayleigh-Taylor acceleration and lambda is the wavelength of the instability. Subsequent processing of the kinetic energy of expansion, through turbulence, resulted in an increase in temperature and magnetic field strength. The model was used to analyze instability effects of density inhomogeneities in the interstellar medium on magnetic field amplification. A model was constructed for Cassiopeia A which gave good agreement with the measured dynamics, radio structure, and secular flux density decrease for the remnant. In order to compare observation with theory a computer routine was written that convolves the surface brightness at the source. The resultant convolved surface brightness graph is in good agreement with Rosenberg's observed ''model profile;'' differences between the graphs can be attributed to the asymmetric expansion of Cassiopeia A

  16. Radio polarimetry signatures of strong magnetic turbulence in Supernova Remnants

    CERN Document Server

    Stroman, Wendy

    2009-01-01

    We discuss the emission and transport of polarized radio-band synchrotron radiation near the forward shocks of young shell-type supernova remnants, for which X-ray data indicate a strong amplification of turbulent magnetic field. Modeling the magnetic turbulence through the superposition of waves, we calculate the degree of polarization and the magnetic polarization direction which is at $90^\\circ$ to the conventional electric polarization direction. We find that isotropic strong turbulence will produce weakly polarized radio emission even in the absence of internal Faraday rotation. If anisotropy is imposed on the magnetic-field structure, the degree of polarization can be significantly increased, provided internal Faraday rotation is inefficient. Both for shock compression and a mixture with a homogeneous field, the increase in polarization degree goes along with a fairly precise alignment of the magnetic-polarization angle with the direction of the dominant magnetic-field component, implying tangential mag...

  17. Azimuthal Density Variations Around the Rim of Tycho's Supernova Remnant

    CERN Document Server

    Williams, Brian J; Ghavamian, Parviz; Hewitt, John W; Mao, S Alwin; Petre, Robert; Reynolds, Stephen P; Blondin, John M

    2013-01-01

    {\\it Spitzer} images of Tycho's supernova remnant in the mid-infrared reveal limb-brightened emission from the entire periphery of the shell and faint filamentary structures in the interior. As with other young remnants, this emission is produced by dust grains, warmed to $\\sim 100$ K in the post-shock environment by collisions with energetic electrons and ions. The ratio of the 70 to 24 $\\mu$m fluxes is a diagnostic of the dust temperature, which in turn is a sensitive function of the plasma density. We find significant variations in the 70/24 flux ratio around the periphery of Tycho's forward shock, implying order-of-magnitude variations in density. While some of these are likely localized interactions with dense clumps of the interstellar medium, we find an overall gradient in the ambient density surrounding Tycho, with densities 3-10 times higher in the NE than in the SW. This large density gradient is qualitatively consistent with the variations in the proper motion of the shock observed in radio and X-r...

  18. Modified equipartition calculation for supernova remnants

    CERN Document Server

    Arbutina, B; Andjelic, M M; Pavlovic, M Z; Vukotic, B

    2011-01-01

    Determination of the magnetic field strength in the interstellar medium is one of the most complex tasks of contemporary astrophysics. We can only estimate the order of magnitude of the magnetic field strength by using a few very limited methods. Besides Zeeman effect and Faraday rotation, the equipartition or the minimum-energy calculation is a widespread method for estimating magnetic field strength and energy contained in the magnetic field and cosmic ray particles by using only the radio synchrotron emission. Despite of its approximate character, it remains a useful tool, especially when there is no other data about the magnetic field in a source. In this paper we give a modified calculation which we think is more appropriate for estimating magnetic field strengths and energetics in supernova remnants (SNRs). Finally, we present calculated estimates of the magnetic field strengths for all Galactic SNRs for which the necessary observational data are available. The web application for calculation of the mag...

  19. An infrared survey of Galactic supernova remnants

    Energy Technology Data Exchange (ETDEWEB)

    Arendt, R.G.

    1989-05-01

    A survey of Galactic supernova remnants (SNRs) in the infrared has been completed. Flux densities or upper limits on the flux densities have been measured for 157 objects in each of the four broad bands surveyed by the Infrared Astronomical Satellite (IRAS). Nearly one-third of the known SNRs exhibit some evidence of infrared emission. Confusion with other Galactic sources is a serious problem. Contour maps and halftone images are presented for 51 SNRs which are probable infrared sources. Initial analysis indicates that both the infrared spectra or colors and the ratio of infrared to radio brightnesses can discriminate between the youngest SNRs and older SNRs. In general, however, SNRs cannot be distinguished from other Galactic sources solely on the basis of their infrared colors. No apparent relation is found between the infrared surface brightnesses and the diameters of SNRs. 32 refs.

  20. An infrared survey of Galactic supernova remnants

    Science.gov (United States)

    Arendt, Richard G.

    1989-01-01

    A survey of Galactic supernova remnants (SNRs) in the infrared has been completed. Flux densities or upper limits on the flux densities have been measured for 157 objects in each of the four broad bands surveyed by the Infrared Astronomical Satellite (IRAS). Nearly one-third of the known SNRs exhibit some evidence of infrared emission. Confusion with other Galactic sources is a serious problem. Contour maps and halftone images are presented for 51 SNRs which are probable infrared sources. Initial analysis indicates that both the infrared spectra or colors and the ratio of infrared to radio brightnesses can discriminate between the youngest SNRs and older SNRs. In general, however, SNRs cannot be distinguished from other Galactic sources solely on the basis of their infrared colors. No apparent relation is found between the infrared surface brightnesses and the diameters of SNRs.

  1. Discovery of optical candidate supernova remnants in Sagittarius

    CERN Document Server

    Alikakos, J; Christopoulou, P E; Goudis, C D

    2012-01-01

    During an [O III] survey for planetary nebulae, we identified a region in Sagittarius containing several candidate Supernova Remnants and obtained deep optical narrow-band images and spectra to explore their nature. The images of the unstudied area have been obtained in the light of Halpha+[N II], [S II] and [O III]. The resulting mosaic covers an area of 1.4x1.0 deg^2 where filamentary and diffuse emission was discovered, suggesting the existence of more than one supernova remnants (SNRs) in the area. Deep long slit spectra were also taken of eight different regions. Both the flux calibrated images and the spectra show that the emission from the filamentary structures originates from shock-heated gas, while the photo-ionization mechanism is responsible for the diffuse emission. Part of the optical emission is found to be correlated with the radio at 4850 MHz suggesting their association, while the WISE infrared emission found in the area at 12 and 22 micron marginally correlates with the optical. The presenc...

  2. Generation of Cosmic rays in Historical Supernova Remnants

    OpenAIRE

    Sinitsyna V.Y.; Sinitsyna V.G.

    2013-01-01

    We present the results of observations of two types of Galactic supernova remnants with the SHALON mirror Cherenkov telescope of Tien-Shan high-mountain Observatory: the shell-type supernova remnants Tycho, Cas A and IC 443; plerions Crab Nebula, 3c58(SN1181) and Geminga (probably plerion). The experimental data 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 supernova remnant. The data obtaineds...

  3. Generation of Cosmic rays in Historical Supernova Remnants

    Science.gov (United States)

    Sinitsyna, V. G.; Sinitsyna, V. Y.

    2013-06-01

    We present the results of observations of two types of Galactic supernova remnants with the SHALON mirror Cherenkov telescope of Tien-Shan high-mountain Observatory: the shell-type supernova remnants Tycho, Cas A and IC 443; plerions Crab Nebula, 3c58(SN1181) and Geminga (probably plerion). The experimental data 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 supernova remnant. The data obtainedsuggest that the very high energy gamma-ray emission in the objects being discussedis different in origin.

  4. Generation of Cosmic rays in Historical Supernova Remnants

    Directory of Open Access Journals (Sweden)

    Sinitsyna V.Y.

    2013-06-01

    Full Text Available We present the results of observations of two types of Galactic supernova remnants with the SHALON mirror Cherenkov telescope of Tien-Shan high-mountain Observatory: the shell-type supernova remnants Tycho, Cas A and IC 443; plerions Crab Nebula, 3c58(SN1181 and Geminga (probably plerion. The experimental data 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 supernova remnant. The data obtainedsuggest that the very high energy gamma-ray emission in the objects being discussedis different in origin.

  5. The X-ray Iron Emission from Tycho's Supernova Remnant

    CERN Document Server

    Hwang, U; Petre, R; Hwang, Una; Hughes, John P.; Petre, Robert

    1997-01-01

    We present the results of broadband fits to the X-ray spectrum of Tycho's supernova remnant obtained by the Solid-State Imaging Spectrometers on the ASCA Observatory. We use single-temperature, single-ionization-age, nonequilibrium ionization models to characterize the ejecta and the blast-shocked interstellar medium. Based on the Fe K emission at 6.5 keV, previous spectral studies have suggested that the Fe ejecta in this Type Ia remnant are stratified interior to the other ejecta. The ASCA data provide important constraints from the Fe L emission near 1 keV as well as the Fe K emission. We find that the simplest models, with emission from the ejecta and blast wave each at a single temperature and ionization age, severely underestimate the Fe K flux. We show that there is little Fe emission associated with the Si and S ejecta shell. The blast-shocked interstellar medium has abundances roughly 0.3 times the solar value, while the ejecta, with the exception of Fe, have relative abundances that are typical of T...

  6. Onion-shell model of cosmic ray acceleration in supernova remnants

    Science.gov (United States)

    Bogdan, T. J.; Volk, H. J.

    1983-01-01

    A method is devised to approximate the spatially averaged momentum distribution function for the accelerated particles at the end of the active lifetime of a supernova remnant. The analysis is confined to the test particle approximation and adiabatic losses are oversimplified, but unsteady shock motion, evolving shock strength, and non-uniform gas flow effects on the accelerated particle spectrum are included. Monoenergetic protons are injected at the shock front. It is found that the dominant effect on the resultant accelerated particle spectrum is a changing spectral index with shock strength. High energy particles are produced in early phases, and the resultant distribution function is a slowly varying power law over several orders of magnitude, independent of the specific details of the supernova remnant.

  7. HST/ACS Narrowband Imaging of the Kepler Supernova Remnant

    Science.gov (United States)

    Sankrit, Ravi; Blair, William P.; Frattare, Lisa M.; Rudnick, Lawrence; DeLaney, Tracey; Harrus, Ilana M.; Ennis, Jessica A.

    2007-01-01

    We present narrowband images of the Kepler supernova remnant obtained with the Advanced Camera for Surveys aboard the Hubble Space Telescope. The images, with an angular resolution of 0.05" reveal the structure of the emitting gas in unprecedented detail. Radiative and nonradiative shocks are found in close proximity, unresolvable in gromd-based spectra, indicating that the pre-shock medium is highly clumped. The ionization structure, traced by differences in the [0 111] to [N 11] flux ratio, varies on subarcsecond scales. The variation is due to 110th differences in shock velocity as well as gradients in the evolutionary stage of the shocks. A prollinent complex of knots protruding beyond the boundary of the rennallt in the northwest is found to consist of bright radiative knots, collected by arcuate nonradiative filaments. Based on the coincidence of the optical emission with a bright isolated knot of X-ray emission, we infer that this feature is due to a Rayleigh-Taylor finger that formed at the contact discontinuity and overtook the primary blast wave.

  8. Connecting the high- and low-energy Universe: dust processing inside Supernova Remnants

    Science.gov (United States)

    Micelotta, Elisabetta; Dwek, Eli; Slavin, Jonathan

    2015-09-01

    The recent detection of large amounts of dust (> 10(7) M_?) at very high redshift (z > 6) raises a fundamental question about the origin of such dust. The main dust producers, i. e., the stars populating the Red Giant Branch and the Asymptotic Giant Branch (RGB and AGB stars) did not have time to evolve. From an evolutionary point of view, young supernovae (SNe) could represent a viable source of dust in high-redshift galaxies, however, a critical issue still needs to be addressed. While recent observations have demonstrated that supernovae are indeed efficient dust factories, at the same time SNe represent the major agent responsible for dust destruction. Supernova blast waves propagating into the interstellar medium destroy the dust residing there, while the fresh dust produced by the supernova itself is threatened by the reverse shock which propagates through the expanding ejecta towards the center of the remnant. We focus here on this second destruction mechanism, with the aim of quantifying the amount of dust able to survive the heavy processing by the reverse shock and to reach the interstellar medium. We present our results for the textbook supernova remnant Cassiopeia A (Cas A). Using recent X-ray and infrared observations, we have developed a model for the evolution of the remnant and the simultaneous processing of the dust by the reverse shock, and derived the expected amount of surviving dust. In addition, we will briefly illustrate the impact of the capabilities of the Athena mission on the variety of astrophysical problems involving the processing of dust particles in extreme environments characterized by the presence of shocked X-ray emitting gas. These range from individual supernova remnants, to starburst super winds up to AGN outflows and the hot intra-cluster medium. The study of dust processing by a shocked gas truly connects the high-energy Universe with the low-energy Universe, and Athena will play a major role in it.

  9. Planck intermediate results. XXXI. Microwave survey of Galactic supernova remnants

    OpenAIRE

    Plank Collaboration; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Benabed, K.; Bernard, J. -P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bond, J.R.; F. R. Bouchet; Catalano, A.

    2014-01-01

    The all-sky Planck survey in 9 frequency bands was used to search for emission from all 274 known Galactic supernova remnants. Of these, 17 were detected in at least two Planck frequencies. The radio-through-microwave spectral energy distributions were compiled to determine the emission mechanism for microwave emission. In only one case, IC 443, is the high-frequency emission clearly from dust associated with the supernova remnant. In all cases, the low-frequency emission is...

  10. Supernova remnant evolution in uniform and non-uniform media

    Science.gov (United States)

    Ferreira, S. E. S.; de Jager, O. C.

    2008-01-01

    Aims:In this work numerical simulations showing the time evolution of supernova remnants (SNRs) in uniform and non-uniform interstellar medium (ISM) are presented. Methods: We use a hydrodynamic model including a kinematic calculation of the interstellar magnetic field. Important parameters influencing SNR evolution include the ejecta mass and energy of the remnant, as well as the ISM density and adiabatic index. Results: By varying these parameters we constructed an analytical expression giving the return time of the SNR reverse shock to the origin, in terms of these parameters. We also found that the reverse shock spends half of its time moving outward and the other half returning to the origin. Also computed is SNR evolution in non-uniform media where the blast wave moves from one medium into either a less or more dense medium. As the SNR moves into a medium of higher density a reflection wave is created at the interface between the two media which is driven back toward the center. This drives mass via a nonspherical flow away from the discontinuity. As this wave moves inward it also drags some of the ISM field lines (if the field is parallel with the interface) with it and heats the inside of the SNR resulting in larger temperatures in this region. When a SNR explodes in a medium with a high density and the blast wave propagates into a medium with a lower density, a cavity is being blown away changing the geometry of the high density region. Also, once the forward shock moves into the medium of less density a second reverse shock will start to evolve in this region.

  11. X-ray emission of the hot gas and of accelerated particles in supernova remnants

    International Nuclear Information System (INIS)

    The current observations seem to support the theory that the shock wave of supernova remnants accelerate electrons (representing about 1% of cosmic rays) of the interstellar medium up to energies of about 1015 eV. However there is still no solid evidence that supernova remnants also accelerate protons (major component of cosmic rays). The X-ray observations of those supernova remnants with the satellite XMM-Newton can provide crucial information on the acceleration mechanisms and on this population of accelerated particles. This thesis presents the X-ray analysis of the supernova remnants RX J1713.7-3946 and SN 1006 for which it has been shown that they accelerate electrons efficiently. As a result, these objects are very good targets to compare the theoretical models of acceleration to the observation. For the first object, I constructed through new XMM-Newton observations, the first high-angular resolution mosaic of the entire supernova remnant. I then compared the X- and gamma-ray emission of this object in order to understand the nature of the gamma-ray emission. This spectral and morphological comparison allowed me to discuss the two possible origins of the gamma-ray radiation (issued by electrons or by protons). For SN 1006, I studied the density of the ambient medium in which the shock wave propagates. This density is a key parameter for the hydrodynamical evolution of the remnant and for studying a future gamma-ray emission. The study of X-ray emission of the gas heated by the shock wave allowed me to better estimate of the value of the density so far poorly constrained for this object. (author)

  12. Laboratory simulation of unmagnetized supernova remnants: Absence of a blast wave

    International Nuclear Information System (INIS)

    Supernova remnants are experimentally simulated by irradiating spherical targets with an eight-beam arbon dioxide laser in a chamber containing finite amounts of neutral gas, the gas being ionized by radiation from the hot target. The expansion velocities of the target plasmas are approximately the same as the expansion velocities of supernova ejecta and the experiment is successfully scaled to the case of a supernova remnant in an unmagnetized, low-density, interstellar medium. NO sweep-up of the ambient plasma is detected, inicating that no hydrodynamic shock wave is formed to couple the target ejecta to the ambient gas. The experiment implies that if supernova ejecta couple to the interstellar medium, magnetic-field effects may be crucial to the physical description

  13. VERITAS Observations of the Geminga Supernova Remnant

    CERN Document Server

    ,

    2015-01-01

    Geminga was first detected as a gamma-ray point source by the SAS-2 gamma-ray satellite observatory and the COS-B X-ray satellite observatory. Subsequent observations have identified Geminga as a heavily obscured radio-quiet pulsar associated with a nearby (250 pc) late Sedov phase (300,000 year) supernova remnant. The Geminga pulsar is the second brightest source detected by the Large Area Telescope aboard the Fermi gamma-ray satellite (Fermi-LAT) and has been frequently advanced as a source of the anomalous excess of cosmic ray positrons reported by PAMELA, Fermi-LAT, and AMS-2. It is surrounded by a compact X-ray pulsar wind nebula. Observations above 10 TeV by the water Cherenkov observatory Milagro have also revealed a diffuse gamma-ray halo around Geminga extending over several square degrees. Since 2007 the VERITAS IACT observatory has performed observations of Geminga and the surrounding halo region. However, the standard methods of source detection in VERITAS data have insufficient sensitivity to ang...

  14. Supernova Remnant Progenitor Masses in M31

    CERN Document Server

    Jennings, Zachary G; Murphy, Jeremiah W; Dalcanton, Julianne J; Gilbert, Karoline M; Dolphin, Andrew E; Fouesneau, Morgan; Weisz, Daniel R

    2012-01-01

    Using HST photometry, we age-date 59 supernova remnants (SNRs) in the spiral galaxy M31 and use these ages to estimate zero-age main sequence masses (MZAMS) for their progenitors. To accomplish this, we create color-magnitude diagrams (CMDs) and use CMD fitting to measure the recent star formation history (SFH) of the regions surrounding cataloged SNR sites. We identify any young coeval population that likely produced the progenitor star and assign an age and uncertainty to that population. Application of stellar evolution models allows us to infer the MZAMS from this age. Because our technique is not contingent on precise location of the progenitor star, it can be applied to the location of any known SNR. We identify significant young SF around 53 of the 59 SNRs and assign progenitor masses to these, representing a factor of 2 increase over currently measured progenitor masses. We consider the remaining 6 SNRs as either probable Type Ia candidates or the result of core-collapse progenitors that have escaped ...

  15. Cosmic Rays and the Monogem Supernova Remnant

    CERN Document Server

    Erlykin, A D

    2004-01-01

    Recent findings indicate that the Monogem Ring supernova remnant (SNR) and the associated pulsar B0656+14 may be the 'Single Source' responsible for the knee in the cosmic ray (CR) energy spectrum at ~3 PeV. We estimate the contribution of this pulsar to CR in the PeV region. We conclude that although the pulsar can contribute to the formation of the knee, it cannot be the domimant source and a SNR is still needed. We also examine the possibility of the pulsar giving the peak of the extensive air shower (EAS) intensity observed from the region inside the Monogem Ring. If the experimental EAS results concerning a narrow source are confirmed, they can be important, since they give evidence: (i) for the acceleration of protons and heavier nuclei by the pulsar; (ii) for the existence of the confinement mechanism in SNR; (iii) that CR produced by the Monogem Ring SNR and associated pulsar B0656+14 were released recently giving rise to the formation of the knee and the observed narrow peak in the EAS intensity; (iv...

  16. Multi-dimensional simulations of the expanding supernova remnant of SN 1987A

    CERN Document Server

    Potter, T M; Reville, B; Ng, C -Y; Bicknell, G V; Sutherland, R S; Wagner, A Y

    2014-01-01

    The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There are still a large number of outstanding questions, such the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova shock. We explore these questions using three-dimensional simulations of the expanding remnant between days 820 and 10,000 after the supernova. We combine a hydrodynamical simulation with semi-analytic treatments of diffusive shock acceleration and magnetic field amplification to derive radio emission as part of an inverse problem. Simulations show that an asymmetric explosion, combined with magnetic field amplification at the expanding shock, is able to replicate the persistent one-sided radio morphology of the remnant. We use an asymmetric Truelove & McKee progenitor with an envelope mass of $10 M_{\\sun}$ and an energy of $1.5 \\times 10^{44} J$. A termination shock in the...

  17. Radio emission from shell-type supernova remnants

    CERN Document Server

    Asvarov, A

    2006-01-01

    The evolution of the radio emission of shell-type Supernova remnants (SNRs) is modeled within the framework of the simple and commonly used assumptions that the mechanism of diffusive shock acceleration (DSA) is responsible for generating radio emitting electrons and that the magnetic field is the typical interstellar field compressed at the shock. It is considered that electrons are injected into the mechanism in test-particle regime directly from the high energy tail of the downstream Maxwellian distribution function. The model can be applied to most of the observed SNRs. It is shown that the model successfully explains the many averaged observational properties of evolved shell-type SNRs. In particular, the radio surface brightness ($\\Sigma$) evolves with diameter as $\\sim D^{-(0.3 \\div 0.5)}$, while the bounding shock is strong (Mach number is ${\\mathcal M} \\geq10$), followed by steep decrease (steeper than $\\sim D^{-4.5}$) for ${\\cal M} <10$. Such evolution of the surface brightness with diameter and ...

  18. A Model Grid for the Spectral Analysis of X-ray Emission in Young Type Ia Supernova Remnants

    OpenAIRE

    Badenes, C.; Bravo, E; Borkowski, K.

    2005-01-01

    We address a new set of models for the spectral analysis of the X-ray emission from young, ejecta-dominated Type Ia supernova remnants. These models are based on hydrodynamic simulations of the interaction between Type Ia supernova explosion models and the surrounding ambient medium, coupled to self-consistent ionization and electron heating calculations in the shocked supernova ejecta, and the generation of synthetic spectra with an appropriate spectral code. The details ar...

  19. Interstellar and Ejecta Dust in the Cas A Supernova Remnant

    Science.gov (United States)

    Arendt, Richard G.; Dwek, Eli; Kober, Gladys; Rho, Jonghee; Hwang, Una

    2013-01-01

    The ejecta of the Cas A supernova remnant has a complex morphology, consisting of dense fast-moving line emitting knots and diffuse X-ray emitting regions that have encountered the reverse shock, as well as more slowly expanding, unshocked regions of the ejecta. Using the Spitzer 5-35 micron IRS data cube, and Herschel 70, 100, and 160 micron PACS data, we decompose the infrared emission from the remnant into distinct spectral components associated with the different regions of the ejecta. Such decomposition allows the association of different dust species with ejecta layers that underwent distinct nuclear burning histories, and determination of the dust heating mechanisms. Our decomposition identified three characteristic dust spectra. The first, most luminous one, exhibits strong emission features at approx. 9 and 21 micron, and a weaker 12 micron feature, and is closely associated with the ejecta knots that have strong [Ar II] 6.99 micron and [Ar III] 8.99 micron emission lines. The dust features can be reproduced by magnesium silicate grains with relatively low MgO-to-SiO2 ratios. A second, very different dust spectrum that has no indication of any silicate features, is best fit by Al2O3 dust and is found in association with ejecta having strong [Ne II] 12.8 micron and [Ne III] 15.6 micron emission lines. A third characteristic dust spectrum shows features that best matched by magnesium silicates with relatively high MgO-to-SiO2 ratio. This dust is primarily associated with the X-ray emitting shocked ejecta and the shocked interstellar/circumstellar material. All three spectral components include an additional featureless cold dust component of unknown composition. Colder dust of indeterminate composition is associated with [Si II] 34.8 micron emission from the interior of the SNR, where the reverse shock has not yet swept up and heated the ejecta. The dust mass giving rise to the warm dust component is about approx. 0.1solar M. However, most of the dust mass is associated with the unidentified cold dust component. Its mass could be anywhere between 0.1 and 1 solar M, and is primarily limited by the mass of refractory elements in the ejecta. Given the large uncertainty in the dust mass, the question of whether supernovae can produce enough dust to account for ISM dust masses in the local and high-z universe remains largely unresolved.

  20. Discovery of optical candidate supernova remnants in Sagittarius

    Science.gov (United States)

    Alikakos, J.; Boumis, P.; Christopoulou, P. E.; Goudis, C. D.

    2012-08-01

    During an [O III] survey of planetary nebulae, we identified a region in Sagittarius containing several candidate supernova remants (SNRs) and obtained deep optical narrow-band images and spectra to explore their nature. We obtained images of the area of interest by acquiring observations in the emission lines of Hα + [N II], [S II] and [O III]. The resulting mosaic covers an area of 1.4° × 1.0°, where both filamentary and diffuse emission was discovered, suggesting that there is more than one SNR in the area. Deep long-slit spectra were also taken of eight different regions. Both the flux-calibrated images and the spectra show that the emission from the filamentary structures originates from shock-heated gas, while the photo-ionization mechanism is responsible for the diffuse emission. Part of the optical emission is found to be correlated with the radio at 4850 MHz suggesting that they are related, while the infrared emission found in the area at 12 μm and 22 μm marginally correlates with the optical. The presence of the [O III] emission line in one of the candidate SNRs implies that the shock velocities in the interstellar "clouds" are between 120 km s-1 and 200 km s-1, while its absence in the other candidate SNRs indicates that the shock velocities there are slower. For all candidate remnants, the [S II] λλ 6716/6731 ratio indicates that the electron densities are below 240 cm-3, while the Hα emission is measured to be between 0.6 and 41 × 10-17 erg s-1 cm-2 arcsec-2. The existence of eight pulsars within 1.5° of the center of the candidate SNRs also implies that there are many SNRs in the area as well as that the detected optical emission could be part of a number of supernovae explosions.

  1. Dynamics of Fe-Ni Bubbles in Young Supernova Remnants

    CERN Document Server

    Blondin, J M; Reynolds, S P

    2001-01-01

    Observations of core-collapse supernovae (SNe) have revealed the presence of extensive mixing of radioactive material in SN ejecta. The mixing of radioactive material, mostly freshly synthesized Ni, is not complete, which leads to a two-phase SN ejecta structure. The low-density phase consists of Fe bubbles, created by the energy input from radioactive Co and Ni, surrounded by compressed high-density metal-rich ejecta. We report on the theoretical investigation of supernova remnant (SNR) dynamics with the two-phase SN ejecta. We first present 3-dimensional hydrodynamic simulations of a single Fe bubble immersed in an outer ejecta envelope, and compare the results with previous work on shock-cloud interactions. We then consider randomly distributed Fe bubbles with an average volume filling fraction of 1/2. We find that the presence of Fe bubbles leads to vigorous turbulence and mixing of Fe with other heavy elements and with the ambient normal-abundance gas. The turbulent energy can be an order of magnitude la...

  2. Acceleration of cosmic rays in supernova-remnants

    International Nuclear Information System (INIS)

    It is commonly accepted that supernova-explosions are the dominant source of cosmic rays up to an energy of 10 to the 14th power eV/nucleon. Moreover, these high energy particles provide a major contribution to the energy density of the interstellar medium (ISM) and should therefore be included in calcuations of interstellar dynamic phenomena. For the following the first order Fermi mechanism in shock waves are considered to be the main acceleration mechanism. The influence of this process is twofold; first, if the process is efficient (and in fact this is the case) it will modify the dynamics and evolution of a supernova-remnant (SNR), and secondly, the existence of a significant high energy component changes the overall picture of the ISM. The complexity of the underlying physics prevented detailed investigations of the full non-linear selfconsistent problem. For example, in the context of the energy balance of the ISM it has not been investigated how much energy of a SN-explosion can be transfered to cosmic rays in a time-dependent selfconsistent model. Nevertheless, a lot of progress was made on many aspects of the acceleration mechnism

  3. Suzaku spectra of a Type II Supernova Remnant Kes 79

    CERN Document Server

    Sato, Tamotsu; Lee, Shiu-Hang; Takahashi, Tadayuki

    2015-01-01

    This paper reports results of a Suzaku observation of the supernova remnant (SNR) Kes 79 (G33.6+0.1). The X-ray spectrum is best fitted by a two-temperature model: a non-equilibrium ionization (NEI) plasma and a collisional ionization equilibrium (CIE) plasma. The NEI plasma is spatially confined within the inner radio shell with kT~0.8 keV, while the CIE plasma is found in more spatially extended regions associated with the outer radio shell with kT~0.2 keV and solar abundance. Therefore, the NEI plasma is attributable to the SN ejecta and the CIE plasma is forward shocked interstellar medium. In the NEI plasma, we discovered K-shell line of Al, Ar and Ca for the first time. The abundance pattern and estimated mass of the ejecta are consistent with the core-collapse supernova explosion of a ~30-40 solar mass progenitor star. An Fe line with center energy of ~6.4 keV is also found in the southeast (SE) portion of the SNR, a close peripheral region around dense molecular clouds. One possibility is that the lin...

  4. Multi-dimensional simulations of the expanding supernova remnant of SN 1987A

    Energy Technology Data Exchange (ETDEWEB)

    Potter, T. M.; Staveley-Smith, L. [International center for Radio Astronomy Research (ICRAR) M468, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Reville, B. [Center for Plasma Physics, Queen' s University Belfast, University Road, Belfast BT7 1NN (United Kingdom); Ng, C.-Y. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Bicknell, G. V.; Sutherland, R. S. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 0200 (Australia); Wagner, A. Y., E-mail: tobympotter@gmail.com [Center for Computational Sciences, Tsukuba University, Tsukuba, Ibaraki, 305-8577 (Japan)

    2014-10-20

    The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There is still a large number of outstanding questions, such as the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova shock. We explore these questions using three-dimensional simulations of the expanding remnant between days 820 and 10,000 after the supernova. We combine a hydrodynamical simulation with semi-analytic treatments of diffusive shock acceleration and magnetic field amplification to derive radio emission as part of an inverse problem. Simulations show that an asymmetric explosion, combined with magnetic field amplification at the expanding shock, is able to replicate the persistent one-sided radio morphology of the remnant. We use an asymmetric Truelove and McKee progenitor with an envelope mass of 10 M {sub ?} and an energy of 1.5 × 10{sup 44} J. A termination shock in the progenitor's stellar wind at a distance of 0.''43-0.''51 provides a good fit to the turn on of radio emission around day 1200. For the H II region, a minimum distance of 0.''63 ± 0.''01 and maximum particle number density of (7.11 ± 1.78) × 10{sup 7} m{sup –3} produces a good fit to the evolving average radius and velocity of the expanding shocks from day 2000 to day 7000 after explosion. The model predicts a noticeable reduction, and possibly a temporary reversal, in the asymmetric radio morphology of the remnant after day 7000, when the forward shock left the eastern lobe of the equatorial ring.

  5. Observations of young core collapse supernova remnants

    Science.gov (United States)

    Tziamtzis, Anestis

    Studies of young remnants offer an opportunity to test theoretical models of stellar evolution, explosion models and nucleosynthesis, as well as our understanding of the compact objects in the centre of the exploded stars. The first part of the thesis involves observations of the Crab nebula. We have used photometric and spectroscopic observations to search for a faint halo around the visible nebula, that could carry the missing mass and kinetic energy of the nebula. No halo was found. In the photometric data due to psf contamination, and in the spectroscopic no fast velocity components were present. We have also used optical and IR photometry to check for variation in the emissivity and dynamic structure of the Crab pulsar wind nebula (PWN), to try to understand the nature of plerionic PWNe. There, we measured flux variations up to 20% in the IR and also shifting of the wisps with velocities up to 0.2c. We also showed that the nearby red knot moves in tandem with the Crab pulsar. The second part of the thesis, deals with photometric & spectroscopic observations of SN 1987A in the LMC. The aim of the project was to monitor the evolution of the outer rings (ORs) of SN 1987A. The fading of the ORs is consistent with recombination and cooling after the initial flash ionization by the supernova. From the spectroscopic data we measured the density and temperature in the ORs where we found temperatures of ~ 12,000 K for the [N II] gas, and ~ 25,000 K for the [O III]. Finally, from the [O II], and [S II] ratios we estimated electron densities of ~ 1,000 cm-3 and ~ 2,500 cm-3, respectively. From the evolution of H?, we argue that the highest density in the ORs could be 5,000 cm-3.

  6. PHYSICAL STRUCTURE AND NATURE OF SUPERNOVA REMNANTS IN M101

    Energy Technology Data Exchange (ETDEWEB)

    Franchetti, Nicholas A.; Gruendl, Robert A.; Chu, You-Hua; Dunne, Bryan C. [Astronomy Department, University of Illinois, 1002 W. Green Street, Urbana, IL 61801 (United States); Pannuti, Thomas G.; Grimes, Caleb K. [Department of Earth and Space Sciences, Space Science Center, Morehead State University, 235 Martindale Drive, Morehead, KY 40351 (United States); Kuntz, Kip D. [Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Chen, C.-H. Rosie [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Aldridge, Tabitha M., E-mail: franche1@illinois.edu, E-mail: gruendl@astro.illinois.edu, E-mail: yhchu@astro.illinois.edu, E-mail: bdunne@astro.illinois.edu, E-mail: t.pannuti@moreheadstate.edu, E-mail: ckgrim01@moreheadstate.edu, E-mail: kuntz@pha.jhu.edu, E-mail: rchen@mpifr-bonn.mpg.de, E-mail: z1611057@students.niu.edu [Department of Geology and Environmental Geosciences, Northern Illinois University, Davis Hall 312, Normal Road, DeKalb, IL 60115 (United States)

    2012-04-15

    Supernova remnant (SNR) candidates in the giant spiral galaxy M101 have been previously identified from ground-based H{alpha} and [S II] images. We have used archival Hubble Space Telescope (HST) H{alpha} and broadband images as well as stellar photometry of 55 SNR candidates to examine their physical structure, interstellar environment, and underlying stellar population. We have also obtained high-dispersion echelle spectra to search for shocked high-velocity gas in 18 SNR candidates, and identified X-ray counterparts to SNR candidates using data from archival observations made by the Chandra X-Ray Observatory. Twenty-one of these 55 SNR candidates studied have X-ray counterparts, although one of them is a known ultraluminous X-ray source. The multi-wavelength information has been used to assess the nature of each SNR candidate. We find that within this limited sample, {approx}16% are likely remnants of Type Ia SNe and {approx}45% are remnants of core-collapse SNe. In addition, about {approx}36% are large candidates which we suggest are either superbubbles or OB/H II complexes. Existing radio observations are not sensitive enough to detect the non-thermal emission from these SNR candidates. Several radio sources are coincident with X-ray sources, but they are associated with either giant H II regions in M101 or background galaxies. The archival HST H{alpha} images do not cover the entire galaxy and thus prevents a complete study of M101. Furthermore, the lack of HST [S II] images precludes searches for small SNR candidates which could not be identified by ground-based observations. Such high-resolution images are needed in order to obtain a complete census of SNRs in M101 for a comprehensive investigation of the distribution, population, and rates of SNe in this galaxy.

  7. Supernova remnant W49B and its environment

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, H.; Tian, W. W.; Zuo, P., E-mail: zhuhui@bao.ac.cn, E-mail: tww@bao.ac.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2014-10-01

    We study gamma-ray supernova remnant (SNR) W49B and its environment using recent radio and infrared data. Spitzer Infrared Spectrograph low resolution data of W49B shows shocked excitation lines of H{sub 2} (0,0) S(0)-S(7) from the SNR-molecular cloud interaction. The H{sub 2} gas is composed of two components with temperatures of ?260 K and ?1060 K, respectively. Various spectral lines from atomic and ionic particles are detected toward W49B. We suggest that the ionic phase has an electron density of ?500 cm{sup –3} and a temperature of ?10{sup 4} K by the spectral line diagnoses. The mid- and far-infrared data from MSX, Spitzer, and Herschel reveal a 151 ± 20 K hot dust component with a mass of 7.5 ± 6.6 × 10{sup –4} M {sub ?} and a 45 ± 4 K warm dust component with a mass of 6.4 ± 3.2 M {sub ?}. The hot dust is likely from materials swept up by the shock of W49B. The warm dust may possibly originate from the evaporation of clouds interacting with W49B. We build the H I absorption spectra of W49B and four nearby H II regions (W49A, G42.90+0.58, G42.43-0.26, and G43.19-0.53) and study the relation between W49B and the surrounding molecular clouds by employing the 2.12 ?m infrared and CO data. We therefore obtain a kinematic distance of ?10 kpc for W49B and suggest that the remnant is likely associated with the CO cloud at about 40 km s{sup –1}.

  8. XMM-Newton observation of the Tycho Supernova Remnant

    CERN Document Server

    Decourchelle, A; Audard, M; Aschenbach, B; Sembay, S; Rothenflug, R; Ballet, J; Stadlbauer, T; West, R G

    2001-01-01

    We present the observation of the Tycho supernova remnant obtained with the EPIC and RGS instruments onboard the XMM-Newton satellite. We compare images and azimuthally averaged radial profiles in emission lines from different elements (silicon and iron) and different transition lines of iron (Fe L and Fe K). While the Fe XVII L line and Si XIII K line images are globally spatially coincident, the Fe K emission clearly peaks at a smaller radius, indicating a higher temperature toward the reverse shock. This is qualitatively the profile expected when the reverse shock, after travelling through the outer power-law density profile, has entered the central plateau of the ejecta. The high energy continuum map has an overall smooth distribution, with a similar extent to the radio emission. Its radial profile peaks further out than the lines emission. Brighter and harder continuum regions are observed with a rough bipolar symmetry in the eastern and western edges. The spectral analysis of the southeastern knots supp...

  9. Interactions Between CRs and MCs in the Vicinity of Supernova Remnants

    Science.gov (United States)

    Hewitt, John W.

    2011-01-01

    Supernovae are incredibly energetic events which drive the dynamic state of the interstellar medium and accelerate cosmic rays up to energies of a few PeV. I present multi-wavelength observations constraining the shocks, chemistry, dust grain processing, and magnetic fields in a large sample of supernova remnants interacting with dense clouds. These are among the most luminous Galactic sources detected by the Fermi Gamma-Ray Space Telescope. Surprisingly, spectral breaks are seen between GeV and TeV energies. Radio spectral breaks have also been detected for a few remnants, providing clear evidence that supernovae are a significant source of hadronic cosmic rays in the Galaxy. Resolving the origin of these spectral breaks will allow the physics of cosmic ray acceleration and diffusion to be probed.

  10. SUPERNOVA REMNANT PROGENITOR MASSES IN M31

    Energy Technology Data Exchange (ETDEWEB)

    Jennings, Zachary G.; Williams, Benjamin F.; Dalcanton, Julianne J.; Gilbert, Karoline M.; Fouesneau, Morgan; Weisz, Daniel R. [Department of Astronomy, University of Washington Seattle, Box 351580, WA 98195 (United States); Murphy, Jeremiah W. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Dolphin, Andrew E., E-mail: zachjenn@uw.edu, E-mail: adolphin@raytheon.com [Raytheon, 1151 East Hermans Road, Tucson, AZ 85706 (United States)

    2012-12-10

    Using Hubble Space Telescope photometry, we age-date 59 supernova remnants (SNRs) in the spiral galaxy M31 and use these ages to estimate zero-age main-sequence masses (M{sub ZAMS}) for their progenitors. To accomplish this, we create color-magnitude diagrams (CMDs) and employ CMD fitting to measure the recent star formation history of the regions surrounding cataloged SNR sites. We identify any young coeval population that likely produced the progenitor star, then assign an age and uncertainty to that population. Application of stellar evolution models allows us to infer the M{sub ZAMS} from this age. Because our technique is not contingent on identification or precise location of the progenitor star, it can be applied to the location of any known SNRs. We identify significant young star formation around 53 of the 59 SNRs and assign progenitor masses to these, representing a factor of {approx}2 increase over currently measured progenitor masses. We consider the remaining six SNRs as either probable Type Ia candidates or the result of core-collapse progenitors that have escaped their birth sites. In general, the distribution of recovered progenitor masses is bottom-heavy, showing a paucity of the most massive stars. If we assume a single power-law distribution, dN/dM{proportional_to}M{sup {alpha}}, then we find a distribution that is steeper than a Salpeter initial mass function (IMF) ({alpha} = -2.35). In particular, we find values of {alpha} outside the range -2.7 {>=} {alpha} {>=} -4.4 to be inconsistent with our measured distribution at 95% confidence. If instead we assume a distribution that follows a Salpeter IMF up to some maximum mass, then we find that values of M{sub Max} > 26 are inconsistent with the measured distribution at 95% confidence. In either scenario, the data suggest that some fraction of massive stars may not explode. The result is preliminary and requires more SNRs and further analysis. In addition, we use our distribution to estimate a minimum mass for core collapse between 7.0 and 7.8 M{sub Sun }.

  11. Far-Ultraviolet Cooling Features of the Antlia Supernova Remnant

    CERN Document Server

    Shinn, Jong-Ho; Sankrit, Ravi; Ryu, Kwang-Sun; Kim, Il-Joong; Han, Wonyong; Nam, Uk-Won; Park, Jang-Hyun; Edelstein, Jerry; Korpela, Eric J

    2007-01-01

    We present far-ultraviolet observations of the Antlia supernova remnant obtained with Far-ultraviolet IMaging Spectrograph (FIMS, also called SPEAR). The strongest lines observed are C IV 1548,1551 and C III 977. The C IV emission of this mixed-morphology supernova remnant shows a clumpy distribution, and the line intensity is nearly constant with radius. The C III 977 line, though too weak to be mapped over the whole remnant, is shown to vary radially. The line intensity peaks at about half the radius, and drops at the edge of the remnant. Both the clumpy distribution of C IV and the rise in the C IV to C III ratio towards the edge suggest that central emission is from evaporating cloudlets rather than thermal conduction in a more uniform, dense medium.

  12. Theory of non-thermal phenomena in thin plasma sources: galaxy clusters, galaxies and supernova remnants

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, A.M

    2004-06-01

    We review current models of energetic particle acceleration and nonthermal emission from objects of very different scales from clusters of galaxies through massive galaxies to supernova remnants. The nonthermal phenomena in clusters and massive galaxies are considered in the context of the hierarchical model of cosmic structure formation by accretion and merging of the dark matter (DM) substructures. The hierarchical model predicts interaction of sub-galactic scale DM halos with massive galaxies. The accretion and merging processes are producing gas shocks. Being the main gas-heating agent, large-scale shocks in the course of cluster/galaxy structure aggregation, could accelerate energetic particles by the same collisionless plasma relaxation processes. Nonthermal emission of the energetic particles in clusters and massive galaxies could be a test to constrain the DM minihalos properties. We also discuss X-ray emission from supernova remnants in a dense galactic environment with applications to deep observations of the Galactic Center region.

  13. Evidence For Particle Acceleration to the Knee of the Cosmic Ray Spectrum in Tycho's Supernova Remnant

    OpenAIRE

    Eriksen, Kristoffer A.; Hughes, John P; Badenes, Carles; Fesen, Robert; Ghavamian, Parviz; Moffett, David; Plucinsky, Paul P.; Rakowski, Cara E.; Reynoso, Estela M.; Slane, Patrick

    2011-01-01

    Supernova remnants (SNRs) have long been assumed to be the source of cosmic rays (CRs) up to the "knee" of the CR spectrum at 10^15 eV, accelerating particles to relativistic energies in their blast waves by the process of diffusive shock acceleration (DSA). Since cosmic ray nuclei do not radiate efficiently, their presence must be inferred indirectly. Previous theoretical calculations and X-ray observations show that CR acceleration modifies significantly the structure of the SNR and greatly...

  14. The TeV Morphology of the Interacting Supernova Remnant IC 443

    CERN Document Server

    Humensky, Brian

    2015-01-01

    The middle-aged supernova remnant IC 443 is interacting with molecular gas in its surroundings. $Fermi$-LAT has established that its gamma-ray emission at low energies shows the "pion bump" that is characteristic of hadronic emission. TeV emission was previously established by MAGIC and VERITAS at a site of interaction between the shock front and a molecular cloud. VERITAS has continued to observe IC 443 and can now resolve the emission on few-arcmin scales. We will present results on the emission morphology and discuss possible sources of the emission, including the shell of the remnant and other gaseous structures in the vicinity.

  15. On the Nonthermal Emission from the Supernova Remnant W51C

    OpenAIRE

    Fang, Jun; Zhang, Li

    2010-01-01

    The middle-aged supernova remnant (SNR) W51C is an interesting source for the interaction of the shell with a molecular cloud. The shell emits intense radio synchrotron photons, and high-energy gamma-rays from the remnant have been detected using the {\\it Fermi} Large Area Telescope (LAT), the H.E.S.S. telescope, and the Milagro gamma-ray observatory. Based on a semi-analytical approach to the nonlinear shock acceleration process, we investigate the multiband nonthermal emis...

  16. Onion-shell model for cosmic ray electrons and radio synchrotron emission in supernova remnants

    Science.gov (United States)

    Beck, R.; Drury, L. O.; Voelk, H. J.; Bogdan, T. J.

    1985-01-01

    The spectrum of cosmic ray electrons, accelerated in the shock front of a supernova remnant (SNR), is calculated in the test-particle approximation using an onion-shell model. Particle diffusion within the evolving remnant is explicity taken into account. The particle spectrum becomes steeper with increasing radius as well as SNR age. Simple models of the magnetic field distribution allow a prediction of the intensity and spectrum of radio synchrotron emission and their radial variation. The agreement with existing observations is satisfactory in several SNR's but fails in other cases. Radiative cooling may be an important effect, especially in SNR's exploding in a dense interstellar medium.

  17. Onion-shell model for cosmic ray electrons and radio synchrotron emission in supernova remnants

    International Nuclear Information System (INIS)

    The spectrum of cosmic ray electrons, accelerated in the shock front of a supernova remnant (SNR), is calculated in the test-particle approximation using an onion-shell model. Particle diffusion within the evolving remnant is explicity taken into account. The particle spectrum becomes steeper with increasing radius as well as SNR age. Simple models of the magnetic field distribution allow a prediction of the intensity and spectrum of radio synchrotron emission and their radial variation. The agreement with existing observations is satisfactory in several SNR's but fails in other cases. Radiative cooling may be an important effect, especially in SNR's exploding in a dense interstellar medium

  18. Interstellar and ejecta dust in the cas a supernova remnant

    International Nuclear Information System (INIS)

    Infrared continuum observations provide a means of investigating the physical composition of the dust in the ejecta and swept up medium of the Cas A supernova remnant (SNR). Using low-resolution Spitzer IRS spectra (5-35 ?m), and broad-band Herschel PACS imaging (70, 100, and 160 ?m), we identify characteristic dust spectra, associated with ejecta layers that underwent distinct nuclear burning histories. The most luminous spectrum exhibits strong emission features at ?9 and 21 ?m and is closely associated with ejecta knots with strong Ar emission lines. The dust features can be reproduced by magnesium silicate grains with relatively low Mg to Si ratios. Another dust spectrum is associated with ejecta having strong Ne emission lines. It has no indication of any silicate features and is best fit by Al2O3 dust. A third characteristic dust spectrum shows features that are best matched by magnesium silicates with a relatively high Mg to Si ratio. This dust is primarily associated with the X-ray-emitting shocked ejecta, but it is also evident in regions where shocked interstellar or circumstellar material is expected. However, the identification of dust composition is not unique, and each spectrum includes an additional featureless dust component of unknown composition. Colder dust of indeterminate composition is associated with emission from the interior of the SNR, where the reverse shock has not yet swept up and heated the ejecta. Most of the dust mass in Cas A is associated with this unidentified cold component, which is ? 0.1 M ?. The mass of warmer dust is only ?0.04 M ?.

  19. Interstellar and ejecta dust in the cas a supernova remnant

    Energy Technology Data Exchange (ETDEWEB)

    Arendt, Richard G. [CRESST, University of Maryland, Baltimore County, Baltimore, MD 21250 (United States); Dwek, Eli; Kober, Gladys [NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Rho, Jeonghee [SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Hwang, Una, E-mail: Richard.G.Arendt@nasa.gov [NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States)

    2014-05-01

    Infrared continuum observations provide a means of investigating the physical composition of the dust in the ejecta and swept up medium of the Cas A supernova remnant (SNR). Using low-resolution Spitzer IRS spectra (5-35 ?m), and broad-band Herschel PACS imaging (70, 100, and 160 ?m), we identify characteristic dust spectra, associated with ejecta layers that underwent distinct nuclear burning histories. The most luminous spectrum exhibits strong emission features at ?9 and 21 ?m and is closely associated with ejecta knots with strong Ar emission lines. The dust features can be reproduced by magnesium silicate grains with relatively low Mg to Si ratios. Another dust spectrum is associated with ejecta having strong Ne emission lines. It has no indication of any silicate features and is best fit by Al{sub 2}O{sub 3} dust. A third characteristic dust spectrum shows features that are best matched by magnesium silicates with a relatively high Mg to Si ratio. This dust is primarily associated with the X-ray-emitting shocked ejecta, but it is also evident in regions where shocked interstellar or circumstellar material is expected. However, the identification of dust composition is not unique, and each spectrum includes an additional featureless dust component of unknown composition. Colder dust of indeterminate composition is associated with emission from the interior of the SNR, where the reverse shock has not yet swept up and heated the ejecta. Most of the dust mass in Cas A is associated with this unidentified cold component, which is ? 0.1 M {sub ?}. The mass of warmer dust is only ?0.04 M {sub ?}.

  20. Supernova 1987A: a Template to Link Supernovae to their Remnants

    CERN Document Server

    Orlando, S; Pumo, M L; Bocchino, F

    2015-01-01

    The emission of supernova remnants reflects the properties of both the progenitor supernovae and the surrounding environment. The complex morphology of the remnants, however, hampers the disentanglement of the two contributions. Here we aim at identifying the imprint of SN 1987A on the X-ray emission of its remnant and at constraining the structure of the environment surrounding the supernova. We performed high-resolution hydrodynamic simulations describing SN 1987A soon after the core-collapse and the following three-dimensional expansion of its remnant between days 1 and 15000 after the supernova. We demonstrated that the physical model reproducing the main observables of SN 1987A during the first 250 days of evolution reproduces also the X-ray emission of the subsequent expanding remnant, thus bridging the gap between supernovae and supernova remnants. By comparing model results with observations, we constrained the explosion energy in the range $1.2-1.4\\times 10^{51}$~erg and the envelope mass in the rang...

  1. The bubble-like interior of the core-collapse supernova remnant Cassiopeia A

    Science.gov (United States)

    Milisavljevic, Dan; Fesen, Robert A.

    2015-01-01

    The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of these catastrophic explosions remain uncertain, due partly to limited observational constraints on asymmetries deep inside the star. Here we present near-infrared observations of the young supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimensional map of its interior unshocked ejecta. The remnant’s interior has a bubble-like morphology that smoothly connects to and helps explain the multiringed structures seen in the remnant's bright reverse-shocked main shell of expanding debris. This internal structure may originate from turbulent mixing processes that encouraged outwardly expanding plumes of radioactive 56Ni-rich ejecta. If this is true, substantial amounts of its decay product, 56Fe, may still reside in these interior cavities.

  2. On the origin of strong magnetic fields in young supernova remnants

    CERN Document Server

    Jun, B I; Jun, Byung Il; Norman, Michael L

    1996-01-01

    Young supernova remnants such as Tycho generally exhibit a bright circular clumpy shell in both radio and X-ray emission. For several young remnants, various arguments suggest that the magnetic field is larger than can be explained by compression of a few \\mu G ambient magnetic field by the shock wave. Radio polarization studies reveal a net radial orientation of magnetic fields in the shell which cannot be explained by the simple compression either. We model Rayleigh-Taylor instability at the interface of the ejecta and the shocked ambient medium to explain these observations. We have performed multidimensional MHD simulations of the instability in the shell of a Type-I supernova remnant for the first time utilizing a moving grid technique which allows us to follow the growth of the instability and its effect on the local magnetic field in detail. We find that the evolution of the instability is very sensitive to the deceleration of the ejecta and the evolutionary stage of the remnant. As the reverse shock e...

  3. New evidence for strong nonthermal effects in Tycho's supernova remnant

    CERN Document Server

    Völk, H J; Ksenofontov, L T

    2005-01-01

    We present for the case of Tycho's supernova remnant (SNR) the relation between the blast wave and contact discontinuity sizes calculated within the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is demonstrated that they are very well confirmed by recently published Chandra measurements, which show that the observed contact discontinuity radius is so close to the shock radius, that it can only be explained by the efficient CR acceleration which in turn makes the medium more compressible. Together with the recently determined new value E_{sn}=1.2x10^{51} erg of the SN explosion energy this gives an additional important confirmation that the predicted gamma-ray flux at TeV-energies (2-5)x10^{-13} erg/(cm^2 s), produced by accelerated nuclear CRs, is indeed expected from Tycho's SNR. Chandra measurements and the HEGRA upper limit of the TeV gamma-ray flux together limit the source distance d to 3.3 < d < 4 kpc.

  4. Revealing the Supernova Remnant Population of M33 with Chandra

    CERN Document Server

    Ghavamian, P; Long, K S; Sasaki, M; Gaetz, T J; Plucinsky, P P; Ghavamian, Parviz; Blair, William P.; Long, Knox S.; Sasaki, Manami; Gaetz, Terrance J.; Plucinsky, Paul P.

    2005-01-01

    We present results of a search for supernova remnants (SNRs) in archival Chandra images of M33. We have identified X-ray SNRs by comparing the list of Chandra, X-ray sources in M33 with tabulations of SNR candidates identified from (1) elevated [S II]/Halpha ratios in the optical, and (2) radio spectral indices. Of the 98 optically known SNRs in M33, 22 have been detected at > 3-sigma level in the soft band (0.35-1.1 keV). At least four of these SNR candidates are spatially extended based on a comparison of the data to simulated images of point sources. Aside from the optically matching SNRs, we have found one soft X-ray source in M33 which exhibits no optical emission and is coincident with a known radio source. The radio spectral index of this source is consistent with particle acceleration in shocks, leading us to suggest that it is a non-radiative SNR. We have also found new optical counterparts to two soft X-ray SNRs in M33. Pending confirmation from optical spectroscopy, the identification of these two ...

  5. Discovery of an Apparent High Latitude Galactic Supernova Remnant

    CERN Document Server

    Fesen, Robert; Black, Christine; Koeppel, Ari

    2015-01-01

    Deep H$\\alpha$ images of a faint emission complex 4.0 x 5.5 degrees in angular extent and located far off the Galactic plane at l = 70.0 degrees, b=-21.5 degrees reveal numerous thin filaments suggestive of a supernova remnant's shock emission. Low dispersion optical spectra covering the wavelength range 4500 - 7500 A show only Balmer line emissions for one filament while three others show a Balmer dominated spectrum along with weak [N I] 5198, 5200 A, [O I] 6300, 6364 A, [N II] 6583 A, [S II] 6716, 6731 A and in one case [O III] 5007 A line emission. Many of the brighter H$\\alpha$ filaments are visible in near UV GALEX images presumably due to C III] 1909 A line emission. ROSAT All Sky Survey images of this region show a faint crescent shaped X-ray emission nebula coincident with the portion of the H$\\alpha$ nebulosity closest to the Galactic plane. The presence of long, thin Balmer dominated emission filaments with associated UV emission and coincident X-ray emission suggests this nebula is a high latitude ...

  6. On the origin of two-shell supernova remnants

    CERN Document Server

    Gvaramadze, V V

    2007-01-01

    The proper motion of massive stars could cause them to explode far from the geometric centers of their wind-driven bubbles and thereby could affect the symmetry of the resulting diffuse supernova remnants. We use this fact to explain the origin of SNRs consisting of two partially overlapping shells (e.g. Cygnus Loop, 3C 400.2, etc.).

  7. An integral view of fast shocks around supernova 1006.

    Science.gov (United States)

    Nikoli?, Sladjana; van de Ven, Glenn; Heng, Kevin; Kupko, Daniel; Husemann, Bernd; Raymond, John C; Hughes, John P; Falcón-Barroso, Jesús

    2013-04-01

    Supernova remnants are among the most spectacular examples of astrophysical pistons in our cosmic neighborhood. The gas expelled by the supernova explosion is launched with velocities ~1000 kilometers per second into the ambient, tenuous interstellar medium, producing shocks that excite hydrogen lines. We have used an optical integral-field spectrograph to obtain high-resolution spatial-spectral maps that allow us to study in detail the shocks in the northwestern rim of supernova 1006. The two-component H? line is detected at 133 sky locations. Variations in the broad line widths and the broad-to-narrow line intensity ratios across tens of atomic mean free paths suggest the presence of suprathermal protons, the potential seed particles for generating high-energy cosmic rays. PMID:23413189

  8. Second Epoch Hubble Space Telescope Observations of Kepler's Supernova Remnant: The Proper Motions of Balmer Filaments

    Science.gov (United States)

    Sankrit, Ravi; Raymond, John C.; Blair, William P.; Long, Knox S.; Williams, Brian J.; Borkowski, Kazimierz J.; Patnaude, Daniel J.; Reynolds, Stephen P.

    2016-01-01

    We report on the proper motions of Balmer-dominated filaments in Kepler’s supernova remnant using high resolution images obtained with the Hubble Space Telescope at two epochs separated by about 10 years. We use the improved proper motion measurements and revised values of shock velocities to derive a distance to Kepler of {5.1}-0.7+0.8 kpc. The main shock around the northern rim of the remnant has a typical speed of 1690 km s-1 and is encountering material with densities of about 8 cm-3. We find evidence for the variation of shock properties over small spatial scales, including differences in the driving pressures as the shock wraps around a curved cloud surface. We find that the Balmer filaments ahead of the ejecta knot on the northwest boundary of the remnant are becoming fainter and more diffuse. We also find that the Balmer filaments associated with circumstellar material in the interior regions of the remnant are due to shocks with significantly lower velocities and that the brightness variations among these filaments trace the density distribution of the material, which may have a disk-like geometry. Based on observations made with the Hubble Space Telescope.

  9. Second Epoch Hubble Space Telescope Observations of Kepler's Supernova Remnant: The Proper Motions of Balmer Filaments

    CERN Document Server

    Sankrit, Ravi; Blair, William P; Long, Knox S; Williams, Brian J; Borkowski, Kazimierz J; Patnaude, Daniel J; Reynolds, Stephen P

    2015-01-01

    We report on the proper motions of Balmer-dominated filaments in Kepler's supernova remnant using high resolution images obtained with the Hubble Space Telescope at two epochs separated by about 10 years. We use the improved proper motion measurements and revised values of shock velocities to derive a distance to Kepler of 5.1 [+0.8, -0.7] kpc. The main shock around the northern rim of the remnant has a typical speed of 1690 km/s and is encountering material with densities of about 8 cm^-3. We find evidence for the variation of shock properties over small spatial scales, including differences in the driving pressures as the shock wraps around a curved cloud surface. We find that the Balmer filaments ahead of the ejecta knot on the northwest boundary of the remnant are becoming fainter and more diffuse. We also find that the Balmer filaments associated with circumstellar material in the interior regions of the remnant are due to shocks with significantly lower velocities and that the brightness variations amon...

  10. Supernova Shock Breakout from a Red Supergiant

    OpenAIRE

    Schawinski, K.; Justham, S.; de Wolf, C.; P. Podsiadlowski; Sullivan, M.; Steenbrugge, KC; Bell, T; Röser, H-J; Walker, ES; ASTIER, P; Balam, D; Balland, C.; Carlberg, R; Conley, A; D. Fouchez

    2008-01-01

    Massive stars undergo a violent death when the supply of nuclear fuel in their cores is exhausted, resulting in a catastrophic "core-collapse" supernova. Such events are usually only detected at least a few days after the star has exploded. Observations of the supernova SNLS-04D2dc with the Galaxy Evolution Explorer space telescope reveal a radiative precursor from the supernova shock before the shock reached the surface of the star and show the initial expansion of the star...

  11. Gamma-ray emission of accelerated particles escaping a supernova remnant in a molecular cloud

    CERN Document Server

    Ellison, Donald C

    2011-01-01

    We present a model of gamma-ray emission from core-collapse supernovae originating from the explosions of massive young stars. The fast forward shock of the supernova remnant (SNR) can accelerate particles by diffusive shock acceleration (DSA) in a cavern blown by a strong, pre-supernova stellar wind. As a fundamental part of nonlinear DSA, some fraction of the accelerated particles escape the shock and interact with a surrounding massive dense shell producing hard photon emission. To calculate this emission, we have developed a new Monte Carlo technique for propagating the cosmic rays (CRs) produced by the forward shock of the SNR, into the dense, external material. This technique is incorporated in a hydrodynamic model of an evolving SNR which includes the nonlinear feedback of CRs on the SNR evolution, the production of escaping CRs along with those that remain trapped within the remnant, and the broad-band emission of radiation from trapped and escaping CRs. While our combined CR-hydro-escape model is qui...

  12. Supernova Remnants Interacting with Molecular Clouds: X-ray and Gamma-ray Signatures

    CERN Document Server

    Slane, P; Ellison, D C; Dubner, G; Castro, D

    2014-01-01

    The giant molecular clouds (MCs) found in the Milky Way and similar galaxies play a crucial role in the evolution of these systems. The supernova explosions that mark the death of massive stars in these regions often lead to interactions between the supernova remnants (SNRs) and the clouds. These interactions have a profound effect on our understanding of SNRs. Shocks in SNRs should be capable of accelerating particles to cosmic ray (CR) energies with efficiencies high enough to power Galactic CRs. X-ray and gamma-ray studies have established the presence of relativistic electrons and protons is some SNRs and provided strong evidence for diffusive shock acceleration as the primary acceleration mechanism, including strongly amplified magnetic fields, temperature and ionization effects on the shock-heated plasmas, and modifications to the dynamical evolution of some systems. Because protons dominate the overall energetics of the CRs, it is crucial to understand this hadronic component even though electrons are ...

  13. A Possible Site of Cosmic Ray Acceleration in the Supernova Remnant IC 443

    CERN Document Server

    Keohane, J W; Gotthelf, E V; Ozaki, M; Koyama, K; Keohane, Jonathan W.

    1997-01-01

    We present evidence for shock acceleration of cosmic rays to high energies (about 10 TeV) in the supernova remnant IC 443. X-ray imaging spectroscopy with ASCA reveals two regions of particularly hard emission: an unresolved source embedded in an extended emission region, and a ridge of emission coincident with the southeastern rim. Both features are located on part of the radio shell where the shock wave is interacting with molecular gas, and together they account for a majority of the emission at 7 keV. Though we would not have noticed it a priori, the unresolved feature is coincident with one resolved by the ROSAT HRI. Because this feature overlaps a unique region of flat radio spectral index (alpha 5,000 km/s). We conclude that the anomalous feature is most likely tracing enhanced particle acceleration by shocks that are formed as the supernova blast wave impacts the ring of molecular clouds.

  14. Supernova Remnants in the Magellanic Clouds. VI. The DEML316 Supernova Remnants

    CERN Document Server

    Williams, R M

    2005-01-01

    The DEML316 system contains two shells, both with the characteristic signatures of supernova remnants (SNRs). We analyze Chandra and XMM-Newton data for DEML316, investigating its spatial and spectral X-ray features. Our Chandra observations resolve the structure of the northeastern SNR (Shell A) as a bright inner ring and a set of "arcs" surrounded by fainter diffuse emission. The spectrum is well fit by a thermal plasma model with temperature ~1.4 keV; we do not find significant spectral differences for different regions of this SNR. The southwestern SNR (Shell B) exhibits an irregular X-ray outline, with a brighter interior ring of emission including a bright knot of emission. Overall the emission of the SNR is well described by a thermal plasma of temperature ~0.6 keV. The Bright Knot, however, is spectrally distinct from the rest of the SNR, requiring the addition of a high-energy spectral component consistent with a power-law spectrum of photon index 1.6--1.8. We confirm the findings of Nishiuchi et al....

  15. Alfven Wave Amplification and Self-Containment of Cosmic-Rays Escaping from a Supernova Remnant

    OpenAIRE

    Fujita, Yutaka; Takahara, Fumio; Ohira, Yutaka; Iwasaki, Kazunari

    2011-01-01

    We study the escape of cosmic-ray (CR) protons accelerated at a supernova remnant (SNR) by numerically solving a diffusion-convection equation from the vicinity of the shock front to the region far away from the front. We consider the amplifications of Alfven waves generated by the escaping CR particles and their effects on CR escape into interstellar medium (ISM). We find that the amplification of the waves significantly delays the escape of the particles even far away from the shock front (...

  16. A Spitzer Space Telescope Infrared Survey of Supernova Remnants in the Inner Galaxy

    CERN Document Server

    Reach, W T; Tappe, A; Pannuti, T G; Brogan, C L; Churchwell, E B; Meade, M R; Babler, B; Indebetouw, R; Whitney, B A; Reach, William T.; Rho, Jeonghee; Tappe, Achim; Pannuti, Thomas G.; Brogan, Crystal L.; Churchwell, Edward B.; Meade, Marilyn R.; Babler, Brian; Indebetouw, Remy; Whitney, Barbara A.

    2005-01-01

    Using Infrared Array Camera (IRAC) images at 3.6, 4.5, 5.8, and 8 microns from the GLIMPSE Legacy science program on the Spitzer Space Telescope, we searched for infrared counterparts to the 95 known supernova remnants that are located within galactic longitudes 65>|l|>10 degrees and latitudes |b|<1 degree. Eighteen infrared counterparts were detected. Many other supernova remnants could have significant infrared emission but are in portions of the Milky Way too confused to allow separation from bright HII regions and pervasive mid-infrared emission from atomic and molecular clouds along the line of sight. Infrared emission from supernova remnants originates from synchrotron emission, shock-heated dust, atomic fine-structure lines, and molecular lines. The detected remnants are G11.2-0.3, Kes 69, G22.7-0.2, 3C 391, W 44, 3C 396, 3C 397, W 49B, G54.4-0.3, Kes 17, Kes 20A, RCW 103, G344.7-0.1, G346.6-0.2, CTB 37A, G348.5-0.0, and G349.7+0.2. The infrared colors suggest emission from molecular lines (9 remnan...

  17. Oxygen emission in remnants of thermonuclear supernovae as a probe for their progenitor system

    CERN Document Server

    Kosenko, D; Kromer, M; Blinnikov, S I; Pakmor, R; Kaastra, J S

    2014-01-01

    Recent progress in numerical simulations of thermonuclear supernova explosions brings up a unique opportunity in studying the progenitors of Type Ia supernovae. Coupling state-of-the-art explosion models with detailed hydrodynamical simulations of the supernova remnant evolution and the most up-to-date atomic data for X-ray emission calculations makes it possible to create realistic synthetic X-ray spectra for the supernova remnant phase. Comparing such spectra with high quality observations of supernova remnants could allow to constrain the explosion mechanism and the progenitor of the supernova. The present study focuses in particular on the oxygen emission line properties in young supernova remnants, since different explosion scenarios predict a different amount and distribution of this element. Analysis of the soft X-ray spectra from supernova remnants in the Large Magellanic Cloud and confrontation with remnant models for different explosion scenarios suggests that SNR 0509-67.5 could originate from a de...

  18. Einstein X-ray observations of the supernova remnant HB21

    International Nuclear Information System (INIS)

    In radio, HB21 is a large (approx. 2 deg diameter) supernova remnant. It has been observed with incomplete coverage by five Einstein IPC fields. Here is reported the first detection of X-ray emission from HB21. The 0.2-4 keV X-ray image of HB21 does not correlate well with radio maps. HB21 has an X-ray temperature of 7(+6, -2)x106 K and a luminosity of 1.9(+7.6, -1.2) x 1034 erg s-1. A Sedov model applied to HB21 gives too large a temperature and shock velocity. Supernova remnant models for expansion into a 3-component ISM can fit HB9, from which an age of 8000-15000 yr is inferred. (author)

  19. Featured Image: A Supernova Remnant in X-Rays

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    This is a three-color X-ray image taken by Chandra of the supernova remnant RCW 103. This supernova remnant is an unusual system: its young, but unlike other remnants of its age, metal-rich ejecta hadnt previously been discovered in it. In this paper, Kari Frank (Pennsylvania State University) and collaborators analyze the three deepest Chandra observations of RCW 103 and find the first evidence for metal-rich ejecta emission scattered throughout the remnant. Their analyses also help to constrain the identity of the mysterious compact stellar object powering the remnant. In this image, red = 0.30.85 keV, green = 0.851.70 keV, and blue = 1.73.0 keV; click on the image for the full view. For more information and the original image, see the paper here:Kari A. Frank et al 2015 ApJ 810 113 doi:10.1088/0004-637X/810/2/113.

  20. Energy Dependence of Synchrotron X-Ray Rims in Tycho's Supernova Remnant

    CERN Document Server

    Tran, Aaron; Petre, Robert; Ressler, Sean M; Reynolds, Stephen P

    2015-01-01

    Several young supernova remnants exhibit thin X-ray bright rims of synchrotron radiation at their forward shocks. Thin rims require strong magnetic field amplification beyond simple shock compression if rim widths are only limited by electron energy losses. But, magnetic field damping behind the shock could produce similarly thin rims with less extreme field amplification. Variation of rim width with energy may thus discriminate between competing influences on rim widths. We measured rim widths around Tycho's supernova remnant in 5 energy bands using an archival 750 ks Chandra observation. Rims narrow with increasing energy and are well described by either loss-limited or damped scenarios, so X-ray rim width-energy dependence does not uniquely specify a model. But, radio counterparts to thin rims are not loss-limited and better reflect magnetic field structure. Joint radio and X-ray modeling favors magnetic damping in Tycho's SNR with damping lengths ~1--5% of remnant radius and magnetic field strengths ~50--...

  1. Hydrodynamics of Young Supernova Remnants and the Implications for their Gamma-ray emission

    CERN Document Server

    Dwarkadas, Vikram

    2014-01-01

    Supernovae (SNe) are generally classified into Type I and Type II. Most SNe (~ 80%), including all the subtypes of Type II, and Type Ib/c, arise from the core-collapse of massive stars. During their lifetime, mass-loss from these stars considerably modifies the medium around the stars. When the stars explode as SNe, the resulting shock wave will expand in this wind-modified medium. In contrast, Type Ia SNe will expand in a relatively uniform medium, but the dynamics are different from those of core-collapse SNe. For young supernova remnants, the properties of the ejecta as well as the surrounding medium are important in determining the subsequent evolution of the SN shock wave, and the dynamics and kinematics of the remnant. This will influence the acceleration of particles at the SN shocks, and consequently affect the gamma-ray emission from the remnant. Herein we discuss the expected properties, especially the density structure, of the medium around various types and sub-types of SNe, as suggested by curren...

  2. ASTRO-H White Paper - Young Supernova Remnants

    CERN Document Server

    Hughes, J P; Bamba, A; Katsuda, S; Leutenegger, M; Long, K S; Maeda, Y; Mori, K; Nakajima, H; Sawada, M; Tanaka, T; Uchida, H; Yamaguchi, H; Aharonian, F; Funk, S; Hiraga, J; Ishida, M; Koyama, K; Matsumoto, H; Nobukawa, M; Ozaki, M; Tamagawa, T; Tsunemi, H; Tomida, H; Uchiyama, Y; Uno, S

    2014-01-01

    Thanks to the unprecedented spectral resolution and sensitivity of the Soft X-ray Spectrometer (SXS) to soft thermal X-ray emission, ASTRO-H will open a new discovery window for understanding young, ejecta-dominated, supernova remnants (SNRs). In particular we study how ASTRO-H observations will address, comprehensively, three key topics in SNR research: (1) using abundance measurements to unveil SNR progenitors, (2) using spatial and velocity distribution of the ejecta to understand supernova explosion mechanisms, (3) revealing the link between the thermal plasma state of SNRs and the efficiency of their particle acceleration.

  3. The Bubble-like Interior of the Core-Collapse Supernova Remnant Cassiopeia A

    CERN Document Server

    Milisavljevic, Dan

    2015-01-01

    The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of how these catastrophic explosions proceed remain uncertain due, in part, to limited observational constraints on various processes that can introduce asymmetries deep inside the star. Here we present near-infrared observations of the young Milky Way supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimensional map of its interior, unshocked ejecta. The remnant's interior has a bubble-like morphology that smoothly connects to and helps explain the multi-ringed structures seen in the remnant's bright reverse shocked main shell of expanding debris. This internal structure may have originated from turbulent mixing processes that encouraged the development of outwardly expanding plumes of radioactive 56Ni-rich ejecta. If this is true, substantial amounts of its decay product, 56Fe, may still reside in these interior cavities.

  4. G306.3-0.9: A Newly Discovered Young Galactic Supernova Remnant

    Science.gov (United States)

    Reynolds, Mark T.; Loi, Syheh T.; Murphy, Tara; Miller, Jon M.; Maitra, Dipankar; Gueltekin, Kayhan; Gehrels, Neil; Kennea, Jamie A.; Siegel, Michael H.; Gelbord, Jonathan; Kuin, Paul; Moss, Vanessa; Reeves, Sarah; Robbins, William J.; Gaensler, B. M.; Reis, Rubens C.; Petre, Robert

    2013-01-01

    We present X-ray and radio observations of the new Galactic supernova remnant (SNR) G306.3-0.9, recently discovered by Swift. Chandra imaging reveals a complex morphology, dominated by a bright shock. The X-ray spectrum is broadly consistent with a young SNR in the Sedov phase, implying an age of 2500 yr for a distance of 8 kpc, plausibly identifying this as one of the 20 youngest Galactic SNRs. Australia Telescope Compact Array imaging reveals a prominent ridge of radio emission that correlates with the X-ray emission. We find a flux density of 160 mJy at 1 GHz, which is the lowest radio flux recorded for a Galactic SNR to date. The remnant is also detected at 24µm, indicating the presence of irradiated warm dust. The data reveal no compelling evidence for the presence of a compact stellar remnant.

  5. G306.3-0.9: A newly discovered young galactic supernova remnant

    CERN Document Server

    Reynolds, Mark; Murphy, Tara; Miller, Jon; Maitra, Dipankar; Gultekin, Kayhan; Gehrels, Neil; Kennea, Jamie; Siegel, Michael; Gelbord, Jonathan; Kuin, Paul; Moss, Vanessa; Reeves, Sarah; Robbins, William; Gaensler, Bryan; Reis, Rubens; Petre, Robert

    2013-01-01

    We present X-ray and radio observations of the new Galactic supernova remnant (SNR) G306.3-0.9, recently discovered by Swift. Chandra imaging reveals a complex morphology, dominated by a bright shock. The X-ray spectrum is broadly consistent with a young SNR in the Sedov phase, implying an age of 2500 yr for a distance of 8 kpc, plausibly identifying this as one of the 20 youngest Galactic SNRs. Australia Telescope Compact Array (ATCA) imaging reveals a prominent ridge of radio emission that correlates with the X-ray emission. We find a flux density of ~ 160 mJy at 1 GHz, which is the lowest radio flux recorded for a Galactic SNR to date. The remnant is also detected at 24microns, indicating the presence of irradiated warm dust. The data reveal no compelling evidence for the presence of a compact stellar remnant.

  6. G306.3-0.9: A NEWLY DISCOVERED YOUNG GALACTIC SUPERNOVA REMNANT

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Mark T.; Miller, Jon M.; Maitra, Dipankar; Gueltekin, Kayhan; Reis, Rubens C. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Loi, Shyeh T.; Murphy, Tara; Moss, Vanessa; Reeves, Sarah; Robbins, William J.; Gaensler, B. M. [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia); Gehrels, Neil; Petre, Robert [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kennea, Jamie A.; Siegel, Michael H.; Gelbord, Jonathan [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Kuin, Paul, E-mail: markrey@umich.edu [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)

    2013-04-01

    We present X-ray and radio observations of the new Galactic supernova remnant (SNR) G306.3-0.9, recently discovered by Swift. Chandra imaging reveals a complex morphology, dominated by a bright shock. The X-ray spectrum is broadly consistent with a young SNR in the Sedov phase, implying an age of 2500 yr for a distance of 8 kpc, plausibly identifying this as one of the 20 youngest Galactic SNRs. Australia Telescope Compact Array imaging reveals a prominent ridge of radio emission that correlates with the X-ray emission. We find a flux density of {approx}160 mJy at 1 GHz, which is the lowest radio flux recorded for a Galactic SNR to date. The remnant is also detected at 24 {mu}m, indicating the presence of irradiated warm dust. The data reveal no compelling evidence for the presence of a compact stellar remnant.

  7. G306.3–0.9: A NEWLY DISCOVERED YOUNG GALACTIC SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    We present X-ray and radio observations of the new Galactic supernova remnant (SNR) G306.3–0.9, recently discovered by Swift. Chandra imaging reveals a complex morphology, dominated by a bright shock. The X-ray spectrum is broadly consistent with a young SNR in the Sedov phase, implying an age of 2500 yr for a distance of 8 kpc, plausibly identifying this as one of the 20 youngest Galactic SNRs. Australia Telescope Compact Array imaging reveals a prominent ridge of radio emission that correlates with the X-ray emission. We find a flux density of ?160 mJy at 1 GHz, which is the lowest radio flux recorded for a Galactic SNR to date. The remnant is also detected at 24 ?m, indicating the presence of irradiated warm dust. The data reveal no compelling evidence for the presence of a compact stellar remnant.

  8. Secondary Accceleration of Cosmic Rays by Supernova Shocks

    CERN Document Server

    Wandel, A

    1997-01-01

    In the common model supernova shock-acceleration of cosmic rays there are two open questions: 1. where does the high energy cosmic rays below the knee (10$^4-10^6$ Gev) come from, and 2. are cosmic ray accelerated only at their origin or contineuosly during their residence in the Galaxy. We show that $10^15$ eV light nuclei are probably accelerted by associations of supernovae. The ratio of the spectra of secondary to primary cosmic rays would be affected by repeated acceleration (also called reacceleration or secondary acceleration) in the ISM during their propagation in the galaxy. The observed secondary and primary CR spectra are used to constrain the amount of such reacceleration by supernova remnants (SNR). Two cases are considered: weak shocks ($13$) of relatively young remnants. It is shown that weak shocks produce more reacceleration than what is permitted in the framework of the standard leaky box (SLB) model, making it inconsistent with dispersed acceleration that should be produced by SNR. If the S...

  9. Galactic Propagation of Cosmic Rays from Individual Supernova Remnants

    CERN Document Server

    Nierstenhoefer, Nils; Schuppan, Florian; Tjus, Julia Becker

    2015-01-01

    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 assuming the decay of neutral pions which are created in hadronic interactions. Therefore, fitting the corresponding gamma spectra allows us to derive the spectra of cosmic rays at the source which are locally injected into our Galaxy. Using these spectra as a starting point, we propagate the cosmic rays through the Galaxy using the publicly available GALPROP code. Here, we will present first results on the contribution of those SNRs to the total cosmic ray flux and discuss implications.

  10. Planck intermediate results. XXXI. Microwave survey of Galactic supernova remnants

    CERN Document Server

    Arnaud, M

    2014-01-01

    The all-sky Planck survey in 9 frequency bands was used to search for emission from all 274 known Galactic supernova remnants. Of these, 17 were detected in at least two Planck frequencies. The radio-through-microwave spectral energy distributions were compiled to determine the emission mechanism for microwave emission. In only one case, IC 443, is the high-frequency emission clearly from dust associated with the supernova remnant. In all cases, the low-frequency emission is from synchrotron radiation. A single power law, as predicted for a population of relativistic particles with energy distribution that extends continuously to high energies, is evident for many sources, including the Crab and PKS 1209-51/52. A decrease in flux density relative to the extrapolation of radio emission is evident in several sources. Their spectral energy distributions can be approximated as broken power laws, $S_\

  11. Escape of cosmic-ray electrons from supernova remnants

    Science.gov (United States)

    Ohira, Yutaka; Yamazaki, Ryo; Kawanaka, Norita; Ioka, Kunihito

    2012-11-01

    We investigate the escape of cosmic ray (CR) electrons from a supernova remnant (SNR) to interstellar space. We show that CR electrons escape in order, from high energies to low energies, like CR nuclei. However, the escape starts later than the beginning of the Sedov phase at an SNR age of 103 to 7 × 103 yr, and the maximum energy of runaway CR electrons is below the knee at about 0.3-50 TeV because, unlike CR nuclei, CR electrons lose their energy as a result of synchrotron radiation. The highest-energy CR electrons might have already been detected by the High Energy Stereoscopic System (HESS) and MAGIC as a cut-off in the CR electron spectrum, and it will be probed by the Alpha Magnetic Spectrometer (AMS-02), the Calorimeteric Electron Telescope (CALET), the Cherenkov Telescope Array (CTA) and the Large High Altitude Air Shower Observatory (LHAASO) experiments. We also calculate the spatial distribution of runaway CR electrons and their radiation spectra around SNRs. Contrary to common belief, maximum-energy photons of synchrotron radiation around 1 keV are emitted by runaway CR electrons, which have been caught up by the shock. Inverse Compton scattering by runaway CR electrons can dominate the gamma-ray emission from runaway CR nuclei via pion decay. Both are detectable by CTA and LHAASO and they can give clues to the origin of CRs and the amplification of magnetic fluctuations around the SNR. We also discuss middle-aged and/or old SNRs as unidentified very-high-energy gamma-ray sources.

  12. High-energy antiprotons from old supernova remnants

    OpenAIRE

    Blasi, Pasquale; Serpico, Pasquale D

    2009-01-01

    A recently proposed model (arXiv:0903.2794) explains the rise in energy of the positron fraction measured by the PAMELA satellite in terms of hadronic production of positrons in aged supernova remnants, and acceleration therein. Here we present a preliminary calculation of the anti-proton flux produced by the same mechanism. While the model is consistent with present data, a rise of the antiproton to proton ratio is predicted at high energy, which strikingly distinguishes th...

  13. Phosphorus in the Young Supernova Remnant Cassiopeia A

    OpenAIRE

    Koo, Bon-Chul; Lee, Yong-Hyun; Moon, Dae-Sik; Yoon, Sung-Chul; Raymond, John C.

    2013-01-01

    Phosphorus ($^{31}$P), which is essential for life, is thought to be synthesized in massive stars and dispersed into interstellar space when these stars explode as supernovae (SNe). Here we report on near-infrared spectroscopic observations of the young SN remnant Cassiopeia A, which show that the abundance ratio of phosphorus to the major nucleosynthetic product iron ($^{56}$Fe) in SN material is up to 100 times the average ratio of the Milky Way, confirming that phosphorus...

  14. X-ray maps of the VELA supernova remnant

    Science.gov (United States)

    Hearn, D. R.; Larsen, S. E.; Richardson, J. A.

    1980-01-01

    X-ray maps of the Vela supernova remnant in two energy channels, 0.1-0.4 keV and 0.4-0.8 keV, are presented. The data were obtained in 1975 from a SAS 3 satellite observation. We describe the Wiener filter technique used to deconvolve the angular response of the instrument from the data. The X-ray structure is compared with the optical and radio features of the region.

  15. Most luminous supernovae produced by shocks

    International Nuclear Information System (INIS)

    The extremely luminous supernova SN2006gy is explained as some other peculiar supernovae: light is produced by a radiative shock propagating in a dense circumstellar envelope. This envelope is formed by a previous weak explosion at a stage of hydrodynamic instability due to creation of electron-positron pairs in stellar interiors. The problems in the theory and observations of supernovae created by multiple explosions are briefly reviewed.

  16. FERMI LARGE AREA TELESCOPE DETECTION OF SUPERNOVA REMNANT RCW 86

    International Nuclear Information System (INIS)

    Using 5.4 yr Fermi Large Area Telescope data, we report the detection of GeV ?-ray emission from the shell-type supernova remnant RCW 86 (G315.4-2.3) with a significance of ?5.1?. The data slightly favors an extended emission of this supernova remnant. The spectral index of RCW 86 is found to be very hard, ? ? 1.4, in the 0.4-300 GeV range. A one-zone leptonic model can well fit the multi-wavelength data from radio to very high energy ?-rays. The very hard GeV ?-ray spectrum and the inferred low gas density seem to disfavor a hadronic origin for the ?-rays. The ?-ray behavior of RCW 86 is very similar to several other TeV shell-type supernova remnants, e.g., RX J1713.7-3946, RX J0852.0-4622, SN 1006, and HESS J1731-347

  17. A Newly Recognized Very Young Supernova Remnant in M83

    CERN Document Server

    Blair, William P; Long, Knox S; Whitmore, Bradley C; Kim, Hwihyun; Soria, Roberto; Kuntz, K D; Plucinsky, Paul P; Dopita, Michael A; Stockdale, Christopher

    2015-01-01

    As part of a spectroscopic survey of supernova remnant candidates in M83 using the Gemini-South telescope and GMOS, we have discovered one object whose spectrum shows very broad lines at H$\\alpha$, [O~I] 6300,6363, and [O~III] 4959,5007, similar to those from other objects classified as `late time supernovae.' Although six historical supernovae have been observed in M83 since 1923, none were seen at the location of this object. Hubble Space Telescope Wide Field Camera 3 images show a nearly unresolved emission source, while Chandra and ATCA data reveal a bright X-ray source and nonthermal radio source at the position. Objects in other galaxies showing similar spectra are only decades post-supernova, which raises the possibility that the supernova that created this object occurred during the last century but was missed. Using photometry of nearby stars from the HST data, we suggest the precursor was at least 17 $\\rm M_{sun}$, and the presence of broad H$\\alpha$ in the spectrum makes a type II supernova likely....

  18. Expected gamma-ray emission of supernova remnant SN 1987A

    CERN Document Server

    Berezhko, E G; Voelk, H J

    2010-01-01

    A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants is employed to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5-100 yr. It is shown that an efficient production of nuclear CRs leads to a strong modification of the outer supernova remnant shock and to a large downstream magnetic field $B_d\\approx$ 20 mG. The shock modification and the strong field are required to yield the steep and concave radio emission spectrum observed, as well as to considerable synchrotron cooling of high energy electrons which diminishes their X-ray synchrotron flux. These features are also consistent with the existing X-ray observations. The expected gamma-ray energy flux at TeV-energies at the current epoch is nearly $\\epsilon_{\\gamma}F_{\\gamma}\\approx 4\\times 10^{-13}$ erg cm$^2$s$^{-1}$ under reasonable assumptions about the overall magnetic field topology and the turbulent perturbations of this field. The general nonthermal strength of the sour...

  19. CHANDRA ACIS Spectroscopy of N157B -- A Young Composite Supernova Remnant in a Superbubble

    CERN Document Server

    Chen, Y; Gotthelf, E V; Jiang, B; Chu, Y H; Gruendl, R A; Chen, Yang; Gotthelf, Eric V.; Jiang, Bing; Chu, You-Hua; Gruendl, Robert

    2006-01-01

    We present Chandra ACIS observations of N157B, a young supernova remnant located in the 30 Doradus star-formation region of the LMC. This remnant contains the most energetic pulsar known (PSR J0537-6910), which is surrounded by a bright nonthermal nebula that likely represents a toroidal pulsar wind terminal shock observed edge-on. We confirm the non-thermal nature of the comet-shaped X-ray emission feature and show that the spectral steepening of this feature away from the pulsar is quantitatively consistent with synchrotron cooling of shocked pulsar wind particles flowing downstream at a bulk velocity close to the speed of light. Around the cometary nebula we unambiguously detect a thermal component, which accounts for about 1/3 of the total 0.5 - 10 keV flux from the remnant. This thermal component is distributed among various clumps of metal-enriched plasma embedded in the low surface brightness X-ray-emitting diffuse gas. The relative metal enrichment pattern suggests that the mass of the supernova proge...

  20. Evidence For Particle Acceleration to the Knee of the Cosmic Ray Spectrum in Tycho's Supernova Remnant

    CERN Document Server

    Eriksen, Kristoffer A; Badenes, Carles; Fesen, Robert; Ghavamian, Parviz; Moffett, David; Plucinsky, Paul P; Rakowski, Cara E; Reynoso, Estela M; Slane, Patrick

    2011-01-01

    Supernova remnants (SNRs) have long been assumed to be the source of cosmic rays (CRs) up to the "knee" of the CR spectrum at 10^15 eV, accelerating particles to relativistic energies in their blast waves by the process of diffusive shock acceleration (DSA). Since cosmic ray nuclei do not radiate efficiently, their presence must be inferred indirectly. Previous theoretical calculations and X-ray observations show that CR acceleration modifies significantly the structure of the SNR and greatly amplifies the interstellar magnetic field. We present new, deep X-ray observations of the remnant of Tycho's supernova (SN 1572, henceforth Tycho), which reveal a previously unknown, strikingly ordered pattern of non-thermal high-emissivity stripes in the projected interior of the remnant, with spacing that corresponds to the gyroradii of 10^14 - 10^15 eV} protons. Spectroscopy of the stripes shows the plasma to be highly turbulent on the (smaller) scale of the Larmor radii of TeV energy electrons. Models of the shock am...

  1. Supernova Ejecta in the Youngest Galactic Supernova Remnant G1.9+0.3

    Science.gov (United States)

    Borkowski, Kazimierz J.; Reynolds, Stephen P.; Hwang, Una; Green, David A.; Petre, Robert; Krishnamurthy, Kalyani; Willett, Rebecca

    2013-01-01

    G1.9+0.3 is the youngest known Galactic supernova remnant (SNR), with an estimated supernova (SN) explosion date of approximately 1900, and most likely located near the Galactic Center. Only the outermost ejecta layers with free-expansion velocities (is) approximately greater than 18,000 km s-1 have been shocked so far in this dynamically young, likely Type Ia SNR. A long (980 ks) Chandra observation in 2011 allowed spatially-resolved spectroscopy of heavy-element ejecta. We denoised Chandra data with the spatio-spectral method of Krishnamurthy et al., and used a wavelet based technique to spatially localize thermal emission produced by intermediate-mass elements (IMEs: Si and S) and iron. The spatial distribution of both IMEs and Fe is extremely asymmetric, with the strongest ejecta emission in the northern rim. Fe K alpha emission is particularly prominent there, and fits with thermal models indicate strongly oversolar Fe abundances. In a localized, outlying region in the northern rim, IMEs are less abundant than Fe, indicating that undiluted Fe-group elements (including 56Ni) with velocities greater than 18,000 km s-1 were ejected by this SN. But in the inner west rim, we find Si- and S-rich ejecta without any traces of Fe, so high-velocity products of O-burning were also ejected. G1.9+0.3 appears similar to energetic Type Ia SNe such as SN 2010jn where iron-group elements at such high free-expansion velocities have been recently detected. The pronounced asymmetry in the ejecta distribution and abundance inhomogeneities are best explained by a strongly asymmetric SN explosion, similar to those produced in some recent 3D delayed-detonation Type Ia models.

  2. Supernova shock breakout from a red supergiant.

    Science.gov (United States)

    Schawinski, Kevin; Justham, Stephen; Wolf, Christian; Podsiadlowski, Philipp; Sullivan, Mark; Steenbrugge, Katrien C; Bell, Tony; Röser, Hermann-Josef; Walker, Emma S; Astier, Pierre; Balam, Dave; Balland, Christophe; Carlberg, Ray; Conley, Alex; Fouchez, Dominique; Guy, Julien; Hardin, Delphine; Hook, Isobel; Howell, D Andrew; Pain, Reynald; Perrett, Kathy; Pritchet, Chris; Regnault, Nicolas; Yi, Sukyoung K

    2008-07-11

    Massive stars undergo a violent death when the supply of nuclear fuel in their cores is exhausted, resulting in a catastrophic "core-collapse" supernova. Such events are usually only detected at least a few days after the star has exploded. Observations of the supernova SNLS-04D2dc with the Galaxy Evolution Explorer space telescope reveal a radiative precursor from the supernova shock before the shock reached the surface of the star and show the initial expansion of the star at the beginning of the explosion. Theoretical models of the ultraviolet light curve confirm that the progenitor was a red supergiant, as expected for this type of supernova. These observations provide a way to probe the physics of core-collapse supernovae and the internal structures of their progenitor stars. PMID:18556514

  3. The structure of TeV-bright shell-type supernova remnants

    OpenAIRE

    Yang, Chuyuan; Liu, Siming; Fang, Jun; LI, HUI

    2014-01-01

    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 emission is produced via Inverse Compton scattering of background soft photons by high-energy electrons accelerated by the shocks of the SNRs. The TeV emissivity is proportional to the magnetic field energy density and MHD simulations can be used to model the TeV ...

  4. Supernova remnants interacting with molecular clouds as seen with H.E.S.S

    CERN Document Server

    Fernandez, D; Eger, P; Laffon, H; Mehault, J; Ohm, S; Oya, I

    2013-01-01

    About 30 Galactic supernova remnants (SNRs) are thought to be physically associated with molecular clouds (MCs). These systems are prime \\g-ray source candidates as the accelerated particles from shock fronts collide with the surrounding high-density medium thus emitting gamma-rays through hadronic interactions. However only a handful of such interacting SNRs are detected at TeV energies. We report the current status of the High Energy Stereoscopic System (H.E.S.S.) observations towards these SNR-MC systems, with a particular emphasis on the latest results.

  5. High-energy Emission from the Composite Supernova Remnant MSH 15-56

    Science.gov (United States)

    Temim, Tea; Slane, Patrick; Castro, Daniel; Plucinsky, Paul; Gelfand, Joseph; Dickel, John R.

    2013-01-01

    MSH 1556 (G326.3-1.8) is a composite supernova remnant (SNR) that consists of an SNR shell and a displaced pulsar wind nebula (PWN) in the radio. We present XMM-Newton and Chandra X-ray observations of the remnant that reveal a compact source at the tip of the radio PWN and complex structures that provide evidence for mixing of the supernova (SN) ejecta with PWN material following a reverse shock interaction. The X-ray spectra are well fitted by a non-thermal power-law model whose photon index steepens with distance from the presumed pulsar, and a thermal component with an average temperature of 0.55 keV. The enhanced abundances of silicon and sulfur in some regions, and the similar temperature and ionization timescale, suggest that much of the X-ray emission can be attributed to SN ejecta that have either been heated by the reverse shock or swept up by the PWN. We find one region with a lower temperature of 0.3 keV that appears to be in ionization equilibrium.Assuming the Sedov model, we derive a number of SNR properties, including an age of 16,500 yr. Modeling of the gamma-ray emission detected by Fermi shows that the emission may originate from the reverse shock-crushed PWN.

  6. HIGH-ENERGY EMISSION FROM THE COMPOSITE SUPERNOVA REMNANT MSH 15-56

    International Nuclear Information System (INIS)

    MSH 15-56 (G326.3–1.8) is a composite supernova remnant (SNR) that consists of an SNR shell and a displaced pulsar wind nebula (PWN) in the radio. We present XMM-Newton and Chandra X-ray observations of the remnant that reveal a compact source at the tip of the radio PWN and complex structures that provide evidence for mixing of the supernova (SN) ejecta with PWN material following a reverse shock interaction. The X-ray spectra are well fitted by a non-thermal power-law model whose photon index steepens with distance from the presumed pulsar, and a thermal component with an average temperature of 0.55 keV. The enhanced abundances of silicon and sulfur in some regions, and the similar temperature and ionization timescale, suggest that much of the X-ray emission can be attributed to SN ejecta that have either been heated by the reverse shock or swept up by the PWN. We find one region with a lower temperature of 0.3 keV that appears to be in ionization equilibrium. Assuming the Sedov model, we derive a number of SNR properties, including an age of 16,500 yr. Modeling of the ?-ray emission detected by Fermi shows that the emission may originate from the reverse shock-crushed PWN.

  7. Molecular environment of the supernova remnant IC 443: Discovery of the molecular shells surrounding the remnant

    International Nuclear Information System (INIS)

    We have carried out 12CO, 13CO, and C18O observations toward the mixed morphology supernova remnant (SNR) IC 443. The observations cover a 1.°5 × 1.°5 area and allow us to investigate the overall molecular environment of the remnant. Some northern and northeastern partial shell structure of CO gas is around the remnant. One of the partial shells, about 5' extending beyond the northeastern border of the remnant's bright radio shell, seems to just confine the faint radio halo. On the other hand, some faint CO clumps can be discerned along the eastern boundary of the faint remnant's radio halo. Connecting the eastern CO clumps, the northeastern partial shell structures, and the northern CO partial shell, we can see that a half molecular ring structure appears to surround the remnant. The LSR velocity of the half-ring structure is in the range of –5 km s–1 to –2 km s–1, which is consistent with that of the –4 km s–1 molecular clouds. We suggest that the half-ring structure of the CO emission at V LSR ∼ –4 km s–1 is associated with the SNR. The structures are possibly swept up by the stellar winds of SNR IC 443's massive progenitor. Based on the Wide-field Infrared Survey Explorer and the Two Micron All Sky Survey near-IR database, 62 young stellar object (YSO) candidates are selected within the radio halo of the remnant. These YSO candidates concentrated along the boundary of the remnant's bright radio shell are likely to be triggered by the stellar winds from the massive progenitor of SNR IC 443.

  8. What We Can Learn From Supernova Remnant Size Distributions

    Science.gov (United States)

    Elwood, Benjamin; Murphy, Jeremiah; Diaz, Mariangelly

    2016-01-01

    Previous literature regarding size distributions of supernova remnants generally discuss a uniform distribution for the radius, occasionally considering a Gaussian alternative. We indeed show that these distributions are consistent with log-normal, which can be considered a natural consequence of the Central Limit Theorem and Sedov expansion. Modeling explosion energy, remnant age, and ambient density as independent, random distributions, we show, using simple Monte Carlo simulations, that the size distribution is indistinguishable from log-normal when the SNR sample size is of order three hundred. This implies that these SNR distributions provide only information on the mean and variance, yielding additional information only when the sample size grows large. We then proceed to Bayesian statistical inference to characterize the information provided by the size distributions. In particular, we use the mean and variance of sizes and explosion energies to subsequently estimate the mean and variance of the ambient medium surrounding SNR progenitors. This in turn allows us to characterize potential bias in studies involving samples of supernova remnants.

  9. Constraining the Progenitor Masses of Core Collapse Supernova Remnants

    Science.gov (United States)

    Díaz Rodríguez, Mariangelly; Murphy, Jeremiah Wayne; Elwood, Benjamin; Williams, Benjamin F.; Rubin, David

    2016-01-01

    Understanding the progenitor mass distribution of supernova explosions is an important observational constraint of stellar evolution theory. Recently, a novel approach was proposed to significantly increase the number of progenitor masses: characterize the progenitor mass of supernova remnants (SNRs) by age-dating the local stellar population. Preliminary statistical analyses suggested that there is a lack of SNRs around the most massive of massive stars. This suggested that there is a maximum mass for core collapse supernova explosions, or there is a bias against finding SNRs associated with the most massive stars. We test for a bias by considering the distribution of SNRs sizes using a Monte Carlo simulation. We find that the distribution of remnants sizes is the same for low mass progenitors and high mass progenitors. This implies that there is no bias against finding SNRs around the most massive progenitors. Our next step is to apply Bayesian statistical inference and obtain the joint probability for all the parameters involved in the statistical distribution model: the minimum mass, maximum mass, and slope of the mass distribution.

  10. Search for surviving companions in type Ia supernova remnants

    CERN Document Server

    Pan, Kuo-Chuan; Taam, Ronald E

    2014-01-01

    The nature of the progenitor systems of type~Ia supernovae is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions. Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- and helium-rich surviving companions, the color and magnitude of main-sequence- and helium-rich surviving companions are predicted as functions of time. The surviving companion candidates in Galactic type~Ia supernova remnants and nearby extragalactic type~Ia supernova remnants are discussed. We find that the maximum detectable distance of main-sequence surviving companions (helium-rich surviving companions) is $0.6-4$~Mpc ($0.4-16$~Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to s...

  11. Interaction between supernova remnant G22.7–0.2 and the ambient molecular clouds

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yang; Yang, Ji; Zhou, Xin [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhou, Ping; Chen, Yang [Department of Astronomy, Nanjing University, 163 Xianlin Avenue, Nanjing 210093 (China)

    2014-12-01

    We have carried out {sup 12}CO (J = 1-0 and 2-1), {sup 13}CO (J = 1-0), and C{sup 18}O (J = 1-0) observations in the direction of the supernova remnant (SNR) G22.7–0.2. A filamentary molecular gas structure, which is likely part of a larger molecular complex with V {sub LSR} ? 75-79 km s{sup –1}, is detected and is found to surround the southern boundary of the remnant. In particular, the high-velocity wing (77-110 km s{sup –1}) in the {sup 12}CO (J = 1-0 and J = 2-1) emission shows convincing evidence of the interaction between SNR G22.7–0.2 and the 75-79 km s{sup –1} molecular clouds (MCs). Spectra with redshifted profiles, a signature of shocked molecular gas, are seen in the southeastern boundary of the remnant. The association between the remnant and the 77 km s{sup –1} MCs places the remnant at the near distance of 4.4 ± 0.4 kpc, which agrees with a location on the Scutum-Crux arm. We suggest that SNR G22.7–0.2, SNR W41, and H II region G022.760-0.485 are at the same distance and are associated with GMC G23.0–0.4.

  12. HFPK 334: An unusual supernova remnant in the Small Magellanic Cloud

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, E. J.; Filipovi?, M. D. [University of Western Sydney (Australia); McEntaffer, R. L.; Brantseg, T.; Heitritter, K.; Roper, Q. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Haberl, F. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany); Uroševi?, D., E-mail: e.crawford@uws.edu.au [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Studentski trg 16, 11000 Belgrade (Serbia)

    2014-11-01

    We present new Australia Telescope Compact Array radio-continuum and XMM-Newton/Chandra X-ray Observatory observations of the unusual supernova remnant (SNR) HFPK 334 in the Small Magellanic Cloud (SMC). The remnant follows a shell-type morphology in the radio continuum and has a size of ?20 pc at the SMC distance. The X-ray morphology is similar; however, we detect a prominent point source close to the center of the SNR exhibiting a spectrum with a best-fit power law with a photon index of ? = 2.7 ± 0.5. This central point source is most likely a background object and cannot be directly associated with the remnant. The high temperature, nonequilibrium conditions in the diffuse region suggest that this gas has been recently shocked and points toward a younger SNR with an age of ? 1800 yr. With an average radio spectral index of ? = –0.59 ± 0.09, we find that an equipartition magnetic field for the remnant is ?90 ?G, a value typical of younger SNRs in low-density environments. Also, we report the detection of scattered radio polarization across the remnant at 20 cm, with a peak fractional polarization level of 25% ± 5%.

  13. Interaction Between Supernova Remnant G22.7-0.2 And The Ambient Molecular Clouds

    CERN Document Server

    Su, Yang; Zhou, Xin; Zhou, Ping; Chen, Yang

    2014-01-01

    We have carried out 12CO (J=1-0 and 2-1), 13CO (J=1-0), and C18O (J=1-0) observations in the direction of the supernova remnant (SNR) G22.7-0.2. A filamentary molecular gas structure, which is likely part of a larger molecular complex with VLSR~75-79 km/s, is detected and is found to surround the southern boundary of the remnant. In particular, the high-velocity wing (77-110 km/s) in the 12CO (J=1-0 and J=2-1) emission shows convincing evidence of the interaction between SNR G22.7-0.2 and the 75-79 km/s molecular clouds (MCs). Spectra with redshifted profiles, a signature of shocked molecular gas, are seen in the southeastern boundary of the remnant. The association between the remnant and the 77 km/s MCs places the remnant at the near distance of 4.0-4.8 kpc, which agrees with a location on the Scutum-Crux arm. We suggest that SNR G22.7-0.2, SNR W41, and HII region G022.760-0.485 are at the same distance and are associated with GMC G23.0-0.4.

  14. Two evolved supernova remnants with newly identified Fe-rich cores in the Large Magellanic Cloud

    Science.gov (United States)

    Kavanagh, P. J.; Sasaki, M.; Bozzetto, L. M.; Points, S. D.; Crawford, E. J.; Dickel, J.; Filipovi?, M. D.; Haberl, F.; Maggi, P.; Whelan, E. T.

    2016-02-01

    Aims: We present a multi-wavelength analysis of the evolved supernova remnants MCSNR J0506-7025 and MCSNR J0527-7104 in the Large Magellanic Cloud. Methods: We used observational data from XMM-Newton, the Australian Telescope Compact Array, and the Magellanic Cloud Emission Line Survey to study their broad-band emission and used Spitzer and H i data to gain a picture of the environment into which the remnants are expanding. We performed a multi-wavelength morphological study and detailed radio and X-ray spectral analyses to determine their physical characteristics. Results: Both remnants were found to have bright X-ray cores, dominated by Fe L-shell emission, which is consistent with reverse shock-heated ejecta with determined Fe masses in agreement with Type Ia explosion yields. A soft X-ray shell, which is consistent with swept-up interstellar medium, was observed in MCSNR J0506-7025, suggestive of a remnant in the Sedov phase. Using the spectral fit results and the Sedov self-similar solution, we estimated the age of MCSNR J0506-7025 to be ~16-28 kyr, with an initial explosion energy of (0.07-0.84) × 1051 erg. A soft shell was absent in MCSNR J0527-7104, with only ejecta emission visible in an extremely elongated morphology that extends beyond the optical shell. We suggest that the blast wave has broken out into a low density cavity, allowing the shock heated ejecta to escape. We find that the radio spectral index of MCSNR J0506-7025 is consistent with the standard -0.5 for supernova remnants. Radio polarisation at 6 cm indicates a higher degree of polarisation along the western front and at the eastern knot with a mean fractional polarisation across the remnant of P ? (20 ± 6)%. Conclusions: The detection of Fe-rich ejecta in the remnants suggests that both resulted from Type Ia explosions. The newly identified Fe-rich cores in MCSNR J0506-7025 and MCSNR J0527-7104 make them members of the expanding class of evolved Fe-rich remnants in the Magellanic Clouds. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

  15. Energy Dependence of Synchrotron X-Ray Rims in Tycho's Supernova Remnant

    Science.gov (United States)

    Tran, Aaron; Williams, Brian J.; Petre, Robert; Ressler, Sean M.; Reynolds, Stephen P.

    2015-10-01

    Several young supernova remnants (SNRs) exhibit thin X-ray bright rims of synchrotron radiation at their forward shocks. Thin rims require strong magnetic field amplification beyond simple shock compression if rim widths are only limited by electron energy losses. But, magnetic field damping behind the shock could produce similarly thin rims with less extreme field amplification. Variation of rim width with energy may thus discriminate between competing influences on rim widths. We measured rim widths around Tycho's SNR in five energy bands using an archival 750 ks Chandra observation. Rims narrow with increasing energy and are well described by either loss-limited or damped scenarios, so X-ray rim width-energy dependence does not uniquely specify a model. But, radio counterparts to thin rims are not loss-limited and better reflect magnetic field structure. Joint radio and X-ray modeling favors magnetic damping in Tycho's SNR with damping lengths ˜1%-5% of remnant radius and magnetic field strengths ˜50-400 ?G assuming Bohm diffusion. X-ray rim widths are ˜1% of remnant radius, somewhat smaller than inferred damping lengths. Electron energy losses are important in all models of X-ray rims, suggesting that the distinction between loss-limited and damped models is blurred in soft X-rays. All loss-limited and damping models require magnetic fields ?20 ?G, affirming the necessity of magnetic field amplification beyond simple compression.

  16. Spitzer IRS Observations of the XA Region in the Cygnus Loop Supernova Remnant

    CERN Document Server

    Sankrit, R; Bautista, M; Gaetz, T J; Williams, B J; Blair, W P; Borkowski, K J; Long, K S

    2014-01-01

    We report on spectra of two positions in the XA region of the Cygnus Loop supernova remnant obtained with the InfraRed Spectrograph on the Spitzer Space Telescope. The spectra span the 10-35 micron wavelength range, which contains a number of collisionally excited forbidden lines. These data are supplemented by optical spectra obtained at the Whipple Observatory and an archival UV spectrum from the International Ultraviolet Explorer. Coverage from the UV through the IR provides tests of shock wave models and tight constraints on model parameters. Only lines from high ionization species are detected in the spectrum of a filament on the edge of the remnant. The filament traces a 180 km/s shock that has just begun to cool, and the oxygen to neon abundance ratio lies in the normal range found for Galactic H II regions. Lines from both high and low ionization species are detected in the spectrum of the cusp of a shock-cloud interaction, which lies within the remnant boundary. The spectrum of the cusp region is mat...

  17. Radio Properties of the Supernova Remnant N157B

    CERN Document Server

    Lazendic, J S; Haynes, R F; Jones, P A; White, G L

    2000-01-01

    A new investigation of the supernova remnant (SNR) N157B was carried out with the Australia Telescope Compact Array. Radio continuum images of the entire 30 Doradus region have been made at 3.5 and 6 cm wavelength with a resolution of 2". These data allow a high resolution study of the spectral index distribution and polarization properties of both N157B and the nearby 30 Doradus nebula (the latter will be reported in a subsequent paper). N157B is an extended Crab-type SNR which may be beginning the transition to a composite remnant. There is little apparent fine structure and the brightest radio region is several parsecs from the probable position of the X-ray pulsar. The SNR has a radio spectral index of -0.19 and is significantly polarized at 3.5 cm but not at longer wavelengths.

  18. Discovery of a pre-existing molecular filament associated with supernova remnant G127.1+0.5

    International Nuclear Information System (INIS)

    We performed millimeter observations in CO lines toward the supernova remnant (SNR) G127.1+0.5. We found a molecular filament at 4-13 km s–1 consisting of two distinct parts: a straight part coming out of the remnant region and a curved part in the remnant region. The curved part is coincides well with the bright SNR shell detected in 1420 MHz radio continuum and mid-infrared observations in the northeastern region. In addition, redshifted line wing broadening is found only in the curved part of the molecular filament, which indicates a physical interaction. These provide strong evidences, for the first time, to confirm the association between an SNR and a pre-existing long molecular filament. Multi-band observations in the northeastern remnant shell could be explained by the interaction between the remnant shock and the dense molecular filament. RADEX radiative transfer modeling of the quiet and shocked components yield physical conditions consistent with the passage of a non-dissociative J-type shock. We argue that the curved part of the filament is fully engulfed by the remnant's forward shock. A spatial correlation between aggregated young stellar objects (YSOs) and the adjacent molecular filament close to the SNR is also found, which could be related to the progenitor's activity.

  19. High-energy antiprotons from old supernova remnants

    CERN Document Server

    Blasi, Pasquale

    2009-01-01

    A recently proposed model (arXiv:0903.2794) explains the rise in energy of the positron fraction measured by the PAMELA satellite in terms of hadronic production of positrons in aged supernova remnants, and acceleration therein. Here we present a preliminary calculation of the anti-proton flux produced by the same mechanism. While the model is consistent with present data, a rise of the antiproton to proton ratio is predicted at high energy, which strikingly distinguishes this scenario from other astrophysical explanations of the positron fraction (like pulsars). We briefly discuss important implications for Dark Matter searches via antimatter.

  20. A method for computing synchrotron and inverse-Compton emission from hydrodynamic simulations of supernova remnants

    Science.gov (United States)

    Obergaulinger, M.; Chimeno, J. M.; Mimica, P.; Aloy, M. A.; Iyudin, A.

    2015-12-01

    The observational signature of supernova remnants (SNRs) is very complex, in terms of both their geometrical shape and their spectral properties, dominated by non-thermal synchrotron and inverse-Compton scattering. We propose a post-processing method to analyse the broad-band emission of SNRs based on three-dimensional hydrodynamical simulations. From the hydrodynamical data, we estimate the distribution of non-thermal electrons accelerated at the shock wave and follow the subsequent evolution as they lose or gain energy by adiabatic expansion or compression and emit energy by radiation. As a first test case, we use a simulation of a bipolar supernova expanding into a cloudy medium. We find that our method qualitatively reproduces the main observational features of typical SNRs and produces fluxes that agree with observations to within a factor of a few allowing for further use in more extended sets of models.

  1. 3D simulations of the non-thermal broad-band emission from young supernova remnants including efficient particle acceleration

    CERN Document Server

    Ferrand, Gilles; Safi-Harb, Samar

    2014-01-01

    Supernova remnants are believed to be the major contributors to Galactic cosmic rays. In this paper, we explore how the non-thermal emission from young remnants can be used to probe the production of energetic particles at the shock (both protons and electrons). Our model couples hydrodynamic simulations of a supernova remnant with a kinetic treatment of particle acceleration. We include two important back-reaction loops upstream of the shock: energetic particles can (i) modify the flow structure and (ii) amplify the magnetic field. As the latter process is not fully understood, we use different limit cases that encompass a wide range of possibilities. We follow the history of the shock dynamics and of the particle transport downstream of the shock, which allows us to compute the non-thermal emission from the remnant at any given age. We do this in 3D, in order to generate projected maps that can be compared with observations. We observe that completely different recipes for the magnetic field can lead to sim...

  2. Effect of stellar structure on supernova remnant evolution

    International Nuclear Information System (INIS)

    One-dimensional hydrodynamic calculations have been done of 1E51 erg explosions in 15M/sub sun/ stars. A steep external density gradient to the pre-supernova model of Weaver et al was appended with the results: (1) the outer shock wave decelerates throughout the pre-Sedov phase, (2) the expanding stellar envelope and the shocked interstellar material are Rayleigh-Taylor stable until the Sedov phase, and (3) steep internal density gradients are R-T unstable during the early expansion and may be the source of high velocity knots seen in Cas A

  3. Biermann Mechanism in Primordial Supernova Remnant and Seed Magnetic Fields

    OpenAIRE

    Hanayama, Hidekazu; Takahashi, Keitaro; Kotake, Kei; Oguri, Masamune; Ichiki, Kiyotomo; Ohno, Hiroshi

    2005-01-01

    We study generation of magnetic fields by the Biermann mechanism in the pair-instability supernovae explosions of first stars. The Biermann mechanism produces magnetic fields in the shocked region between the bubble and interstellar medium (ISM), even if magnetic fields are absent initially. We perform a series of two-dimensional magnetohydrodynamic simulations with the Biermann term and estimate the amplitude and total energy of the produced magnetic fields. We find that ma...

  4. Biermann Mechanism in Primordial Supernova Remnant and Seed Fields

    OpenAIRE

    Hanayama, Hidekazu; Takahashi, Keitaro; Kotake, Kei; Oguri, Masamune; Ichiki, Kiyotomo; Ohno, Hiroshi

    2005-01-01

    We have studied the generation of magnetic fields by the Biermann mechanism in the pair-instability supernovae explosions of the first stars. The Biermann mechanism produces magnetic fields in the shocked region between the bubble and interstellar medium (ISM), even if magnetic fields are absent initially. We have performed a series of two-dimensional magnetohydrodynamic simulations with the Biermann term and estimate the amplitude and total energy of the produced magnetic f...

  5. High-Energy Emission from the Composite Supernova Remnant MSH 15-56

    CERN Document Server

    Temim, Tea; Castro, Daniel; Plucinsky, Paul; Gelfand, Joseph; Dickel, John R

    2013-01-01

    MSH 15-56 (G326.3-1.8) is a composite supernova remnant (SNR) that consists of an SNR shell and a displaced pulsar wind nebula (PWN) in the radio. We present XMM-Newton and Chandra X-ray observations of the remnant that reveal a compact source at the tip of the radio PWN and complex structures that provide evidence for mixing of the supernova (SN) ejecta with PWN material following a reverse shock interaction. The X-ray spectra are well fitted by a non-thermal power-law model whose photon index steepens with distance from the presumed pulsar, and a thermal component with an average temperature of 0.55 keV. The enhanced abundances of silicon and sulfur in some regions, and the similar temperature and ionization timescale, suggest that much of the X-ray emission can be attributed to SN ejecta that have either been heated by the reverse shock or swept up by the PWN. We find one region with a lower temperature of 0.3 keV that appears to be in ionization equilibrium. Assuming the Sedov model, we derive a number of...

  6. Radio and X-ray Profiles in Supernova Remnants Undergoing Efficient Cosmic Ray Production

    CERN Document Server

    Ellison, D C; Ellison, Donald C.; Cassam-Chenai, Gamil

    2005-01-01

    The strong shocks in young supernova remnants (SNRs) should accelerate cosmic rays (CRs) and no doubt exists that \\rel electrons are produced in SNRs. However, direct and convincing evidence that SNRs produce CR nuclei has not yet been obtained and may, in fact, be long in coming if current gamma-ray observatories do not see an unambiguous pion-decay feature. Nevertheless, the lack of an observed pion-decay feature does not necessarily mean that CR ions are not abundantly produced since ions do not radiate efficiently. If CR ions are produced efficiently by diffusive shock acceleration (DSA), their presence will modify the hydrodynamics of the SNR and produce morphological effects which can be clearly seen in radiation produced by electrons. We describe in some detail our CR-hydro model, which couples DSA with the remnant hydrodynamics, and the synchrotron emission expected for two distinct parameter sets representing type Ia and type II supernovae. Several morphological features emerge in radial profiles, in...

  7. Spitzer Observations of the Type Ia Supernova Remnant N103B: Kepler's Older Cousin?

    CERN Document Server

    Williams, Brian J; Reynolds, Stephen P; Ghavamian, Parviz; Raymond, John C; Long, Knox S; Blair, William P; Winkler, P Frank; Sankrit, Ravi; Hendrick, Sean P

    2014-01-01

    We report results from Spitzer observations of SNR 0509-68.7, also known as N103B, a young Type Ia supernova remnant in the Large Magellanic Cloud that shows interaction with a dense medium in its western hemisphere. Our images show that N103B has strong IR emission from warm dust in the post-shock environment. The post-shock gas density we derive, 45 cm$^{-3}$, is much higher than in other Type Ia remnants in the LMC, though a lack of spatial resolution may bias measurements towards regions of higher than average density. This density is similar to that in Kepler's SNR, a Type Ia interacting with a circumstellar medium. Optical images show H$\\alpha$ emission along the entire periphery of the western portion of the shock, with [O III] and [S II] lines emitted from a few dense clumps of material where the shock has become radiative. The dust is silicate in nature, though standard silicate dust models fail to reproduce the "18 $\\mu$m" silicate feature that peaks instead at 17.3 $\\mu$m. We propose that the dense...

  8. SPITZER OBSERVATIONS OF DUST DESTRUCTION IN THE PUPPIS A SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    The interaction of the Puppis A supernova remnant (SNR) with a neighboring molecular cloud provides a unique opportunity to measure the amount of grain destruction in an SNR shock. Spitzer Space Telescope MIPS imaging of the entire SNR at 24, 70, and 160 ?m shows an extremely good correlation with X-ray emission, indicating that the SNR's IR radiation is dominated by the thermal emission of swept-up interstellar dust, collisionally heated by the hot shocked gas. Spitzer IRS spectral observations targeted both the Bright Eastern Knot (BEK) of the SNR where a small cloud has been engulfed by the supernova blast wave and outlying portions of the associated molecular cloud that are yet to be hit by the shock front. Modeling the spectra from both regions reveals the composition and the grain size distribution of the interstellar dust, both in front of and behind the SNR shock front. The comparison shows that the ubiquitous polycyclic aromatic hydrocarbons of the interstellar medium are destroyed within the BEK, along with nearly 25% of the mass of graphite and silicate dust grains.

  9. POLYCYCLIC AROMATIC HYDROCARBON PROCESSING IN THE BLAST WAVE OF THE SUPERNOVA REMNANT N132D

    International Nuclear Information System (INIS)

    We present Spitzer Infrared Spectrograph 14-36 ?m mapping observations of the supernova remnant N132D in the Large Magellanic Cloud. This study focuses on the processing of polycyclic aromatic hydrocarbons (PAHs) that we previously identified in the southern blast wave. The mid-infrared spectra show strong continuum emission from shock-heated dust and a unique, nearly featureless plateau in the 15-20 ?m region, which we attribute to PAH molecules. The typical PAH emission bands observed in the surrounding interstellar medium ahead of the blast wave disappear, which indicates shock processing of PAH molecules. The PAH plateau appears most strongly at the outer edge of the blast wave and coincides with diffuse X-ray emission that precedes the brightest X-ray and optical filaments. This suggests that PAH molecules in the surrounding medium are swept up and processed in the hot gas of the blast wave shock, where they survive the harsh conditions long enough to be detected. We also observe a broad emission feature at 20 ?m appearing with the PAH plateau. We speculate that this feature is either due to FeO dust grains or connected to the processing of PAHs in the supernova blast wave shock.

  10. Radio Emission from a Young Supernova Remnant Interacting with an Interstellar Cloud: MHD Simulation with Relativistic Electrons

    OpenAIRE

    Jun, Byung-Il; Jones, T.W.

    1998-01-01

    We present two-dimensional MHD simulations of the evolution of a young Type Ia supernova remnant during its interaction with an interstellar cloud of comparable size at impact. We include for the first time in such simulations explicit relativistic electron transport, including spectral information using a simple but effective scheme that follows their acceleration at shocks and subsequent transport. From this information we also model radio synchrotron emission, including s...

  11. MEASURING DUST PRODUCTION IN THE SMALL MAGELLANIC CLOUD CORE-COLLAPSE SUPERNOVA REMNANT 1E 0102.2-7219

    International Nuclear Information System (INIS)

    We present mid-infrared spectral mapping observations of the core-collapse supernova remnant 1E 0102.2-7219 in the Small Magellanic Cloud using the InfraRed Spectrograph on the Spitzer Space Telescope. The remnant shows emission from fine structure transitions of neon and oxygen as well as continuum emission from dust. Comparison of the mid-IR dust emission with observations at X-ray, radio, and optical wavelengths shows that the dust is associated with the supernova ejecta and is thus newly formed in the remnant. The spectrum of the newly formed dust is well reproduced by a model that includes 3 x 10-3 M sun of amorphous carbon dust at 70 K and 2 x 10-5 M sun of Mg2SiO4 (forsterite) at 145 K. Our observations place a lower limit on the amount of dust in the remnant since we are not sensitive to the cold dust in the unshocked ejecta. We compare our results to observations of other core-collapse supernovae and remnants, particularly Cas A where very similar spectral mapping observations have been carried out. We observe a factor of ?10 less dust in E 0102 than seen in Cas A, although the amounts of amorphous carbon and forsterite are comparable. Finally, we present evidence suggesting that the grain size distribution of the newly formed dust in E 0102 has been altered by the hot plasma behind the reverse shock.

  12. The many sides of RCW 86: a Type Ia supernova remnant evolving in its progenitor's wind bubble

    Science.gov (United States)

    Broersen, Sjors; Chiotellis, Alexandros; Vink, Jacco; Bamba, Aya

    2014-07-01

    We present the results of a detailed investigation of the Galactic supernova remnant RCW 86 using the XMM-Newton X-ray telescope. RCW 86 is the probable remnant of SN 185 A.D., a supernova that likely exploded inside a wind-blown cavity. We use the XMM-Newton Reflection Grating Spectrometer to derive precise temperatures and ionization ages of the plasma, which are an indication of the interaction history of the remnant with the presumed cavity. We find that the spectra are well fitted by two non-equilibrium ionization models, which enables us to constrain the properties of the ejecta and interstellar matter plasma. Furthermore, we performed a principal component analysis on EPIC MOS and pn data to find regions with particular spectral properties. We present evidence that the shocked ejecta, emitting Fe K and Si line emission, are confined to a shell of approximately 2 pc width with an oblate spheroidal morphology. Using detailed hydrodynamical simulations, we show that general dynamical and emission properties at different portions of the remnant can be well reproduced by a Type Ia supernova that exploded in a non-spherically symmetric wind-blown cavity. We also show that this cavity can be created using general wind properties for a single degenerate system. Our data and simulations provide further evidence that RCW 86 is indeed the remnant of SN 185, and is the likely result of a Type Ia explosion of single degenerate origin.

  13. Spitzer IRS observations of the XA region in the cygnus loop supernova remnant

    Energy Technology Data Exchange (ETDEWEB)

    Sankrit, Ravi [SOFIA Science Center, NASA Ames Research Center, M/S N211-3, Moffett Field, CA 94035 (United States); Raymond, John C.; Gaetz, Terrance J. [Smithsonian Astrophysical Observatory, 60 Garden Street, MS 15, Cambridge, MA 02138 (United States); Bautista, Manuel [Department of Physics, Western Michigan University, Kalamazoo MI 49008-5252 (United States); Williams, Brian J. [Goddard Space Flight Center, Mail Code 662, Greenbelt, MD 20771 (United States); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Borkowski, Kazimierz J. [North Carolina State University, Raleigh, NC 27607 (United States); Long, Knox S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-05-20

    We report on spectra of two positions in the XA region of the Cygnus Loop supernova remnant obtained with the InfraRed Spectrograph on the Spitzer Space Telescope. The spectra span the 10-35 ?m wavelength range, which contains a number of collisionally excited forbidden lines. These data are supplemented by optical spectra obtained at the Whipple Observatory and an archival UV spectrum from the International Ultraviolet Explorer. Coverage from the UV through the IR provides tests of shock wave models and tight constraints on model parameters. Only lines from high ionization species are detected in the spectrum of a filament on the edge of the remnant. The filament traces a 180 km s{sup –1} shock that has just begun to cool, and the oxygen to neon abundance ratio lies in the normal range found for Galactic H II regions. Lines from both high and low ionization species are detected in the spectrum of the cusp of a shock-cloud interaction, which lies within the remnant boundary. The spectrum of the cusp region is matched by a shock of about 150 km s{sup –1} that has cooled and begun to recombine. The post-shock region has a swept-up column density of about 1.3 × 10{sup 18} cm{sup –2}, and the gas has reached a temperature of 7000-8000 K. The spectrum of the Cusp indicates that roughly half of the refractory silicon and iron atoms have been liberated from the grains. Dust emission is not detected at either position.

  14. A study of the infrared emission of galactic supernova remnants

    International Nuclear Information System (INIS)

    This work aims to investigate the nature of the infrared (IR) emission of supernova remnants (SNRs), and to use this radiation to reveal the physical properties of SNRs and the gas and dust they contain. This project has been made possible only recently, following the success of the Infrared Astronomical Satellite (IRAS) in 1983. The first part of this thesis attempts to find the general characteristics of the IR emission of SNRs. A survey of the known galactic SNRs in the IRAS database has been completed. It is found that only one third of the galactic SNRs show detectable IR emission. Many remnants are confused with other galactic IR sources. The youngest SNRs exhibit spectra of relatively warm dust at ?90 K. Older SNRs, exhibit spectra that indicate dust grains within the SNRs have temperatures spanning a range from ?150 K to ?30 K. Supernova remnants can not be distinguished from other galactic IR sources on the basis of their IR colors alone. The second part of this work is a detailed study of the dust within and the IR emission of a single SRN, Puppis A. The IR morphology of Puppis A and its environment reveals that the appearance of the SNR is strongly influenced by its interaction with a nearby molecular cloud. Detailed analysis of the IR emission shows that small grains (?10 angstrom) must be present in the SNR to account for this emission observed at 12 ?m and 25 ?m. There is some evidence of destruction of grains within the SNR. The temperature and density of the gas in which the dust is embedded, and the geometry of the emitting regions are inferred from the IR emission at specific locations across the SNR

  15. Dynamical evolution of supernova remnants breaking through molecular clouds

    CERN Document Server

    Cho, Wankee; Koo, Bon-Chul

    2015-01-01

    We carry out three-dimensional hydrodynamic simulations of the supernova remnants (SNRs) produced inside molecular clouds (MCs) near their surface using the HLL code (Harten et al. 1983). We explore the dynamical evolution and the X-ray morphology of SNRs after breaking through the MC surface for ranges of the explosion depths below the surface and the density ratios of the clouds to the intercloud media (ICM). We find that if an SNR breaks out through an MC surface in its Sedov stage, the outermost dense shell of the remnant is divided into several layers. The divided layers are subject to the Rayleigh-Taylor instability and fragmented. On the other hand, if an SNR breaks through an MC after the remnant enters the snowplow phase, the radiative shell is not divided to layers. We also compare the predictions of previous analytic solutions for the expansion of SNRs in stratified media with our onedimensional simulations. Moreover, we produce synthetic X-ray surface brightness in order to research the center-bri...

  16. THE MIPSGAL VIEW OF SUPERNOVA REMNANTS IN THE GALACTIC PLANE

    International Nuclear Information System (INIS)

    We report the detection of Galactic supernova remnants (SNRs) in the mid-infrared (at 24 and 70 ?m), in the coordinate ranges 100 0 and 2850 0, |b| 0, using MIPS aboard the Spitzer Space Telescope. We search for infrared counterparts to SNRs in Green's catalog and identify 39 out of 121, i.e., a detection rate of about 32%. Such a relatively low detection fraction is mainly due to confusion with nearby foreground/background sources and diffuse emission. The SNRs in our sample show a linear trend in [F8/F24] versus [F70/F24]. We compare their infrared fluxes with their corresponding radio flux at 1.4 GHz and find that most remnants have a ratio of 70 ?m to 1.4 GHz which is similar to those found in previous studies of SNRs (with the exception of a few that have ratios closer to those of H II regions). Furthermore, we retrieve a slope close to unity when correlating infrared (24 and 70 ?m) with 1.4 GHz emission. Our survey is more successful in detecting remnants with bright X-ray emission, which we find is well correlated with the 24 ?m morphology. Moreover, by comparing the power emitted in the X-ray, infrared, and radio, we conclude that the energy released in the infrared is comparable to the cooling in the X-ray range.

  17. The 1st Fermi Lat Supernova Remnant Catalog

    CERN Document Server

    Acero, Fabio; Ajello, Marco; Baldini, Luca; Ballet, Jean; Barbiellini, Guido; Bastieri, Denis; Bellazzini, Ronaldo; Bissaldi, E; Blandford, Roger; Bloom, E D; Bonino, Raffaella; Bottacini, Eugenio; Bregeon, J; Bruel, Philippe; Buehler, Rolf; Buson, S; Caliandro, G A; Cameron, Rob A; Caputo, R; Caragiulo, Micaela; Caraveo, Patrizia A; Casandjian, Jean Marc; Cavazzuti, Elisabetta; Cecchi, Claudia; Chekhtman, A; Chiang, J; Chiaro, G; Ciprini, Stefano; Claus, R; Cohen, J M; Cohen-Tanugi, Johann; Cominsky, L R; Condon, B; Conrad, Jan; Cutini, S; D'Ammando, F; Angelis, A; Palma, F; Desiante, Rachele; Digel, S W; Venere, L; Drell, Persis S; Drlica-Wagner, Alex; Favuzzi, C; Ferrara, E C; Franckowiak, Anna; Fukazawa, Prof Yasushi; Funk, Prof Stefan; Fusco, P; Gargano, Fabio; Gasparrini, Dario; Giglietto, Nicola; Giommi, Paolo; Giordano, Francesco; Giroletti, Marcello; Glanzman, Tom; Godfrey, Gary; Gomez-Vargas, G A; Grenier, I A; Grondin, M -H; Guillemot, L; Guiriec, Sylvain; Gustafsson, M; Hadasch, D; Harding, A K; Hayashida, M; Hays, Elizabeth; Hewitt, J W; Hill, A B; Horan, Deirdre; Hou, X; Iafrate, Giulia; Jogler, Tobias; J'ohannesson, G; Johnson, Anthony S; Kamae, T; Katagiri, Hideaki; Kataoka, Prof Jun; Katsuta, Junichiro; Kerr, Matthew; Knodlseder, J; Kocevski, Prof Dale; Kuss, M; Laffon, Helene; Lande, J; Larsson, S; Latronico, Luca; Lemoine-Goumard, Marianne; Li, J; Li, L; Longo, Francesco; Loparco, Francesco; Lovellette, Michael N; Lubrano, Pasquale; Magill, J; Maldera, S; Marelli, Martino; Mayer, Michael; Mazziotta, M N; Michelson, Peter F; Mitthumsiri, Warit; Mizuno, Tsunefumi; Moiseev, Alexander A; Monzani, Maria Elena; Moretti, E; Morselli, Aldo; Moskalenko, Igor V; Murgia, Prof Simona; Nemmen, Prof Rodrigo; Nuss, Eric; Ohsugi, Takashi; Omodei, Nicola; Orienti, Monica; Orlando, Elena; Ormes, Jonathan F; Paneque, David; Perkins, J S; Pesce-Rollins, Melissa; Petrosian, Prof Vahe'; Piron, Frederic; Pivato, Giovanna; Porter, Troy; Rain`o, S; Rando, Riccardo; Razzano, Massimiliano; Razzaque, Soebur; Reimer, Anita; Reimer, Prof Olaf; Renaud, Matthieu; Reposeur, Thierry; Rousseau, Mr Romain; Parkinson, P M; Schmid, J; Schulz, A; Sgr`o, C; Siskind, Eric J; Spada, Francesca; Spandre, Gloria; Spinelli, Paolo; Strong, Andrew W; Suson, Daniel; Tajima, Hiro; Takahashi, Hiromitsu; Tanaka, T; Thayer, Jana B; Thompson, D J; Tibaldo, L; Tibolla, Omar; Torres, Prof Diego F; Tosti, Gino; Troja, Eleonora; Uchiyama, Yasunobu; Vianello, G; Wells, B; Wood, Kent; Wood, M; Yassine, Manal; Zimmer, Stephan

    2015-01-01

    To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope. Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which the positions of known remnants are scrambled in Galactic longitude, allows us to determine an upper limit of 22% on the number of GeV candidates falsely identified as SNRs. We have also developed a method to estimate spectral and spatial systematic errors arising from the diffuse interstellar emission model, a key component of all Galactic Fermi LAT analyses. By studying remnants uniformly in aggregate, we measure the GeV properties common to these objects and provide a crucial context for the detailed modeling of individual SNRs. Combining our GeV results with multiwavele...

  18. Cygnus Loop supernova remnant: new observations and a framework for understanding its structure and evolution

    International Nuclear Information System (INIS)

    New observational data on the Cygnus Loop supernova remnant (SNR) include: (1) a detailed high resolution comparison of x-ray and optical emission for a field in the SE; (2) a map of the [O III] electron temperature for the field previously studied by Hester, Parker, and Dufour (1983); and (3) CCD imagery of the NE limb in the light of four emission lines. A wide range of new and existing observations of the Loop are for the first time interpreted within the context of a single physical description. The Cygnus Loop is not an evaporative SNR evolving into the McKee and Ostriker (1977) ISM, nor are tiny cloudlets necessary to explain its morphology. The data show the Cygnus Loop to be evolving into a medium consisting primarily of an intercloud phase with N0 approx. 0.1 cm-3 containing clouds with parsec dimensions and N0 less than or equal to 10 cm-3. The optical emission arises from extensive sheet like radiative shock fronts driven into the clouds. These fronts locally form the outer boundary of the remnant. The appearance of x-ray emission outside the optical emission on the limbs is due solely to projection effects. The distorted and bumpy shock front is shown to give rise in projection to the filamentary morphology of the remnant

  19. A Spatial and Spectral Study of Nonthermal Filaments in Historical Supernova Remnants: Observational Results with Chandra

    CERN Document Server

    Bamba, A; Yoshida, T; Terasawa, T; Koyama, K; Bamba, Aya; Yamazaki, Ryo; Yoshida, Tatsuo; Terasawa, Toshio; Koyama, Katsuji

    2004-01-01

    The outer shells of young supernova remnants (SNRs) are the most plausible acceleration sites of high-energy electrons with the diffusive shock acceleration (DSA) mechanism. We studied spatial and spectral properties close to the shock fronts in four historical SNRs (Cas A, Kepler's remnant, Tycho's remnant, and RCW 86) with excellent spatial resolution of {\\it Chandra}. In all of the SNRs, hard X-ray emissions were found on the rims of the SNRs, which concentrate in very narrow regions (so-called "filaments"); apparent scale widths on the upstream side are below or in the order of the point spread function of {\\it Chandra}, while 0.5--40 arcsec (0.01--0.4 pc) on the downstream side with most reliable distances. The spectra of these filaments can be fitted with both thermal and nonthermal (power-law and {\\tt SRCUT}) models. The former requires unrealistic high temperature ($\\ga$2 keV) and low abundances ($\\la$1 solar) for emission from young SNRs and may be thus unlikely. The latter reproduces the spectra wit...

  20. Alfven Wave Amplification and Self-Containment of Cosmic-Rays Escaping from a Supernova Remnant

    CERN Document Server

    Fujita, Yutaka; Ohira, Yutaka; Iwasaki, Kazunari

    2011-01-01

    We study the escape of cosmic-ray (CR) protons accelerated at a supernova remnant (SNR) by numerically solving a diffusion-convection equation from the vicinity of the shock front to the region far away from the front. We consider the amplifications of Alfven waves generated by the escaping CR particles and their effects on CR escape into interstellar medium (ISM). We find that the amplification of the waves significantly delays the escape of the particles even far away from the shock front (on a scale of the SNR). This means that the energy spectrum of CR particles measured through gamma-ray observations at molecular clouds around SNRs is seriously affected by the particle scattering by the waves.

  1. Dust in a Type Ia Supernova Progenitor: Spitzer Spectroscopy of Kepler's Supernova Remnant

    CERN Document Server

    Williams, Brian J; Reynolds, Stephen P; Ghavamian, Parviz; Blair, William P; Long, Knox S; Sankrit, Ravi

    2012-01-01

    Characterization of the relatively poorly-understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's Supernova Remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 $\\mu$m infrared (IR) spectra of the remnant, obtained with the {\\it Spitzer Space Telescope}, dominated by emission from warm dust. Broad spectral features at 10 and 18 $\\mu$m, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the AGB stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength IRS and IRAC data. This could imply a mixed chemistry in the atmosphere of the p...

  2. Molecules and dust in Cassiopeia A: II - Dust sputtering and diagnosis for dust survival in supernova remnants

    CERN Document Server

    Biscaro, Chiara

    2015-01-01

    We study the dust evolution in the supernova remnant Cassiopeia A. We follow the processing of dust grains formed in the Type II-b supernova by modelling the sputtering of grains located in dense ejecta clumps crossed by the reverse shock. Further sputtering in the inter-clump medium once the clumps are disrupted by the reverse shock is investigated. The dust evolution in the dense ejecta clumps of Type II-P supernovae and their remnants is also studied. We study oxygen-rich clumps that describe the ejecta oxygen core, and carbon-rich clumps that correspond to the outermost carbon-rich ejecta zone. We consider the dust components formed in the supernova, several reverse shock velocities and inter-clump gas temperatures, and derive dust grain size distributions and masses as a function of time. We find that non-thermal sputtering in clumps is important and accounts for reducing the grain population by ~ 40% to 80% in mass, depending on the clump gas over-density and the grain type and size. A Type II-b SN form...

  3. Supernova Shock Breakout from a Red Supergiant

    CERN Document Server

    Schawinski, Kevin; Wolf, Christian; Podsiadlowski, Philipp; Sullivan, Mark; Steenbrugge, Katrien C; Bell, Tony; Roeser, Hermann-Josef; Walker, Emma; Astier, Pierre; Balam, Dave; Balland, Christophe; Basa, Stephane; Carlberg, Ray; Conley, Alex; Fouchez, Dominque; Guy, Julien; Hardin, Delphine; Hook, Isobel; Howell, Andy; Pain, Reynald; Perrett, Kathy; Pritchet, Chris; Regnault, Nicolas; Yi, Sukyoung K

    2008-01-01

    Massive stars undergo a violent death when the supply of nuclear fuel in their cores is exhausted, resulting in a catastrophic `core-collapse' supernova. Such events are usually detected long after the star has exploded. Here we report the first detection of the radiative precursor from a supernova shock before it has reached the surface of a star followed by the initial expansion of the star at the beginning of the explosion. Theoretical models of the ultraviolet light curve show that the progenitor was a red supergiant, as expected for this type of supernova. These observations provide a promising and novel way to probe the physics of core-collapse supernovae and the internal structures of their progenitors.

  4. The structure of TeV-bright shell-type supernova remnants

    CERN Document Server

    Yang, Chuyuan; Fang, Jun; Li, Hui

    2014-01-01

    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 emission is produced via Inverse Compton scattering of background soft photons by high-energy electrons accelerated by the shocks of the SNRs. The TeV emissivity is proportional to the magnetic field energy density and MHD simulations can be used to model the TeV structure of such remnants directly. 2D MHD simulations for SNRs are then performed under the assumption that the ambient interstellar medium is turbulent with the magnetic field and density fluctuations following a Kolmogorov-like power-law spectrum. Results. (1) As expected, these simulations confirm early 1D and 2D modelings of these sources, namely the hydrodynamical evolution of the shock waves and amplification of magnetic field by Rayleigh-Taylor convective flows and by shocks propagating in a turbulent medium; (2)...

  5. Dusty Blastwaves of Two Young LMC Supernova Remnants: Constraints on Postshock Compression

    CERN Document Server

    Williams, Brian J; Reynolds, Stephen P; Ghavamian, Parviz; Raymond, John C; Long, Knox S; Blair, William P; Sankrit, Ravi; Smith, R Chris; Points, Sean; Winkler, P Frank; Hendrick, Sean P

    2011-01-01

    We present results from mid-IR spectroscopic observations of two young supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) done with the {\\it Spitzer Space Telescope}. We imaged SNRs B0509-67.5 and B0519-69.0 with {\\it Spitzer} in 2005, and follow-up spectroscopy presented here confirms the presence of warm, shock heated dust, with no lines present in the spectrum. We use model fits to {\\it Spitzer} IRS data to estimate the density of the postshock gas. Both remnants show asymmetries in the infrared images, and we interpret bright spots as places where the forward shock is running into material that is several times denser than elsewhere. The densities we infer for these objects depend on the grain omposition assumed, and we explore the effects of differing grain porosity on the model fits. We also analyze archival {\\it XMM-Newton} RGS spectroscopic data, where both SNRs show strong lines of both Fe and Si, coming from ejecta, as well as strong O lines, which may come from ejecta or shocked ambient ...

  6. ISOCAM spectro-imaging of the $H_{2}$ rotational lines in the supernova remnant IC443

    CERN Document Server

    Cesarsky, D A; Pineau des Forêts, G; Van Dishoeck, E F; Boulanger, F; Wright, C M

    1999-01-01

    We report spectro-imaging observations of the bright western ridge of the supernova remnant IC 443 obtained with the ISOCAM circular variable filter (CVF) on board the Infrared Space Observatory (ISO). This ridge corresponds to a location where the interaction between the blast wave of the supernova and ambient molecular gas is amongst the strongest. The CVF data show that the 5 to 14 micron spectrum is dominated by the pure rotational lines of molecular hydrogen (v = 0--0, S(2) to S(8) transitions). At all positions along the ridge, the H2 rotational lines are very strong with typical line fluxes of 10^{-4} to 10^{-3} erg/sec/cm2/sr. We compare the data to a new time-dependent shock model; the rotational line fluxes in IC 443 are reproduced within factors of 2 for evolutionary times between 1,000 and 2,000 years with a shock velocity of 30 km/sec and a pre-shock density of 10^4 /cm3.

  7. Supernova Remnants Interacting with Molecular Clouds: X-Ray and Gamma-Ray Signatures

    Science.gov (United States)

    Slane, Patrick; Bykov, Andrei; Ellison, Donald C.; Dubner, Gloria; Castro, Daniel

    2015-05-01

    The giant molecular clouds (MCs) found in the Milky Way and similar galaxies play a crucial role in the evolution of these systems. The supernova explosions that mark the death of massive stars in these regions often lead to interactions between the supernova remnants (SNRs) and the clouds. These interactions have a profound effect on our understanding of SNRs. Shocks in SNRs should be capable of accelerating particles to cosmic ray (CR) energies with efficiencies high enough to power Galactic CRs. X-ray and ?-ray studies have established the presence of relativistic electrons and protons in some SNRs and provided strong evidence for diffusive shock acceleration as the primary acceleration mechanism, including strongly amplified magnetic fields, temperature and ionization effects on the shock-heated plasmas, and modifications to the dynamical evolution of some systems. Because protons dominate the overall energetics of the CRs, it is crucial to understand this hadronic component even though electrons are much more efficient radiators and it can be difficult to identify the hadronic component. However, near MCs the densities are sufficiently high to allow the ?-ray emission to be dominated by protons. Thus, these interaction sites provide some of our best opportunities to constrain the overall energetics of these particle accelerators. Here we summarize some key properties of interactions between SNRs and MCs, with an emphasis on recent X-ray and ?-ray studies that are providing important constraints on our understanding of cosmic rays in our Galaxy.

  8. Investigations of supernovae and supernova remnants in the era of SKA

    CERN Document Server

    Wang, Lingzhi; Zhu, Hui; Tian, Wenwu; Wang, Xiaofeng

    2015-01-01

    Two main physical mechanisms are used to explain supernova explosions: thermonuclear explosion of a white dwarf(Type Ia) and core collapse of a massive star (Type II and Type Ib/Ic). Type Ia supernovae serve as distance indicators that led to the discovery of the accelerating expansion of the Universe. The exact nature of their progenitor systems however remain unclear. Radio emission from the interaction between the explosion shock front and its surrounding CSM or ISM provides an important probe into the progenitor star's last evolutionary stage. No radio emission has yet been detected from Type Ia supernovae by current telescopes. The SKA will hopefully detect radio emission from Type Ia supernovae due to its much better sensitivity and resolution. There is a 'supernovae rate problem' for the core collapse supernovae because the optically dim ones are missed due to being intrinsically faint and/or due to dust obscuration. A number of dust-enshrouded optically hidden supernovae should be discovered via SKA1-...

  9. Radio spectra of complete sample of galactic supernova remnants

    CERN Document Server

    Trushkin, S A

    1998-01-01

    We present compiled radio continuum spectra for 200 Galactic supernova remnants (SNRs) from 220 known and included in Green's (1998) catalog. These spectra include most of the measurements available in literature, as well as multi-frequency measurements of nearly 120 SNRs with the RATAN-600 radio telescope in 1, 2 and 4 Galactic quadrants and from the Galactic plane survey at 960 and 3900 MHz. The measurements have been placed on the same absolute flux density scale. The presented compilation has given a possibility of plotting quite accurate spectra with the thermal plasma free-free absorption in fitting the spectra accounted for. An analysis of 190 spectra showed that 70 SNRs (37%) have clear low-frequency turnover caused, apparently, by absorption in the thermal foreground of the Milky Way. We did not find considerable correlation between spectral index and Galactic coordinates $l$ and $b$ of SNRs. The turnover frequencies do not correlate with $l$ and $b$.

  10. Galactic Gamma-Ray Background Radiation from Supernova Remnants

    CERN Document Server

    Berezhko, E G; Berezhko, Evgeny G.; Völk, Heinrich J.

    2000-01-01

    The contribution of the Source Cosmic Rays (SCRs), confined in Supernova Remnants, to the diffuse high energy \\gr emission above 1 GeV from the Galactic disk is studied. \\grs produced by the SCRs have a much harder spectrum compared with those generated by the Galactic Cosmic Rays which occupy a much larger residence volume uniformly. SCRs contribute less than 10% at GeV energies and become dominant at \\gr energies above 100 GeV. The contributions from $\\pi^0$-decay and Inverse Compton \\grs have comparable magnitude and spectral shape, whereas the Bremsstrahlung component is negligible. At TeV energies the contribution from SCRs increases the expected diffuse \\gr flux almost by an order of magnitude. It is shown that for the inner Galaxy the discrepancy between the observed diffuse intensity and previous model predictions at energies above a few GeV can be attributed to the SCR contribution.

  11. Origin of Galactic Cosmic Rays from Supernova Remnants

    International Nuclear Information System (INIS)

    We analyze the results of recent measurements of Galactic cosmic ray (GCRs) energy spectra and the spectra of nonthermal emission from supernova remnants (SNRs) in order to determine their consistency with GCR origin in SNRs. It is shown that the measured primary and secondary CR nuclei energy spectra as well as the observed positron-to-electron ratio are consistent with the origin of GCRs up to the energy 1017 eV in SNRs. Existing SNR emission data provide evidences for efficient CR production in SNRs accompanied by significant magnetic field amplification. In some cases the nature of the detected ?-ray emission is difficult to determine because key SNR parameters are not known or poorly constrained

  12. Origin of Galactic Cosmic Rays from Supernova Remnants

    CERN Document Server

    Berezhko, E G

    2014-01-01

    We analyze the results of recent measurements of Galactic cosmic ray (GCRs) energy spectra and the spectra of nonthermal emission from supernova remnants (SNRs) in order to determine their consistency with GCR origin in SNRs. It is shown that the measured primary and secondary CR nuclei energy spectra as well as the observed positron-to-electron ratio are consistent with the origin of GCRs up to the energy 10^17 eV in SNRs. Existing SNR emission data provide evidences for efficient CR production in SNRs accompanied by significant magnetic field amplification. In some cases the nature of the detected gamma-ray emission is difficult to determine because key SNR parameters are not known or poorly constrained.

  13. H I ABSORPTION SPECTRA TOWARD MAGPIS SUPERNOVA REMNANT CANDIDATES

    International Nuclear Information System (INIS)

    The Multi-Array Galactic Plane Imaging Survey is an ongoing project to map out the northern Galactic plane in the 21 cm radio continuum. The survey identified 30 probable supernova remnant candidates in the Galactic plane from 18 deg. < l< 32 deg. H I absorption spectra were taken toward these sources using data from the VLA Galactic Plane Survey. Using both circular and hydrodynamical Galactic rotation models, the corresponding distances were calculated. Of the 30 candidates, distances to nine of them were determined, and another eight sources had their distances constrained with upper and lower bounds. Many of these sources have detectable radio recombination line emission toward them, and we comment on the possible nature of these emissions.

  14. Type Ia supernova remnants: shaping by iron bullets

    Science.gov (United States)

    Tsebrenko, Danny; Soker, Noam

    2015-10-01

    Using 2D numerical hydrodynamical simulations of Type Ia supernova remnants (SNR Ia) we show that iron clumps few times denser than the rest of the SN ejecta might form protrusions in an otherwise spherical SNR. Such protrusions exist in some SNR Ia, e.g. SNR 1885 and Tycho. Iron clumps are expected to form in the deflagration to detonation explosion model. In SNR Ia where there are two opposite protrusions, termed `ears', such as Kepler's SNR and SNR G1.9+0.3, our scenario implies that the dense clumps, or iron bullets, were formed along an axis. Such a preferred axis can result from a rotating white dwarf progenitor. If our claim holds, this offers an important clue to the SN Ia explosion scenario.

  15. Phosphorus in the young supernova remnant Cassiopeia A.

    Science.gov (United States)

    Koo, Bon-Chul; Lee, Yong-Hyun; Moon, Dae-Sik; Yoon, Sung-Chul; Raymond, John C

    2013-12-13

    Phosphorus ((31)P), which is essential for life, is thought to be synthesized in massive stars and dispersed into interstellar space when these stars explode as supernovae (SNe). Here, we report on near-infrared spectroscopic observations of the young SN remnant Cassiopeia A, which show that the abundance ratio of phosphorus to the major nucleosynthetic product iron ((56)Fe) in SN material is up to 100 times the average ratio of the Milky Way, confirming that phosphorus is produced in SNe. The observed range is compatible with predictions from SN nucleosynthetic models but not with the scenario in which the chemical elements in the inner SN layers are completely mixed by hydrodynamic instabilities during the explosion. PMID:24337291

  16. Phosphorus in the Young Supernova Remnant Cassiopeia A

    CERN Document Server

    Koo, Bon-Chul; Moon, Dae-Sik; Yoon, Sung-Chul; Raymond, John C

    2013-01-01

    Phosphorus ($^{31}$P), which is essential for life, is thought to be synthesized in massive stars and dispersed into interstellar space when these stars explode as supernovae (SNe). Here we report on near-infrared spectroscopic observations of the young SN remnant Cassiopeia A, which show that the abundance ratio of phosphorus to the major nucleosynthetic product iron ($^{56}$Fe) in SN material is up to 100 times the average ratio of the Milky Way, confirming that phosphorus is produced in SNe. The observed range is compatible with predictions from SN nucleosynthetic models but not with the scenario in which the chemical elements in the inner SN layers are completely mixed by hydrodynamic instabilities during the explosion.

  17. Type Ia Supernova Remnants: Shaping by Iron Bullets

    CERN Document Server

    Tsebrenko, Danny

    2015-01-01

    Using 2D numerical hydrodynamical simulations of type Ia supernova remnants (SNR Ia) we show that iron clumps few times denser than the rest of the SN ejecta might form protrusions in an otherwise spherical SNR. Such protrusions exist in some SNR Ia, e.g., SNR 1885 and Tycho. Iron clumps are expected to form in the deflagration to detonation explosion model. In SNR Ia where there are two opposite protrusions, termed ears, such as Kepler's SNR and SNR G1.9+0.3, our scenario implies that the dense clumps, or iron bullets, were formed along an axis. Such a preferred axis can result from a rotating white dwarf progenitor. If our claim holds, this offers an important clue to the SN Ia explosion scenario.

  18. The Likely Fermi detection of the supernova remnant SN 1006

    CERN Document Server

    Xing, Yi; Zhang, Xiao; Chen, Yang

    2016-01-01

    We report the likely detection of gamma-ray emission from the northeast shell region of the historical supernova remnant (SNR) SN 1006. Having analyzed 7 years of Fermi LAT Pass 8 data for the region of SN 1006, we found a GeV gamma-ray source detected with 4 sigma significance. Both the position and spectrum of the source match those of HESS J1504-418 respectively, which is TeV emission from SN 1006. Considering the source as the GeV gamma-ray counterpart to SN~1006, the broadband spectral energy distribution is found to be approximately consistent with the leptonic scenario that has been proposed for the TeV emission from the SNR. Our result has likely confirmed the previous study of the SNRs with TeV shell-like morphology: SN 1006 is one of them sharing very similar peak luminosity and spectral shape.

  19. Origin of Galactic Cosmic Rays from Supernova Remnants

    Energy Technology Data Exchange (ETDEWEB)

    Berezhko, E.G., E-mail: berezhko@ikfia.ysn.ru

    2014-11-15

    We analyze the results of recent measurements of Galactic cosmic ray (GCRs) energy spectra and the spectra of nonthermal emission from supernova remnants (SNRs) in order to determine their consistency with GCR origin in SNRs. It is shown that the measured primary and secondary CR nuclei energy spectra as well as the observed positron-to-electron ratio are consistent with the origin of GCRs up to the energy 10{sup 17} eV in SNRs. Existing SNR emission data provide evidences for efficient CR production in SNRs accompanied by significant magnetic field amplification. In some cases the nature of the detected γ-ray emission is difficult to determine because key SNR parameters are not known or poorly constrained.

  20. HAWC Observation of Supernova Remnants and Pulsar Wind Nebulae

    CERN Document Server

    Hui, C M

    2015-01-01

    The majority of Galactic TeV gamma-ray sources are pulsar wind nebulae (PWNe) and supernova remnants (SNRs), and the most common association for unidentified sources is PWN. Many of these sources were discovered in TeV by imaging air Cherenkov telescopes using overlapping pointed observations over sections of the Galactic plane. The HAWC observatory is a survey type instrument in the Northern hemisphere with an energy range of 100 GeV to 100 TeV. Preliminary analysis of data recorded with the partially completed HAWC array taken since 2013 shows extended detections that are coincident with known TeV SNRs and PWNe. The full array became operational in early 2015 and has been steadily surveying the Northern sky since. I will discuss detections in HAWC data taken since 2013 associated with PWNe and SNRs.

  1. Powerful Tools for Dissecting Supernova Remnants Observed with Chandra

    Science.gov (United States)

    Lopez, Laura A.; Ramirez-Ruiz, E.; Pooley, D.; Huppenkothen, D.

    2008-03-01

    We introduce powerful new methods to quantify X-ray morphology of supernova remnants observed with Chandra. We demonstrate application of three techniques -- a power-ratio method, two-point correlation, and wavelet-transform analysis -- to archival ACIS observations of twenty galactic SNRs of all types and a variety of ages to measure chemical segregation and mixing, distribution asymmetries, and local substructure. Detailed comparison between sources provides crucial insights regarding the nature of the explosion, the effects of heating and dense environments, and particle acceleration properties. For each remnant, we have created individual images of observed spectral features (emission lines, thermal and non-thermal emission). Using two-point correlation, we disentangle the thermal and non-thermal emitting regions, and we measure with great accuracy the sizes and locations of thermal and non-thermal clumps with wavelet-transform analysis. The non-thermal continuum is located predominantly around the rim of our sources, and it has great excess power at small scales compared to the thermal component. Application of our methods to radio data reveals how the size of non-thermal emitting regions changes as a function of photon energy, which provides crucial insight to understand the magnetic-field properties and particle acceleration mechanisms. We extract XMM-Newton spectra of the regions with and without line emission as identified by the wavelet-transform analysis. Detailed knowledge of the X-ray substructure enables much more precise ejecta mass estimates than any previous SNR studies, key to constraining the supernova explosion histories. Additionally, we map rigorously the temperature and ion intensity variation within each source. Using these methods, we distinguish whether asymmetric chemical distributions arise from inhomogeneous heating or from an anisotropic explosion. In brief, we present three mathematical techniques that are superbly suited for analysis of high-resolution X-ray images, and we show their use for probing many outstanding questions that are vital to advance SNR understanding.

  2. Spectra of accelerated particles at supernova shocks in the presence of neutral hydrogen: the case of Tycho

    CERN Document Server

    Morlino, G

    2015-01-01

    The presence of neutral hydrogen in the shock proximity changes the structure of the shock and affects the spectra of particles accelerated through the first order Fermi mechanism. This phenomenon has profound implications for the interpretation of the multifrequency spectra of radiation from supernova remnants. Neutrals that undergo charge exchange with hot ions downstream of the shock may result in fast neutrals moving towards the upstream gas, where they can suffer additional charge exchange or ionisation reactions, thereby depositing energy and momentum upstream. Here we discuss the implications of this neutral return flux, already predicted in our previous work on neutral mediated supernova shocks and show how the spectra of accelerated particles turn out to be appreciably steeper than $p^{-4}$, thereby affecting the gamma ray spectra from supernova remnants in general and from Tycho specifically. The theory that describes non-linear diffusive shock acceleration in the presence of neutral hydrogen has be...

  3. Fermi LAT gamma-ray observations of the supernova remnant HB21

    CERN Document Server

    Pivato, G; Tibaldo, L

    2013-01-01

    We present the analysis of Fermi Large Area Telescope (LAT) \\g-ray observations of HB 21, a mixed-morphology supernova remnant. Such supernova remnants are characterized by an interior thermal X-ray plasma, surrounded by a wider nonthermal shell emitting at radio frequencies. HB 21 has a large angular size, making it a good candidate for detailed morphological and spectral studies with the LAT. The radio extension is $2^\\circ\\times1^\\circ$, compared to the LAT 68% containment angle of $\\sim1^\\circ$ at 1 GeV. To understand the origin of \\g-ray emission, we compare LAT observations with other wavelengths that trace non-thermal radio synchrotron, nearby molecular clouds, shocked molecular clumps, and the central X-ray plasma. Finally, we model possible hadronic and leptonic emission mechanisms. We conclude that \\g-rays from HB 21 are likely the result of electron bremsstrahlung or proton-proton collisions with dense material due to interaction with the nearby clouds.

  4. RADIOACTIVE SCANDIUM IN THE YOUNGEST GALACTIC SUPERNOVA REMNANT G1.9+0.3

    International Nuclear Information System (INIS)

    We report the discovery of thermal X-ray emission from the youngest Galactic supernova remnant G1.9+0.3, from a 237 ks Chandra observation. We detect strong K? lines of Si, S, Ar, Ca, and Fe. In addition, we detect a 4.1 keV line with 99.971% confidence which we attribute to 44Sc, produced by electron capture from 44Ti. Combining the data with our earlier Chandra observation allows us to detect the line in two regions independently. For a remnant age of 100 yr, our measured total line strength indicates synthesis of (1-7) x 10-5 M sun of 44Ti, in the range predicted for both Type Ia and core-collapse supernovae (SNe), but somewhat smaller than the 2 x 10-4 M sun reported for Cas A. The line spectrum indicates supersolar abundances. The Fe emission has a width of about 28,000 km s-1, consistent with an age of ?100 yr and with the inferred mean shock velocity of 14,000 km s-1 deduced assuming a distance of 8.5 kpc. Most thermal emission comes from regions of lower X-ray but higher radio surface brightness. Deeper observations should allow more detailed spatial mapping of 44Sc, with significant implications for models of nucleosynthesis in Type Ia SNe.

  5. Radioactive Scandium in the Youngest Galactic Supernova Remnant G1.9+0.3

    CERN Document Server

    Borkowski, Kazimierz J; Green, David A; Hwang, Una; Petre, Robert; Krishnamurthy, Kalyani; Willett, Rebecca

    2010-01-01

    We report the discovery of thermal X-ray emission from the youngest Galactic supernova remnant (SNR) G1.9+0.3, from a 237-ks Chandra observation. We detect strong K-shell lines of Si, S, Ar, Ca, and Fe. In addition, we detect a 4.1 keV line with 99.971% confidence which we attribute to 44Sc, produced by electron capture from 44Ti. Combining the data with our earlier Chandra observation allows us to detect the line in two regions independently. For a remnant age of 100 yr, our measured total line strength indicates synthesis of $(1 - 7) \\times 10^{-5}$ solar masses of 44Ti, in the range predicted for both Type Ia and core-collapse (CC) supernovae, but somewhat smaller than the $2 \\times 10^{-4}$ solar masses reported for Cas A. The line spectrum indicates supersolar abundances. The Fe emission has a width of about 26,000 km/s, consistent with an age of about 100 yr and with the inferred mean shock velocity of 14,000 km/s deduced assuming a distance of 8.5 kpc. Most thermal emission comes from regions of lower ...

  6. Nonthermal radiation of young supernova remnants: The case of Cas A

    International Nuclear Information System (INIS)

    The processes responsible for the broadband radiation of the young supernova remnant Cas A are explored by using a new code that is designed for a detailed treatment of the diffusive shock acceleration of particles in the nonlinear regime. The model is based on spherically symmetric hydrodynamic equations complemented with transport equations for relativistic particles. Electrons, protons, and the oxygen ions accelerated by forward and reverse shocks are included in the numerical calculations. We show that the available multi-wavelength observations in the radio, X-ray, and gamma-ray bands can be best explained by invoking particle acceleration by both forward and reversed shocks. Although the TeV gamma-ray observations can be interpreted by interactions of both accelerated electrons and protons/ions, the measurements by Fermi Large Area Telescope at energies below 1 GeV give a tentative preference to the hadronic origin of gamma-rays. Then, the acceleration efficiency in this source, despite the previous claims, should be very high; 25% of the explosion energy (or approximately 3 × 1050 erg) should already be converted to cosmic rays, mainly by the forward shock. At the same time, the model calculations do not provide extension of the maximum energy of accelerated protons beyond 100 TeV. In this model, the acceleration of electrons is dominated by the reverse shock; the required 1048 erg can be achieved under the assumption that the injection of electrons (positrons) is supported by the radioactive decay of 44Ti.

  7. Searches for Continuous Gravitational Waves from Nine Young Supernova Remnants

    Science.gov (United States)

    Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J. S.; Ast, S.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barclay, S.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Bartlett, J.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauer, Th. S.; Baune, C.; Bavigadda, V.; Behnke, B.; Bejger, M.; Belczynski, C.; Bell, A. S.; Bell, C.; Benacquista, M.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackburn, L.; Blair, C. D.; Blair, D.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bojtos, P.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchman, S.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Calderón Bustillo, J.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M., Jr.; Conte, A.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Cutler, C.; Dahl, K.; Dal Canton, T.; Damjanic, M.; Danilishin, S. L.; D’Antonio, S.; Danzmann, K.; Dartez, L.; Dattilo, V.; Dave, I.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Dominguez, E.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Edwards, M.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fuentes-Tapia, S.; Fulda, P.; Fyffe, M.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gatto, A.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Gossler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guido, C. J.; Guo, X.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hacker, J.; Hall, E. D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heinzel, G.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E.; Howell, E. J.; Hu, Y. M.

    2015-11-01

    We describe directed searches for continuous gravitational waves (GWs) in data from the sixth Laser Interferometer Gravitational-wave Observatory (LIGO) science data run. The targets were nine young supernova remnants not associated with pulsars; eight of the remnants are associated with non-pulsing suspected neutron stars. One target's parameters are uncertain enough to warrant two searches, for a total of 10. Each search covered a broad band of frequencies and first and second frequency derivatives for a fixed sky direction. The searches coherently integrated data from the two LIGO interferometers over time spans from 5.3–25.3 days using the matched-filtering {F}-statistic. We found no evidence of GW signals. We set 95% confidence upper limits as strong (low) as 4 × 10?25 on intrinsic strain, 2 × 10?7 on fiducial ellipticity, and 4 × 10?5 on r-mode amplitude. These beat the indirect limits from energy conservation and are within the range of theoretical predictions for neutron-star ellipticities and r-mode amplitudes.

  8. XMM-Newton observation of Kepler's supernova remnant

    CERN Document Server

    Cassam-Chenai, G; Ballet, J; Hwang, U; Hughes, J P; Petre, R

    2003-01-01

    We present the first results coming from the observation of Kepler's supernova remnant obtained with the EPIC instruments on board the XMM-Newton satellite. We focus on the images and radial profiles of the emission lines (Si K, Fe L, Fe K) and of the high energy continuum. Chiefly, the Fe L and Si K emission-line images are generally consistent with each other and the radial profiles show that the Si K emission extends to a larger radius than the Fe L emission (distinctly in the southern part of the remnant). Therefore, in contrast to Cas A, no inversion of the Si- and Fe-rich ejecta layers is observed in Kepler. Moreover, the Fe K emission peaks at a smaller radius than the Fe L emission, which implies that the temperature increases inwards in the ejecta. The 4-6 keV high energy continuum map shows the same distribution as the asymmetric emission-line images except in the southeast where there is a strong additional emission. A two color image of the 4-6 keV and 8-10 keV high energy continuum illustrates th...

  9. Searches for continuous gravitational waves from nine young supernova remnants

    CERN Document Server

    Aasi, J; Abbott, R; Abbott, T; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V; Affeldt, C; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Ain, A; Ajith, P; Alemic, A; Allen, B; Allocca, A; Amariutei, D; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C; Areeda, J S; Ast, S; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Aylott, B E; Babak, S; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Barayoga, J C; Barbet, M; Barclay, S; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Bartlett, J; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Bauer, Th S; Baune, C; Bavigadda, V; Behnke, B; Bejger, M; Belczynski, C; Bell, A S; Bell, C; Benacquista, M; Bergman, J; Bergmann, G; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Birch, J; Biscans, S; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blackburn, L; Blair, C D; Blair, D; Bloemen, S; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bojtos, P; Bond, C; Bondu, F; Bonelli, L; Bonnand, R; Bork, R; Born, M; Boschi, V; Bose, Sukanta; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Bridges, D O; Brillet, A; Brinkmann, M; Brisson, V; Brooks, A F; Brown, D A; Brown, D D; Brown, N M; Buchman, S; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Cadonati, L; Cagnoli, G; Bustillo, J Calderón; Calloni, E; Camp, J B; Cannon, K C; Cao, J; Capano, C D; Carbognani, F; Caride, S; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, Y; Chincarini, A; Chiummo, A; Cho, H S; Cho, M; Chow, J H; Christensen, N; Chu, Q; Chua, S; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P -F; Colla, A; Collette, C; Colombini, M; Cominsky, L; Constancio,, M; Conte, A; Cook, D; Corbitt, T R; Cornish, N; Corsi, A; Costa, C A; Coughlin, M W; Coulon, J -P; Countryman, S; Couvares, P; Coward, D M; Cowart, M J; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Creighton, T D; Cripe, J; Crowder, S G; Cumming, A; Cunningham, L; Cuoco, E; Cutler, C; Dahl, K; Canton, T Dal; Damjanic, M; Danilishin, S L; D'Antonio, S; Danzmann, K; Dartez, L; Dattilo, V; Dave, I; Daveloza, H; Davier, M; Davies, G S; Daw, E J; Day, R; DeBra, D; Debreczeni, G; Degallaix, J; De Laurentis, M; Deléglise, S; Del Pozzo, W; Denker, T; Dent, T; Dereli, H; Dergachev, V; De Rosa, R; DeRosa, R T; DeSalvo, R; Dhurandhar, S; Díaz, M; Di Fiore, L; Di Lieto, A; Di Palma, I; Di Virgilio, A; Dojcinoski, G; Dolique, V; Dominguez, E; Donovan, F; Dooley, K L; Doravari, S; Douglas, R; Downes, T P; Drago, M; Driggers, J C; Du, Z; Ducrot, M; Dwyer, S; Eberle, T; Edo, T; Edwards, M; Effler, A; Eggenstein, H -B; Ehrens, P; Eichholz, J; Eikenberry, S S; Essick, R; Etzel, T; Evans, M; Evans, T; Factourovich, M; Fafone, V; Fairhurst, S; Fan, X; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fays, M; Fehrmann, H; Fejer, M M; Feldbaum, D; Ferrante, I; Ferreira, E C; Ferrini, F; Fidecaro, F; Fiori, I; Fisher, R P; Flaminio, R; Fournier, J -D; Franco, S; Frasca, S; Frasconi, F; Frei, Z; Freise, A; Frey, R; Fricke, T T; Fritschel, P; Frolov, V V; Fuentes-Tapia, S; Fulda, P; Fyffe, M; Gair, J R; Gammaitoni, L; Gaonkar, S; Garufi, F; Gatto, A; Gehrels, N; Gemme, G; Gendre, B; Genin, E; Gennai, A; Gergely, L Á; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gleason, J; Goetz, E; Goetz, R; Gondan, L; González, G; Gordon, N; Gorodetsky, M L; Gossan, S; Goßler, S; Gouaty, R; Gräf, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greenhalgh, R J S; Gretarsson, A M; Groot, P; Grote, H; Grunewald, S; Guidi, G M; Guido, C J; Guo, X; Gushwa, K; Gustafson, E K; Gustafson, R; Hacker, J; Hall, E D; Hammond, G; Hanke, M; Hanks, J; Hanna, C; Hannam, M D; Hanson, J; Hardwick, T; Harms, J; Harry, G M; Harry, I W; Hart, M; Hartman, M T; Haster, C -J; Haughian, K; Hee, S; Heidmann, A; Heintze, M; Heinzel, G; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Heptonstall, A W; Heurs, M; Hewitson, M; Hild, S; Hoak, D; Hodge, K A; Hofman, D; Hollitt, S E; Holt, K; Hopkins, P; Hosken, D J; Hough, J; Houston, E; Howell, E J; Hu, Y M; Huerta, E; Hughey, B; Husa, S; Huttner, S H; Huynh, M; Huynh-Dinh, T; Idrisy, A; Indik, N; Ingram, D R; Inta, R; Islas, G; Isler, J C; Isogai, T; Iyer, B R; Izumi, K; Jacobson, M; Jang, H; Jaranowski, P; Jawahar, S; Ji, Y; Jiménez-Forteza, F; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; K, Haris; Kalogera, V; Kandhasamy, S; Kang, G; Kanner, J B; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, H; Kaufer, S; Kaur, T; Kawabe, K; Kawazoe, F; Kéfélian, F; Keiser, G M; Keitel, D; Kelley, D B; Kells, W; Keppel, D G; Key, J S; Khalaidovski, A; Khalili, F Y; Khazanov, E A; Kim, C; Kim, K; Kim, N G; Kim, N; Kim, Y -M; King, E J; King, P J; Kinzel, D L; Kissel, J S; Klimenko, S; Kline, J; Koehlenbeck, S; Kokeyama, K; Kondrashov, V; Korobko, M; Korth, W Z; Kowalska, I; Kozak, D B; Kringel, V; Krishnan, B; Królak, A; Krueger, C; Kuehn, G; Kumar, A; Kumar, P; Kuo, L; Kutynia, A; Landry, M; Lantz, B; Larson, S; Lasky, P D; Lazzarini, A; Lazzaro, C; Le, J; Leaci, P; Leavey, S; Lebigot, E; Lebigot, E O; Lee, C H; Lee, H K; Lee, H M; Leonardi, M; Leong, J R; Leroy, N; Letendre, N; Levin, Y; Levine, B; Lewis, J; Li, T G F; Libbrecht, K; Libson, A; Lin, A C; Littenberg, T B; Lockerbie, N A; Lockett, V; Logue, J; Lombardi, A L; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J; Lubinski, M J; Lück, H; Lundgren, A P; Lynch, R; Ma, Y; Macarthur, J; MacDonald, T; Machenschalk, B; MacInnis, M; Macleod, D M; Magaña-Sandoval, F; Magee, R; Mageswaran, M; Maglione, C; Mailand, K; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Mandel, I; Mandic, V; Mangano, V; Mansell, G L; Mantovani, M; Marchesoni, F; Marion, F; Márka, S; Márka, Z; Markosyan, A; Maros, E; Martelli, F; Martellini, L; Martin, I W; Martin, R M; Martynov, D; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Matichard, F; Matone, L; Mavalvala, N; Mazumder, N; Mazzolo, G; McCarthy, R; McClelland, D E; McCormick, S; McGuire, S C; McIntyre, G; McIver, J; McLin, K; McWilliams, S; Meacher, D; Meadors, G D; Meidam, J; Meinders, M; Melatos, A; Mendell, G; Mercer, R A; Meshkov, S; Messenger, C; Meyers, P M; Mezzani, F; Miao, H; Michel, C; Middleton, H; Mikhailov, E E; Milano, L; Miller, A; Miller, J; Millhouse, M; Minenkov, Y; Ming, J; Mirshekari, S; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moe, B; Moggi, A; Mohan, M; Mohanty, S D; Mohapatra, S R P; Moore, B; Moraru, D; Moreno, G; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, C L; Mueller, G; Mukherjee, S; Mullavey, A; Munch, J; Murphy, D; Murray, P G; Mytidis, A; Nagy, M F; Nardecchia, I; Nash, T; Naticchioni, L; Nayak, R K; Necula, V; Nedkova, K; Nelemans, G; Neri, I; Neri, M; Newton, G; Nguyen, T; Nielsen, A B; Nissanke, S; Nitz, A H; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Ochsner, E; O'Dell, J; Oelker, E; Ogin, G H; Oh, J J; Oh, S H; Ohme, F; Oppermann, P; Oram, R; O'Reilly, B; Ortega, W; O'Shaughnessy, R; Osthelder, C; Ott, C D; Ottaway, D J; Ottens, R S; Overmier, H; Owen, B J; Padilla, C; Pai, A; Pai, S; Palashov, O; Palomba, C; Pal-Singh, A; Pan, H; Pankow, C; Pannarale, F; Pant, B C; Paoletti, F; Papa, M A; Paris, H; Pasqualetti, A; Passaquieti, R; Passuello, D; Patrick, Z; Pedraza, M; Pekowsky, L; Pele, A; Penn, S; Perreca, A; Phelps, M; Pichot, M; Piergiovanni, F; Pierro, V; Pillant, G; Pinard, L; Pinto, I M; Pitkin, M; Poeld, J; Poggiani, R; Post, A; Poteomkin, A; Powell, J; Prasad, J; Predoi, V; Premachandra, S; Prestegard, T; Price, L R; Prijatelj, M; Principe, M; Privitera, S; Prix, R; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; Pürrer, M; Qin, J; Quetschke, V; Quintero, E; Quiroga, G; Quitzow-James, R; Raab, F J; Rabeling, D S; Rácz, I; Radkins, H; Raffai, P; Raja, S; Rajalakshmi, G; Rakhmanov, M; Ramirez, K; Rapagnani, P; Raymond, V; Razzano, M; Re, V; Reed, C M; Regimbau, T; Rei, L; Reid, S; Reitze, D H; Reula, O; Ricci, F; Riles, K; Robertson, N A; Robie, R; Robinet, F; Rocchi, A; Rolland, L; Rollins, J G; Roma, V; Romano, R; Romanov, G; Romie, J H; Rosińska, D; Rowan, S; Rüdiger, A; Ruggi, P; Ryan, K; Sachdev, S; Sadecki, T; Sadeghian, L; Saleem, M; Salemi, F; Sammut, L; Sandberg, V; Sanders, J R; Sannibale, V; Santiago-Prieto, I; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Savage, R; Sawadsky, A; Scheuer, J; Schilling, R; Schmidt, P; Schnabel, R; Schofield, R M S; Schreiber, E; Schuette, D; Schutz, B F; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Serna, G; Sevigny, A; Shaddock, D A; Shah, S; Shahriar, M S; Shaltev, M; Shao, Z; Shapiro, B; Shawhan, P; Shoemaker, D H; Sidery, T L; Siellez, K; Siemens, X; Sigg, D; Silva, A D; Simakov, D; Singer, A; Singer, L; Singh, R; Sintes, A M; Slagmolen, B J J; Smith, J R; Smith, M R; Smith, R J E; Smith-Lefebvre, N D; Son, E J; Sorazu, B; Souradeep, T; Staley, A; Stebbins, J; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stephens, B C; Steplewski, S; Stevenson, S; Stone, R; Strain, K A; Straniero, N; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Sutton, P J; Swinkels, B; Szczepanczyk, M; Szeifert, G; Tacca, M; Talukder, D; Tanner, D B; Tápai, M; Tarabrin, S P; Taracchini, A; Taylor, R; Tellez, G; Theeg, T; Thirugnanasambandam, M P; Thomas, M; Thomas, P; Thorne, K A; Thorne, K S; Thrane, E; Tiwari, V; Tomlinson, C; Tonelli, M; Torres, C V; Torrie, C I; Travasso, F; Traylor, G; Tse, M; Tshilumba, D; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; Vallisneri, M; van Bakel, N; van Beuzekom, M; Brand, J F J van den; Broeck, C van den; van der Sluys, M V; van Heijningen, J; van Veggel, A A; Vass, S; Vasúth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Vetrano, F; Viceré, A; Vincent-Finley, R; Vinet, J -Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Vousden, W D; Vyatchanin, S P; Wade, A R; Wade, L; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, H; Wang, M; Wang, X; Ward, R L; Warner, J; Was, M; Weaver, B; Wei, L -W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Wessels, P; Westphal, T; Wette, K; Whelan, J T; White, D J; Whiting, B F; Wilkinson, C; Williams, L; Williams, R; Williamson, A R; Willis, J L; Willke, B; Wimmer, M; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Worden, J; Xie, S; Yablon, J; Yakushin, I; Yam, W; Yamamoto, H; Yancey, C C; Yang, Q; Yvert, M; Zadrożny, A; Zanolin, M; Zendri, J -P; Zhang, Fan; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhu, X J; Zucker, M E; Zuraw, S; Zweizig, J

    2014-01-01

    We describe directed searches for continuous gravitational waves in data from the sixth LIGO science data run. The targets were nine young supernova remnants not associated with pulsars; eight of the remnants are associated with non-pulsing suspected neutron stars. One target's parameters are uncertain enough to warrant two searches, for a total of ten. Each search covered a broad band of frequencies and first and second frequency derivatives for a fixed sky direction. The searches coherently integrated data from the two LIGO interferometers over time spans from 5.3-25.3 days using the matched-filtering F-statistic. We found no credible gravitational-wave signals. We set 95% confidence upper limits as strong (low) as $4\\times10^{-25}$ on intrinsic strain, $2\\times10^{-7}$ on fiducial ellipticity, and $4\\times10^{-5}$ on r-mode amplitude. These beat the indirect limits from energy conservation and are within the range of theoretical predictions for neutron-star ellipticities and r-mode amplitudes.

  10. Two Radio Supernova Remnants Discovered in the Outer Galaxy

    CERN Document Server

    Foster, Tyler; Reich, Wolfgang; Kothes, Roland; West, Jennifer; 10.1051/0004-6361/201220362

    2013-01-01

    We report on the discovery of two supernova remnants (SNRs) designated G152.4-2.1 and G190.9-2.2, using Canadian Galactic Plane Survey data. The aims of this paper are, first, to present evidence that favours the classification of both sources as SNRs, and, second, to describe basic parameters (integrated flux density, spectrum, and polarization) as well as properties (morphology, line-of-sight velocity, distance and physical size) to facilitate and motivate future observations. Spectral and polarization parameters are derived from multiwavelength data from existing radio surveys carried out at wavelengths between 6 and 92cm. In particular for the source G152.4-2.1 we also use new observations at 11cm done with the Effelsberg 100m telescope. The interstellar medium around the discovered sources is analyzed using 1-arcminute line data from neutral hydrogen (HI) and 45-arcsecond 12CO(J=1-0). G152.4-2.1 is a barrel shaped SNR with two opposed radio-bright polarized flanks on the North and South. The remnant, whi...

  11. Non-Cosmological FRB's from Young Supernova Remnant Pulsars

    CERN Document Server

    Connor, Liam; Pen, Ue-Li

    2015-01-01

    We propose a new extragalactic but non-cosmological explanation for FRB's based on very young pulsars in supernova remnants. Within a few hundred years of a core-collapse supernova the ejecta is confined within $\\sim$1 pc, providing a high enough column density of free electrons for the observed 500-1500 pc/cm$^3$. By extrapolating a Crab-like pulsar to its infancy in an environment like that of SN 1987A, we hypothesize such an object could emit supergiant pulses sporadically which would be bright enough to be seen at a few hundred megaparsecs. In this scenario Faraday rotation at the source gives RM's much larger than the expected cosmological contribution. If the emission were pulsar-like, then the polarization vector could swing over the duration of the burst, which is not expected from non-rotating objects. In this model, the scattering, large DM, and commensurate RM all come from one place which is not the case for the cosmological interpretation. The model also provides testable predictions of the flux ...

  12. Search for surviving companions in type Ia supernova remnants

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Kuo-Chuan [Physik Department, Universität Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Ricker, Paul M. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Taam, Ronald E., E-mail: kuo-chuan.pan@unibas.ch, E-mail: pmricker@illinois.edu, E-mail: r-taam@northwestern.edu, E-mail: taam@asiaa.sinica.edu.tw [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)

    2014-09-01

    The nature of the progenitor systems of type Ia supernovae (SNe Ia) is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions (SCs). Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- (MS-) and helium-rich SCs, the color and magnitude of MS- and helium-rich SCs are predicted as functions of time. The SC candidates in Galactic type Ia supernova remnants (Ia SNR) and nearby extragalactic Ia SNRs are discussed. We find that the maximum detectable distance of MS SCs (helium-rich SCs) is 0.6-4 Mpc (0.4-16 Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to search for SCs. However, only five Ia SNRs have been searched for SCs, showing little support for the standard channels in the singe-degenerate scenario. To better understand the progenitors of SNe Ia, we encourage the search for SCs in other nearby Ia SNRs.

  13. EVOLUTION OF THE RADIO REMNANT OF SUPERNOVA 1987A: MORPHOLOGICAL CHANGES FROM DAY 7000

    International Nuclear Information System (INIS)

    We present radio imaging observations of supernova remnant 1987A at 9 GHz, taken with the Australia Telescope Compact Array over 21 years from 1992 to 2013. By employing a Fourier modeling technique to fit the visibility data, we show that the remnant structure has evolved significantly since day 7000 (mid-2006): the emission latitude has gradually decreased such that the overall geometry has become more similar to a ring structure. Around the same time, we find a decreasing trend in the east-west asymmetry of the surface emissivity. These results could reflect the increasing interaction of the forward shock with material around the circumstellar ring, and the relative weakening of the interaction with the lower-density material at higher latitudes. The morphological evolution caused an apparent break in the remnant expansion measured with a torus model, from a velocity of 4600+150-200 km s–1 between day 4000 and 7000 to 2400+100-200 km s–1 after day 7000. However, we emphasize that there is no conclusive evidence for a physical slowing of the shock at any given latitude in the expanding remnant, and that a change of radio morphology alone appears to dominate the evolution. This is supported by our ring-only fits which show a constant expansion of 3890 ± 50 km s–1 without deceleration between days 4000 and 9000. We suggest that once the emission latitude no longer decreases, the expansion velocity obtained from the torus model should return to the same value as that measured with the ring model

  14. EVOLUTION OF THE RADIO REMNANT OF SUPERNOVA 1987A: MORPHOLOGICAL CHANGES FROM DAY 7000

    Energy Technology Data Exchange (ETDEWEB)

    Ng, C.-Y. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Zanardo, G.; Potter, T. M.; Staveley-Smith, L. [International Centre for Radio Astronomy Research (ICRAR), The University of Western Australia, Crawley, WA 6009 (Australia); Gaensler, B. M. [Australian Research Council, Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia); Manchester, R. N.; Tzioumis, A. K., E-mail: ncy@bohr.physics.hku.hk [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Marsfield, NSW 1710 (Australia)

    2013-11-10

    We present radio imaging observations of supernova remnant 1987A at 9 GHz, taken with the Australia Telescope Compact Array over 21 years from 1992 to 2013. By employing a Fourier modeling technique to fit the visibility data, we show that the remnant structure has evolved significantly since day 7000 (mid-2006): the emission latitude has gradually decreased such that the overall geometry has become more similar to a ring structure. Around the same time, we find a decreasing trend in the east-west asymmetry of the surface emissivity. These results could reflect the increasing interaction of the forward shock with material around the circumstellar ring, and the relative weakening of the interaction with the lower-density material at higher latitudes. The morphological evolution caused an apparent break in the remnant expansion measured with a torus model, from a velocity of 4600{sup +150}{sub -}200 km s{sup –1} between day 4000 and 7000 to 2400{sup +100}{sub -200} km s{sup –1} after day 7000. However, we emphasize that there is no conclusive evidence for a physical slowing of the shock at any given latitude in the expanding remnant, and that a change of radio morphology alone appears to dominate the evolution. This is supported by our ring-only fits which show a constant expansion of 3890 ± 50 km s{sup –1} without deceleration between days 4000 and 9000. We suggest that once the emission latitude no longer decreases, the expansion velocity obtained from the torus model should return to the same value as that measured with the ring model.

  15. High-Resolution X-Ray Spectroscopy of the Galactic Supernova Remnant Puppis A with the XMM-Newton RGS

    CERN Document Server

    Katsuda, Satoru; Mori, Koji; Uchida, Hiroyuki; Petre, Robert; Yamada, Shin'ya; Tamagawa, Toru

    2012-01-01

    We present high-resolution X-ray spectra of cloud-shock interaction regions in the eastern and northern rims of the Galactic supernova remnant Puppis A, using the Reflection Grating Spectrometer onboard the XMM-Newton satellite. A number of emission lines including K alpha triplets of He-like N, O, and Ne are clearly resolved for the first time. Intensity ratios of forbidden to resonance lines in the triplets are found to be higher than predictions by thermal emission models having plausible plasma parameters. The anomalous line ratios cannot be reproduced by effects of resonance scattering, recombination, or inner-shell ionization processes, but could be explained by charge-exchange emission that should arise at interfaces between the cold/warm clouds and the hot plasma. Our observations thus provide observational support for charge-exchange X-ray emission in supernova remnants.

  16. High-Resolution X-Ray Spectroscopy of the Galactic Supernova Remnant Puppis A with the XMM-Newton RGS

    Science.gov (United States)

    Katsuda, Satoru; Tsunemi, Hiroshi; Mori, Koji; Uchida, Hiroyuki; Petre, Robert; Yamada, Shinya; Akamatsu, Hiroki; Konami, Saori; Tamagawa, Toru

    2012-01-01

    We present high-resolution X-ray spectra of cloud-shock interaction regions in the eastern and northern rims of the Galactic supernova remnant Puppis A, using the Reflection Grating Spectrometer onboard the XMM-Newton satellite. A number of emission lines including K(alpha) triplets of He-like N, O , and Ne are clearly resolved for the first time. Intensity ratios of forbidden to resonance lines in the triplets are found to be higher than predictions by thermal emission models having plausible plasma parameters. The anomalous line ratios cannot be reproduced by effects of resonance scattering, recombination, or inner-shell ionization processes, but could be explained by charge-exchange emission that should arise at interfaces between the cold/warm clouds and the hot plasma. Our observations thus provide observational support for charge-exchange X-ray emission in supernova remnants.

  17. FERMI-LAT DISCOVERY OF GeV GAMMA-RAY EMISSION FROM THE YOUNG SUPERNOVA REMNANT CASSIOPEIA A

    International Nuclear Information System (INIS)

    We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant (SNR) with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2? above 500 MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation-Cassiopeia A (Cas A). The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as W CR ? (1-4) x 1049 erg thanks to the well-known density in the remnant assuming that the observed gamma ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B ? 0.1 mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta.

  18. Fermi-LAT Discovery of GeV Gamma-ray Emission from the Young Supernova Remnant Cassiopeia A

    International Nuclear Information System (INIS)

    We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2? above 500 MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation - Cassiopeia A. The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as WCR ? (1-4) x 1049 erg thanks to the well-known density in the remnant assuming that the observed gamma-ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B (ge) 0.1 mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta.

  19. Nonthermal Radiation from Supernova Remnants: Effects of Magnetic Field Amplification and Particle Escape

    Science.gov (United States)

    Kang, Hyesung; Jones, T. W.; Edmon, Paul P.

    2013-11-01

    We explore nonlinear effects of wave-particle interactions on the diffusive shock acceleration (DSA) process in Type Ia-like supernova remnant (SNR) blast waves by implementing phenomenological models for magnetic field amplification (MFA), Alfvénic drift, and particle escape in time-dependent numerical simulations of nonlinear DSA. For typical SNR parameters, the cosmic-ray (CR) protons can be accelerated to PeV energies only if the region of amplified field ahead of the shock is extensive enough to contain the diffusion lengths of the particles of interest. Even with the help of Alfvénic drift, it remains somewhat challenging to construct a nonlinear DSA model for SNRs in which of the order of 10% of the supernova explosion energy is converted into CR energy and the magnetic field is amplified by a factor of 10 or so in the shock precursor, while, at the same time, the energy spectrum of PeV protons is steeper than E -2. To explore the influence of these physical effects on observed SNR emission, we also compute the resulting radio-to-gamma-ray spectra. Nonthermal emission spectra, especially in X-ray and gamma-ray bands, depend on the time-dependent evolution of the CR injection process, MFA, and particle escape, as well as the shock dynamic evolution. This result comes from the fact that the high-energy end of the CR spectrum is composed of particles that are injected in the very early stages of the blast wave evolution. Thus, it is crucial to better understand the plasma wave-particle interactions associated with collisionless shocks in detailed modeling of nonthermal radiation from SNRs.

  20. NONTHERMAL RADIATION FROM SUPERNOVA REMNANTS: EFFECTS OF MAGNETIC FIELD AMPLIFICATION AND PARTICLE ESCAPE

    International Nuclear Information System (INIS)

    We explore nonlinear effects of wave-particle interactions on the diffusive shock acceleration (DSA) process in Type Ia-like supernova remnant (SNR) blast waves by implementing phenomenological models for magnetic field amplification (MFA), Alfvénic drift, and particle escape in time-dependent numerical simulations of nonlinear DSA. For typical SNR parameters, the cosmic-ray (CR) protons can be accelerated to PeV energies only if the region of amplified field ahead of the shock is extensive enough to contain the diffusion lengths of the particles of interest. Even with the help of Alfvénic drift, it remains somewhat challenging to construct a nonlinear DSA model for SNRs in which of the order of 10% of the supernova explosion energy is converted into CR energy and the magnetic field is amplified by a factor of 10 or so in the shock precursor, while, at the same time, the energy spectrum of PeV protons is steeper than E –2. To explore the influence of these physical effects on observed SNR emission, we also compute the resulting radio-to-gamma-ray spectra. Nonthermal emission spectra, especially in X-ray and gamma-ray bands, depend on the time-dependent evolution of the CR injection process, MFA, and particle escape, as well as the shock dynamic evolution. This result comes from the fact that the high-energy end of the CR spectrum is composed of particles that are injected in the very early stages of the blast wave evolution. Thus, it is crucial to better understand the plasma wave-particle interactions associated with collisionless shocks in detailed modeling of nonthermal radiation from SNRs

  1. NONTHERMAL RADIATION FROM SUPERNOVA REMNANTS: EFFECTS OF MAGNETIC FIELD AMPLIFICATION AND PARTICLE ESCAPE

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyesung [Department of Earth Sciences, Pusan National University, Pusan 609-735 (Korea, Republic of); Jones, T. W. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Edmon, Paul P., E-mail: kang@uju.es.pusan.ac.kr, E-mail: twj@msi.umn.edu, E-mail: pedmon@cfa.harvard.edu [Research Computing, Harvard University, Cambridge, MA 02138 (United States)

    2013-11-01

    We explore nonlinear effects of wave-particle interactions on the diffusive shock acceleration (DSA) process in Type Ia-like supernova remnant (SNR) blast waves by implementing phenomenological models for magnetic field amplification (MFA), Alfvénic drift, and particle escape in time-dependent numerical simulations of nonlinear DSA. For typical SNR parameters, the cosmic-ray (CR) protons can be accelerated to PeV energies only if the region of amplified field ahead of the shock is extensive enough to contain the diffusion lengths of the particles of interest. Even with the help of Alfvénic drift, it remains somewhat challenging to construct a nonlinear DSA model for SNRs in which of the order of 10% of the supernova explosion energy is converted into CR energy and the magnetic field is amplified by a factor of 10 or so in the shock precursor, while, at the same time, the energy spectrum of PeV protons is steeper than E {sup –2}. To explore the influence of these physical effects on observed SNR emission, we also compute the resulting radio-to-gamma-ray spectra. Nonthermal emission spectra, especially in X-ray and gamma-ray bands, depend on the time-dependent evolution of the CR injection process, MFA, and particle escape, as well as the shock dynamic evolution. This result comes from the fact that the high-energy end of the CR spectrum is composed of particles that are injected in the very early stages of the blast wave evolution. Thus, it is crucial to better understand the plasma wave-particle interactions associated with collisionless shocks in detailed modeling of nonthermal radiation from SNRs.

  2. Hard X-ray emission and $^{44}$Ti line features of Tycho Supernova Remnant

    CERN Document Server

    Wang, Wei

    2014-01-01

    A deep hard X-ray survey of the INTEGRAL satellite first detected the non-thermal emission up to 90 keV in the Tycho supernova (SN) remnant. Its 3 -- 100 keV spectrum is fitted with a thermal bremsstrahlung of $kT\\sim 0.81\\pm 0.45$ keV plus a power-law model of $\\Gamma \\sim 3.01\\pm 0.16$. Based on the diffusive shock acceleration theory, this non-thermal emission, together with radio measurements, implies that Tycho remnant may not accelerate protons up to $>$PeV but hundreds TeV. Only heavier nuclei may be accelerated to the cosmic ray spectral "knee". In addition, we search for soft gamma-ray lines at 67.9 and 78.4 keV coming from the decay of radioactive $^{44}$Ti in Tycho remnant by INTEGRAL. A bump feature in the 60-90 keV energy band, potentially associated with the $^{44}$Ti line emission, is found with a marginal significance level of $\\sim$ 2.6 $\\sigma$. The corresponding 3 $\\sigma$ upper limit on the $^{44}$Ti line flux amounts to 1.5 $\\times$ 10$^{-5}$ ph cm$^{-2}$ s$^{-1}$. Implications on the pro...

  3. Multi-wavelength analysis of the Galactic supernova remnant MSH 11-61A

    CERN Document Server

    Auchettl, Katie; Castro, Daniel; Foster, Adam R; Smith, Randall K

    2015-01-01

    Due to its centrally bright X-ray morphology and limb brightened radio profile, MSH 11-61A (G290.1-0.8) is classified as a mixed morphology supernova remnant (SNR). H$\\textsc{i}$ and CO observations determined that the SNR is interacting with molecular clouds found toward the north and southwest regions of the remnant. In this paper we report on the detection of $\\gamma$-ray emission coincident with MSH 11-61A, using 70 months of data from the Large Area Telescope on board the \\textit{Fermi Gamma-ray Space Telescope}. To investigate the origin of this emission, we perform broadband modelling of its non-thermal emission considering both leptonic and hadronic cases and concluding that the $\\gamma$-ray emission is most likely hadronic in nature. Additionally we present our analysis of a 111 ks archival \\textit{Suzaku} observation of this remnant. Our investigation shows that the X-ray emission from MSH 11-61A arises from shock-heated ejecta with the bulk of the X-ray emission arising from a recombining plasma, w...

  4. Two evolved supernova remnants with newly identified Fe-rich cores in the Large Magellanic Cloud

    CERN Document Server

    Kavanagh, Patrick J; Bozzetto, Luke M; Points, Sean D; Crawford, Evan J; Dickel, John; Filipovic, Miroslav D; Haberl, Frank; Maggi, Pierre; Whelan, Emma T

    2016-01-01

    Aims. We present a multi-wavelength analysis of the evolved supernova remnants MCSNR J0506-7025 and MCSNR J0527-7104 in the Large Magellanic Cloud. Methods. We used data from XMM-Newton, the Australian Telescope Compact Array, and the Magellanic Cloud Emission Line Survey to study their broadband emission and used Spitzer and HI data to gain a picture of their environments. We performed a multi-wavelength morphological study and detailed radio and X-ray spectral analyses to determine their physical characteristics. Results. Both remnants were found to have bright X-ray cores, dominated by Fe L-shell emission, consistent with reverse shock heated ejecta with determined Fe masses in agreement with Type Ia explosion yields. A soft X-ray shell, consistent with swept-up interstellar medium, was observed in MCSNR J0506-7025, suggestive of a remnant in the Sedov phase. Using the spectral fit results and the Sedov self-similar solution, we estimated the age of MCSNR J0506-7025 to be ~16-28 kyr, with an initial explos...

  5. Hard X-ray emission and 44Ti line features of the Tycho supernova remnant

    International Nuclear Information System (INIS)

    A deep hard X-ray survey of the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected for the first time non-thermal emission up to 90 keV in the Tycho supernova (SN) remnant. Its 3-100 keV spectrum is fitted with a thermal bremsstrahlung of kT ? 0.81 ± 0.45 keV plus a power-law model of ? ? 3.01 ± 0.16. Based on diffusive shock acceleration theory, this non-thermal emission, together with radio measurements, implies that the Tycho remnant may not accelerate protons up to >PeV but to hundreds TeV. Only heavier nuclei may be accelerated to the cosmic ray spectral 'knee'. In addition, using INTEGRAL, we search for soft gamma-ray lines at 67.9 and 78.4 keV that come from the decay of radioactive 44Ti in the Tycho remnant. A bump feature in the 60-90 keV energy band, potentially associated with the 44Ti line emission, is found with a marginal significance level of ?2.6?. The corresponding 3? upper limit on the 44Ti line flux amounts to 1.5 × 10–5 photon cm–2 s–1. Implications on the progenitor of the Tycho SN, considered to be a Type Ia SN prototype, are discussed.

  6. Evolution of the Radio Remnant of Supernova 1987A: Morphological Changes from Day 7000

    CERN Document Server

    Ng, C -Y; Potter, T M; Staveley-Smith, L; Gaensler, B M; Manchester, R N; Tzioumis, A K

    2013-01-01

    We present radio imaging observations of supernova remnant 1987A at 9 GHz, taken with the Australia Telescope Compact Array over 21 years from 1992 to 2013. By employing a Fourier modeling technique to fit the visibility data, we show that the remnant structure has evolved significantly since day 7000 (mid-2006): the emission latitude has gradually decreased, such that the overall geometry has become more similar to a ring structure. Around the same time, we find a decreasing trend in the east-west asymmetry of the surface emissivity. These results could reflect the increasing interaction of the forward shock with material around the circumstellar ring, and the relative weakening of the interaction with the lower-density material at higher latitudes. The morphological evolution caused an apparent break in the remnant expansion measured with a torus model, from a velocity of 4600+150-200 km/s between day 4000 and 7000 to 2400+100-200 km/s after day 7000. However, we emphasize that there is no conclusive eviden...

  7. HI 21 cm Emission Line Study of Southern Galactic Supernova Remnants

    CERN Document Server

    Koo, B C; McClure-Griffiths, N M; Koo, Bon-Chul; Kang, Ji-hyun

    2004-01-01

    We have searched for HI 21 cm line emission from shocked atomic gas associated with southern supernova remnants (SNRs) using data from the Southern Galactic Plane Survey. Among the 97 sources studied, we have detected 10 SNRs with high-velocity HI emission confined to the SNR. The large velocity and the spatial confinement suggest that the emission is likely from the gas accelerated by the SN blast wave. We also detected 22 SNRs which show HI emission significantly brighter than the surrounding regions over a wide ($>10$\\kms) velocity interval. The association with these SNRs is less certain. We present the parameters and maps of the excess emission in these SNRs. We discuss in some detail the ten individual SNRs with associated high-velocity HI emission.

  8. X-rays of IC443 - remnant of Tang dynasty supernova.

    Science.gov (United States)

    Wang, Zhenru

    Hard X-rays with energies up to 20 keV were observed from IC443 by the X-ray satellite Ginga. The X-ray flux below 6 keV is found consistent with that of earlier observations with Einstein and HEAO 1, and the X-ray spectrum smoothly extends to 20 keV. The feature of Fe K line is not conspicuous; an upper limit of the equivalent width for its emission is 250 eV. It is likely that the hard X-rays are emitted from a shock-heated plasma with a temperature higher than 10 keV and a number density smaller than 0.1 cm-3 which is probably located in the SW and W regions of IC443. This model predicts the age of IC443 to be about 1000 years. It is suggested that IC443 is the remnant of a supernova in AD 837.

  9. Escaping the accelerator; how, when and in what numbers do cosmic rays get out of supernova remnants?

    CERN Document Server

    Drury, Luke O'C

    2010-01-01

    The escape of charged particles accelerated by diffusive shock acceleration from supernova remnants is shown to be a more complex process than normally appreciated. Using a box model it is shown that the high-energy end of the spectrum can exhibit spectral breaks even with no formal escape as a result of geometrical dilution and changing time-scales. It is pointed out that the bulk of the cosmic ray particles at lower energies must be produced and released in the late stages of the remnant's evolution whereas the high energy particles are produced early on; this may explain recent observations of slight compositional variations with energy. Escape resulting from ion-neutral friction in dense and partially ionized media is discussed briefly and some comments made on the use of so-called "free escape boundary conditions". Finally estimates are made of the total production spectrum integrated over the life of the remnant.

  10. A Study of the Non-Thermal X-Ray Emission of Shell-Type Supernova Remnants

    Science.gov (United States)

    Allen, Glenn E.

    2002-01-01

    The term of the second year of the award is the period from March 15, 2001 to March 14, 2002. As was the specified goal of the second year, we analyzed the spatial and spectral X-ray data for several young supernova remnants. I published a paper about an analysis of the ROSAT, ASCA, and RXTE data for the supernova remnant SN 1006. A copy of this paper is enclosed. As described in the paper, we believe that we accurately modeled the nonthermal X-ray emission from the remnant. The results of this analysis are used to infer properties about the cosmic rays accelerated in the remnant and to argue that the strength of the magnetic field in the remnant is considerably larger than the value of about 10 micro G reported elsewhere. The results were presented at the August 2001 International Cosmic Ray Conference in Hamburg, German),. I began analyzing new Chandra X-ray data for SN 1006. This analysis will yield the first measure of the strength of the magnetic field in the remnant for the first time. Preliminary results support our previous conclusion that the magnetic field strength in the remnant is much larger than 10 micro G. The field strength seems to be about the strength expected based on an equipartition calculation. The result supports recent models that describe the how the shock structure is influenced by the efficient acceleration of cosmic rays. This work will be presented at the April 2002 High Energy Astrophysics Division meeting in Albuquerque and published this summer. A copy of the abstract for the talk is enclosed. I began studying new Chandra X-ray data for the supernova remnant Cas A. The results of this work show that the forward shock is a region where cosmic-ray electrons are accelerated, which is consistent with theoretical expectations. The work was presented at the September 2001 Two Years of Science with Chandra symposium in Washington, DC. A copy of the poster paper is enclosed. Dr. Thomas Pannuti, whose research work is supported by the award, analyzed ROSAT, ASCA, and RXTE data for the supernova remnant G347.3-0.5. The results show for the first time that thermal X-ray emission is produced in the remnant. As expected, the thermal emission is consistent with a model in which the remnant is expanding into a very low density environment. The results also provide an accurate description of the nonthermal emission from the remnant. Dr. Pannuti presented this work at several conferences. A copy of the paper for the proceedings of the August 2001 Neutron Stars in Supernova Remnants symposium in enclosed. The work will be submitted to the Astrophysical Journal in the next few months.

  11. The unequivocal evidence of hadron acceleration in Tycho's Supernova Remnant

    CERN Document Server

    Morlino, G

    2011-01-01

    We apply the non-linear diffusive shock acceleration theory in order to describe the properties of SN 1572 (G120.1+1.4, hereafter simply Tycho). By analyzing its multi-wavelength spectrum, we show how Tycho's forward shock is accelerating protons up to ~500 TeV, channelling into cosmic rays more than 10% of its kinetic energy. Our model allows us to take into account self-consistently the dynamical reaction of the accelerated particles, the generation of magnetic fields in the shock proximity and the dynamical reaction of the magnetic field as well. We find that the streaming instability induced by cosmic rays is consistent with all the observational evidences indicating a very efficient magnetic field amplification (up to ~300 uG, in particular the radio and X-ray morphology of the remnant. In such a strong magnetic field, the velocity of the scattering centers in the upstream may be enhanced and make accelerated particles feel an effective compression factor lower than 4, in turn leading to an energy spectr...

  12. Comparing supernova remnants around strongly magnetized and canonical pulsars

    Science.gov (United States)

    Martin, J.; Rea, N.; Torres, D. F.; Papitto, A.

    2014-11-01

    The origin of the strong magnetic fields measured in magnetars is one of the main uncertainties in the neutron star field. On the other hand, the recent discovery of a large number of such strongly magnetized neutron stars is calling for more investigation on their formation. The first proposed model for the formation of such strong magnetic fields in magnetars was through alpha-dynamo effects on the rapidly rotating core of a massive star. Other scenarios involve highly magnetic massive progenitors that conserve their strong magnetic moment into the core after the explosion, or a common envelope phase of a massive binary system. In this work, we do a complete re-analysis of the archival X-ray emission of the supernova remnants (SNRs) surrounding magnetars, and compare our results with all other bright X-ray emitting SNRs, which are associated with compact central objects (which are proposed to have magnetar-like B-fields buried in the crust by strong accretion soon after their formation), high-B pulsars and normal pulsars. We find that emission lines in SNRs hosting highly magnetic neutron stars do not differ significantly in elements or ionization state from those observed in other SNRs, neither averaging on the whole remnants, nor studying different parts of their total spatial extent. Furthermore, we find no significant evidence that the total X-ray luminosities of SNRs hosting magnetars, are on average larger than that of typical young X-ray SNRs. Although biased by a small number of objects, we found that for a similar age, there is the same percentage of magnetars showing a detectable SNR than for the normal pulsar population.

  13. Supernova remnant evolution in an interstellar medium with evaporating clouds

    Science.gov (United States)

    White, Richard L.; Long, Knox S.

    1991-01-01

    A new similarity solution that describes the evolution of an SNR expanding into a cloudy interstellar medium is expounded. The solution incorporates a reasonable model of the conductive evaporation of cold clouds embedded in the hot gas behind the shock. The model has two new parameters in addition to those describing the usual Sedov solution for a uniform interstellar medium. The X-ray, infrared, and optical luminosities of remnants with evaporating clouds are calculated, and some of the expected spectral characteristics in the various wavebands are discussed. The effects described may explain the class of remnants observed to have centrally peaked X-ray emission and shell-like radio emission. The total H-alpha luminosity from evaporating clouds predicted by this model is less than that observed for SNRs with centrally peaked thermal X-ray emission. A detailed calculation of the X-ray and optical line emission from evaporating clouds would be very useful in testing this model against the observations.

  14. The composite form of the supernova remnant 3C 400.2: two interacting supernova remnants or a single supernova remnant with a blow-out?

    Directory of Open Access Journals (Sweden)

    Patricia Ambrocio-Cruz

    2006-01-01

    Full Text Available 3C 400.2 es un remanente de supernova galáctico que presenta una morfología que asemeja dos cascarones de diámetros diferentes que se traslapan. Estudiamos la cinemática de ambos cascarones para saber si esta morfología especial es debida al resultado de dos explosiones de supernova diferentes, o bien, a la explosión de una única supernova en un medio que tenga un gradiente de densidad abrupto. Los datos cinemáticos concuerdan mejor con la segunda hipótesis.

  15. Discovery of New Interacting Supernova Remnants in the Inner Galaxy

    CERN Document Server

    Hewitt, John W

    2009-01-01

    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 with OH masers: G5.4-1.2, G5.7-0.0, G8.7-0.1 and G9.7-0.0. The newly detected interacting SNRs G5.7-0.0 and G8.7-0.1 have TeV gamma-ray counterparts which may indicate a local cosmic ray enhancement. It has been noted that maser-emitting SNRs are preferentially distributed in the Molecular Ring and Nuclear Disk. We use the present and existing surveys to demonstrate that masers are strongly confined to within 50 degrees Galactic longitude at a rate of 15 percent of the total SNR population. All new detections are within 10 degrees Galactic longitude emphasizing this trend. Additionally, a substantial number of SNR masers have peak fluxes at or below the detection threshold of existing surveys. This calls into question whether maser surveys of Galactic SNRs can be considered ...

  16. Escape of cosmic-ray electrons from supernova remnants

    CERN Document Server

    Ohira, Yutaka; Kawanaka, Norita; Ioka, Kunihito

    2011-01-01

    We investigate the escape of cosmic ray (CR) electrons from a supernova remnant (SNR) to the interstellar space. We show that CR electrons escape in order from high to low energy with a similar spectrum to CR nuclei, while the escape starts later than the beginning of the Sedov phase at an SNR age of 1-7 10^3 yrs and the maximum energy of runaway CR electrons is below the knee about 0.3-50 TeV because unlike CR nuclei, CR electrons lose their energy due to synchrotron radiation. Highest energy CR electrons will be directly probed by AMS-02, CALET, CTA and LHAASO experiments, or have been already detected by H.E.S.S. as the spectral cutoff. Furthermore, we also calculate the spatial distribution of runaway CR electrons and their radiation spectra around SNRs. Contrary to common belief, maximum-energy photons of synchrotron radiation around 1 keV are emitted by runaway CR electrons inside the SNR. Inverse Compton scattering by runaway CR electrons can dominate the gamma-ray emission from runaway CR nuclei via p...

  17. Grammage of cosmic rays around Galactic supernova remnants

    CERN Document Server

    D'Angelo, Marta; Amato, Elena

    2015-01-01

    The residence time of cosmic rays (CRs) in the Galaxy is usually inferred from the measurement of the ratio of secondary-to-primary nuclei, such as the boron (B)/carbon (C) ratio, which provides an estimate of the amount of matter traversed by CRs during their propagation, the so called CR grammage. However, after being released by their parent sources, for instance supernova remnants (SNRs), CRs must cross the disc of the Galaxy, before entering the much lower density halo, in which they are believed to spend most of the time before eventually escaping the Galaxy. In the near-source region, the CR propagation is shown to be dominated by the non-linear self-generation of waves. Here we show that due to this effect, the time that CRs with energies up to $\\sim$ 10 TeV spend within a distance $L_{c}\\sim 100$ pc from the sources is much larger than naive estimates would suggest. The corresponding grammage is close to current estimates of the total grammage traversed throughout the whole Galaxy. Moreover, there is...

  18. Non-thermal emission from old supernova remnants

    CERN Document Server

    Fang, Jun

    2007-01-01

    We study the non-thermal emission from old shell-type supernova remnants (SNRs) on the frame of a time-dependent model. In this model, the time-dependent non-thermal spectra of both primary electrons and protons as well as secondary electron/positron ($e^{\\pm}$) pairs can be calculated numerically by taking into account the evolution of the secondary $e^{\\pm}$ pairs produced from proton-proton (p-p) interactions due to the accelerated protons collide with the ambient matter in an SNR. The multi-wavelength photon spectrum for a given SNR can be produced through leptonic processes such as electron/positron synchrotron radiation, bremsstrahlung and inverse Compton scattering as well as hadronic interaction. Our results indicate that the non-thermal emission of the secondary $e^{\\pm}$ pairs is becoming more and more prominent when the SNR ages in the radiative phase because the source of the primary electrons has been cut off and the electron synchrotron energy loss is significant for a radiative SNR, whereas the...

  19. Comparing supernova remnants around strongly magnetized and canonical pulsars

    CERN Document Server

    Martin, J; Torres, D F; Papitto, A

    2014-01-01

    The origin of the strong magnetic fields measured in magnetars is one of the main uncertainties in the neutron star field. On the other hand, the recent discovery of a large number of such strongly magnetized neutron stars, is calling for more investigation on their formation. The first proposed model for the formation of such strong magnetic fields in magnetars was through alpha-dynamo effects on the rapidly rotating core of a massive star. Other scenarios involve highly magnetic massive progenitors that conserve their strong magnetic moment into the core after the explosion, or a common envelope phase of a massive binary system. In this work, we do a complete re-analysis of the archival X-ray emission of the Supernova Remnants (SNR) surrounding magnetars, and compare our results with all other bright X-ray emitting SNRs, which are associated with Compact Central Objects (CCOs; which are proposed to have magnetar-like B-fields buried in the crust by strong accretion soon after their formation), high-B pulsar...

  20. The likely Fermi Detection of the Supernova Remnant RCW 103

    CERN Document Server

    Xing, Yi; Zhang, Xiao; Chen, Yang

    2013-01-01

    We report on the results from our $\\gamma$-ray analysis of the supernova remnant (SNR) RCW 103 region. The data were taken with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. An extended source is found at a position consistent with that of RCW 103, and its emission was only detected above 1 GeV (10$\\sigma$ significance), having a power-law spectrum with a photon index of 2.0$\\pm$0.1. We obtain its 1--300 GeV spectrum, and the total flux gives a luminosity of 8.3$\\times 10^{33}$ erg s$^{-1}$ at a source distance of 3.3 kpc. Given the positional coincidence and property similarities of this source with other SNRs, we identify it as the likely Fermi $\\gamma$-ray counterpart to RCW 103. Including radio measurements of RCW 103, the spectral energy distribution (SED) is modeled by considering emission mechanisms based on both hadronic and leptonic scenarios. We find that models in the two scenarios can reproduce the observed SED, although in the hadronic scenario, the total proton energy (5...

  1. WHAM Observations of High-latitude Supernova Remnants

    Science.gov (United States)

    Orchard, Alexander; Haffner, L. Matthew; Benjamin, Robert A.; Gostisha, Martin

    2016-01-01

    The Wisconsin H-Alpha Mapper Sky Survey (WHAM-SS) traces numerous large-angle, diffuse regions containing filamentary and shell-like structures. The largest of these are complex supershells that harbor recent and on-going star formation, such as the Orion-Eridanus complex, the Gum Nebula, and the extended emission above and below the W3/W4/W5 star-forming regions in the Perseus Arm. Several large-diameter regions with simpler morphologies are also present, which we focus on here. While some of these structures are diffuse H II regions powered by nearby, isolated stars, others are clearly supernova remnants (SNRs) due to their association with X-ray or non-thermal radio emission. We highlight the structure, kinematics, and multi-wavelength properties of several SNRs using Hα maps from the WHAM-SS and data from on-going WHAM multi-wavelength surveys. WHAM research and operations are supported through NSF Award AST-1108911.

  2. Infrared Spectral Mapping of Supernova Remnants. I. N63A and Its Environment

    Science.gov (United States)

    Caulet, Adeline; Williams, Rosa M.

    2012-12-01

    We present Spitzer Space Telescope spectra of the supernova remnant (SNR) N63A and its native H II region N63 in the Large Magellanic Cloud. We measure nebular fine-structure lines, H2 lines, and polycyclic aromatic hydrocarbons (PAHs). The lines contribute half of the flux in the Spitzer 24 μm image of N63A shocked lobes, but only Electron densities are low everywhere; the differences in mid-IR line ratios separate N63A plasma and its high-excitation surroundings from N63A low-excitation optical lobes. We compare the observed line fluxes and ratios within N63A's shocked lobes and plasma with the predictions from models for moderate and fast shocks to constrain pre-shock densities and shock velocities. N63A's photoionized lobe contains a warm photodissociation region in pressure equilibrium with optically ionized gas. We apply a physical dust model to our spectra supplemented by MIPS photometry. We derive the intensity of radiation heating the dust, the mass fraction due to PAHs, and the masses of dust within our sampled regions and of cooler grains in the diffuse interstellar medium. N63A's shocked lobes and plasma contain ~0.07 M ⊙ of hot grains, comparable to amounts in other SNRs. Within N63A there is ~0.7 M ⊙ of warm grains exposed to >=100 times the intensity of the local interstellar radiation field. Within the regions, 92% of the total dust mass resides in cool grains emitting <=27% of their mid-IR luminosity. In loving memory of Sylvie Caulet-Maugendre: "I used to believe in forever, but forever is too good to be true." A. A. Milne, Winnie-the-Pooh.

  3. INFRARED SPECTRAL MAPPING OF SUPERNOVA REMNANTS. I. N63A AND ITS ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    Caulet, Adeline [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801-3080 (United States); Williams, Rosa M., E-mail: adel-col@orange.fr [Department of Earth and Space Sciences, Columbus State University, 701 Front Ave., Columbus, GA 31901 (United States)

    2012-12-20

    We present Spitzer Space Telescope spectra of the supernova remnant (SNR) N63A and its native H II region N63 in the Large Magellanic Cloud. We measure nebular fine-structure lines, H{sub 2} lines, and polycyclic aromatic hydrocarbons (PAHs). The lines contribute half of the flux in the Spitzer 24 {mu}m image of N63A shocked lobes, but only {<=}10% elsewhere. The mid-IR flux is largely due to thermal continuum emission from dust in and around N63A plasma. Electron densities are low everywhere; the differences in mid-IR line ratios separate N63A plasma and its high-excitation surroundings from N63A low-excitation optical lobes. We compare the observed line fluxes and ratios within N63A's shocked lobes and plasma with the predictions from models for moderate and fast shocks to constrain pre-shock densities and shock velocities. N63A's photoionized lobe contains a warm photodissociation region in pressure equilibrium with optically ionized gas. We apply a physical dust model to our spectra supplemented by MIPS photometry. We derive the intensity of radiation heating the dust, the mass fraction due to PAHs, and the masses of dust within our sampled regions and of cooler grains in the diffuse interstellar medium. N63A's shocked lobes and plasma contain {approx}0.07 M{sub Sun} of hot grains, comparable to amounts in other SNRs. Within N63A there is {approx}0.7 M{sub Sun} of warm grains exposed to {>=}100 times the intensity of the local interstellar radiation field. Within the regions, 92% of the total dust mass resides in cool grains emitting {<=}27% of their mid-IR luminosity.

  4. Chandra X-ray Observatory Arcsecond Imaging of the Young, Oxygen-rich Supernova Remnant 1E0102.2-7219

    OpenAIRE

    Gaetz, T. J.; Butt, Yousaf M.; Edgar, Richard J.; Eriksen, Kristoffer A.; Plucinsky, Paul P.; Schlegel, Eric M.; Smith, Randall K

    2000-01-01

    We present observations of the young, Oxygen-rich supernova remnant 1E0102.2-7219 taken by the Chandra X-ray Observatory during Chandra's Orbital Activation and Checkout phase. The boundary of the blast wave shock is clearly seen for the first time, allowing the diameter of the remnant and the mean blast wave velocity to be determined accurately. The prominent X-ray bright ring of material may be the result of the reverse shock encountering ejecta; the radial variation of O ...

  5. INVESTIGATING THE COSMIC-RAY IONIZATION RATE NEAR THE SUPERNOVA REMNANT IC 443 THROUGH H+3 OBSERVATIONS ,

    International Nuclear Information System (INIS)

    Observational and theoretical evidence suggests that high-energy Galactic cosmic rays are primarily accelerated by supernova remnants. If also true for low-energy cosmic rays, the ionization rate near a supernova remnant should be higher than in the general Galactic interstellar medium (ISM). We have searched for H+3 absorption features in six sight lines which pass through molecular material near IC 443-a well-studied case of a supernova remnant interacting with its surrounding molecular material-for the purpose of inferring the cosmic-ray ionization rate in the region. In two of the sight lines (toward ALS 8828 and HD 254577) we find large H+3 column densities, N(H+3) ? 3 x 1014 cm-2, and deduce ionization rates of ?2 ? 2 x 10-15 s-1, about five times larger than inferred toward average diffuse molecular cloud sight lines. However, the 3? upper limits found for the other four sight lines are consistent with typical Galactic values. This wide range of ionization rates is likely the result of particle acceleration and propagation effects, which predict that the cosmic-ray spectrum and thus ionization rate should vary in and around the remnant. While we cannot determine if the H+3 absorption arises in post-shock (interior) or pre-shock (exterior) gas, the large inferred ionization rates suggest that IC 443 is in fact accelerating a large population of low-energy cosmic rays. Still, it is unclear whether this population can propagate far enough into the ISM to account for the ionization rate inferred in diffuse Galactic sight lines.

  6. X-RAY EJECTA KINEMATICS OF THE GALACTIC CORE-COLLAPSE SUPERNOVA REMNANT G292.0+1.8

    Energy Technology Data Exchange (ETDEWEB)

    Bhalerao, Jayant; Park, Sangwook [Department of Physics, University of Texas at Arlington, P.O. Box 19059, Arlington, TX 76019 (United States); Dewey, Daniel [MIT Kavli Institute, Cambridge, MA 02139 (United States); Hughes, John P. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States); Mori, Koji [Department of Applied Physics, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki 889-2192 (Japan); Lee, Jae-Joon, E-mail: jayant.bhalerao@mavs.uta.edu [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

    2015-02-10

    We report on the results from the analysis of our 114 ks Chandra High Energy Transmision Grating Spectrometer observation of the Galactic core-collapse supernova remnant G292.0+1.8. To probe the three-dimensional structure of the clumpy X-ray emitting ejecta material in this remnant, we measured Doppler shifts in emission lines from metal-rich ejecta knots projected at different radial distances from the expansion center. We estimate radial velocities of ejecta knots in the range of –2300 ? v{sub r}  ? 1400 km s{sup –1}. The distribution of ejecta knots in velocity versus projected-radius space suggests an expanding ejecta shell with a projected angular thickness of ?90'' (corresponding to ?3 pc at d = 6 kpc). Based on this geometrical distribution of the ejecta knots, we estimate the location of the reverse shock approximately at the distance of ?4 pc from the center of the supernova remnant, putting it in close proximity to the outer boundary of the radio pulsar wind nebula. Based on our observed remnant dynamics and the standard explosion energy of 10{sup 51} erg, we estimate the total ejecta mass to be ?8 M {sub ?}, and we propose an upper limit of ?35 M {sub ?} on the progenitor's mass.

  7. THE ORIGIN OF RADIALLY ALIGNED MAGNETIC FIELDS IN YOUNG SUPERNOVA REMNANTS

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Tsuyoshi; Shimoda, Jiro; Ohira, Yutaka; Yamazaki, Ryo, E-mail: inouety@phys.aoyama.ac.jp [Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara, Kanagawa 252-5258 (Japan)

    2013-08-01

    It has been suggested by radio observations of polarized synchrotron emissions that downstream magnetic fields in some young supernova remnants (SNRs) are oriented radially. We study the magnetic field distribution of turbulent SNRs driven by the Richtmyer-Meshkov instability (RMI)-in other words, the effect of rippled shock-by using three-dimensional magnetohydrodynamics simulations. We find that the induced turbulence has radially biased anisotropic velocity dispersion that leads to a selective amplification of the radial component of the magnetic field. The RMI is induced by the interaction between the shock and upstream density fluctuations. Future high-resolution polarization observations can distinguish the following candidates responsible for the upstream density fluctuations: (1) inhomogeneity caused by the cascade of large-scale turbulence in the interstellar medium, the so-called big power-law in the sky; (2) structures generated by the Drury instability in the cosmic-ray modified shock; and (3) fluctuations induced by the nonlinear feedback of the cosmic-ray streaming instability.

  8. Identification of Ambient Molecular Clouds Associated with Galactic Supernova Remnant IC443

    CERN Document Server

    Lee, Jae-Joon; Snell, Ronald L; Yun, Min S; Heyer, Mark H; Burton, Michael G

    2012-01-01

    The Galactic supernova remnant (SNR) IC443 is one of the most studied core-collapse SNRs for its interaction with molecular clouds. However, the ambient molecular clouds with which IC443 is interacting have not been thoroughly studied and remain poorly understood. Using Five College Radio Astronomy Observatory 14m telescope, we obtained fully sampled maps of ~ 1{\\deg} \\times 1{\\deg} region toward IC443 in the 12CO J=1-0 and HCO+ J=1-0 lines. In addition to the previously known molecular clouds in the velocity range v_lsr = -6 to -1 km/s (-3 km/s clouds), our observations reveal two new ambient molecular cloud components: small (~ 1') bright clouds in v_lsr = -8 to -3 km/s (SCs), and diffuse clouds in v_lsr = +3 to +10 km/s (+5 km/s clouds). Our data also reveal the detailed kinematics of the shocked molecular gas in IC443, however the focus of this paper is the physical relationship between the shocked clumps and the ambient cloud components. We find strong evidence that the SCs are associated with the shocke...

  9. Nonuniform Expansion of the Youngest Galactic Supernova Remnant G1.9+0.3

    Science.gov (United States)

    Borkowski, Kazimierz J.; Reynolds, Stephen P.; Green, David A.; Hwang, Una; Petre, Robert; Krishnamurthy, Kalyani; Willett, Rebecca

    2014-01-01

    We report measurements of the X-ray expansion of the youngest Galactic supernova remnant, G1.9+0.3, using Chandra observations in 2007, 2009, and 2011. The measured rates strongly deviate from uniform expansion, decreasing radially by about 60 along the X-ray bright SE-NW axis from 0.84 plus or minus 0.06% yr(exp -1) to 0.52% plus or minus 0.03 yr(exp -1). This corresponds to undecelerated ages of 120-190 yr, confirming the young age of G1.9+0.3 and implying a significant deceleration of the blast wave. The synchrotron-dominated X-ray emission brightens at a rate of 1.9% plus or minus 0.4% yr(exp -1). We identify bright outer and inner rims with the blast wave and reverse shock, respectively. Sharp density gradients in either the ejecta or ambient medium are required to produce the sudden deceleration of the reverse shock or the blast wave implied by the large spread in expansion ages. The blast wave could have been decelerated recently by an encounter with a modest density discontinuity in the ambient medium, such as may be found at a wind termination shock, requiring strong mass loss in the progenitor.

  10. The Fermi Bubbles as a Scaled-up Version of Supernova Remnants

    CERN Document Server

    Fujita, Yutaka; Yamazaki, Ryo

    2013-01-01

    In this study, we treat the Fermi bubbles as a scaled-up version of supernova remnants (SNRs). The bubbles are created through activities of the super-massive black hole (SMBH) or starbursts at the Galactic center (GC). Cosmic-rays (CRs) are accelerated at the forward shocks of the bubbles like SNRs, which means that we cannot decide whether the bubbles were created by the SMBH or starbursts from the radiation from the CRs. We follow the evolution of CR distribution by solving a diffusion-advection equation, considering the reduction of the diffusion coefficient by CR streaming. In this model, gamma-rays are created through hadronic interaction between CR protons and the gas in the Galactic halo. In the GeV band, we can well reproduce the observed flat distribution of gamma-ray surface brightness, because some amount of gas is left behind the shock. The edge of the bubbles is fairly sharp owing to the high gas density behind the shock and the reduction of the diffusion coefficient there. The latter also contr...

  11. From E. Fermi to Fermi-LAT: watching particle acceleration in supernova remnants

    CERN Document Server

    Caprioli, Damiano

    2013-01-01

    Supernova remnants (SNRs) have been regarded for many decades as the sources of Galactic cosmic rays (CRs) up to a few PeV. However, only with the advent of Fermi-LAT it has been possible to detect - at least in some SNRs - \\gamma-rays whose origin is unequivocally hadronic, namely due to the decay of neutral pions produced by collisions between relativistic nuclei and the background plasma. When coupled with observations in other bands (from radio to TeV \\gamma-rays), Fermi-LAT data present evidence for CR spectra significantly steeper than the standard prediction of diffusive shock acceleration, forcing us to rethink our theoretical understanding of efficient particle energization at strong shocks. We outline how, by including the effects of CR-triggered magnetic field amplification, it is possible to reconcile non-linear models of diffusive shock acceleration with \\gamma-ray observations, in particular providing a successful application of such a theory to Tycho's SNR. Finally, we show how kinetic simulati...

  12. Numerical code for fitting radial emission profile of a shell supernova remnant: Application

    Directory of Open Access Journals (Sweden)

    Opsenica Slobodan

    2011-01-01

    Full Text Available We present IDL (Interactive Data Language codes for fitting a theoretical emission profile of a shell supernova remnant (SNR to the mean profile of an SNR obtained from radio observations. Two considered theoretical models are: 1 a shell with constant emissivity and 2 a synchrotron shell with radially aligned magnetic field. The codes were applied to several observed supernova remnants. Good results are obtained in five considered cases, which justify the use of our code for remnants that are bright (so that observational errors are not large and spherically symmetric enough.

  13. Nuclear lines revealing the injection of cosmic rays in supernova remnants

    OpenAIRE

    Tibolla, O.; Mannheim, K.; Summa, A.; A. Paravac; Greiner, J.; G. Kanbach

    2011-01-01

    At high energies, the hadronic origin of gamma rays from supernova remnants is still debated. Assuming the observed gamma-rays from the Wolf-Rayet supernova remnant Cas A are due to accelerated protons and ions, we predict the nuclear de-excitation line emission arising from interactions with the heavy elements in the supernova ejecta. This illustrative example highlights the importance of MeV gamma ray observations of the hadronic fingerprint of cosmic rays. The lines could be observed in th...

  14. The structure of TeV-bright shell-type supernova remnants

    Science.gov (United States)

    Yang, Chuyuan; Liu, Siming; Fang, Jun; Li, Hui

    2015-01-01

    Aims: Two-dimensional magnetohydrodynamic (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 ?-ray emission is produced via inverse Compton scattering of background soft photons by high-energy electrons accelerated by the shocks of the SNRs. In a previous paper, we showed that since the energy densities of the cosmic microwave background radiation and that of the IR/optical background photons are much higher than that of the photons produced by the same high-energy electrons via the synchrotron process, the observed correlation between X-ray and TeV brightness of SNR RX J1713.7-3946 can be readily explained with the assumption that the energy density of relativistic electrons is proportional to that of the magnetic field. The TeV emissivity is therefore proportional to the magnetic field energy density and MHD simulations can be used to model the TeV structure of such remnants directly. Two-dimensional MHD simulations for SNRs are then performed under the assumption that the ambient interstellar medium is turbulent with the magnetic field and density fluctuations, following a Kolmogorov-like power-law spectrum. Results: (1) As expected, these simulations confirm early 1D and 2D modelings of these sources, namely the hydrodynamical evolution of the shock waves and amplification of magnetic field by Rayleigh-Taylor convective flows and by shocks propagating in a turbulent medium; (2) we reproduce rather complex morphological structure for ?-rays, for example, the bright thin rim and significant asymmetry, suggesting intrinsic variations of the source morphology not related to the structure of the progenitor and environment; and (3) the observed radial profile of several remnants are well reproduced with an ambient medium density of 0.1-1 cm-3. An even lower ambient density leads to a sharper drop of the TeV brightness with radius than what is observed near the outer edge of these remnants. Conclusions: In a turbulent background medium, we can reproduce the observed characteristics of several shell-type TeV SNRs with reasonable parameters except for a higher ambient density than that inferred from X-ray observations.

  15. Supernova Remnant Kes 17: Efficient Cosmic Ray Accelerator inside a Molecular Cloud

    CERN Document Server

    Gelfand, Joseph D; Slane, Patrick O; Temim, Tea; Hughes, John P; Rakowski, Cara

    2013-01-01

    Supernova remnant Kes 17 (SNR G304.6+0.1) is one of a few but growing number of remnants detected across the electromagnetic spectrum. In this paper, we analyze recent radio, X-ray, and gamma-ray observations of this object, determining that efficient cosmic ray acceleration is required to explain its broadband non-thermal spectrum. These observations also suggest that Kes 17 is expanding inside a molecular cloud, though our determination of its age depends on whether thermal conduction or clump evaporation is primarily responsible for its center-filled thermal X-ray morphology. Evidence for efficient cosmic ray acceleration in Kes 17 supports recent theoretical work that the strong magnetic field, turbulence, and clumpy nature of molecular clouds enhances cosmic ray production in supernova remnants. While additional observations are needed to confirm this interpretation, further study of Kes 17 is important for understanding how cosmic rays are accelerated in supernova remnants.

  16. Re-examination of the Expected Gamma-Ray Emission of Supernova Remnant SN 1987A

    Science.gov (United States)

    Berezhko, E. G.; Ksenofontov, L. T.; Völk, H. J.

    2015-09-01

    A nonlinear kinetic theory, combining cosmic-ray (CR) acceleration in supernova remnants (SNRs) with their gas dynamics, is used to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5-50 year. This spherically symmetric model is approximately applied to the different features of the SNR, consisting of (i) a blue supergiant wind and bubble, and (ii) of the swept-up red supergiant (RSG) wind structures in the form of an H ii region, an equatorial ring (ER), and an hourglass region. The RSG wind involves a mass loss rate that decreases significantly with elevation above and below the equatorial plane. The model adapts recent three-dimensional hydrodynamical simulations by Potter et al. in 2014 that use a significantlysmaller ionized mass of the ER than assumed in the earlier studies by the present authors. The SNR shock recently swept up the ER, which is the densest region in the immediate circumstellar environment. Therefore, the expected gamma-ray energy flux density at TeV energies in the current epoch has already reached its maximal value of ˜10-13 erg cm-2 s-1. This flux should decrease by a factor of about two over the next 10 years.

  17. G11.2-0.3: The Young Remnant of a Stripped-Envelope Supernova

    CERN Document Server

    Borkowski, Kazimierz J; Roberts, Mallory S E

    2016-01-01

    We present results of a 400-ks Chandra observation of the young shell supernova remnant (SNR) G11.2-0.3, containing a pulsar and pulsar-wind nebula (PWN). We measure a mean expansion rate for the shell since 2000 of 0.0277+/-0.0018% per yr, implying an age between 1400 and 2400 yr, and making G11.2-0.3 one of the youngest core-collapse SNRs in the Galaxy. However, we find very high absorption ($A_V \\sim 16^m \\pm 2^m$), confirming near-IR determinations and ruling out a claimed association with the possible historical SN of 386 CE. The PWN shows strong jets and a faint torus within a larger, more diffuse region of radio emission and nonthermal X-rays. Central soft thermal X-ray emission is anticorrelated with the PWN; that, and more detailed morphological evidence, indicates that the reverse shock has already reheated all ejecta and compressed the PWN. The pulsar characteristic energy-loss timescale is well in excess of the remnant age, and we suggest that the bright jets have been produced since the recompres...

  18. 3D Hydrodynamic Simulations of the Galactic Supernova Remnant CTB 109

    CERN Document Server

    Bolte, Jan; Breitschwerdt, Dieter

    2015-01-01

    Using detailed 3D hydrodynamic simulations we study the nature of the Galactic supernova remnant (SNR) CTB 109 (G109.1-1.0), which is well-known for its semicircular shape and a bright diffuse X-ray emission feature inside the SNR. Our model has been designed to explain the observed morphology, with a special emphasis on the bright emission feature inside the SNR. Moreover, we determine the age of the remnant and compare our findings with X-ray observations. With CTB 109 we test a new method of detailed numerical simulations of diffuse young objects, using realistic initial conditions derived directly from observations. We performed numerical 3D simulations with the RAMSES code. The initial density structure has been directly taken from $^{12}$CO emission data, adding an additional dense cloud, which, when it is shocked, causes the bright emission feature. From parameter studies we obtained the position $(\\ell , b)=(109.1545^\\circ , -1.0078^\\circ)$ for an elliptical cloud with $n_\\text{cloud}=25~\\text{cm}^{-3...

  19. Re-examination of the Expected gamma-ray emission of supernova remnant SN 1987A

    CERN Document Server

    Berezhko, E G; Voelk, H J

    2015-01-01

    A nonlinear kinetic theory, combining cosmic ray (CR) acceleration in supernova remnants (SNRs) with their gas dynamics, is used to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5-50 yr. This spherically symmetric model is approximately applied to the different features of the SNR which consist of (i) a blue supergiant wind and bubble, and (ii) of the swept-up red supergiant (RSG) wind structures in the form of an HII region, an equatorial ring (ER), and an hourglass region. The RSG wind involves a mass loss rate that decreases significantly with elevation above and below the equatorial plane. The model adapts recent three-dimensional hydrodynamical simulations by Potter et al. (2014) which use a significantly smaller ionized mass of the ER than assumed in the earlier studies by the present authors. The SNR shock has recently swept up the ER which is the densest region in the immediate circumstellar environment. Therefore the expected gamma-ray energy f...

  20. The structure of supernova shock waves

    International Nuclear Information System (INIS)

    The structure of strong shock waves is calculated over the range of shock energies (1 to 100 MeV nucleon-1) and initial number densities (1015--1022 cm-3) believed likely to occur in the red-giant-like envelopes of stars undergoing Type II supernova explosions. The general equations governing the structure of such shocks are developed on the basis of a plasma composed of ions, electrons, positrons, and photons, making use of diffusion theory to evaluate the dissipative and transfer terms. The present treatment differs from previous calculations in that the effects of radiation transport on the energy and momentum balance in the shock are taken into account, as well as the relativistic contributions to radiative emission rates due to nondipole electron-ion bremsstrahlung, electron-electron bremsstrahlung, and radiative Compton scattering. An implicit treatment of inverse Compton scattering is also developed in terms of the creation and diffusion of effective photons.Severalmodels of strong shock structure are formulated and solved on the basis of these equations and physical processes

  1. G 2.4 + 1.4: a supernova remnant or ring nebula around a peculiar star

    International Nuclear Information System (INIS)

    G2.4+1.4 is a probable nonthermal radio source and an optical nebula which appears to be a supernova remnant (SNR). It also contains an O vi sequence star of great excitation. We present new radiofrequency continuum and (nil) H 92? observations, optical spectroscopy, and Fabry-Perot scanner observations of the nebula. The object distance (5 kpc), origin of gas kinematics (SNR expansion), and mode of excitation of the gas (photoexcitation and/or shock wave) remain uncertain. We discuss the possible roles of the O vi star as ''runaway'' in a SNR, as a source of photoexcitation, and as an ejector of a ''counterfeit'' SNR

  2. Nonthermal radiation of young supernova remnants: The case of Cas A

    Energy Technology Data Exchange (ETDEWEB)

    Zirakashvili, V. N. [Pushkov Institute for Terrestrial Magnetism, Ionosphere and Radiowave Propagation, 142190 Troitsk, Moscow Region (Russian Federation); Aharonian, F. A.; Yang, R.; Oña-Wilhelmi, E.; Tuffs, R. J. [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2014-04-20

    The processes responsible for the broadband radiation of the young supernova remnant Cas A are explored by using a new code that is designed for a detailed treatment of the diffusive shock acceleration of particles in the nonlinear regime. The model is based on spherically symmetric hydrodynamic equations complemented with transport equations for relativistic particles. Electrons, protons, and the oxygen ions accelerated by forward and reverse shocks are included in the numerical calculations. We show that the available multi-wavelength observations in the radio, X-ray, and gamma-ray bands can be best explained by invoking particle acceleration by both forward and reversed shocks. Although the TeV gamma-ray observations can be interpreted by interactions of both accelerated electrons and protons/ions, the measurements by Fermi Large Area Telescope at energies below 1 GeV give a tentative preference to the hadronic origin of gamma-rays. Then, the acceleration efficiency in this source, despite the previous claims, should be very high; 25% of the explosion energy (or approximately 3 × 10{sup 50} erg) should already be converted to cosmic rays, mainly by the forward shock. At the same time, the model calculations do not provide extension of the maximum energy of accelerated protons beyond 100 TeV. In this model, the acceleration of electrons is dominated by the reverse shock; the required 10{sup 48} erg can be achieved under the assumption that the injection of electrons (positrons) is supported by the radioactive decay of {sup 44}Ti.

  3. Geneva University: Particle Acceleration in supernova remnants and its implications for the origin of galactic cosmic rays

    CERN Multimedia

    Université de Genève

    2012-01-01

    GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92 Wednesday 28 March 2012 SEMINAIRE DE PHYSIQUE CORPUSCULAIRE 11h15 - Science III, Auditoire 1S081 Particle Acceleration in supernova remnants and its implications for the origin of galactic cosmic rays Prof. Pasquale BLASI INAF, Arcetri Observatory, Firenze The process of cosmic ray energization in supernova remnant shocks is described by the theory of non linear diffusive shock acceleration (NLDSA). Such theory is able to describe the acceleration itself, the dynamical reaction of accelerated particles on the shock, and the crucial phenomenon of the magnetic field amplification, the very key to generate high energy cosmic rays. I will illustrate the basic aspects of this theoretical framework, as well as its successes and problems. I will then discuss the observations, in X-rays an...

  4. Light Curve Models of Supernovae and X-ray spectra of Supernova Remnants

    CERN Document Server

    Blinnikov, S I; Kozyreva, A V; Sorokina, E I

    2004-01-01

    We compare parameters of well-observed type II SN1999em derived by M.Hamuy and D.Nadyozhin based on Litvinova-Nadyozhin (1985) analytic fits with those found from the simulations with our radiative hydro code Stella. The difference of SN parameters is quite large for the long distance scale. The same code applied to models of SN1993J allows us to estimate systematic errors of extracting foreground extinction toward SN1993J suggested by Clocchiatti et al. (1995). A new implicit two-temperature hydro code code Supremna is introduced which self-consistently takes into account the kinetics of ionization, electron thermal conduction, and radiative losses for predicting X-ray spectra of young supernova remnants such as Tycho and Kepler.

  5. CHANDRA AND XMM OBSERVATIONS OF THE COMPOSITE SUPERNOVA REMNANT G327.1-1.1

    International Nuclear Information System (INIS)

    We present new X-ray imaging and spectroscopy of a composite supernova remnant G327.1-1.1 using the Chandra and XMM-Newton X-ray observatories. G327.1-1.1 has an unusual morphology consisting of a symmetric radio shell and an off center nonthermal component that indicates the presence of a pulsar wind nebula (PWN). Radio observations show a narrow finger of emission extending from the PWN structure toward the northwest. X-ray studies with ASCA, ROSAT, and BeppoSAX revealed elongated extended emission and a compact source at the tip of the finger that may be coincident with the actual pulsar. The high resolution Chandra observations provide new insight into the structure of the inner region of the remnant. The images show a compact source embedded in a cometary structure from which a trail of X-ray emission extends in the southeast direction. The Chandra images also reveal two prong-like structures that appear to originate from the vicinity of the compact source and extend into a large bubble that is oriented in the northwest direction, opposite from the bright radio PWN. The emission from the entire radio shell is detected in the XMM data and can be characterized by a thermal plasma model with a temperature of ? 0.3 keV, which we use to estimate the physical properties of the remnant. The peculiar morphology of G327.1-1.1 may be explained by the emission from a moving pulsar and a relic PWN that has been disrupted by the reverse shock.

  6. Inverse Compton Emission from Galactic Supernova Remnants: Effect of the Interstellar Radiation Field

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Troy A.; /UC, Santa Cruz; Moskalenko, Igor V.; /Stanford U., HEPL; Strong, Andrew W.; /Garching, Max Planck Inst., MPE

    2006-08-01

    The evidence for particle acceleration in supernova shells comes from electrons whose synchrotron emission is observed in radio and X-rays. Recent observations by the HESS instrument reveal that supernova remnants also emit TeV {gamma}-rays; long awaited experimental evidence that supernova remnants can accelerate cosmic rays up to the ''knee'' energies. Still, uncertainty exists whether these {gamma}-rays are produced by electrons via inverse Compton scattering or by protons via {pi}{sup 0}-decay. The multi-wavelength spectra of supernova remnants can be fitted with both mechanisms, although a preference is often given to {pi}{sup 0}-decay due to the spectral shape at very high energies. A recent study of the interstellar radiation field indicates that its energy density, especially in the inner Galaxy, is higher than previously thought. In this paper we evaluate the effect of the interstellar radiation field on the inverse Compton emission of electrons accelerated in a supernova remnant located at different distances from the Galactic Centre. We show that contribution of optical and infra-red photons to the inverse Compton emission may exceed the contribution of cosmic microwave background and in some cases broaden the resulted {gamma}-ray spectrum. Additionally, we show that if a supernova remnant is located close to the Galactic Centre its {gamma}-ray spectrum will exhibit a ''universal'' cutoff at very high energies due to the Klein-Nishina effect and not due to the cut-off of the electron spectrum. As an example, we apply our calculations to the supernova remnants RX J1713.7-3946 and G0.9+0.1 recently observed by HESS.

  7. Chandra and XMM Observations of the Composite Supernova Remnant G327.1-1.1

    Science.gov (United States)

    Temim, Tea; Slane, Patrick; Gaensler, Bryan; Hughes, John; van der Swaluw, Eric

    We present Chandra and XMM imaging and spectroscopy of G327.1-1.1, a composite supernova remnant with a an unusual morphology consisting of a symmetric radio shell and an off center nonthermal component that indicates the presence of a pulsar wind nebula (PWN). Radio observations show a narrow ridge of emission extending from the PWN structure towards the northwest, possibly interpreted as a trail of emission left behind by the moving pulsar. X- ray studies with ASCA, ROSAT, and BeppoSAX revealed elongated extended emission and a compact source at the tip of the ridge that may be coincident with the actual pulsar. The high resolution Chandra observations provide new insight into the structure of the inner region of the remnant. The images show a compact source embedded in a bow-shock like structure, from which a trail of x-ray emission extends in the southeast direction. The Chandra images also reveal a prong like structure that appears to originate from the vicinity of the compact source and extends into a large bubble, three arcminutes in diameter. The emission from the entire radio shell is detected in the XMM data and can be characterized by a thermal plasma model with a temperature of 0.3 keV. The peculiar morphology of G327.1-1.1 may be explained by the emission from a moving pulsar and a relic PWN that has been disrupted by the reverse shock. Support for this work is provided by NASA Grant GO6-7053X.

  8. Synchrotron X-ray diagnostics of cutoff shape of nonthermal electron spectrum at young supernova remnants

    CERN Document Server

    Yamazaki, Ryo; Sawada, Makoto; Bamba, Aya

    2014-01-01

    Context: The synchrotron X-rays can be a useful tool to investigate the electron acceleration at young supernova remnants (SNRs). Aims: At present, since the magnetic field configuration around the shocks of SNRs is uncertain, it is not clear whether the electron acceleration is limited by SNR age, synchrotron cooling, or even escape from the acceleration region. We study if the acceleration mechanism can be constrained by the cutoff shape of the electron spectrum around the maximum energy. Methods: We derive analytical formulae of the cutoff shape in each case where the maximum electron energy is determined by SNR age, synchrotron cooling and escape from the shock. They are related to the energy dependence of the electron diffusion coefficient. Next, we discuss whether information on the cutoff shape is provided by near future observations which gives simply the photon indices and the flux ratios in the soft and hard X-ray bands. Results: If the power-law index of the electron spectrum is independently deter...

  9. ASTRO-H White Paper - Older Supernova Remnants and Pulsar Wind Nebulae

    CERN Document Server

    Long, K S; Aharonian, F; Foster, A; Funk, S; Hiraga, J; Hughes, J; Ishida, M; Katsuda, S; Matsumoto, H; Mori, K; Nakajima, H; Nakamori, T; Ozaki, M; Safi-Harb, S; Sawada, M; Tamagawa, T; Tamura, K; Tanaka, T; Tsunemi, H; Uchida, H; Uchiyama, Y; Yamauchi, S

    2014-01-01

    Most supernova remnants (SNRs) are old, in the sense that their structure has been profoundly modified by their interaction with the surrounding interstellar medium (ISM). Old SNRs are very heterogenous in terms of their appearance, reflecting differences in their evolutionary state, the environments in which SNe explode and in the explosion products. Some old SNRs are seen primarily as a result of a strong shock wave interacting with the ISM. Others, the so-called mixed-morphology SNRs, show central concentrations of emission, which may still show evidence of emission from the ejecta. Yet others, the pulsar wind nebulae (PWNe), are seen primarily as a result of emission powered by a pulsar; these SNRs often lack the detectable thermal emission from the primary shock. The underlying goal in all studies of old SNRs is to understand these differences, in terms of the SNe that created them, the nature of the ISM into which they are expanding, and the fundamental physical processes that govern their evolution. He...

  10. Nonuniform Expansion of the Youngest Galactic Supernova Remnant G1.9+0.3

    CERN Document Server

    Borkowski, K J; Green, D A; Hwang, U; Petre, R; Krishnamurthy, K; Willett, R

    2014-01-01

    We report measurements of X-ray expansion of the youngest Galactic supernova remnant (SNR), G1.9+0.3, using Chandra observations in 2007, 2009, and 2011. The measured rates strongly deviate from uniform expansion, decreasing radially by about 60% along the X-ray bright SE-NW axis from 0."84% +/- 0."06% per yr to 0."52% +/- 0."03% per yr. This corresponds to undecelerated ages of 120-190 yr, confirming the young age of G1.9+0.3, and implying a significant deceleration of the blast wave. The spatially-integrated dominantly synchrotron X-ray flux increases at 1.9% +/- 0.4% per yr. We identify the outer and inner rims with the blast wave and reverse shock, respectively. Sudden large density gradients in either ejecta or ambient medium are required to produce the sudden deceleration of the reverse shock or the blast wave implied by the large spread in expansion ages. The blast wave could have been decelerated recently by an encounter with a modest density discontinuity in the ambient medium, such as found at a win...

  11. Cosmic-ray acceleration in supernova remnants: non-linear theory revised

    CERN Document Server

    Caprioli, Damiano

    2012-01-01

    A rapidly growing amount of evidences, mostly coming from the recent gamma-ray observations of Galactic supernova remnants (SNRs), is seriously challenging our understanding of how particles are accelerated at fast shocks. The cosmic-ray (CR) spectra required to account for the observed phenomenology are in fact as steep as $E^{-2.2}--E^{-2.4}$, i.e., steeper than the test-particle prediction of first-order Fermi acceleration, and significantly steeper than what expected in a more refined non-linear theory of diffusive shock acceleration. By accounting for the dynamical back-reaction of the non-thermal particles, such a theory in fact predicts that the more efficient the particle acceleration, the flatter the CR spectrum. In this work we put forward a self-consistent scenario in which the account for the magnetic field amplification induced by CR streaming produces the conditions for reversing such a trend, allowing --- at the same time --- for rather steep spectra and CR acceleration efficiencies (about 20%)...

  12. Observational study of ion-electron equilibration and of cloud evaporation in supernova remnants under the HEAO-2 guest investigator program

    Science.gov (United States)

    Teske, R. G.

    1986-01-01

    Observations of three selected supernovae remnants (Cygnus Loop, IC 443, and Puppis A) were made in the forbidden coronal iron lines (Fe X) lambda 6374 and (Fe XIV) lambda 5303. The resulting data was compared quantitatively with Einstein images of the same objects, and an attempt was made to determine (a) the process by which ion and electron energies are equilibrated behind the shock front in the ISM and (b) whether cloud evaporation occurs within the hot remnant interiors. Spatially-resolved X ray emission were modeled for Sedov-Taylor blast wave models of supernovae remnants (SNR) under conditions of non-equlibrium ionization. The computations are intended to provide results that can be directly compared with Einstein high resolution image (HRI) and imaging proportional counter (IPS) data. The computer program for predicting the spatial distribution of HRI and IPS counting rates was completed, and final testing of it had begun.

  13. SUPERNOVA REMNANTS AND THE INTERSTELLAR MEDIUM OF M83: IMAGING AND PHOTOMETRY WITH THE WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE

    International Nuclear Information System (INIS)

    We present Wide Field Camera 3 images taken with the Hubble Space Telescope within a single field in the southern grand design star-forming galaxy M83. Based on their size, morphology, and photometry in continuum-subtracted H?, [S II], H?, [O III], and [O II] filters, we have identified 60 supernova remnant (SNR) candidates, as well as a handful of young ejecta-dominated candidates. A catalog of these remnants, their sizes and, where possible, their H? fluxes are given. Radiative ages and pre-shock densities are derived from those SNRs that have good photometry. The ages lie in the range 2.62 rad/yr) 0/cm-3 min = 16+7-5 Msun. Finally, we give evidence for the likely detection of the remnant of the historical supernova, SN1968L.

  14. Einstein IPC imaging and spectral observations of the supernova remnant HB 9

    International Nuclear Information System (INIS)

    In radio wavelengths, HB 9 is a large supernova remnant. The central area of HB 9 has been observed with fairly complete coverage by four Einstein IPC fields. A soft X-ray image and results from analysis of X-ray spectra from the IPC observations are presented. HB 9 has spatial variations in X-ray temperature from 0.4 to 1.2 keV, with the temperature decreasing from center to edge. For a distance of 1.1 kpc, the 0.2-4 keV luminosity is 5 x 10 to the 34th ergs/s. A Sedov supernova remnant model does not fit HB 9's properties. Supernova remnant models for expansion into a three-component ISM give a satisfactory fit and yield an age of 14,000 yr. 19 references

  15. RX-J0852?4622: THE NEAREST HISTORICAL SUPERNOVA REMNANT – AGAIN

    Directory of Open Access Journals (Sweden)

    Bernd Aschenbach

    2013-12-01

    Full Text Available RX-J0852?4622, a supernova remnant, is demonstrated to be closer than 500 pc, based on the measurements of the angular radius, the angular expansion rate and the TeV g-ray flux. This is a new method of limiting the distance to any supernova remnant with hadronic induced TeV g-ray flux. The progenitor star of RX-J0852?4622 probably exploded in its blue supergiant wind, like SN 1987A, preceeded by a red supergiant phase. A cool dense shell, expected around the outskirts of the red wind, my have been identified. The distance (200 pc and age (680 yr of the supernova remnant, originally proposed, are supported.

  16. The acceleration of cosmic-ray protons in the supernova remnant RX J1713.7-3946

    CERN Document Server

    Enomoto, R

    2002-01-01

    Protons with energies up to 10^15 eV are the main component[1] of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking[2]. Electrons are known to be accelerated to cosmic-ray energies in supernova remnants[3, 4], and the shock waves associated with such remnants, when they hit the surrounding interstellar medium, could also provide the energy to accelerate protons. The signature of such a process would be the decay of pions (pi0), which are generated when the protons collide with atoms and molecules in an interstellar cloud: pion decay results in g-rays with a particular spectral-energy distribution[5, 6]. Here we report the observation of cascade showers of optical photons resulting fromg-rays at energies of 10^12 eV hitting Earth's upper atmosphere, in the direction of the supernova remnant RX J1713.7-3946. The spectrum is a good match to that predicted by pion decay, and cannot be explained by other mechanisms.

  17. The many sides of RCW 86: a type Ia supernova remnant evolving in its progenitor's wind bubble

    CERN Document Server

    Broersen, Sjors; Vink, Jacco; Bamba, Aya

    2014-01-01

    We present the results of a detailed investigation of the Galactic supernova remnant RCW 86 using the XMM-Newton X-ray telescope. RCW 86 is the probable remnant of SN 185 A.D, a supernova that likely exploded inside a wind-blown cavity. We use the XMM-Newton Reflection Grating Spectrometer (RGS) to derive precise temperatures and ionization ages of the plasma, which are an indication of the interaction history of the remnant with the presumed cavity. We find that the spectra are well fitted by two non-equilibrium ionization models, which enables us to constrain the properties of the ejecta and interstellar matter plasma. Furthermore, we performed a principal component analysis on EPIC MOS and pn data to find regions with particular spectral properties. We present evidence that the shocked ejecta, emitting Fe-K and Si line emission, are confined to a shell of approximately 2 pc width with an oblate spheroidal morphology. Using detailed hydrodynamical simulations, we show that general dynamical and emission pro...

  18. Spitzer observations of the type IA supernova remnant N103B: Kepler's older cousin?

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Brian J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Borkowski, Kazimierz J.; Reynolds, Stephen P. [Physics Department, North Carolina State University, Raleigh, NC 27695-8202 (United States); Ghavamian, Parviz [Department of Physics, Chemistry, and Geosciences, Towson University, Towson, MD 21252 (United States); Raymond, John C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Long, Knox S. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2686 (United States); Sankrit, Ravi [SOFIA Science Center, NASA AMES Research Center, M/S N211-3, Moffett Field, CA 94035 (United States); Winkler, P. Frank [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Hendrick, Sean P., E-mail: brian.j.williams@nasa.gov [Physics Department, Millersville University, P.O. Box 1002, Millersville, PA 17551 (United States)

    2014-08-01

    We report results from Spitzer observations of SNR 0509-68.7, also known as N103B, a young Type Ia supernova remnant (SNR) in the Large Magellanic Cloud (LMC) that shows interaction with a dense medium in its western hemisphere. Our images show that N103B has strong IR emission from warm dust in the post-shock environment. The post-shock gas density we derive, 45 cm{sup –3}, is much higher than in other Type Ia remnants in the LMC, though a lack of spatial resolution may bias measurements toward regions of higher than average density. This density is similar to that in Kepler's SNR, a Type Ia interacting with a circumstellar medium (CSM). Optical images show H? emission along the entire periphery of the western portion of the shock, with [O III] and [S II] lines emitted from a few dense clumps of material where the shock has become radiative. The dust is silicate in nature, though standard silicate dust models fail to reproduce the '18 ?m' silicate feature that peaks instead at 17.3 ?m. We propose that the dense material is circumstellar material lost from the progenitor system, as with Kepler. If the CSM interpretation is correct, this remnant would become the second member, along with Kepler, of a class of Type Ia remnants characterized by interaction with a dense CSM hundreds of years post-explosion. A lack of N enhancement eliminates symbiotic asymptotic giant branch progenitors. The white dwarf companion must have been relatively unevolved at the time of the explosion.

  19. The interaction of a supernova remnant with interstellar clouds using high order local adaptive mesh refinement methods

    International Nuclear Information System (INIS)

    The interaction between supernova remnants (SNR) and interstellar clouds in the galaxy is known to play a major role in determining the structure of the interstellar medium (ISM). We know that the ISM is highly inhomogeneous, consisting of both diffuse atomic clouds (T?100K) and dense molecular clouds (T?10K) surrounded by a low density warm ionized gas (T?104K) and by a very hot coronal gas (T?106K). Next to radiation directly from stars, supernova explosions represent the most important form of energy injection into the ISM; they determine the velocity of interstellar clouds, accelerate cosmic rays, and can compress clouds to gravitational instability, possibly spawning a new generation of star formation. The shock waves from supernova remnants can compress, accelerate, disrupt and render hydrodynamically unstable interstellar clouds, thereby ejecting mass back into the intercloud medium. Thus, while the interaction of the SNR blast wave with cloud inhomogeneities can clearly alter the appearance of the ISM, the cloud inhomogeneities can similarly have a profound effect on the structure of the SNR

  20. A model for OH(1720 MHz) masers associated with supernova remnants, and an application to Sgr A East

    CERN Document Server

    Wardle, M; Geballe, T R; Wardle, Mark; Yusef-Zadeh, Farhad

    1998-01-01

    OH(1720 MHz) masers unaccompanied by 1665/7 MHz line masers have recently been proposed as indicators of the interaction of supernova remnants (SNRs) and molecular clouds. We present a model for the masing region in which water produced in a C-type shock wave driven into the molecular cloud is dissociated as a result of the X-ray flux from the SNR. We note that the magnetic field strengths inferred from Zeeman splitting of the 1720 MHz line measure the internal pressure of the supernova remnant. In addition, we discuss the interaction of Sgr A East, a SNR candidate, with the 50 km/s cloud at the Galactic Centre and present near-infrared observations of H_2 emission towards the regions where OH(1720 MHz) maser emission is concentrated. The magnetic field strength obtained from earlier Zeeman measurements is consistent with rough pressure equilibrium between the postshock gas and the X-ray gas filling Sgr A East detected by ASCA. Further, the intensity of the v=1-0 S(1) line of H_2 is consistent with the shock ...

  1. Fermi LAT gamma-ray observations of the supernova remnant HB21

    OpenAIRE

    Pivato, G.; Hewitt, J. W.; collaboration, L. Tibaldo for the Fermi LAT

    2013-01-01

    We present the analysis of Fermi Large Area Telescope (LAT) {\\gamma}-ray observations of HB 21, a mixed-morphology supernova remnant. Such supernova remnants are characterized by an interior thermal X-ray plasma, surrounded by a wider nonthermal shell emitting at radio frequencies. HB 21 has a large angular size, making it a good candidate for detailed morphological and spectral studies with the LAT. The radio extension is 2{\\deg}x1{\\deg}.5, compared to the LAT 68% containme...

  2. High Resolution X-ray Imaging of Supernova Remnant 1987A

    OpenAIRE

    Ng, C. -Y.; Gaensler, B.M.; Murray, S. S.; Slane, P. O.; Park, S.; Staveley-Smith, L; Manchester, R N; Burrows, D.N.

    2009-01-01

    We report observations of the remnant of Supernova 1987A with the High Resolution Camera (HRC) onboard the Chandra X-ray Observatory. A direct image from the HRC resolves the annular structure of the X-ray remnant, confirming the morphology previously inferred by deconvolution of lower resolution data from the Advanced CCD Imaging Spectrometer. Detailed spatial modeling shows that the a thin ring plus a thin shell gives statistically the best description of the overall remna...

  3. X-Rays from Supernova Shocks in Dense Mass Loss

    OpenAIRE

    Chevalier, Roger A.; Irwin, Christopher M.

    2012-01-01

    Type IIn and related supernovae show evidence for an interaction with a dense circumstellar medium that produces most of the supernova luminosity. X-ray emission from shock heated gas is crucial for the energetics of the interaction and can provide diagnostics on the shock interaction. Provided that the shock is at an optical depth tau_w\\la c/v_s in the wind, where c is the speed of light and v_s is the shock velocity, a viscous shock is expected that heats the gas to a high...

  4. TeV Neutrinos from SuperNova Remnants embedded in Giant Molecular Clouds

    OpenAIRE

    Vincenzo CavasinniPisa U. and INFN, Pisa; Dario GrassoSNS and INFN, Pisa; Luca MaccioneSISSA, Trieste, and INFN, Pisa

    2006-01-01

    The recent detection of $\\gamma$-rays with energy up to 10 TeV from dense regions surrounding some Supernova Remnants (SNR) provides strong, though still not conclusive, evidence that the nucleonic component of galactic Cosmic Rays is accelerated in the supernova outflows. Neutrino telescopes could further support the validity of such scenario by detecting neutrinos coming from the same regions. We re-evaluate the TeV range neutrino-photon flux ratio to be expected from pion...

  5. Cosmic-ray-induced ionization in molecular clouds adjacent to supernova remnants - Tracing the hadronic origin of GeV gamma radiation

    OpenAIRE

    Schuppan, F.; J.K. Becker; Black, J.H.; Casanova, S.

    2012-01-01

    Energetic gamma rays (GeV to TeV photon energy) have been detected toward several supernova remnants (SNR) associated with molecular clouds. If the gamma rays are produced mainly by hadronic processes rather than leptonic processes like bremsstrahlung, then the flux of energetic cosmic ray (CR) nuclei (>1 GeV) required to produce the gamma rays can be inferred at the site where the particles are accelerated in SNR shocks. It is of great interest to understand the acceleratio...

  6. Observations of supernova remnants and molecular clouds from the mm to the gamma-ray domain: bridging low and high energy cosmic rays

    CERN Document Server

    Gabici, Stefano

    2015-01-01

    New evidence that cosmic rays (hadronic component) are accelerated by supernova remnant shocks all the way from low energies to high energies, has come from recent works combining gamma-ray observations in the sub-GeV to TeV domain on the one hand, and in the submm-mm domain on the other hand. These observations concern the specific cases of supernova remnants interacting with molecular cloud complexes, that have long been suspected to be ideal laboratories to study in situ cosmic ray acceleration and diffusion. Indeed, enhanced gamma-ray emission from neutral pion decay, as well as enhanced ionization (both by at least one order of magnitude with respect to average galactic values) have been observed in several regions of massive star formation housing supernova remnants interacting with molecular cloud complexes. This paper summarizes the main physical and chemical processes at work, as well as recent observations, that further support the paradigm of cosmic ray acceleration by supernova remnants all the wa...

  7. Search for cosmic ray origins by the study of supernova remnants associated with molecular clouds with HESS and test of HESS II sampling system

    International Nuclear Information System (INIS)

    The H.E.S.S. telescope (High energy Stereoscopic System), located in Namibia, is currently the most efficient for the observation of very high energy (VHE) gamma-ray sources. It is composed of 4 large diameter telescopes working in stereoscopic mode and allows an unequaled survey of the galactic plane at these extreme wavelengths. The H.E.S.S. experiment showed the presence of high energy particles up to 100 TeV within supernova remnant. This astrophysical objects are believed to be the main particle accelerator within the Galaxy. However, the particle nature remains unclear. This thesis presents a new observational approach in order to show hadronic particles acceleration through diffusive shock within supernova remnant. A search of supernova remnant associated with molecular cloud have been led within the HESS source catalog and the H.E.S.S. observations. An analysis of the new VHE gamma-ray source in Monoceros and its interpretation are presented. As well, the analysis and interpretation of new observations of the unidentified source HESS J1745-303 are presented. The multi-wavelength analysis of the new source HESS J1714-385, coincident with the supernova remnant CTB37A is presented. A contribution to the H.E.S.S. phase II building is also presented. This second phase consists in the building of a fifth telescope at the center of the existing system. The series tests of the new camera sampling system are reported. (author)

  8. Saturated magnetic field amplification at supernova shocks

    CERN Document Server

    Luo, Qinghuan

    2009-01-01

    Cosmic-ray streaming instabilities at supernova shocks are discussed in the quasilinear diffusion formalism which takes into account the feedback effect of wave growth on the cosmic ray streaming motion. In particular, the nonresonant instability that leads to magnetic field amplification in the short wavelength regime is considered. The linear growth rate is calculated using kinetic theory for a streaming distribution. We show that the nonresonant instability is actually driven by a compensating current in the background plasma. The nonresonant instability can develop into a nonlinear regime generating turbulence. The saturation of the amplified magnetic fields due to particle diffusion in the turbulence is derived analytically. It is shown that the evolution of parallel and perpendicular cosmic-ray pressures is predominantly determined by nonresonant diffusion. However, the saturation is determined by resonant diffusion which tends to reduce the streaming motion through pitch angle scattering. The saturated...

  9. Modelling of X-ray emission supernova remnants observed by the European satellite XMM-Newton

    International Nuclear Information System (INIS)

    This thesis deals with the X-ray emission of supernova remnants (SNRs) observed by the European satellite XMM-Newton. In SNRs, the matter heated to millions of degrees shines brightly in X-rays. This emission depends on the hydrodynamical evolution of the SNR, on the chemical composition of the ejected matter and on the ambient medium. Moreover, the blast-wave is considered to be the prime site of the production and the acceleration of cosmic-rays in our Galaxy. XMM-Newton is one of the first to allow the investigation of these different aspects thanks to its spatially-resolved spectroscopy and its very good sensitivity. l first studied Kepler's SNR (SN 1604) whose X-ray emission is dominated by the ejecta. Its observation has allowed to obtain information on the nucleosynthesis products, on their spatial distribution and on the temperature structure in the shocked ejecta. This gives strong constraints on the physics of the explosion and on the progenitor's type. l have shown also that the X-ray emission at the shock is likely to be non-thermal. Then, l studied the SNR G347.3-0.5 whose X-ray emission is entirely due to the synchrotron radiation of relativistic (TeV) electrons accelerated at the shock. From five pointing, l made a full mapping of the X-ray emission characteristics (brightness, absorption and spectral index) at small scale. Combined to radio observations, these results have indicated a clear interaction between the SNR and molecular clouds located at 1 kpc and not at 6 kpc as previously estimated. Lastly, in the framework of a self-similar hydrodynamical model coupled with non-linear particle acceleration, l have obtained the synchrotron emission profile in SNRs, including the adiabatic and radiative losses of the accelerated electrons. (author)

  10. DEM L241, A SUPERNOVA REMNANT CONTAINING A HIGH-MASS X-RAY BINARY

    Energy Technology Data Exchange (ETDEWEB)

    Seward, F. D. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Charles, P. A. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Foster, D. L. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935, Cape Town (South Africa); Dickel, J. R.; Romero, P. S. [Department of Physics and Astronomy, University of New Mexico, 1919 Lomas Boulevard NE, Albuquerque, NM 87131 (United States); Edwards, Z. I.; Perry, M.; Williams, R. M. [Department of Earth and Space Sciences, Columbus State University, Coca Cola Space Science Center, 701 Front Avenue, Columbus, GA 31901 (United States)

    2012-11-10

    A Chandra observation of the Large Magellanic Cloud supernova remnant DEM L241 reveals an interior unresolved source which is probably an accretion-powered binary. The optical counterpart is an O5III(f) star making this a high-mass X-ray binary with an orbital period likely to be of the order of tens of days. Emission from the remnant interior is thermal and spectral information is used to derive density and mass of the hot material. Elongation of the remnant is unusual and possible causes of this are discussed. The precursor star probably had mass >25 M {sub Sun}.

  11. DEM L241, A SUPERNOVA REMNANT CONTAINING A HIGH-MASS X-RAY BINARY

    International Nuclear Information System (INIS)

    A Chandra observation of the Large Magellanic Cloud supernova remnant DEM L241 reveals an interior unresolved source which is probably an accretion-powered binary. The optical counterpart is an O5III(f) star making this a high-mass X-ray binary with an orbital period likely to be of the order of tens of days. Emission from the remnant interior is thermal and spectral information is used to derive density and mass of the hot material. Elongation of the remnant is unusual and possible causes of this are discussed. The precursor star probably had mass >25 M ?

  12. Monochromatic photography of the Cygnus Loop supernova remnant. Plotting of isophotes of partial nebula radiation in the [OIII] and [NII]+H? lines

    International Nuclear Information System (INIS)

    System of the isophotes of the 9' size in the west part of the Cyg Loop supernova remnant using monochromatic photographs in the [O3] and [N2]+Hsub(?) lines is obtained. A relative displacement of the regions of emission in these lines is discovered and explained by temperature reduction due to radiative losses behind the shock wave of the supernova explosion. The morphology difference between the [O3] and [N2]+Hsub(?) lxnes is explained. Anomalously large intensity ratios Isub([O3])/Isub(Hsub(?)) are supposed to be due to spatial separation of the corresponding emission regions

  13. THE MAGELLAN/IMACS CATALOG OF OPTICAL SUPERNOVA REMNANT CANDIDATES IN M83

    Energy Technology Data Exchange (ETDEWEB)

    Blair, William P. [Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Winkler, P. Frank [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Long, Knox S., E-mail: wpb@pha.jhu.edu, E-mail: winkler@middlebury.edu, E-mail: long@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2012-11-15

    We present a new optical imaging survey of supernova remnants (SNRs) in M83, using data obtained with the Magellan I 6.5 m telescope and IMACS instrument under conditions of excellent seeing. Using the criterion of strong [S II] emission relative to H{alpha}, we confirm all but three of the 71 SNR candidates listed in our previous survey, and expand the SNR candidate list to 225 objects, more than tripling the earlier sample. Comparing the optical survey with a new deep X-ray survey of M83 with Chandra, we find that 61 of these SNR candidates have X-ray counterparts. We also identify an additional list of 46 [O III]-selected nebulae for follow-up as potential ejecta-dominated remnants, seven of which have associated X-ray emission that makes them strong candidates. Some of the other [O III]-bright objects could also be normal interstellar medium (ISM) dominated SNRs with shocks fast enough to doubly ionize oxygen, but with H{alpha} and [S II] emission faint enough to have been missed. A few of these objects may also be H II regions with abnormally high [O III] emission compared with the majority of M83 H II regions, compact nebulae excited by young Wolf-Rayet stars, or even background active galactic nuclei. The SNR H{alpha} luminosity function in M83 is shifted by a factor of {approx}4.5 times higher than for M33 SNRs, indicative of a higher mean ISM density in M83. We describe the search technique used to identify the SNR candidates and provide basic information and finder charts for the objects.

  14. Suzaku spectra of a Type-II Supernova Remnant, Kes 79

    Science.gov (United States)

    Sato, Tamotsu; Koyama, Katsuji; Lee, Shiu-Hang; Takahashi, Tadayuki

    2016-01-01

    This paper reports on results of a Suzaku observation of the supernova remnant (SNR) Kes 79 (G33.6+0.1). The X-ray spectrum is best fitted by a two-temperature model: a non-equilibrium ionization (NEI) plasma and a collisional ionization equilibrium (CIE) plasma. The NEI plasma is spatially confined within the inner radio shell with kT ˜ 0.8 keV, while the CIE plasma is found in more spatially extended regions associated with the outer radio shell with kT ˜0.2 keV and solar abundance. Therefore, the NEI plasma is attributable to the SN ejecta, and the CIE plasma is the forward shocked interstellar medium. In the NEI plasma, we discovered K-shell lines of Al, Ar, and Ca for the first time. The abundance pattern and estimated mass of the ejecta are consistent with a core-collapse supernova explosion of a ˜30-40M⊙ progenitor star. An Fe line with a center energy of ˜6.4 keV is also found in the southeast (SE) portion of the SNR, a close peripheral region around dense molecular clouds. One possibility is that the line is associated with the ejecta. However, the centroid energy of ˜6.4 keV and the spatial distribution of enhancement near the SE peripheral do not favor this scenario. Since the ˜6.4 keV emitting region coincides with the molecular clouds, we propose another possibility, that the Fe line is due to K-shell ionization of neutral Fe by the interaction of locally accelerated protons (LECRp) with the surrounding molecular cloud. Both of these possibilities, heated ejecta or LECRp origin, are discussed based on the observational facts.

  15. Supernova Remnants in the Sedov Expansion Phase Thermal X-Ray Emission

    CERN Document Server

    Borkowski, K J; Reynolds, S P

    2001-01-01

    Improved calculations of X-ray spectra for supernova remnants (SNRs) in the Sedov-Taylor phase are reported, which for the first time include reliable atomic data for Fe L-shell lines. This new set of Sedov models also allows for a partial collisionless heating of electrons at the blast wave and for energy transfer from ions to electrons through Coulomb collisions. X-ray emission calculations are based on the updated Hamilton-Sarazin spectral model. The calculated X-ray spectra are succesfully interpreted in terms of three distribution functions: the electron temperature and ionization timescale distributions, and the ionization timescale averaged electron temperature distribution. The comparison of Sedov models with a frequently used single nonequilibrium ionization (NEI) timescale model reveals that this simple model is generally not an appropriate approximation to X-ray spectra of SNRs. We find instead that plane-parallel shocks provide a useful approximation to X-ray spectra of SNRs, particularly for youn...

  16. Suzaku study on the ejecta of the supernova remnant G272.2-3.2

    Science.gov (United States)

    Kamitsukasa, Fumiyoshi; Koyama, Katsuji; Nakajima, Hiroshi; Hayashida, Kiyoshi; Mori, Koji; Katsuda, Satoru; Uchida, Hiroyuki; Tsunemi, Hiroshi

    2015-11-01

    We report reanalyses of the Suzaku observations of the Galactic supernova remnant (SNR) G272.2-3.2, for which previous studies were limited below 3 keV. With careful data reduction and background subtraction, we discover the K-shell lines of Ar, Ca, and Fe above 3 keV. The X-ray spectrum of G272.2-3.2 consists of two components, a low-temperature collisional ionization equilibrium (CIE) plasma (kTe ˜ 0.2 keV) and a high-temperature non-equilibrium ionization (NEI) plasma (kTe = 0.6-3 keV). The CIE plasma has solar abundances over the entire area, hence it originates from the interstellar medium. On the other hand, the abundances of the NEI plasma increase toward the inner region, suggesting ejecta origin. The line center energy of the Fe K-shell emission (˜6.4 keV) suggests that the ejecta are recently heated by reverse shock, a common feature in Type Ia SNRs.

  17. Suzaku study on the Ejecta of the Supernova Remnant G272.2$-$3.2

    CERN Document Server

    Kamitsukasa, Fumiyoshi; Nakajima, Hiroshi; Hayashida, Kiyoshi; Mori, Koji; Katsuda, Satoru; Uchida, Hiroyuki; Tsunemi, Hiroshi

    2015-01-01

    We report re-analyses of the Suzaku observations of the Galactic supernova remnant (SNR), G272.2$-$3.2, for which the previous studies were limited below 3 keV. With careful data reduction and background subtraction, we discover the K-shell lines of Ar, Ca, and Fe above 3 keV. The X-ray spectrum of G272.2$-$3.2 consists of two components, a low-temperature collisional ionization equilibrium (CIE) plasma ($kT_{\\rm e} \\sim 0.2$ keV) and a high-temperature non-equilibrium ionization (NEI) plasma ($kT_{\\rm e} = 0.6$-$3$ keV). The CIE plasma has solar abundances over the entire area, hence it would originate from the interstellar medium. On the other hand, the abundances of the NEI plasma increase toward the inner region, suggesting the ejecta origin. The line center energy of the Fe K-shell emission ($\\sim 6.4$ keV) suggests that the ejecta are recently heated by the reverse shock, a common feature in Type Ia SNRs.

  18. Radio spectral characteristics of the supernova remnant Puppis A and nearby sources

    CERN Document Server

    Reynoso, E M

    2015-01-01

    This paper presents a new study of the spectral index distribution of the supernova remnant (SNR) Puppis A. The nature of field compact sources is also investigated according to the measured spectral indices. This work is based on new observations of Puppis A and its surroundings performed with the Australia Telescope Compact Array in two configurations using the Compact Array Broad-band Backend centered at 1.75 GHz. We find that the global spectral index of Puppis A is -0.563 +/- 0.013. Local variations have been detected, however this global index represents well the bulk of the SNR. At the SE, we found a pattern of parallel strips with a flat spectrum compatible with small-scale filaments, although not correlated in detail. The easternmost filament agrees with the idea that the SN shock front is interacting with an external cloud. There is no evidence of the previously suggested correlation between emissivity and spectral index. A number of compact features are proposed to be evolved clumps of ejecta based...

  19. Infrared Supernova Remnants and their Infrared to X-ray Flux Ratios

    CERN Document Server

    Koo, Bon-Chul; Jeong, Il-Gyo; Seok, Ji Yeon; Kim, Hyun-Jeong

    2016-01-01

    Recent high-resolution infrared space missions have revealed supernova remnants (SNRs) of diverse morphology in infrared (IR) dust emission that is often very different from their X-ray appearance. The observed range of infrared-to-X-ray (IRX) flux ratios of SNRs are also wide. For a sample of 20 Galactic SNRs, we obtain their IR and X-ray properties and investigate the physical causes for such large differences. We find that the observed IRX flux ratios ($R_{IRX.obs}$) are related to the IRX morphology, with SNRs with the largest $R_{IRX,obs}$ showing anticorrelated IRX morphology. By analyzing the relation of $R_{IRX,obs}$ to X-ray and IR parameters, we show that the $R_{IRX,obs}$ of some SNRs agree with theoretical ratios of SNR shocks in which dust grains are heated and destroyed by collisions with plasma particles. For the majority of SNRs, however, $R_{IRX,obs}$ values are either significantly smaller or significantly larger than the theoretical ratios. The latter SNRs have relatively low dust temperatu...

  20. Dust processing in Supernova Remnants: Spitzer MIPS SED and IRS Observations

    CERN Document Server

    Andersen, M; Reach, W T; Hewitt, J W; Bernard, J P

    2011-01-01

    We present Spitzer MIPS SED and IRS observations of 14 Galactic Supernova Remnants previously identified in the GLIMPSE survey. We find evidence for SNR/molecular cloud interaction through detection of [OI] emission, ionic lines, and emission from molecular hydrogen. Through black-body fitting of the MIPS SEDs we find the large grains to be warm, 29-66 K. The dust emission is modeled using the DUSTEM code and a three component dust model composed of populations of big grains, very small grains, and polycyclic aromatic hydrocarbons. We find the dust to be moderately heated, typically by 30-100 times the interstellar radiation field. The source of the radiation is likely hydrogen recombination, where the excitation of hydrogen occurred in the shock front. The ratio of very small grains to big grains is found for most of the molecular interacting SNRs to be higher than that found in the plane of the Milky Way, typically by a factor of 2--3. We suggest that dust shattering is responsible for the relative over-abu...

  1. Study of TeV shell supernova remnants at gamma-ray energies

    CERN Document Server

    Acero, F; Renaud, M; Ballet, J; Hewitt, J W; Rousseau, R; Tanaka, T

    2015-01-01

    The breakthrough developments of Cherenkov telescopes in the last decade have led to angular resolution of 0.1{\\deg} and an unprecedented sensitivity. This has allowed the current generation of Cherenkov telescopes to discover a population of supernova remnants (SNRs) radiating in very-high-energy (VHE, E>100 GeV) gamma-rays. A number of those VHE SNRs exhibit a shell-type morphology spatially coincident with the shock front of the SNR. The members of this VHE shell SNR club are RX J1713.7-3946, Vela Jr, RCW 86, SN 1006, and HESS J1731-347. The latter two objects have been poorly studied in high-energy (HE, 0.1 5 sigma. With this Fermi analysis, we now have a complete view of the HE to VHE gamma-ray emission of TeV shell SNRs. All five sources have a hard HE photon index (<1.8) suggesting a common scenario where the bulk of the emission is produced by accelerated electrons radiating from radio to VHE gamma-rays through synchrotron and inverse Compton processes. In addition when correcting for the distance,...

  2. Systematic search for gamma-ray emitting molecular clouds in the vicinity of supernova remnants

    CERN Document Server

    Häffner, Stephanie; Stegmann, Christian

    2013-01-01

    Observations of very-high-energy (VHE) gamma-ray emission from supernova remnants (SNR) established them as sources of accelerated particles up to energies of 100 TeV. The dominant process - leptonic or hadronic - responsible for the VHE emission is still not proven for most of the SNRs. Molecular clouds (MCs) in the vicinity of SNRs provide increased amount of target material for accelerated particles escaping the SNRs, thus making MCs potential gamma-ray sources. The predicted gamma-ray flux for MCs offset from the SNR shock depends on the applied diffusion model for VHE particles and the SNR and MC properties, which encounter large uncertainties. While the the average galactic diffusion coefficient is estimated, the spatially resolved propagation properties of VHE cosmic rays are unknown. gamma-ray emitting MCs provide a unique possibility to derive new information on the propagation of VHE particles through the ISM and on the acceleration of hadrons at SNRs. We present in this paper a strategy and first r...

  3. Dust in the bright supernova remnant N49 in the LMC

    CERN Document Server

    Otsuka, M; Long, K S; Meixner, M; Matsuura, M; Reach, W T; Roman-Duval, J; Gordon, K; Sauvage, M; Hony, S; Misselt, K; Engelbracht, C; Panuzzo, P; Okumura, K; Woods, P M; Kemper, F; Sloan, G

    2010-01-01

    We investigate the dust associated with the supernova remnant (SNR) N49 in the Large Magellanic Cloud (LMC) as observed with the Herschel Space Observatory. N49 is unusually bright because of an interaction with a molecular cloud along its eastern edge. We have used PACS and SPIRE to measure the far IR flux densities of the entire SNR and of a bright region on the eastern edge of the SNR where the SNR shock is encountering the molecular cloud. Using these fluxes supplemented with archival data at shorter wavelengths, we estimate the dust mass associated with N49 to be about 10 Msun. The bulk of the dust in our simple two-component model has a temperature of 20-30 K, similar to that of nearby molecular clouds. Unfortunately, as a result of the limited angular resolution of Herschel at the wavelengths sampled with SPIRE, the uncertainties are fairly large. Assuming this estimate of the dust mass associated with the SNR is approximately correct, it is probable that most of the dust in the SNR arises from regions...

  4. Fermi Large Area Telescope Observations of the Cygnus Loop Supernova Remnant

    Energy Technology Data Exchange (ETDEWEB)

    Katagiri, H.; /Ibaraki U., Mito; Tibaldo, L.; /INFN, Padua /Padua U. /Paris U., VI-VII; Ballet, J.; /Paris U., VI-VII; Giordano, F.; /Bari U. /Bari Polytechnic /INFN, Bari; Grenier, I.A.; /Paris U., VI-VII; Porter, T.A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Roth, M.; /Washington U., Seattle; Tibolla, O.; /Wurzburg U.; Uchiyama, Y.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Yamazaki, R.; /Sagamihara, Aoyama Gakuin U.

    2011-11-08

    We present an analysis of the gamma-ray measurements by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region of the supernova remnant (SNR) Cygnus Loop (G74.0-8.5). We detect significant gamma-ray emission associated with the SNR in the energy band 0.2-100 GeV. The gamma-ray spectrum shows a break in the range 2-3 GeV. The gamma-ray luminosity is {approx} 1 x 10{sup 33} erg s{sup -1} between 1-100 GeV, much lower than those of other GeV-emitting SNRs. The morphology is best represented by a ring shape, with inner/outer radii 0{sup o}.7 {+-} 0{sup o}.1 and 1{sup o}.6 {+-} 0{sup o}.1. Given the association among X-ray rims, H{alpha} filaments and gamma-ray emission, we argue that gamma rays originate in interactions between particles accelerated in the SNR and interstellar gas or radiation fields adjacent to the shock regions. The decay of neutral pions produced in nucleon-nucleon interactions between accelerated hadrons and interstellar gas provides a reasonable explanation for the gamma-ray spectrum.

  5. The Interaction of Supernova Remnant G357.7+0.3 with the Interstellar Medium

    CERN Document Server

    Phillips, J P; 10.1111/j.1365-2966.2010.17340.x

    2010-01-01

    The supernova remnant (SNR) G357.7+0.3 appears to have caused considerable shredding of the local interstellar medium (ISM), leading to the formation of multiple cloud fragments having bright rims and cometary structures. We investigate five of these regions using mid-infrared (MIR) imaging and photometry deriving from the Spitzer Space Telescope (SST), as well as photometry deriving from the 2MASS near-infrared all sky survey, the Mid-Course Science Experiment (MSX), and the Multiband Imaging Photometer for Spitzer (MIPSGAL) survey of the Galactic plane. It is noted that two of the rims show evidence for emission by shock excited H2 transitions, whilst the centres of the clouds also show evidence for dark extinction cores, observed in silhouette against the bright emission rims. Levels of extinction for these cores are determined to be of order AV ~ 17-26 mag, whilst densities n(HI) are of order ~ 10^4 cm^(-3), and masses in the region of ~40-100 Msun. It is shown that the wavelength dependence of extinction...

  6. Radio spectral characteristics of the supernova remnant Puppis A and nearby sources

    Science.gov (United States)

    Reynoso, E. M.; Walsh, A. J.

    2015-08-01

    This paper presents a new study of the spectral index distribution of the supernova remnant (SNR) Puppis A. The nature of field compact sources is also investigated according to the measured spectral indices. This work is based on new observations of Puppis A and its surroundings performed with the Australia Telescope Compact Array in two configurations using the Compact Array Broad-band Backend centred at 1.75 GHz. We find that the global spectral index of Puppis A is ? = -0.563 ± 0.013. Local variations have been detected, however this global index represents well the bulk of the SNR. At the SE, we found a pattern of parallel strips with a flat spectrum compatible with small-scale filaments, although not correlated in detail. The easternmost filament agrees with the idea that the SNR shock front is interacting with an external cloud. There is no evidence of the previously suggested correlation between emissivity and spectral index. A number of compact features are proposed to be evolved clumps of ejecta based on their spectral indices, although dynamic measurements are needed to confirm this hypothesis. We estimate precise spectral indices for the five previously known field sources, two of which are found to be double (one of them, probably triple), and catalogue 40 new sources. In the light of these new determinations, the extragalactic nature previously accepted for some compact sources is now in doubt.

  7. Time-Dependent Escape of Cosmic Rays from Supernova Remnants, and their Interaction with Dense Media

    CERN Document Server

    Telezhinsky, I; Pohl, M

    2011-01-01

    Context. Supernova Remnants (SNRs) are thought to be the main source of Galactic cosmic rays (CRs) up to the "knee". During the evolution of a SNR, the bulk of the CRs are confined within the SNR shell. The highest-energy particles leave the system continuously, while the remaining adiabatically-cooled particles are released when the SNR has sufficiently expanded and slowed down so that the magnetic field (MF) at the shock is no longer able to confine them. Particles escaping from the parent system may end up interacting with nearby molecular clouds (MCs), producing $\\gamma$-rays in the process via pion decay. The soft gamma-ray spectra observed from a number of SNRs interacting with molecular clouds (MCs) however challenge current theories of non-linear particle acceleration that predict harder spectra. Aims. To study how the spectrum of escaped particles depends on the time-dependent acceleration history in both type-Ia and core-collapse SNRs, as well as on different assumptions about the diffusion coeffici...

  8. Observations of supernova remnants and pulsar wind nebulae at gamma-ray energies

    CERN Document Server

    Hewitt, John W

    2015-01-01

    In the past few years, gamma-ray astronomy has entered a golden age thanks to two major breakthroughs: Cherenkov telescopes on the ground and the Large Area Telescope (LAT) onboard the Fermi satellite. The sample of supernova remnants (SNRs) detected at gamma-ray energies is now much larger: it goes from evolved supernova remnants interacting with molecular clouds up to young shell-type supernova remnants and historical supernova remnants. Studies of SNRs are of great interest, as these analyses are directly linked to the long standing issue of the origin of the Galactic cosmic rays. In this context, pulsar wind nebulae (PWNe) need also to be considered since they evolve in conjunction with SNRs. As a result, they frequently complicate interpretation of the gamma-ray emission seen from SNRs and they could also contribute directly to the local cosmic ray spectrum, particularly the leptonic component. This paper reviews the current results and thinking on SNRs and PWNe and their connection to cosmic ray product...

  9. A statistical study of the correlation of galactic supernova remnants and spiral arms

    International Nuclear Information System (INIS)

    A statistical study of the correlation of galactic supernova remnants with spiral arms and the disk is presented. SNR apparently have a larger radial scale length than disk stars. The authors estimate that only about 10 percent of the galactic SNR have been detected

  10. A Spitzer Space Telescope Infrared Survey of Supernova Remnants in the Inner Galaxy

    OpenAIRE

    Reach, William T.; Rho, Jeonghee; Tappe, Achim; Pannuti, Thomas G.; Brogan, Crystal L.; Churchwell, Edward B.; Meade, Marilyn R.; Babler, Brian; Indebetouw, Remy; Whitney, Barbara A.

    2005-01-01

    Using Infrared Array Camera (IRAC) images at 3.6, 4.5, 5.8, and 8 microns from the GLIMPSE Legacy science program on the Spitzer Space Telescope, we searched for infrared counterparts to the 95 known supernova remnants that are located within galactic longitudes 65>|l|>10 degrees and latitudes |b|

  11. sup 4 sup 4 Ti decay gamma-ray emission from young galactic supernova remnants

    CERN Document Server

    Iyudin, A F

    1999-01-01

    The discovery by COMPTEL of the sup 4 sup 4 Ti line emission at 1.16 MeV from the youngest known Galactic supernova remnant (SNR) Cas A has opened a new window for the investigation of SNR properties. This discovery also shows a way that could help to uncover missing young remnants of Galactic SNe that might have occurred some hundred years ago. Contrary to the situation at other wavelengths, in the gamma-ray band the Galaxy is almost transparent, so that otherwise obscured supernova remnants may be detectable up to A sub v approx 10 sup 3 in gamma-ray line emission. This is one of the direct ways to complement historical observations of Galactic SNe. Here we present preliminary results of the 6 year sup 4 sup 4 Ti line emission survey performed by COMPTEL on-board the Compton Gamma-Ray Observatory (CGRO).

  12. Nuclear lines revealing the injection of cosmic rays in supernova remnants

    CERN Document Server

    Tibolla, O; Summa, A; Paravac, A; Greiner, J; Kanbach, G

    2011-01-01

    At high energies, the hadronic origin of gamma rays from supernova remnants is still debated. Assuming the observed gamma-rays from the Wolf-Rayet supernova remnant Cas A are due to accelerated protons and ions, we predict the nuclear de-excitation line emission arising from interactions with the heavy elements in the supernova ejecta. This illustrative example highlights the importance of MeV gamma ray observations of the hadronic fingerprint of cosmic rays. The lines could be observed in the MeV band with a future space mission such as GRIPS which has been proposed to ESA as an all-sky survey mission with gamma-ray, X-ray and near-infrared telescopes. In MeV gamma rays, its sensitivity will improve by a factor of 40 compared with previous missions.

  13. X-ray emission from supernova remnants with particular reference to the Cygnus Loop

    International Nuclear Information System (INIS)

    Observational or theoretical results related to the study of supernova remnants (SNRs) are described. Some background information is given by reviewing the present status of our knowledge of supernovae and supernova remnants, both from theory and observations. Also the distribution of all known radio, optical, and X-ray SNRs in the Galaxy is shown and a comparison is made. The X-ray observations of the well-known X-ray SNR the Cygnus Loop are discussed in detail and the discovery of a new X-ray emitting SNR W44 is described. Other radio sources are investigated, and the observed X-ray emission of SNRs are analysed using thermal spectra like exponential or bremsstrahlung spectra. The X-ray line spectrum that emerges from SNRs is described in detail. (Auth.)

  14. A CR-hydro-NEI model of the structure and broadband emission from Tycho's supernova remnant

    International Nuclear Information System (INIS)

    Tycho's supernova remnant (SNR) is well-established as a source of particle acceleration to very high energies. Constraints from numerous studies indicate that the observed ?-ray emission results primarily from hadronic processes, providing direct evidence of highly relativistic ions that have been accelerated by the SNR. Here we present an investigation of the dynamical and spectral evolution of Tycho's SNR by carrying out hydrodynamical simulations that include diffusive shock acceleration of particles in the amplified magnetic field at the forward shock of the SNR. Our simulations provide a consistent view of the shock positions, the nonthermal emission, the thermal X-ray emission from the forward shock, and the brightness profiles of the radio and X-ray emission. We compare these with the observed properties of Tycho to determine the density of the ambient material, the particle acceleration efficiency and maximum energy, the accelerated electron-to-proton ratio, and the properties of the shocked gas downstream of the expanding SNR shell. We find that evolution of a typical Type Ia supernova in a low ambient density (n 0 ? 0.3 cm–3), with an upstream magnetic field of ?5 ?G, and with ?16% of the SNR kinetic energy being converted into relativistic electrons and ions through diffusive shock acceleration, reproduces the observed properties of Tycho. Under such a scenario, the bulk of observed ?-ray emission at high energies is produced by ?0-decay resulting from the collisions of energetic hadrons, while inverse-Compton emission is significant at lower energies, comprising roughly half of the flux between 1 and 10 GeV.

  15. Raising the Dead: Clues to Type Ia Supernova Physics from the Remnant 0509-67.5

    CERN Document Server

    Warren, J S

    2004-01-01

    We present Chandra X-ray observations of the young supernova remnant (SNR) 0509-67.5 in the Large Magellanic Cloud (LMC), believed to be the product of a Type Ia supernova (SN Ia). The remnant is very round in shape, with a distinct clumpy shell-like structure. Our Chandra data reveal the remnant to be rich in silicon, sulfur, and iron. The yields of our fits to the global spectrum confirm that 0509-67.5 is the remnant of an SN Ia and show a clear preference for delayed detonation explosion models for SNe Ia. We study the spectrum of the single brightest isolated knot in the remnant and find that it is enhanced in iron by a factor of roughly two relative to the global remnant abundances. This feature, along with similar knots seen in Tycho's SNR, argues for the presence of modest small-scale composition inhomogeneities in SNe Ia. The presence of both Si and Fe, with abundance ratios that vary from knot to knot, indicates that these came from the transition region between the Si- and Fe-rich zones in the explo...

  16. Resonant neutrino spin-flavor precession and supernova shock revival

    International Nuclear Information System (INIS)

    A new mechanism of supernova shock revival is proposed which involves the resonant spin-flavor precession of neutrinos with a transition magnetic moment in the magnetic field of the supernova. The mechanism can be operative in supernovae for transition magnetic moments as small as 10-14?B provided the neutrino mass squared difference is in the range ?m2?(3 eV)2-(600eV)2. It is shown that this mechanism can increase the neutrino-induced shock reheating energy by about 60%. copyright 1997 The American Physical Society

  17. The complex relations between Supernova Remnants and Neutron Stars

    Directory of Open Access Journals (Sweden)

    G. Dubner

    2002-01-01

    Full Text Available Se espera que la mayor a de las supernovas (SN produzca una estrella de neutrones (EN observable como pulsar en ondas de radio. Las observaciones, sin embargo, muestran escasas coincidencias entre restos de supernovas (RSN y EN. Se presenta una puesta al d a de resultados de observaciones multiespectrales llevadas a cabo para investigar este aspecto. El trabajo se focaliza en la comprensi on actual de las nebulosas de viento de pulsares, as como en las diferentes formas en que puede manifestarse una estrella de neutrones, tales como pulsares an omalos en rayos X, estrellas de neutrones radio-quietas y repetidores en rayos blandos.

  18. Infrared and X-Ray Spectroscopy of the Kes 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties

    CERN Document Server

    Temim, Tea; Arendt, Richard G; Dwek, Eli

    2011-01-01

    We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of ~ 1.5 keV, or with two thermal components with temperatures of 1.5 and 0.2 keV. Previous studies suggest that the hot component may originate from reverse-shocked SN ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from supernova (SN) ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and IR emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the ...

  19. Star Formation Around the Youngest Supernova Remnants in the Large Magellanic Cloud: Implications for Type Ia Supernova Progenitors

    CERN Document Server

    Badenes, Carles; Zaritsky, Dennis; Prieto, Jose Luis

    2009-01-01

    We use the star formation history map of the Large Magellanic Cloud recently published by Harris & Zaritsky to study the sites of the youngest Type Ia supernova remnants. We find that most Type Ia remnants are associated with old, metal-poor stellar populations, with little or no recent star formation. These include SNR 0509-67.5 which is known to have been originated by an extremely bright SN 1991T-like event, and yet is located very far away from any star forming regions. The Type Ia remnant SNR N103B, however, is associated with vigorous star formation activity in the last 100 Myr, and might have had a relatively younger and more massive progenitor.

  20. Kinematics of the galactic supernova remnant G206.9+2.3

    Scientific Electronic Library Online (English)

    P., Ambrocio-Cruz; M., Rosado; E., Le Coarer; A., Bernal; L., Gutiérrez.

    Full Text Available Se realizó un estudio cinemático del remanente de supernova galáctico G206.9+2.3 (PKS 0646+06) en las líneas [SII]?6717 y 6731 Å. Este es uno de los primeros pasos de un proyecto a largo plazo de determinación de distancias cinemáticas a RSN galácticos con contraparte óptica. Se obtuvo la distancia [...] cinemática a esta nebulosa, mostrando primero que los filamentos detectados son realmente la contraparte óptica del RSN en radio. La distancia estimada en este trabajo es ligeramente mayor que la distancia de Monoceros. Se estimó que G206.9+2.3 está localizada a 2.2 kpc del Sol, en una región del cielo donde se observan varias nebulosas superpuestas a diferentes velocidades. Se midió una velocidad de choque de 86 kms-1 y un diámetro lineal de 18 pe. Finalmente se calculó que la energía depositada al medio interestelar por la explosión de supernova es de 1.7 x 10(49) ergs por lo que se concluyó que G206.9+2.3 está en la fase radiativa de su evolución, con una edad de 6.4 x 10(4) años. Abstract in english We studied the kinematics of the galactic supernova remnant (SNR) G206.9+2.3 (PKS 0646+06) in the [SII]?6717 and 6731 Å lines, as one of the initial steps of a long-term project to determine kinematical distances to galactic SNRs with optical counterparts. We obtained the kinematic distance to this [...] nebula by first showing that the filaments detected were in fact the optical counterpart of the radio SNR. The distance estimated here is slightly greater than that of the Monoceros Loop. We estimate that G206.9+2.3 is located about 2.2 kpc from the Sun, in a zone where several background and foreground nebulae at different velocities are seen in projection. We measured a shock velocity of 86 kms-1 and a linear diameter of 18 pc. Finally, we calculated the energy deposited in the interstellar medium by the SN explosion as 1.7 x 10(49) ergs and concluded that the SNR is in the radiative phase of evolution with an age of 6.4 x 10(4) years.

  1. Scaling laws for evaporative supernovae remnants in the Mc KEE and Ostriker theory of the interstellar medium

    International Nuclear Information System (INIS)

    The theory of the Interstellar Medium proposed by Mc Kee and Ostriker is dominated by the unusual properties of Evaporative Supernovae Remnants (ESNR). We present here the basic features of this model, with emphasis upon: (i) the evolution of supernovae remnants in an inhomogeneous evaporative medium, (ii) the collective effects of such ESNRs upon the structure of the interstellar medium. Following Mc Kee and Ostriker, we will derive the time dependent evolution of evaporative supernovae remnants, then determine the conditions for percolation and finally identify the mean physical properties of the medium with the mean properties inside ESNRs at percolation

  2. G55.0+0.3 A Highly Evolved Supernova Remnant

    CERN Document Server

    Matthews, B C; Taylor, A R

    1997-01-01

    Multi-frequency analysis has revealed the presence of a new supernova remnant, G55.0+0.3, in the Galactic plane. A kinematic distance of 14 kpc has been measured from HI spectral line data. The faint, clumpy half-shell is non-thermal and has a physical radius of 70 pc. Using an evolutionary model, the age of the remnant is estimated to be on the order of one million years, which exceeds conventional limits by a factor of five. The remnant may be associated with the nearby pulsar J1932+2020, which has a spin-down age of 1.1 million years. This work implies that the radiative lifetimes of remnants could be much longer than previously suggested.

  3. A high-resolution radio survey of the Vela supernova remnant

    CERN Document Server

    Bock, D; Green, A J

    1998-01-01

    This paper presents a high-resolution radio continuum (843 MHz) survey of the Vela supernova remnant. The contrast between the structures in the central pulsar-powered nebula of the remnant and the synchrotron radiation shell allows the remnant to be identified morphologically as a member of the composite class. The data are the first of a composite remnant at spatial scales comparable with those available for the Cygnus Loop and the Crab Nebula, and make possible a comparison of radio, optical and soft X-ray emission from the resolved shell filaments. The survey, made with the Molonglo Observatory Synthesis Telescope, covers an area of 50 square degrees at a resolution of 43'' x 60'', while imaging structures on scales up to 30'.

  4. ON THE AMPLIFICATION OF MAGNETIC FIELD BY A SUPERNOVA BLAST SHOCK WAVE IN A TURBULENT MEDIUM

    International Nuclear Information System (INIS)

    We have performed extensive two-dimensional magnetohydrodynamic simulations to study the amplification of magnetic fields when a supernova blast wave propagates into a turbulent interstellar plasma. The blast wave is driven by injecting high pressure in the simulation domain. The interstellar magnetic field can be amplified by two different processes, occurring in different regions. One is facilitated by the fluid vorticity generated by the 'rippled' shock front interacting with the background turbulence. The resulting turbulent flow keeps amplifying the magnetic field, consistent with earlier work. The other process is facilitated by the growth of the Rayleigh-Taylor instability at the contact discontinuity between the ejecta and the shocked medium. This can efficiently amplify the magnetic field and tends to produce the highest magnetic field. We investigate the dependence of the amplification on numerical parameters such as grid-cell size and on various physical parameters. We show that the magnetic field has a characteristic radial profile such that the downstream magnetic field gets progressively stronger away from the shock. This is because the downstream magnetic field needs a finite time to reach the efficient amplification, and will get further amplified in the Rayleigh-Taylor region. In our simulation, we do not observe a systematic strong magnetic field within a small distance to the shock. This indicates that if the magnetic-field amplification in supernova remnants indeed occurs near the shock front, other processes such as three-dimensional instabilities, plasma kinetics, and/or cosmic ray effect may need to be considered to explain the strong magnetic field in supernova remnants.

  5. Identification campaign of supernova remnant candidates in the Milky Way. II. X-ray studies of G38.7-1.4

    CERN Document Server

    Huang, R H H; Hui, C Y; Seo, K A; Trepl, L; Kong, A K H

    2014-01-01

    We report on XMM-Newton and Chandra observations of the Galactic supernova remnant candidate G38.7-1.4, together with complementary radio, infrared, and gamma-ray data. An approximately elliptical X-ray structure is found to be well correlated with radio shell as seen by the Very Large Array. The X-ray spectrum of G38.7-1.4 can be well-described by an absorbed collisional ionization equilibrium plasma model, which suggests the plasma is shock heated. Based on the morphology and the spectral behaviour, we suggest that G38.7-1.4 is indeed a supernova remnant belongs to a mix-morphology category.

  6. Four new X-ray-selected supernova remnants in the Large Magellanic Cloud

    CERN Document Server

    Maggi, P; Kavanagh, P J; Points, S D; Dickel, J; Bozzetto, L M; Sasaki, M; Chu, Y -H; Gruendl, R A; Filipovic, M D; Pietsch, W

    2013-01-01

    Aims: We present a detailed multi-wavelength study of four new supernova remnants (SNRs) in the Large Magellanic Cloud (LMC). The objects were identified as SNR candidates in X-ray observations performed during the survey of the LMC with XMM-Newton. Methods: Data obained with XMM-Newton are used to investigate the morphological and spectral features of the remnants in X-rays. We measure the plasma conditions, look for supernova (SN) ejecta emission, and constrain some of the SNR properties (e.g. age and ambient density). We supplement the X-ray data with optical, infrared, and radio-continuum archival observations, which allow us to understand the conditions resulting in the current appearance of the remnants. Based on the spatially-resolved star formation history (SFH) of the LMC together with the X-ray spectra, we attempt to type the supernovae that created the remnants. Results: We confirm all four objects as SNRs, to which we assign the names MCSNR J0508-6830, MCSNR J0511-6759, MCSNR J0514-6840, and MCSNR...

  7. INVESTIGATION OF THE PROGENITORS OF THE TYPE Ia SUPERNOVAE ASSOCIATED WITH THE LMC SUPERNOVA REMNANTS 0505-67.9 AND 0509-68.7

    Energy Technology Data Exchange (ETDEWEB)

    Pagnotta, Ashley [Department of Astrophysics, American Museum of Natural History, New York, NY 10024 (United States); Schaefer, Bradley E. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States)

    2015-01-20

    Although Type Ia supernovae have been heavily scrutinized due to their use in making cosmological distance estimates, we are still unable to definitively identify the progenitors for the entire population. While answers have been presented for certain specific systems, a complete solution remains elusive. We present observations of two supernova remnants (SNRs) in the Large Magellanic Cloud, SNR 0505-67.9 and SNR 0509-68.7, for which we have identified the center of the remnant and the 99.73% containment central region in which any companion star left over after the supernova must be located. Both remnants have a number of potential ex-companion stars near their centers; all possible single and double degenerate progenitor models remain viable for these two supernovae. Future observations may be able to identify the true ex-companions for both remnants.

  8. Swift/BAT detection of hard X-rays from Tycho's Supernova Remnant: Evidence for Titanium-44

    CERN Document Server

    Troja, E; La Parola, V; Hartmann, D; Baumgartner, W; Markwardt, C; Barthelmy, S; Cusumano, G; Gehrels, N

    2014-01-01

    We report Swift/BAT survey observations of the Tycho's supernova remnant, performed over a period of 104 months since the mission's launch. The remnant is detected with high significance (>10 sigma) below 50 keV. We detect significant hard X-ray emission in the 60-85 keV band, above the continuum level predicted by a simple synchrotron model. The location of the observed excess is consistent with line emission from radioactive Titanium-44, so far reported only for Type II supernova explosions. We discuss the implications of these results in the context of the galactic supernova rate, and nucleosynthesis in Type Ia supernova.

  9. Tools for Dissecting Supernova Remnants Observed with Chandra: Methods and Application to the Galactic Remnant W49B

    CERN Document Server

    Lopez, Laura A; Pooley, David A; Jeltema, Tesla E

    2008-01-01

    We introduce methods to quantify the X-ray morphologies of supernova remnants observed with the Chandra X-ray Telescope. These include a power-ratio technique to measure morphological asymmetries, correlation-length analysis to probe chemical segregation and distribution, and wavelet-transform analysis to quantify X-ray substructure. We demonstrate the utility and accuracy of these techniques on relevant synthetic data. Additionally, we show the methods' capabilities by applying them to the 55-ks Chandra ACIS observation of the galactic supernova remnant W49B. We analyze the images of prominent emission lines in W49B and use the results to discern physical properties. We find that the iron morphology is very distinct from the other elements: it is statistically more asymmetric, more segregated, and has 25% larger emitting substructures than the lighter ions. Comparatively, the silicon, sulfur, argon, and calcium are well-mixed, more isotropic, and have smaller, equally-sized emitting substructures. Based on f...

  10. 3D Simulations of the Thermal X-ray Emission from Young Supernova Remnants Including Efficient Particle Acceleration

    CERN Document Server

    Ferrand, Gilles; Safi-Harb, Samar

    2012-01-01

    Supernova remnants (SNRs) are believed to be the major contributors to Galactic cosmic rays. The detection of non-thermal emission from SNRs demonstrates the presence of energetic particles, but direct signatures of protons and other ions remain elusive. If these particles receive a sizeable fraction of the explosion energy, the morphological and spectral evolution of the SNR must be modified. To assess this, we run 3D hydrodynamic simulations of a remnant coupled with a non-linear acceleration model. We obtain the time-dependent evolution of the shocked structure, impacted by the Rayleigh-Taylor hydrodynamic instabilities at the contact discontinuity and by the back-reaction of particles at the forward shock. We then compute the progressive temperature equilibration and non-equilibrium ionization state of the plasma, and its thermal emission in each cell. This allows us to produce the first realistic synthetic maps of the projected X-ray emission from the SNR. Plasma conditions (temperature, ionization age) ...

  11. Utilizing Supernova Remnants as Probes of Explosion Mechanisms and Progenitor Systems

    Science.gov (United States)

    Milisavljevic, Dan

    2015-08-01

    Theory and observation strongly favor the notion that asymmetric explosions drive core-collapse supernovae. Where and how this asymmetry is introduced is uncertain, in part because of limited constraints on the various processes that may be taking place deep inside massive stars. Observations of extragalactic supernovae have shed some light on the issue. However, distant supernovae, by nature, appear as unresolved point sources, which severely restricts our ability to extract key properties of the explosion dynamics via detailed knowledge of the three-dimensional kinematics of the expanding ejecta. Progress requires an alternative approach, and to this end there have been successful efforts towards understanding core-collapse supernova explosions through studies of their remnants in our own Milky Way galaxy. Such investigations provide information about the explosion-driven mixing of the progenitor star's chemically distinct layers, the star's mass loss history before explosion, and the fate of its remnant core - all at extremely fine scales. Particularly of note are observations of the young supernova remnant Cassiopeia A, which is the descendant of a massive star that was mostly stripped of its hydrogen envelope. Cassiopeia A's debris field has a bubble-like morphology that may have originated from turbulent mixing processes that encouraged the development of outwardly expanding plumes of radioactive 56Ni-rich ejecta. Important aspects of these observations conflict with sophisticated explosion models and we presently do not have a good understanding of how the 56Ni was mixed. Considering Cassiopeia A's kinematic properties are not unique and likely reflect a common phenomenon of core-collapse supernovae, this conflict represents a big problem that cannot be ignored. Unraveling whether the mixing that we see originates from an asymmetric explosion mechanism or is more tightly associated with a turbulent interior structure will be a challenge, but there is hope.

  12. The Progenitor of the New COMPTEL/ROSAT Supernova Remnant in Vela

    CERN Document Server

    Chen, W; Chen, Wan

    1998-01-01

    We propose that (1) the newly discovered supernova remnant (SNR), GRO J0852--4642/RX J0852.0--4622, was probably created by a core-collapse supernova of a massive star, and (2) the same supernova event which produced the $^{44}$Ti detected by COMPTEL from this source is probably also responsible for a large fraction of the observed $^{26}$Al emission in the Vela region detected by the same instrument. We show that the remnant is currently expanding too slowly for its young age to be due to a Type Ia supernova (SNIa). Even for a massive star progenitor, the SNR is required to be $\\sim250$ pc away in a dense environment at the edge of the Gum nebula. The progenitor has a preferred ejecta mass of $\\le10M_\\odot$ and a large kinetic energy of $\\ge 2\\times 10^{51}$ ergs, and therefore, it is probably a Type Ib or Type Ic supernova. The required high ambient density of $n_H > 300$ cm$^{-3}$, however, has yet to be confirmed by observations. An SNIa progenitor at the same distance may still be possible but it would n...

  13. Re-examination of the Expected gamma-ray emission of supernova remnant SN 1987A

    OpenAIRE

    Berezhko, E. G.; Ksenofontov, L. T.; Voelk, H J

    2015-01-01

    A nonlinear kinetic theory, combining cosmic-ray (CR) acceleration in supernova remnants (SNRs) with their gas dynamics, is used to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5-50 yr. This spherically symmetric model is approximately applied to the different features of the SNR which consist of (i) a blue supergiant wind and bubble, and (ii) of the swept-up red supergiant (RSG) wind structures in the form of an H II...

  14. SEARCH FOR GAMMA-RAY EMISSION FROM THE SUPERNOVA REMNANT IC 443 WITH THE MAGIC TELESCOPE

    Directory of Open Access Journals (Sweden)

    R. J. García López

    2009-01-01

    Full Text Available TeV observations of Supernova remnants (SNRs and, in particular, of SNRs which appear to be physically related to EGRET sources are a prime target for the MAGIC telescope. MAGIC's spatial resolution and sensi- tivity can probe the main mechanism responsible for producing high energy photons in the SNR neighbourhood. Based on a recent systematical analysis of the molecular environment of the vicinity of all SNR-EGRET source pairs, the IC 443 remnant was chosen for observations with MAGIC. We brie y describe the observational strategy which provided the detection of a new very-high energy gamma-ray source: MAGIC 0616+225.

  15. Radioactive Scandium in the Youngest Galactic Supernova Remnant G1.9+0.3

    OpenAIRE

    Borkowski, Kazimierz J.; Reynolds, Stephen P.; Green, David A.; Hwang, Una; Petre, Robert; Krishnamurthy, Kalyani; Willett, Rebecca

    2010-01-01

    We report the discovery of thermal X-ray emission from the youngest Galactic supernova remnant G1.9+0.3, from a 237-ks Chandra observation. We detect strong K-shell lines of Si, S, Ar, Ca, and Fe. In addition, we detect a 4.1 keV line with 99.971% confidence which we attribute to 44Sc, produced by electron capture from 44Ti. Combining the data with our earlier Chandra observation allows us to detect the line in two regions independently. For a remnant age of 100 yr, our meas...

  16. The Morphology and Dynamics of Jet-Driven Supernova Remnants: the Case of W49B

    OpenAIRE

    Gonzalez-Casanova, Diego F.; De Colle, Fabio; Ramirez-Ruiz, Enrico; Lopez, Laura A.

    2013-01-01

    The circumstellar medium (CSM) of a massive star is modified by its winds before a supernova (SN) explosion occurs, and thus the evolution of the resulting supernova remnant (SNR) is influenced by both the geometry of the explosion as well as the complex structure of the CSM. Motivated by recent work suggesting the SNR W49B was a jet-driven SN expanding in a complex CSM, we explore how the dynamics and the metal distributions in a jet-driven explosion are modified by the int...

  17. Nonthermal properties of supernova remnant G1.9+0.3

    OpenAIRE

    Ksenofontov, L. T.; Voelk, H J; Berezhko, E. G.

    2010-01-01

    The properties of the - presumably - youngest Galactic supernova remnant (SNR) G1.9+0.3 are investigated within the framework of nonlinear kinetic theory of cosmic ray acceleration in SNRs. The observed angular size and expansion speed as well as the radio and X-ray emission measurements are used to determine relevant physical parameters of this SNR. Under the assumption that SNR G1.9+0.3 is the result of a Type Ia supernova near the Galactic center (at the distance d=8.5 kp...

  18. The Impact of Efficient Particle Acceleration on the Evolution of Supernova Remnants in the Sedov-Taylor Phase

    CERN Document Server

    Castro, Daniel; Patnaude, Daniel J; Ellison, Donald C

    2011-01-01

    We investigate the effects of the efficient production of cosmic rays on the evolution of supernova remnants (SNRs) in the adiabatic Sedov-Taylor phase. We model the SNR by coupling the hydrodynamic evolution with nonlinear diffusive shock acceleration (DSA), and track self-consistently the ionization state of the shock-heated plasma. Using a plasma emissivity code and the results of the model, we predict the thermal X-ray emission and combine it with the non-thermal component in order to obtain the complete spectrum in this energy range. Hence, we study how the interpretation of thermal X-ray observations is affected by the efficiency of the DSA process, and find that, compared to test particle cases, the efficient DSA example yields a smaller shock radius and speed, a larger compression ratio, and lower intensity X-ray thermal emission. We also find that a model where the shock is not assumed to produce CRs can fit the X-ray observational properties of an example with efficient particle acceleration, with a...

  19. Detection of Extremely Broad Water Emission from the molecular cloud interacting Supernova Remnant G349.7+0.2

    CERN Document Server

    Rho, J; Boogert, A; Kaufman, M; Gusdorf, A

    2015-01-01

    We performed Herschel HIFI, PACS and SPIRE observations towards the molecular cloud interacting supernova remnant G349.7+0.2. An extremely broad emission line was detected at 557 GHz from the ground state transition 1_{10}-1_{01} of ortho-water. This water line can be separated into three velocity components with widths of 144, 27 and 4 km/s. The 144 km/s component is the broadest water line detected to date in the literature. This extremely broad line width shows importance of probing shock dynamics. PACS observations revealed 3 additional ortho-water lines, as well as numerous high-J carbon monoxide (CO) lines. No para-water lines were detected. The extremely broad water line is indicative of a high velocity shock, which is supported by the observed CO rotational diagram that was reproduced with a J-shock model with a density of 10^4 cm^{-3} and a shock velocity of 80 km/s. Two far-infrared fine-structure lines, [O~I] at 145 micron and [C~II] line at 157 micron, are also consistent with the high velocity J-...

  20. Gamma-ray emission from the shell of supernova remnant W44 revealed by the Fermi LAT.

    Science.gov (United States)

    Abdo, A A; Ackermann, M; Ajello, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Celik, O; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cognard, I; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Cutini, S; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Espinoza, C; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giavitto, G; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hughes, R E; Jackson, M S; Jóhannesson, G; Johnson, A S; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Katsuta, J; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Kramer, M; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Lyne, A G; Madejski, G M; Makeev, A; Mazziotta, M N; McEnery, J E; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nolan, P L; Norris, J P; Noutsos, A; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Paneque, D; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Rochester, L S; Rodriguez, A Y; Romani, R W; Roth, M; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stappers, B W; Stecker, F W; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J B; Thayer, J G; Theureau, G; Thompson, D J; Tibaldo, L; Tibolla, O; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Vasileiou, V; Venter, C; Vilchez, N; Vitale, V; Waite, A P; Wang, P; Winer, B L; Wood, K S; Yamazaki, R; Ylinen, T; Ziegler, M

    2010-02-26

    Recent observations of supernova remnants (SNRs) hint that they accelerate cosmic rays to energies close to ~10(15) electron volts. However, the nature of the particles that produce the emission remains ambiguous. We report observations of SNR W44 with the Fermi Large Area Telescope at energies between 2 x 10(8) electron volts and 3 x10(11) electron volts. The detection of a source with a morphology corresponding to the SNR shell implies that the emission is produced by particles accelerated there. The gamma-ray spectrum is well modeled with emission from protons and nuclei. Its steepening above approximately 10(9) electron volts provides a probe with which to study how particle acceleration responds to environmental effects such as shock propagation in dense clouds and how accelerated particles are released into interstellar space. PMID:20056857

  1. The Fast and the Furious: Energetic Phenomena in Isolated Neutron Stars, Pulsar Wind Nebulae and Supernova Remnants

    Science.gov (United States)

    Ness, J.-U.

    2013-07-01

    Online Presentations of 'The Fast and the Furious: Energetic Phenomena in Isolated Neutron Stars, Pulsar Wind Nebulae and Supernova Remnants', a workshop organized by the XMM-Newton Science Operations Centre of the European Space Agency (ESA)

  2. ON THE RADIO POLARIZATION SIGNATURE OF EFFICIENT AND INEFFICIENT PARTICLE ACCELERATION IN SUPERNOVA REMNANT SN 1006

    Energy Technology Data Exchange (ETDEWEB)

    Reynoso, Estela M. [Instituto de Astronomia y Fisica del Espacio (IAFE), C. C. 67, Suc. 28, 1428 Buenos Aires (Argentina); Hughes, John P. [Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854-8019 (United States); Moffett, David A., E-mail: ereynoso@iafe.uba.ar, E-mail: jph@physics.rutgers.edu, E-mail: david.moffett@furman.edu [Department of Physics, Furman University, Greenville, SC 29613 (United States)

    2013-04-15

    Radio polarization observations provide essential information on the degree of order and orientation of magnetic fields, which themselves play a key role in the particle acceleration processes that take place in supernova remnants (SNRs). Here we present a radio polarization study of SN 1006, based on combined Very Large Array and Australia Telescope Compact Array observations at 20 cm that resulted in sensitive images with an angular resolution of 10 arcsec. The fractional polarization in the two bright radio and X-ray lobes of the SNR is measured to be 0.17, while in the southeastern sector, where the radio and non-thermal X-ray emission are much weaker, the polarization fraction reaches a value of 0.6 {+-} 0.2, close to the theoretical limit of 0.7. We interpret this result as evidence of a disordered, turbulent magnetic field in the lobes, where particle acceleration is believed to be efficient, and a highly ordered field in the southeast, where the acceleration efficiency has been shown to be very low. Utilizing the frequency coverage of our observations, an average rotation measure of {approx}12 rad m{sup -2} is determined from the combined data set, which is then used to obtain the intrinsic direction of the magnetic field vectors. While the orientation of magnetic field vectors across the SNR shell appear to be radial, a large fraction of the magnetic vectors lie parallel to the Galactic plane. Along the highly polarized southeastern rim, the field is aligned tangent to the shock, and therefore also nearly parallel to the Galactic plane. These results strongly suggest that the ambient field surrounding SN 1006 is aligned with this direction (i.e., from northeast to southwest) and that the bright lobes are due to a polar cap geometry. Our study establishes that the most efficient particle acceleration and generation of magnetic turbulence in SN 1006 is attained for shocks in which the magnetic field direction and shock normal are quasi-parallel, while inefficient acceleration and little to no generation of magnetic turbulence are obtained for the quasi-perpendicular case.

  3. On the Radio Polarization Signature of Efficient and Inefficient Particle Acceleration in Supernova Remnant SN 1006

    Science.gov (United States)

    Reynoso, Estela M.; Hughes, John P.; Moffett, David A.

    2013-04-01

    Radio polarization observations provide essential information on the degree of order and orientation of magnetic fields, which themselves play a key role in the particle acceleration processes that take place in supernova remnants (SNRs). Here we present a radio polarization study of SN 1006, based on combined Very Large Array and Australia Telescope Compact Array observations at 20 cm that resulted in sensitive images with an angular resolution of 10 arcsec. The fractional polarization in the two bright radio and X-ray lobes of the SNR is measured to be 0.17, while in the southeastern sector, where the radio and non-thermal X-ray emission are much weaker, the polarization fraction reaches a value of 0.6 ± 0.2, close to the theoretical limit of 0.7. We interpret this result as evidence of a disordered, turbulent magnetic field in the lobes, where particle acceleration is believed to be efficient, and a highly ordered field in the southeast, where the acceleration efficiency has been shown to be very low. Utilizing the frequency coverage of our observations, an average rotation measure of ~12 rad m-2 is determined from the combined data set, which is then used to obtain the intrinsic direction of the magnetic field vectors. While the orientation of magnetic field vectors across the SNR shell appear to be radial, a large fraction of the magnetic vectors lie parallel to the Galactic plane. Along the highly polarized southeastern rim, the field is aligned tangent to the shock, and therefore also nearly parallel to the Galactic plane. These results strongly suggest that the ambient field surrounding SN 1006 is aligned with this direction (i.e., from northeast to southwest) and that the bright lobes are due to a polar cap geometry. Our study establishes that the most efficient particle acceleration and generation of magnetic turbulence in SN 1006 is attained for shocks in which the magnetic field direction and shock normal are quasi-parallel, while inefficient acceleration and little to no generation of magnetic turbulence are obtained for the quasi-perpendicular case.

  4. FERMI LAT DISCOVERY OF EXTENDED GAMMA-RAY EMISSION IN THE DIRECTION OF SUPERNOVA REMNANT W51C

    International Nuclear Information System (INIS)

    The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant (?104 yr) with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 x 1036 erg s-1 given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral ? mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to n-barHWp?5 x 1051 (D/6 kpc)2 erg cm-3. Electron density constraints from the radio and X-ray bands render it difficult to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays.

  5. Fermi-LAT Discovery of Extended Gamma-Ray Emission in the Direction of Supernova Remnant W51C

    Energy Technology Data Exchange (ETDEWEB)

    Abdo, A.A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Baring, M.G.; /Rice U.; Bastieri, D.; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Blandford, R.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, E.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bouvier, A.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique /Washington U., Seattle /Padua U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /Milan Polytechnic /DAPNIA, Saclay /INFN, Perugia /Perugia U. /NASA, Goddard /NASA, Goddard /CSST, Baltimore /Naval Research Lab, Wash., D.C. /George Mason U. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Sonoma State U. /Stockholm U. /Stockholm U., OKC /ASDC, Frascati /Naval Research Lab, Wash., D.C. /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /UC, Santa Cruz /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Montpellier U. /Bari U. /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Ecole Polytechnique; /more authors..

    2012-03-30

    The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant ({approx}10{sup 4} yr) with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 x 10{sup 36} erg s{sup -1} given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral p mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to {bar n}{sub H} W{sub p} {approx_equal} 5 x 10{sup 51} (D/6 kpc){sup 2} erg cm{sup -3}. Electron density constraints from the radio and X-ray bands render it difficult to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays.

  6. A Search for Supernova-Remnant Masers Toward Unidentified EGRET Sources

    CERN Document Server

    Arzoumanian, Z; Lazio, T J W

    2001-01-01

    Supernova remnants expanding into adjacent molecular clouds are believed to be sites of cosmic ray acceleration and sources of energetic gamma-rays. Under certain environmental conditions, such interactions also give rise to unusual OH masers in which the 1720 MHz satellite line dominates over the more common 1665/7 MHz emission. Motivated by the apparent coincidence of a handful of EGRET sources with OH(1720 MHz) maser-producing supernova remnants, we have carried out a search using the Very Large Array for new OH(1720 MHz) masers within the error regions of 11 unidentified EGRET sources at low Galactic latitude. While a previously known maser associated with an HII region was serendipitously detected, initial results indicate that no new masers were found down to a limiting flux of, typically, 50 mJy. We discuss the implications of this result on the nature of the unidentified Galactic EGRET sources.

  7. A survey of infrared supernova remnants in the Large Magellanic Cloud

    Energy Technology Data Exchange (ETDEWEB)

    Seok, Ji Yeon [Academia Sinica Institute for Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Koo, Bon-Chul [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Onaka, Takashi, E-mail: jyseok@asiaa.sinica.edu.tw [Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2013-12-20

    We present a comprehensive infrared study of supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using near- to mid-infrared images taken by Infrared Array Camera (IRAC; 3.6, 4.5, 5.8, and 8 ?m) and Multiband Imaging Photometer (MIPS; 24 and 70 ?m) onboard the Spitzer Space Telescope. Among the 47 bona fide LMC SNRs, 29 were detected in infrared, giving a high detection rate of 62%. All 29 SNRs show emission at 24 ?m, and 20 out of 29 show emission in one or several IRAC bands. We present their 4.5, 8, 24, and 70 ?m images and a table summarizing their Spitzer fluxes. We find that the LMC SNRs are considerably fainter than the Galactic SNRs, and that, among the LMC SNRs, Type Ia SNRs are significantly fainter than core-collapse SNRs. We conclude that the MIPS emission of essentially all SNRs originates from dust emission, whereas their IRAC emissions originate from ionic/molecular lines, polycyclic aromatic hydrocarbons emission, or synchrotron emission. The infrared fluxes show correlation with radio and X-ray fluxes. For SNRs that have similar morphology in infrared and X-rays, the ratios of 24 to 70 ?m fluxes have good correlation with the electron density of hot plasma. The overall correlation is explained well by the emission from collisionally heated silicate grains of 0.1 ?m size, but for mature SNRs with relatively low gas temperatures, the smaller-sized grain population is favored more. For those that appear different between infrared and X-rays, the emission in the MIPS bands is probably from dust heated by shock radiation.

  8. NEUTRAL PION EMISSION FROM ACCELERATED PROTONS IN THE SUPERNOVA REMNANT W44

    Energy Technology Data Exchange (ETDEWEB)

    Giuliani, A.; Caraveo, P.; Chen, A.; Contessi, T. [INAF-IASF Milano, via E. Bassini 15, 20133 Milano (Italy); Cardillo, M.; Tavani, M.; Costa, E.; Monte, E. Del; Donnarumma, I.; Evangelista, Y.; Feroci, M. [INAF/IASF-Roma,via Del Fosso del Cavaliere 100, 00133 Roma (Italy); Fukui, Y.; Yoshiike, S.; Torii, K. [Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Dubner, G.; Castelletti, G. [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), 1428 Buenos Aires (Argentina); Barbiellini, G. [Dipartimento di Fisica and INFN, Via Valerio 2, I-34127 Trieste (Italy); Bulgarelli, A.; Gianotti, F. [INAF/IASF-Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Cattaneo, P. W. [INFN-Pavia, Via Bassi 6, I-27100 Pavia (Italy); and others

    2011-12-15

    We present the AGILE gamma-ray observations in the energy range 50 MeV-10 GeV of the supernova remnant (SNR) W44, one of the most interesting systems for studying cosmic-ray production. W44 is an intermediate-age SNR ({approx}20, 000 years) and its ejecta expand in a dense medium as shown by a prominent radio shell, nearby molecular clouds, and bright [S II] emitting regions. We extend our gamma-ray analysis to energies substantially lower than previous measurements which could not conclusively establish the nature of the radiation. We find that gamma-ray emission matches remarkably well both the position and shape of the inner SNR shocked plasma. Furthermore, the gamma-ray spectrum shows a prominent peak near 1 GeV with a clear decrement at energies below a few hundreds of MeV as expected from neutral pion decay. Here we demonstrate that (1) hadron-dominated models are consistent with all W44 multiwavelength constraints derived from radio, optical, X-ray, and gamma-ray observations; (2) ad hoc lepton-dominated models fail to explain simultaneously the well-constrained gamma-ray and radio spectra, and require a circumstellar density much larger than the value derived from observations; and (3) the hadron energy spectrum is well described by a power law (with index s = 3.0 {+-} 0.1) and a low-energy cut-off at E{sub c} = 6 {+-} 1 GeV. Direct evidence for pion emission is then established in an SNR for the first time.

  9. DUST PROCESSING IN SUPERNOVA REMNANTS: SPITZER MIPS SPECTRAL ENERGY DISTRIBUTION AND INFRARED SPECTROGRAPH OBSERVATIONS

    International Nuclear Information System (INIS)

    We present Spitzer Multiband Imaging Photometer (MIPS) spectral energy distribution (SED) and Infrared Spectrograph (IRS) observations of 14 Galactic supernova remnants (SNRs) previously identified in the GLIMPSE survey. We find evidence for SNR/molecular cloud interaction through detection of [O I] emission, ionic lines, and emission from molecular hydrogen. Through blackbody fitting of the MIPS SEDs we find the large grains to be warm, 29-66 K. The dust emission is modeled using the DUSTEM code and a three-component dust model composed of populations of big grains (BGs), very small grains (VSGs), and polycyclic aromatic hydrocarbons. We find the dust to be moderately heated, typically by 30-100 times the interstellar radiation field. The source of the radiation is likely hydrogen recombination, where the excitation of hydrogen occurred in the shock front. The ratio of VSGs to BGs is found for most of the molecular interacting SNRs to be higher than that found in the plane of the Milky Way, typically by a factor of 2-3. We suggest that dust shattering is responsible for the relative overabundance of small grains, in agreement with the prediction from dust destruction models. However, two of the SNRs are best fitted with a very low abundance of carbon grains to silicate grains and with a very high radiation field. A likely reason for the low abundance of small carbon grains is sputtering. We find evidence for silicate emission at 20 ?m in their SEDs, indicating that they are young SNRs based on the strong radiation field necessary to reproduce the observed SEDs.

  10. A survey of infrared supernova remnants in the Large Magellanic Cloud

    International Nuclear Information System (INIS)

    We present a comprehensive infrared study of supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using near- to mid-infrared images taken by Infrared Array Camera (IRAC; 3.6, 4.5, 5.8, and 8 ?m) and Multiband Imaging Photometer (MIPS; 24 and 70 ?m) onboard the Spitzer Space Telescope. Among the 47 bona fide LMC SNRs, 29 were detected in infrared, giving a high detection rate of 62%. All 29 SNRs show emission at 24 ?m, and 20 out of 29 show emission in one or several IRAC bands. We present their 4.5, 8, 24, and 70 ?m images and a table summarizing their Spitzer fluxes. We find that the LMC SNRs are considerably fainter than the Galactic SNRs, and that, among the LMC SNRs, Type Ia SNRs are significantly fainter than core-collapse SNRs. We conclude that the MIPS emission of essentially all SNRs originates from dust emission, whereas their IRAC emissions originate from ionic/molecular lines, polycyclic aromatic hydrocarbons emission, or synchrotron emission. The infrared fluxes show correlation with radio and X-ray fluxes. For SNRs that have similar morphology in infrared and X-rays, the ratios of 24 to 70 ?m fluxes have good correlation with the electron density of hot plasma. The overall correlation is explained well by the emission from collisionally heated silicate grains of 0.1 ?m size, but for mature SNRs with relatively low gas temperatures, the smaller-sized grain population is favored more. For those that appear different between infrared and X-rays, the emission in the MIPS bands is probably from dust heated by shock radiation.

  11. Dust Processing in Supernova Remnants: Spitzer MIPS SED and IRS Observations

    Science.gov (United States)

    Hewitt, John W.; Petre, Robert; Katsuda Satoru; Andersen, M.; Rho, J.; Reach, W. T.; Bernard, J. P.

    2011-01-01

    We present Spitzer MIPS SED and IRS observations of 14 Galactic Supernova Remnants previously identified in the GLIMPSE survey. We find evidence for SNR/molecular cloud interaction through detection of [OI] emission, ionic lines, and emission from molecular hydrogen. Through black-body fitting of the MIPS SEDs we find the large grains to be warm, 29-66 K. The dust emission is modeled using the DUSTEM code and a three component dust model composed of populations of big grains, very small grains, and polycyclic aromatic hydrocarbons. We find the dust to be moderately heated, typically by 30-100 times the interstellar radiation field. The source of the radiation is likely hydrogen recombination, where the excitation of hydrogen occurred in the shock front. The ratio of very small grains to big grains is found for most of the molecular interacting SNRs to be higher than that found in the plane of the Milky Way, typically by a factor of 2--3. We suggest that dust shattering is responsible for the relative over-abundance of small grains, in agreement with prediction from dust destruction models. However, two of the SNRs are best fit with a very low abundance of carbon grains to silicate grains and with a very high radiation field. A likely reason for the low abundance of small carbon grains is sputtering. We find evidence for silicate emission at 20 $\\mu$m in their SEDs, indicating that they are young SNRs based on the strong radiation field necessary to reproduce the observed SEDs.

  12. Unraveling the Origin of Overionized Plasma in the Galactic Supernova Remnant W49B

    OpenAIRE

    Lopez, Laura A.; Pearson, Sarah; Ramirez-Ruiz, Enrico; Castro, Daniel; Yamaguchi, Hiroya; Slane, Patrick O; Smith, Randall K

    2013-01-01

    Recent observations have shown several supernova remnants (SNRs) have overionized plasmas, those where ions are stripped of more electrons than they would be if in equilibrium with the electron temperature. Rapid electron cooling is necessary to produce this situation, yet the physical origin of that cooling remains uncertain. To assess the cooling scenario responsible for overionization, in this paper, we identify and map the overionized plasma in the Galactic SNR W49B base...

  13. The Bubble-like Interior of the Core-Collapse Supernova Remnant Cassiopeia A

    OpenAIRE

    Milisavljevic, Dan; Fesen, Robert A.

    2015-01-01

    The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of how these catastrophic explosions proceed remain uncertain due, in part, to limited observational constraints on various processes that can introduce asymmetries deep inside the star. Here we present near-infrared observations of the young Milky Way supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimen...

  14. CANGAROO-III Search for Gamma Rays from Kepler's Supernova Remnant

    CERN Document Server

    Enomoto, R; Yoshida, T; Tanimori, T

    2008-01-01

    Kepler's supernova, discovered in October 1604, produced a remnant that has been well studied observationally in the radio, infrared, optical, and X-ray bands, and theoretically. Some models have predicted a TeV gamma-ray flux that is detectable with current Imaging Cherenkov Atmospheric Telescopes. We report on observations carried out in 2005 April with the CANGAROO-III telescope. No statistically significant excess was observed, and limitations on the allowed parameter range in the model are discussed.

  15. Analytical and Monte Carlo results for the surface-brightness diameter relationship in supernova remnants

    OpenAIRE

    ZANINETTI, Lorenzo

    2012-01-01

    The surface brightness diameter relationship for supernovae remnants (SNRs) is explained by adopting a model of direct conversion of the flux of kinetic energy into synchrotron luminosity. Two laws of motion are adopted, a power law model for the radius-time relationship, and a model which uses the thin layer approximation. The fluctuations on the log-log surface diameter relationship are modeled by a Monte Carlo simulation. In this model a new probability density function f...

  16. A progenitor binary and an ejected mass donor remnant of faint type Ia supernovae

    OpenAIRE

    Geier, S.; Marsh, T. R.; Wang, B; Dunlap, B.; Barlow, B. N; Schaffenroth, V; Chen, X.; Irrgang, A.; Maxted, P. F. L; Ziegerer, E.; Kupfer, T; B. Miszalski; Heber, U.; Han, Z; Shporer, A.

    2013-01-01

    Type Ia supernovae (SN Ia) are the most important standard candles for measuring the expansion history of the universe. The thermonuclear explosion of a white dwarf can explain their observed properties, but neither the progenitor systems nor any stellar remnants have been conclusively identified. Underluminous SN Ia have been proposed to originate from a so-called double-detonation of a white dwarf. After a critical amount of helium is deposited on the surface through accre...

  17. The Interaction of Supernova Remnant G357.7+0.3 with the Interstellar Medium

    OpenAIRE

    Phillips, J. P.; Marquez-Lugo, R. A.

    2010-01-01

    The supernova remnant (SNR) G357.7+0.3 appears to have caused considerable shredding of the local interstellar medium (ISM), leading to the formation of multiple cloud fragments having bright rims and cometary structures. We investigate five of these regions using mid-infrared (MIR) imaging and photometry deriving from the Spitzer Space Telescope (SST), as well as photometry deriving from the 2MASS near-infrared all sky survey, the Mid-Course Science Experiment (MSX), and the Multiband Imagin...

  18. A kinetic approach to cosmic ray induced streaming instability at supernova shocks

    CERN Document Server

    Amato, Elena

    2008-01-01

    We show here that a purely kinetic approach to the excitation of waves by cosmic rays in the vicinity of a shock front leads to predict the appearance of a non-alfv\\'enic fastly growing mode which has the same dispersion relation as that previously found by \\cite{bell04} by treating the plasma in the MHD approximation. The kinetic approach allows us to investigate the dependence of the dispersion relation of these waves on the microphysics of the current which compensates the cosmic ray flow. We also show that a resonant and a non-resonant mode may appear at the same time and one of the two may become dominant on the other depending on the conditions in the acceleration region. We discuss the role of the unstable modes for magnetic field amplification and particle acceleration in supernova remnants at different stages of the remnant evolution.

  19. Isothermal self-similar blast wave theory of supernova remnants driven by relativistic gas pressure

    International Nuclear Information System (INIS)

    The spherically symmetric, self-similar flow behind a blast wave from a point explosion in a medium whose density varies with distance as rsup(-?) is investigated with the assumption that the flow is both isothermal and contains a relativistic component of pressure. A self-similar solution is shown to exist only if both the blast wave speed, usub(s), and the local sound speed, w, are constant. If ? [equivalent to ?(1-w2/c2)] lies in 1 >?>0, there exists a critical point in the radial distance-flow velocity plane. To be physically acceptable, the solution must pass through the origin and through the critical point and then through to the blast front; solution branches between these points exist, although a proper connection at the critical point has not been demonstrated. It is concluded that isothermal self-similar blast waves do not provide a valid model for a supernova remnant driven by a relativistic gas pressure. Since the validity of the adiabatic blast wave models has elsewhere been shown to be questionable, it is doubtful whether the self-similar property can be involved at all in the case of supernova remnants. This raises serious questions of interpretation of quantities deduced for supernova remnants on the basis of the use of self-similar models. (Auth.)

  20. Diffuse neutrinos from extragalactic supernova remnants: Dominating the 100 TeV IceCube flux

    Directory of Open Access Journals (Sweden)

    Sovan Chakraborty

    2015-05-01

    Full Text Available IceCube has measured a diffuse astrophysical flux of TeV–PeV neutrinos. The most plausible sources are unique high energy cosmic ray accelerators like hypernova remnants (HNRs and remnants from gamma ray bursts in star-burst galaxies, which can produce primary cosmic rays with the required energies and abundance. In this case, however, ordinary supernova remnants (SNRs, which are far more abundant than HNRs, produce a comparable or larger neutrino flux in the ranges up to 100–150 TeV energies, implying a spectral break in the IceCube signal around these energies. The SNRs contribution in the diffuse flux up to these hundred TeV energies provides a natural baseline and then constrains the expected PeV flux.

  1. Dust-to-gas ratios in the Kepler supernova remnant

    OpenAIRE

    Contini, M

    2004-01-01

    A new method to evaluate the dust-to-gas ratios in the Kepler SNR is presented. Dust emission in the infrared and bremsstrahlung are calculated consistently, considering that dust grains are collisionally heated by the gas throughout the front and downstream of both the expanding and the reverse shocks. The dust-to-gas ratios are determined by the ratio of the dust emission bump and bremsstrahlung in the infrared. A maximum dust mass < 0.16 Mo is calculated.

  2. Extended supernova shock breakout signals from inflated stellar envelopes

    CERN Document Server

    Moriya, Takashi J; Langer, Norbert

    2015-01-01

    Stars close to the Eddington luminosity can have large low-density inflated envelopes. We show that the rise times of shock breakout signals from supernovae can be extended significantly if supernova progenitors have an inflated stellar envelope. If the shock breakout occurs in such inflated envelopes, the shock breakout signals diffuse in them, and their rise time can be significantly extended. Then, the rise times of the shock breakout signals are dominated by the diffusion time in the inflated envelope rather than the light-crossing time of the progenitors. We show that our inflated Wolf-Rayet star models whose radii are of the order of the solar radius can have shock breakout signals which are longer than ~100 sec. The existence of inflated envelopes in Wolf-Rayet supernova progenitors may be related to the mysterious long shock breakout signal observed in Type Ib SN 2008D. Extended shock breakout signals may provide evidence for the existence of inflated stellar envelopes and can be used to constrain the...

  3. X-RAY STRIPES IN TYCHO'S SUPERNOVA REMNANT: SYNCHROTRON FOOTPRINTS OF A NONLINEAR COSMIC-RAY-DRIVEN INSTABILITY

    International Nuclear Information System (INIS)

    High-resolution Chandra observations of Tycho's supernova remnant (SNR) have revealed several sets of quasi-steady, high-emissivity, nearly parallel X-ray stripes in some localized regions of the SNR. These stripes are most likely the result of cosmic-ray (CR) generated magnetic turbulence at the SNR blast wave. However, for the amazingly regular pattern of these stripes to appear, simultaneous action of a number of shock-plasma phenomena is required, which is not predicted by most models of magnetic field amplification. A consistent explanation of these stripes yields information on the complex nonlinear plasma processes connecting efficient CR acceleration and magnetic field fluctuations in strong collisionless shocks. The nonlinear diffusive shock acceleration (NL-DSA) model described here, which includes magnetic field amplification from a CR-current-driven instability, does predict stripes consistent with the synchrotron observations of Tycho's SNR. We argue that the local ambient mean magnetic field geometry determines the orientation of the stripes and therefore it can be reconstructed with the high-resolution X-ray imaging. The estimated maximum energy of the CR protons responsible for the stripes is ?1015 eV. Furthermore, the model predicts that a specific X-ray polarization pattern, with a polarized fraction ?50%, accompanies the stripes, which can be tested with future X-ray polarimeter missions.

  4. Fermi-LAT Observation of Supernova Remnant S147

    Energy Technology Data Exchange (ETDEWEB)

    Katsuta, J.; Uchiyama, Y.; Tanaka, T.; /SLAC /KIPAC, Menlo Park; Tajima, H.; /SLAC /KIPAC, Menlo Park /Nagoya U., Solar-Terrestrial Environ. Lab.; Bechtol, K.; Funk, S.; Lande, J.; /SLAC /KIPAC, Menlo Park; Ballet, J.; /AIM, Saclay; Hanabata, Y.; /Hiroshima U.; Lemoine-Goumard, M.; /CENBG, Gradignan; Takahashi, T.; /JAXA, Sagamihara

    2012-08-17

    We present an analysis of gamma-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region around SNR S147 (G180.0-1.7). A spatially extended gamma-ray source detected in an energy range of 0.2-10 GeV is found to coincide with SNR S147. We confirm its spatial extension at >5{sigma} confidence level. The gamma-ray flux is (3.8 {+-} 0.6) x 10{sup -8} photons cm{sup -2} s{sup -1}, corresponding to a luminosity of 1.3 x 10{sup 34} (d/1.3 kpc){sup 2} erg s{sup -1} in this energy range. The gamma-ray emission exhibits a possible spatial correlation with prominent H{alpha} filaments of S147. There is no indication that the gamma-ray emission comes from the associated pulsar PSR J0538+2817. The gamma-ray spectrum integrated over the remnant is likely dominated by the decay of neutral {pi} mesons produced through the proton-proton collisions in the filaments. Reacceleration of pre-existing CRs and subsequent adiabatic compression in the filaments is sufficient to provide the required energy density of high-energy protons.

  5. Chandra and XMM-Newton Study of the Supernova Remnant Kes 73 Hosting the Magnetar 1E 1841-045

    Science.gov (United States)

    Kumar, Harsha S.; Safi-Harb, Samar; Slane, Patrick O.; Gotthelf, E. V.

    2014-01-01

    We present a Chandra and XMM-Newton study of the supernova remnant (SNR) Kes 73 hosting the anomalous X-ray pulsar 1E 1841-045. The Chandra image reveals clumpy structures across the remnant with enhanced emission along the western rim. The X-ray emission fills the radio shell and spatially correlates with the infrared image. The global X-ray spectrum is described by a two-component thermal model with a column density N H = 2.6^{+0.4}_{-0.3}\\times1022 cm-2 and a total luminosity of LX = 3.3^{+0.7}_{-0.5}\\times1037 erg s-1 (0.5-10 keV, at an assumed distance of 8.5 kpc). The soft component is characterized by a temperature kTs = 0.5^{+0.1}_{-0.2} keV, a high ionization timescale, and enhanced Si and S abundances, suggesting emission that is dominated by shocked ejecta. The hard component has a temperature kTh = 1.6^{+0.8}_{-0.7} keV, a relatively low ionization timescale, and mostly solar abundances suggesting emission that is dominated by interstellar/circumstellar shocked material. A spatially resolved spectroscopy study reveals no significant variations in the spectral properties. We infer an SNR age ranging between 750 yr and 2100 yr, an explosion energy of 3.0^{+2.8}_{-1.8}\\times1050 erg and a shock velocity of (1.2 ± 0.3)×103 km s-1 (under the Sedov phase assumption). We also discuss the possible scenario for Kes 73 expanding into the late red-supergiant wind phase of its massive progenitor. Comparing the inferred metal abundances to core-collapse nucleosynthesis model yields, we estimate a progenitor mass gsim20 M ?, adding a candidate to the growing list of highly magnetized neutron stars proposed to be associated with very massive progenitors.

  6. A DETAILED X-RAY INVESTIGATION OF PSR J2021+4026 AND THE ?-CYGNI SUPERNOVA REMNANT

    Energy Technology Data Exchange (ETDEWEB)

    Hui, C. Y.; Seo, K. A. [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of); Lin, L. C. C.; Huang, R. H. H.; Wu, J. H. K.; Kong, A. K. H. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China); Hu, C. P.; Chou, Y. [Graduate Institute of Astronomy, National Central University, Jhongli 32001, Taiwan (China); Trepl, L. [Astrophysikalisches Institut und Universitäts-Sternwarte, Universität Jena, Schillergäßchen 2-3, D-07745 Jena (Germany); Takata, J.; Wang, Y.; Cheng, K. S., E-mail: cyhui@cnu.ac.kr [Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong)

    2015-01-20

    We have investigated the field around the radio-quiet ?-ray pulsar, PSR J2021+4026, with a ?140 ks XMM-Newton observation and ?56 ks archival Chandra data. Through analyzing the pulsed spectrum, we show that the X-ray pulsation is purely thermal in nature, which suggests that the pulsation originated from a hot polar cap with T ? 3 × 10{sup 6} K on the surface of a rotating neutron star. On the other hand, the power-law (PL) component that dominates the pulsar emission in the hard band is originated from off-pulse phases, which possibly comes from a pulsar wind nebula. In re-analyzing the Chandra data, we have confirmed the presence of a bow-shock nebula that extends from the pulsar to the west by ?10 arcsec. The orientation of this nebular feature suggests that the pulsar is probably moving eastward, which is consistent with the speculated proper motion by extrapolating from the nominal geometrical center of the supernova remnant (SNR) G78.2+2.1 to the current pulsar position. For G78.2+2.1, our deep XMM-Newton observation also enables a study of the central region and part of the southeastern region with superior photon statistics. The column absorption derived for the SNR is comparable to that for PSR J2021+4026, which supports their association. The remnant emission in both of the examined regions is in a non-equilibrium ionization state. Also, the elapsed time of both regions after shock-heating is apparently shorter than the Sedov age of G78.2+2.1. This might suggest that the reverse shock has reached the center not long ago. Apart from PSR J2021+4026 and G78.2+2.1, we have also serendipitously detected an X-ray flash-like event, XMM J202154.7+402855, from this XMM-Newton observation.

  7. A DETAILED X-RAY INVESTIGATION OF PSR J2021+4026 AND THE ?-CYGNI SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    We have investigated the field around the radio-quiet ?-ray pulsar, PSR J2021+4026, with a ?140 ks XMM-Newton observation and ?56 ks archival Chandra data. Through analyzing the pulsed spectrum, we show that the X-ray pulsation is purely thermal in nature, which suggests that the pulsation originated from a hot polar cap with T ? 3 × 106 K on the surface of a rotating neutron star. On the other hand, the power-law (PL) component that dominates the pulsar emission in the hard band is originated from off-pulse phases, which possibly comes from a pulsar wind nebula. In re-analyzing the Chandra data, we have confirmed the presence of a bow-shock nebula that extends from the pulsar to the west by ?10 arcsec. The orientation of this nebular feature suggests that the pulsar is probably moving eastward, which is consistent with the speculated proper motion by extrapolating from the nominal geometrical center of the supernova remnant (SNR) G78.2+2.1 to the current pulsar position. For G78.2+2.1, our deep XMM-Newton observation also enables a study of the central region and part of the southeastern region with superior photon statistics. The column absorption derived for the SNR is comparable to that for PSR J2021+4026, which supports their association. The remnant emission in both of the examined regions is in a non-equilibrium ionization state. Also, the elapsed time of both regions after shock-heating is apparently shorter than the Sedov age of G78.2+2.1. This might suggest that the reverse shock has reached the center not long ago. Apart from PSR J2021+4026 and G78.2+2.1, we have also serendipitously detected an X-ray flash-like event, XMM J202154.7+402855, from this XMM-Newton observation

  8. A Detailed X-Ray Investigation of PSR J2021+4026 and the ?-Cygni Supernova Remnant

    Science.gov (United States)

    Hui, C. Y.; Seo, K. A.; Lin, L. C. C.; Huang, R. H. H.; Hu, C. P.; Wu, J. H. K.; Trepl, L.; Takata, J.; Wang, Y.; Chou, Y.; Cheng, K. S.; Kong, A. K. H.

    2015-01-01

    We have investigated the field around the radio-quiet ?-ray pulsar, PSR J2021+4026, with a ~140 ks XMM-Newton observation and ~56 ks archival Chandra data. Through analyzing the pulsed spectrum, we show that the X-ray pulsation is purely thermal in nature, which suggests that the pulsation originated from a hot polar cap with T ~ 3 × 106 K on the surface of a rotating neutron star. On the other hand, the power-law (PL) component that dominates the pulsar emission in the hard band is originated from off-pulse phases, which possibly comes from a pulsar wind nebula. In re-analyzing the Chandra data, we have confirmed the presence of a bow-shock nebula that extends from the pulsar to the west by ~10 arcsec. The orientation of this nebular feature suggests that the pulsar is probably moving eastward, which is consistent with the speculated proper motion by extrapolating from the nominal geometrical center of the supernova remnant (SNR) G78.2+2.1 to the current pulsar position. For G78.2+2.1, our deep XMM-Newton observation also enables a study of the central region and part of the southeastern region with superior photon statistics. The column absorption derived for the SNR is comparable to that for PSR J2021+4026, which supports their association. The remnant emission in both of the examined regions is in a non-equilibrium ionization state. Also, the elapsed time of both regions after shock-heating is apparently shorter than the Sedov age of G78.2+2.1. This might suggest that the reverse shock has reached the center not long ago. Apart from PSR J2021+4026 and G78.2+2.1, we have also serendipitously detected an X-ray flash-like event, XMM J202154.7+402855, from this XMM-Newton observation.

  9. Chandra and XMM-Newton study of the supernova remnant Kes 73 hosting the magnetar 1E 1841-045

    International Nuclear Information System (INIS)

    We present a Chandra and XMM-Newton study of the supernova remnant (SNR) Kes 73 hosting the anomalous X-ray pulsar 1E 1841–045. The Chandra image reveals clumpy structures across the remnant with enhanced emission along the western rim. The X-ray emission fills the radio shell and spatially correlates with the infrared image. The global X-ray spectrum is described by a two-component thermal model with a column density N H = 2.6?0.3+0.4×1022 cm–2 and a total luminosity of LX = 3.3?0.5+0.7×1037 erg s–1 (0.5-10 keV, at an assumed distance of 8.5 kpc). The soft component is characterized by a temperature kTs = 0.5?0.2+0.1 keV, a high ionization timescale, and enhanced Si and S abundances, suggesting emission that is dominated by shocked ejecta. The hard component has a temperature kTh = 1.6?0.7+0.8 keV, a relatively low ionization timescale, and mostly solar abundances suggesting emission that is dominated by interstellar/circumstellar shocked material. A spatially resolved spectroscopy study reveals no significant variations in the spectral properties. We infer an SNR age ranging between 750 yr and 2100 yr, an explosion energy of 3.0?1.8+2.8×1050 erg and a shock velocity of (1.2 ± 0.3)×103 km s–1 (under the Sedov phase assumption). We also discuss the possible scenario for Kes 73 expanding into the late red-supergiant wind phase of its massive progenitor. Comparing the inferred metal abundances to core-collapse nucleosynthesis model yields, we estimate a progenitor mass ?20 M ?, adding a candidate to the growing list of highly magnetized neutron stars proposed to be associated with very massive progenitors.

  10. Failed supernovae explain the compact remnant mass function

    International Nuclear Information System (INIS)

    One explanation for the absence of higher mass red supergiants (16.5 M ? ? M ? 25 M ?) as the progenitors of Type IIP supernovae (SNe) is that they die in failed SNe creating black holes. Simulations show that such failed SNe still eject their hydrogen envelopes in a weak transient, leaving a black hole with the mass of the star's helium core (5-8 M ?). Here we show that this naturally explains the typical masses of observed black holes and the gap between neutron star and black hole masses without any fine-tuning of stellar mass loss, binary mass transfer, or the SN mechanism, beyond having it fail in a mass range where many progenitor models have density structures that make the explosions more likely to fail. There is no difficulty including this ?20% population of failed SNe in any accounting of SN types over the progenitor mass function. And, other than patience, there is no observational barrier to either detecting these black hole formation events or limiting their rates to be well below this prediction.

  11. The Cassiopeia A Supernova Remnant in X-Rays

    Directory of Open Access Journals (Sweden)

    J. Martin Laming

    2007-01-01

    Full Text Available Revisamos el progreso alcanzado hasta la fecha en el an alisis del proyecto de observaci on \\1 million second Chandra Very Large Project (VLP" en el remanente de supernova Cassiopeia A. Exploramos la posibilidad de que Cas A explotase en un \\burbuja". El viento de supergigante roja dentro del cual se expande la onda de choque de la explosi on, fue posiblemente seguido por un per odo corto de viento tenue y r apido de Wolf-Rayet previo a la explosi on, dejando una regi on de baja densidad en el centro, rodeado por el viento de supergigante roja de mayor densidad. Tambi en revisamos el estado actual de las observaciones de rayos X duros y la determinaci on de la masa de 44Ti que se piensa que se eyect o en la explosi on, con miras a las restricciones que esto pone a la explosi on en si misma, y d onde se puedan encontrar los productos del decaimiento del 44Ti

  12. An atlas of supernova remnant candidates in Messier 31

    Science.gov (United States)

    Braun, R.; Walterbos, R. A. M.

    1993-01-01

    Narrow-band CCD imagery in H-alpha and forbidden SII of a large fraction of the spiral arms in the Northeast half of Messier 31 has been used to isolate a sample of 52 'forbidden-line' SNR candidates for which the integrated ratio forbidden SII:H-alpha is greater than 0.5. An atlas of images in these emission lines, red optical continuum, and 1465 MHz radio continuum is presented, together with the tabulated integral properties of these sources. Assessing the completeness of the sample yields a crude estimate of the massive supernova rate (due to stars more massive than 7 solar masses) of 1 in 80 yr. The range of measured luminosities in both H-alpha and radio continuum is fully consistent with those found for 'forbidden-line' SNR in Messier 33, the LMC, and the Galaxy. With the inclusion of our candidates the number of extragalactic SNRs (with well-known distances) now exceeds the number of known galactic SNRs.

  13. Photoionization of galactic halo gas by old supernova remnants

    Directory of Open Access Journals (Sweden)

    Jonathan D. Slavin

    2000-01-01

    Full Text Available Presentamos nuevos c alculos de la contribuci on del enfriamiento del gas caliente en remanentes de supernova (SNRs viejos a la fotoionizaci on del gas ionizado tibio en nuestra Galaxia. Mostramos que la emisi on de SNRs que se enfr an es de radiaci on suave ( E 20 eV, de manera que hay una alta e ciencia de conversi on de la energ a de la explosi on en fotones ionizantes, 30 { 40%. Dada esta alta e - ciencia, las SNRs pueden ser responsables de hasta un 50% de la medida de emisi on observada en el medio ionizado tibio de nuestra Galaxia. Los ujos obtenidos son tambi en consistentes con el fondo de rayos-X suaves a altas latitudes y las observaciones de rayos-X suaves en galaxias externas. Encontramos que nuestro modelo puede explicar la ionizaci on de las nubes observadas en la direcci on de la estrella del halo HD 93521, donde no hay estrellas O cercanas a la l nea de visi on.

  14. Multi-frequency study of the newly confirmed supernova remnant MCSNR J0512-6707 in the Large Magellanic Cloud

    CERN Document Server

    Kavanagh, P J; Bozzetto, L M; Points, S D; Filipovic, M D; Maggi, P; Haberl, F; Crawford, E J

    2015-01-01

    We present a study of the supernova remnant MCSNR J0512-6707 in the Large Magellanic Cloud. We used new data from XMM-Newton to characterise the X-ray emission and data from the Australian Telescope Compact Array, the Magellanic Cloud Emission Line Survey, and Spitzer to gain a picture of the environment into which the remnant is expanding. We performed a morphological study, determined radio polarisation and magnetic field orientation, and performed an X-ray spectral analysis. We estimated the its size to be 24.9 (\\pm1.5) x 21.9 (\\pm1.5) pc, with the major axis rotated ~29 deg east of north. Radio polarisation at 3 cm and 6 cm indicate a higher degree of polarisation in the NW and SE tangentially oriented to the SNR shock front, indicative of an SNR compressing the magnetic field threading the interstellar medium. The X-ray spectrum is unusual as it requires a soft (~0.2 keV) CIE thermal plasma of interstellar medium abundance, in addition to a harder component. Using our results and the Sedov dynamical mode...

  15. The Detection of Far Ultraviolet Line Emission from Balmer-Dominated Supernova Remnants in the Large Magellanic Cloud

    CERN Document Server

    Ghavamian, Parviz; Sankrit, Ravi; Hughes, John P; Raymond, John C

    2007-01-01

    We present the first far ultraviolet (FUV) spectra of the four known Balmer-dominated supernova remnants (SNRs) in the Large Magellanic Cloud, acquired with the Far Ultraviolet Spectroscopic Explorer. The remnants DEM L 71 (0505-67.9), 0509-67.5, 0519-69.0 and 0548-70.4 are all in the non-radiative stages of evolution and exhibit expansion speeds ranging from ~ 500 km/s to ~ 5000 km/s. We have detected broad emission lines of Ly beta, Ly gamma, C III and O VI in DEM L 71 (V(FWHM) ~ 1000 km/s) and have detected broad Ly beta and O VI emission in 0519-69.0, (V(FWHM) ~ 3000 km/s). In addition, broad Ly beta emission (V(FWHM) ~ 3700 km/s) has been observed in 0509-67.5, the first detection of broad line emission from this SNR. No emission was detected in our FUSE spectrum of 0548-70.4, allowing us to place only upper limits on the FUV line fluxes. The spectra of these SNRs are unaffected by postshock cooling, and provide valuable probes of collisionless heating efficiency in high Mach number shocks. We have used ...

  16. Multi-frequency study of the newly confirmed supernova remnant MCSNR J0512-6707 in the Large Magellanic Cloud

    Science.gov (United States)

    Kavanagh, P. J.; Sasaki, M.; Bozzetto, L. M.; Points, S. D.; Filipovi?, M. D.; Maggi, P.; Haberl, F.; Crawford, E. J.

    2015-11-01

    Aims: We present a multi-frequency study of the supernova remnant MCSNR J0512-6707 in the Large Magellanic Cloud. Methods: We used new data from XMM-Newton to characterise the X-ray emission and data from the Australian Telescope Compact Array, the Magellanic Cloud Emission Line Survey, and Spitzer to gain a picture of the environment into which the remnant is expanding. We performed a morphological study, determined radio polarisation and magnetic field orientation, and performed an X-ray spectral analysis. Results: We estimated the remnant's size to be 24.9 ( ± 1.5) × 21.9 ( ± 1.5) pc, with the major axis rotated ~29° east of north. Radio polarisation images at 3 cm and 6 cm indicate a higher degree of polarisation in the northwest and southeast tangentially oriented to the SNR shock front, indicative of an SNR compressing the magnetic field threading the interstellar medium. The X-ray spectrum is unusual as it requires a soft (~0.2 keV) collisional ionisation equilibrium thermal plasma of interstellar medium abundance, in addition to a harder component. Using our fit results and the Sedov dynamical model, we showed that the thermal emission is not consistent with a Sedov remnant. We suggested that the thermal X-rays can be explained by MCSNR J0512-6707 having initially evolved into a wind-blown cavity and is now interacting with the surrounding dense shell. The origin of the hard component remains unclear. We could not determine the supernova type from the X-ray spectrum. Indirect evidence for the type is found in the study of the local stellar population and star formation history in the literature, which suggests a core-collapse origin. Conclusions: MCSNR J0512-6707 likely resulted from the core-collapse of high mass progenitor which carved a low density cavity into its surrounding medium, with the soft X-rays resulting from the impact of the blast wave with the surrounding shell. The unusual hard X-ray component requires deeper and higher spatial resolution radio and X-ray observations to confirm its origin. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

  17. Fermi-Lat and WMAP Observations of the Puppis a Supernova Remnant

    Science.gov (United States)

    Hewitt, John William; Grondin, M. H.; Lemoine-Goumard, M.; Reposeur, T.; Ballet, J.; Tanaka, T.

    2012-01-01

    We report the detection of GeV gamma-ray emission from the supernova remnant Puppis A with the Fermi Gamma-Ray Space Telescope. Puppis A is among the faintest supernova remnants yet detected at GeV energies, with a luminosity of only 2.7×10(exp 34) (D/2.2 kpc)(exp 2) erg s(exp -1) between 1 and 100 GeV. The gamma-ray emission from the remnant is spatially extended, with a morphology matching that of the radio and X-ray emission, and is well described by a simple power law with an index of 2.1. We attempt to model the broadband spectral energy distribution, from radio to gamma-rays, using standard nonthermal emission mechanisms. To constrain the relativistic electron population we use 7 years of WMAP data to extend the radio spectrum up to 93 GHz. Both leptonic and hadronic dominated models can reproduce the nonthermal spectral energy distribution, requiring a total content of cosmic ray (CR) electrons and protons accelerated in Puppis A of at least WCR is approx. (1 - 5)×10 (exp 49) erg.

  18. Four new X-ray-selected supernova remnants in the Large Magellanic Cloud

    Science.gov (United States)

    Maggi, P.; Haberl, F.; Kavanagh, P. J.; Points, S. D.; Dickel, J.; Bozzetto, L. M.; Sasaki, M.; Chu, Y.-H.; Gruendl, R. A.; Filipovi?, M. D.; Pietsch, W.

    2014-01-01

    Aims: We present a detailed multi-wavelength study of four new supernova remnants (SNRs) in the Large Magellanic Cloud (LMC). The objects were identified as SNR candidates in X-ray observations performed during the survey of the LMC with XMM-Newton. Methods: Data obained with XMM-Newton are used to investigate the morphological and spectral features of the remnants in X-rays. We measure the plasma conditions, look for supernova (SN) ejecta emission, and constrain some of the SNR properties (e.g. age and ambient density). We supplement the X-ray data with optical, infrared, and radio-continuum archival observations, which allow us to understand the conditions resulting in the current appearance of the remnants. Based on the spatially-resolved star formation history (SFH) of the LMC together with the X-ray spectra, we attempt to type the supernovae that created the remnants. Results: We confirm all four objects as SNRs, to which we assign the names MCSNR J0508-6830, MCSNR J0511-6759, MCSNR J0514-6840, and MCSNR J0517-6759. In the first two remnants, an X-ray bright plasma is surrounded by very faint [S ii] emission. The emission from the central plasma is dominated by Fe L-shell lines, and the derived iron abundance is greatly in excess of solar. This establishes their type Ia (i.e. thermonuclear) SN origin. They appear to be more evolved versions of other Magellanic Cloud iron-rich SNRs which are centrally-peaked in X-rays. From the two other remnants (MCSNR J0514-6840 and MCSNR J0517-6759), we do not see ejecta emission. At all wavelengths at which they are detected, the local environment plays a key role in their observational appearance. We present evidence that MCSNR J0517-6759 is close to and interacting with a molecular cloud, suggesting a massive progenitor. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

  19. An X-ray View of the Zoo of Compact Objects and Associated Supernova Remnants

    Science.gov (United States)

    Safi-Harb, Samar

    2015-08-01

    Core-collapse explosions of massive stars leave behind some of the most exotic compact objects in the Universe. These include: rotation-powered pulsars like the Crab, powering pulsar wind nebulae (PWNe) observed across the electromagnetic spectrum; highly magnetized neutron stars ("magnetars") shining or bursting at high-energies; and X-ray emitting “Central Compact Objects” (CCOs) with intrinsic properties and emission mechanism that remain largely unknown. I will highlight this observed diversity of compact stellar remnants from an X-ray perspective, and address the connection between their properties and those of their hosting supernova remnants (SNRs). In particular I will highlight topics related to their formation and evolution, including: 1) which supernovae make magnetars and the shell-less PWNe?, 2) what can we learn from the apparent age discrepancy between SNRs and their associated pulsars? I will conclude with prospects for observations of SNRs with the upcoming ASTRO-H X-ray mission. The unprecedented spectral resolution on board of ASTRO-H’s micro-calorimeter will particularly open a new discovery window for supernova progenitors' science.

  20. A study of galactic supernova remnants, based on Molonglo-Parkes observational data

    International Nuclear Information System (INIS)

    Observations with the Molonglo and Parkes radio telescopes have recently produced improved radio frequency data for the southern galactic supernova remnants (SNRs). These observations have now been used to investigate the general evolutionary properties of SNRs - the first such large-scale analysis based on a near-homogeneous data set. Empirical relationships are derived which describe in general terms the expansion of SNRs, at least during the adiabatic phase of their evolution. An improved SNR distance scale is established, based largely on Parkes HI absorption measurements, and the resulting relationship between surface brightness and linear diameter for galactic SNRs is found to be compatible with that determined for the Magellanic Cloud SNRs, contrary to earlier conclusions. Completeness in the catalogue down to a uniform level of surace brightness permits an improved estimate of the number of SNRs in the Galaxy and suggests that this number has previously been overestimated. Consequently, a larger characteristic interval is inferred between supernova events (of a kind giving rise to typical radio remnants) of approximately 150 yr. Furthermore, on the assumption that most of the brighter SNRs are in the Sedov adiabatic expansion phase, the typical value of E0/n (ratio of energy released in a supernova outburst to the number density of H atoms in the surrounding interstellar medium) implied by the data is 5 x 1051 erg cm3, which is considerably higher than was commonly assumed in earlier work. (author)

  1. Magnetar Driven Shock Breakout and Double Peaked Supernova Light Curves

    CERN Document Server

    Kasen, Daniel; Bildsten, Lars

    2015-01-01

    The light curves of some luminous supernovae are suspected to be powered by the spindown energy of a rapidly rotating magnetar. Here we describe a possible signature of the central engine: a burst of shock breakout emission occurring several days after the supernova explosion. The energy input from the magnetar inflates a high-pressure bubble that drives a shock through the pre-exploded supernova ejecta. If the magnetar is powerful enough, that shock will near the ejecta surface and become radiative. At the time of shock breakout, the ejecta will have expanded to a large radius (~10^{14} cm) so that the radiation released is at optical/ultraviolet wavelengths (T ~ 20,000 K) and lasts for several days. The luminosity and timescale of this magnetar driven shock breakout are similar to the first peak observed recently in the double-peaked light curve of SN-LSQ14BDQ. However, for a large region of model parameter space, the breakout emission is predicted to be dimmer than the diffusive luminosity from direct magn...

  2. Coupling of matter and radiation at supernova shock breakout

    CERN Document Server

    Tolstov, A G; Nadyozhin, D K

    2012-01-01

    Some features of the physics of radiation-dominated shock waves are discussed with emphasis on the peculiarities which are important for correct numerical modeling of shock breakouts in supernova. With account of those peculiarities, a number of models for different supernova types is constructed based on multigroup radiation transfer coupled to hydrodynamics. We describe the implementation of a new algorithm RADA, designed for modeling photon transfer at extremely-relativistic motions of matter, into our older code STELLA. The results of numerical simulations of light curves, and continuum spectra are presented. The influence of effects of photon scattering on electrons, of thermalization depth and of special relativity in transfer equation is considered. Some cases are demonstrated, when the appearance of hard X-ray emission is possible at the shock breakout. The necessary refinements in numerical algorithms for radiative transfer and hydrodynamics are pointed out. Prospects for using the results of numeric...

  3. An expanded HST/WFC3 survey of M83: Project overview and targeted supernova remnant search

    Energy Technology Data Exchange (ETDEWEB)

    Blair, William P.; Kuntz, K. D. [The Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Chandar, Rupali [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Dopita, Michael A. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Ghavamian, Parviz [Department of Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252 (United States); Hammer, Derek; Long, Knox S.; Whitmore, Bradley C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Soria, Roberto [Curtin Institute of Radio Astronomy, Curtin University, 1 Turner Avenue, Bentley WA 6102 (Australia); Frank Winkler, P., E-mail: wpb@pha.jhu.edu, E-mail: kuntz@pha.jhu.edu, E-mail: Rupali.Chandar@utoledo.edu, E-mail: Michael.Dopita@anu.edu.au, E-mail: pghavamian@towson.edu, E-mail: long@stsci.edu, E-mail: hammer@stsci.edu, E-mail: whitmore@stsci.edu, E-mail: roberto.soria@icrar.org, E-mail: winkler@middlebury.edu [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States)

    2014-06-10

    We present an optical/NIR imaging survey of the face-on spiral galaxy M83, using data from the Hubble Space Telescope Wide Field Camera 3 (WFC3). Seven fields are used to cover a large fraction of the inner disk, with observations in nine broadband and narrowband filters. In conjunction with a deep Chandra survey and other new radio and optical ground-based work, these data enable a broad range of science projects to be pursued. We provide an overview of the WFC3 data and processing and then delve into one topic, the population of young supernova remnants (SNRs). We used a search method targeted toward soft X-ray sources to identify 26 new SNRs. Many compact emission nebulae detected in [Fe II] 1.644 ?m align with known remnants and this diagnostic has also been used to identify many new remnants, some of which are hard to find with optical images. We include 37 previously identified SNRs that the data reveal to be <0.''5 in angular size and thus are difficult to characterize from ground-based data. The emission line ratios seen in most of these objects are consistent with shocks in dense interstellar material rather than showing evidence of ejecta. We suggest that the overall high elemental abundances in combination with high interstellar medium pressures in M83 are responsible for this result. Future papers will expand on different aspects of the these data including a more comprehensive analysis of the overall SNR population.

  4. Systematic search for molecular clouds near supernova remnants as sources of very-high-energy ?-ray emission

    Science.gov (United States)

    Häffner, Stephanie; Stegmann, Christian; Jung-Richardt, Ira

    2015-12-01

    Supernova remnants accelerate particles up to energies of at least 100 TeV as established by observations in very-high-energy ?-ray astronomy. Molecular clouds in their vicinity provide an increased amount of target material for proton-proton interaction and subsequent neutral pion decay into ?-rays of accelerated hadrons escaping the remnant. Therefore, these molecular clouds are potential ?-ray sources. The ?-ray emission from these clouds provides a unique environment to derive information on the propagation of very-high-energy particles through the interstellar medium as well as on the acceleration of hadrons in supernova remnants. Current Imaging Atmospheric Cherenkov Telescope systems are suitable to explore a large parameter space of the propagation properties depending on the age of the supernova remnant and the distance between the remnant and the nearby molecular cloud. In this paper we present our strategy and results of a systematic search for ?-ray emitting molecular clouds near supernova remnants which are potentially detectable with current experiments in the TeV energy range and explore the prospects of future experiments.

  5. Peering into the heart of the M82 starburst: Type II supernova remnants and a possible relic GRB?

    Science.gov (United States)

    Fenech, Danielle Marie; Beswick, Robert; Muxlow, Tom; Argo, Megan

    2015-08-01

    M82 is considered the archetypal starburst galaxy and at a distance of ~3.6 Mpc is one of the closest examples of its kind. It therefore provides a unique opportunity to study a star-forming environment in detail and particularly the discrete products of star-formation such as supernova remnants (SNR) and HII regions. Supernovae and supernova remnants play an important role in the feedback of energy and material into the surrounding interstellar medium as evidenced in M82 by the galactic superwind driven by the numerous supernovae, SNR and massive stellar winds.Radio observations can be used to see into the core of the star-forming region in the centre of M82 as they are unaffected by the gas and dust associated with such an intense starburst environment. Since their discovery in the 1970s, radio observations have been used to study and monitor the evolution of the ~100 supernova remnants at the heart of this galaxy.We present multi-epoch millarcsecond resolution images of the most compact supernova remnants in M82, spanning 25 years of evolution. In particular, we will discuss one of the quintessential SNR 43.31+59.2 as well as the unusual object 41.95+57.5 and its potential as a GRB afterglow.

  6. Tachyonic cascade spectra of supernova remnants and TeV blazars

    International Nuclear Information System (INIS)

    The superluminal spectral densities of relativistic electrons in uniform motion are derived, semiclassically and in second quantization. The effect of electron spin on the tachyonic radiation field, a Proca field with negative mass-square, is studied. There is a longitudinally polarized spectral component due to the negative mass-square of the tachyonic quanta. The radiation densities are averaged with electron distributions, and high- and low-temperature expansions are obtained. Spectral fits to the ?-ray spectra of the Crab Nebula, the supernova remnant RX J1713.7-3946, and the BL Lacertae objects H1426+428, 1ES 1959+650, Mkn 501, and Mkn 421 are performed. In contrast to TeV photons, the extragalactic tachyon flux is not attenuated by interaction with the background light; there is no absorption of tachyonic ?-rays, as tachyons do not interact with infrared photons. The curvature of the TeV spectra in double-logarithmic plots is caused by the Boltzmann factor of the electron densities generating the tachyon flux. The extended spectral plateau in the GeV band, visible in the spectral maps of the two Galactic supernova remnants as well as in the flare spectra of the BL Lacertae objects, is reproduced by the tachyonic radiation densities. Estimates of the electron populations in the supernova remnants and active galactic nuclei are inferred from the spectral fits, such as power-law indices, electron temperatures, and source counts. Upper bounds on the Lorentz factors in the source populations are derived and compared to the breaks in the high-energy cosmic-ray spectrum. (orig.)

  7. CANGAROO-III Observations of the supernova remnant RX J0852.0$-$4622

    CERN Document Server

    Enomoto, R; Tanimori, T

    2006-01-01

    Sub-TeV gamma-ray emission from the North-West rim of the supernova remnant RX J0852.0$-$4622 was detected with the CANGAROO-II telescope and recently confirmed by the H.E.S.S. group. In addition, the H.E.S.S. data revealed a very wide (up to two degrees in diameter), shell-like profile of the gamma-ray emission. We have carried out CANGAROO-III observations in January and February 2005 with three telescopes and show here the results of three-fold coincidence data. We confirm the H.E.S.S. results about the morphology and the energy spectrum, and find the energy spectrum in the NW-rim is consistent with that of the whole remnant.

  8. X-ray characteristics of the Lupus Loop and SN1006 supernova remnants

    International Nuclear Information System (INIS)

    The spatial extent of the Lupus Loop and spectra for the Lupus Loop and SN1006 supernova remnants have been determined with a rocket-borne payload. The Lupus Loop is an extended source of soft X-rays (approx. 300' diam) that shows a correlation between its brightest X-ray and radio-emission regions. Its spectrum is characterized by a temperature of 350 eV. Thus, the Lupus Loop appears similar to Vela X and Cygnus Loop, although much weaker. Emission from SN1006 is spatially unresolved and exhibits a harder spectrum than that of the Lupus Loop. All spectral data (0.2 100 keV) from our observation and previous observations are satisfactorily fit with a power law (index = 2.15). This spectral dependence suggests the possibility that a rotating neutron star is the underlying source of the radiated energy although such an interpretation appears inconsistent with the remnant's morphology. (orig.)

  9. AN X-RAY INVESTIGATION OF THREE SUPERNOVA REMNANTS IN THE LARGE MAGELLANIC CLOUD

    International Nuclear Information System (INIS)

    We have investigated three supernova remnants (SNRs) in the LMC using multi-wavelength data. These SNRs are generally fainter than the known sample (see Section 4) and may represent a previously missed population. One of our SNRs is the second LMC remnant analyzed which is larger than any Galactic remnant for which a definite size has been established. The analysis of such a large remnant contributes to the understanding of the population of highly evolved SNRs. We have obtained X-ray images and spectra of three of these recently identified SNRs using the XMM-Newton observatory. These data, in conjunction with pre-existing optical emission-line images and spectra, were used to determine the physical conditions of the optical- and X-ray-emitting gas in the SNRs. We have compared the morphologies of the SNRs in the different wavebands. The physical properties of the warm ionized shell were determined from the H? surface brightness and the SNR expansion velocity. The X-ray spectra were fit with a thermal plasma model and the physical conditions of the hot gas were derived from the model fits. Finally, we have compared our observations with simulations of SNR evolution.

  10. X-Ray Emission Line Imaging and Spectroscopy of Tycho's Supernova Remnant

    CERN Document Server

    Hwang, U; Hwang, Una; Gotthelf, Eric V.

    1996-01-01

    We present X-ray images of Tycho's supernova remnant in emission line features of Mg, Si, S, Ar, Ca, and Fe, plus the continuum, using data obtained by the imaging spectrometers onboard the ASCA X-ray satellite. All the images show the shell-like morphology characteristic of previously obtained broad-band X-ray images, but are clearly distinct from each other. We use image reconstruction techniques to achieve a spatial resolution of ~0.8'. Line intensity ratios are used to make inferences about the remnant's physical state, on average for the entire remnant, and with angular position around the rim. The average temperature (T) of the Si and S ejecta in the remnant is (0.8-1.1) X 10^7 K and the average ionization age (nt) is (0.8-1.3) X 10^11 cm^-3 s. For a constant nt, the observed relative brightness variations of Si and S line image profiles with azimuthalangle imply differences of roughly a factor of 1.3-1.8 in the temperature. We compare the radial brightness profiles of our images to simple geometrical m...

  11. HIGH RESOLUTION 36 GHz IMAGING OF THE SUPERNOVA REMNANT OF SN 1987A

    International Nuclear Information System (INIS)

    The aftermath of supernova (SN) 1987A continues to provide spectacular insights into the interaction between an SN blastwave and its circumstellar environment. We here present 36 GHz observations from the Australia Telescope Compact Array of the radio remnant of SN 1987A. These new images, taken in 2008 April and 2008 October, substantially extend the frequency range of an ongoing monitoring and imaging program conducted between 1.4 and 20 GHz. Our 36.2 GHz images have a diffraction-limited angular resolution of 0.''3-0.''4, which covers the gap between high resolution, low dynamic range VLBI images of the remnant and low resolution, high dynamic range images at frequencies between 1 and 20 GHz. The radio morphology of the remnant at 36 GHz is an elliptical ring with enhanced emission on the eastern and western sides, similar to that seen previously at lower frequencies. Model fits to the data in the Fourier domain show that the emitting region is consistent with a thick inclined torus of mean radius 0.''85, and a 2008 October flux density of 27 ± 6 mJy at 36.2 GHz. The spectral index for the remnant at this epoch, determined between 1.4 GHz and 36.2 GHz, is ? = -0.83. There is tentative evidence for an unresolved central source with flatter spectral index.

  12. High Resolution X-ray Imaging of Supernova Remnant 1987A

    CERN Document Server

    Ng, C -Y; Murray, S S; Slane, P O; Park, S; Staveley-Smith, L; Manchester, R N; Burrows, D N

    2009-01-01

    We report observations of the remnant of Supernova 1987A with the High Resolution Camera (HRC) onboard the Chandra X-ray Observatory. A direct image from the HRC resolves the annular structure of the X-ray remnant, confirming the morphology previously inferred by deconvolution of lower resolution data from the Advanced CCD Imaging Spectrometer. Detailed spatial modeling shows that the a thin ring plus a thin shell gives statistically the best description of the overall remnant structure, and suggests an outer radius 0.96" +/- 0.05" +/- 0.03" for the X-ray-emitting region, with the two uncertainties corresponding to the statistical and systematic errors, respectively. This is very similar to the radius determined by a similar modeling technique for the radio shell at a comparable epoch, in contrast to previous claims that the remnant is 10-15% smaller at X-rays than in the radio band. The HRC observations put a flux limit of 0.010 cts/s (99% confidence level, 0.08-10 keV range) on any compact source at the rem...

  13. THREE-DIMENSIONAL SIMULATIONS OF THE THERMAL X-RAY EMISSION FROM YOUNG SUPERNOVA REMNANTS INCLUDING EFFICIENT PARTICLE ACCELERATION

    International Nuclear Information System (INIS)

    Supernova remnants (SNRs) are believed to be the major contributors to Galactic cosmic rays. The detection of non-thermal emission from SNRs demonstrates the presence of energetic particles, but direct signatures of protons and other ions remain elusive. If these particles receive a sizeable fraction of the explosion energy, the morphological and spectral evolution of the SNR must be modified. To assess this, we run three-dimensional hydrodynamic simulations of a remnant coupled with a nonlinear acceleration model. We obtain the time-dependent evolution of the shocked structure, impacted by the Rayleigh-Taylor hydrodynamic instabilities at the contact discontinuity and by the back-reaction of particles at the forward shock. We then compute the progressive temperature equilibration and non-equilibrium ionization state of the plasma, and its thermal emission in each cell. This allows us to produce the first realistic synthetic maps of the projected X-ray emission from the SNR. Plasma conditions (temperature and ionization age) can vary widely over the projected surface of the SNR, especially between the ejecta and the ambient medium owing to their different composition. This demonstrates the need for spatially resolved spectroscopy. We find that the integrated emission is reduced with particle back-reaction, with the effect being more significant for the highest photon energies. Therefore, different energy bands, corresponding to different emitting elements, probe different levels of the impact of particle acceleration. Our work provides a framework for the interpretation of SNR observations with current X-ray missions (Chandra, XMM-Newton, and Suzaku) and with upcoming X-ray missions (such as Astro-H).

  14. Distance and Evolutionary State of the Supernova Remnant 3C 397 (G41.1-0.3)

    Science.gov (United States)

    Leahy, D. A.; Ranasinghe, S.

    2016-01-01

    In this paper, we analyze 1420 MHz continuum and H i observations of the supernova remnant (SNR) 3C 397 (G41.1-0.3). The H i absorption spectra show clear absorption up to the tangent point velocity and also the absence of absorption at 50–60 km s?1. This yields lower and upper limits to the distances of 6.3 ± 0.1 and 9.7 ± 0.3 kpc, which are better and more robust than previous estimates. We apply generalized SNR models to 3C 397, including the ejecta-dominated phase and the transition-to-Sedov phase. Using emission measures from the X-ray and mean gas density from the infrared, we show that the hard X-ray component has the dominant filling factor and the soft X-ray component has a very small filling factor. The models are required to be consistent with 3C 397's measured properties, including the observed shock temperatures and shock radii. Consistent models are found if 3C 397 has a distance in the range of ?8–9.7 kpc. For an 8 kpc distance, the estimated age is ?1350 years and the explosion energy is 1.0 × 1051 erg, while for 9.7 kpc, the the most probable age is ?1750 years and the energy 1.5 × 1051 erg.

  15. Nonthermal properties of supernova remnant G1.9+0.3

    CERN Document Server

    Ksenofontov, L T; Berezhko, E G

    2010-01-01

    The properties of the - presumably - youngest Galactic supernova remnant (SNR) G1.9+0.3 are investigated within the framework of nonlinear kinetic theory of cosmic ray acceleration in SNRs. The observed angular size and expansion speed as well as the radio and X-ray emission measurements are used to determine relevant physical parameters of this SNR. Under the assumption that SNR G1.9+0.3 is the result of a Type Ia supernova near the Galactic center (at the distance d=8.5 kpc) the nonthermal properties are calculated. In particular, the expected TeV gamma-ray spectral energy density is predicted to be as low as $\\epsilon_{\\gamma}F_{\\gamma} \\approx 5\\times 10^{-15}$ erg cm$^{-2}$ s$^{-1}$, strongly dependent ($F_{\\gamma}\\propto d^{-11}$) upon the source distance d.

  16. Newly Synthesized Elements and Pristine Dust in the Cassiopeia A Supernova Remnant

    CERN Document Server

    Arendt, R G; Moseley, S H

    1999-01-01

    Spectroscopic observations at 2.4 - 45 microns of the young supernova remnant Cas A with the Infrared Space Observatory (ISO) Short Wavelength Spectrometer (SWS) reveal strong emission lines of O, Ne, Si, S, and Ar. These lines are observed at high velocities (several thousand km/s), and are therefore associated with the supernova ejecta known as the fast-moving knots (FMKs). Continuum emission from dust is also seen in the Cas A spectrum. The continuum strength is spatially well correlated with the O and Ar line strengths, indicating that the dust emission also arises from the FMKs. The dust continuum has an emission feature at ~22 microns which cannot be fit by typical astronomical silicates, but can be fit with a particular class of silicate minerals. This suggests that the dust in Cas A is silicate material that has freshly condensed from the Cas A ejecta into a mineral form that is uncharacteristic of typical ISM dust grains.

  17. Bilateral symmetry in supernova remnants and the connection to the Galactic magnetic field

    Science.gov (United States)

    West, Jennifer Lorraine; Safi-Harb, Samar; Jaffe, Tess; Kothes, Roland; Foster, Tyler; Landecker, Tom

    2015-08-01

    Supernova explosions are some of the most significant and transformative events in our Universe. Understanding Supernova Remnants (SNRs), the leftover remains of these explosions, is fundamental to our understanding of the chemical enrichment and magnetism in galaxies, including our own Milky Way. We model the radio synchrotron emission from Galactic SNRs using the “Hammurabi” synchrotron modelling code. We incorporate current models of Galactic magnetic field and electron density to simulate the emission from the SNRs as a function of their position in the Galaxy. We do this in an effort to understand the connection between SNRs and their environment and to investigate the relationship between the angle of the symmetry axis of the SNR and the Galactic Magnetic field. This relationship has implications for understanding the magnetic field geometry and cosmic ray electron distribution in SNRs, and possibly even a new method for determining or constraining the distances to SNRs.

  18. NONTHERMAL PROPERTIES OF SUPERNOVA REMNANT G1.9+0.3

    International Nuclear Information System (INIS)

    The properties of the-presumably-youngest Galactic supernova remnant (SNR) G1.9+0.3 are investigated within the framework of nonlinear kinetic theory of cosmic ray acceleration in SNRs. The observed angular size and expansion speed as well as the radio and X-ray emission measurements are used to determine relevant physical parameters of this SNR. Under the assumption that SNR G1.9+0.3 is the result of a Type Ia supernova near the Galactic center (at the distance d = 8.5 kpc), the nonthermal properties are calculated. In particular, the expected TeV gamma-ray spectral energy density is predicted to be as low as ?? F? ? 5 x 10-15 erg cm-2 s-1, strongly dependent (F? ? d -11) upon the source distance d.

  19. Evolved Fe-rich supernova remnants in the Large Magellanic Cloud with Athena

    Science.gov (United States)

    Kavanagh, Patrick; Sasaki, Manami; Maggi, Pierre; Haberl, Frank

    2015-09-01

    Recently, a new class of evolved supernova remnants (SNRs) with centrally peaked Fe-rich emission has been identified in the Magellanic Clouds. The Fe-rich cores result from reverse shock-heated ejecta, the composition of which is consistent with a type Ia explosion, and are spectrally evident as very pronounced Fe L-shell emission lines. Observations with the current generation of X-ray facilities show that the interior Fe-rich plasmas exhibit long ionisation ages, requiring higher central densities than expected from standard type Ia models. It has been suggested that the high interior densities are the result of seeding of the circumstellar medium by the stellar companion leading up to the explosion, which could be facilitated by the most massive "prompt" type Ia progenitor systems. Thus far, these studies have focussed on integrated Fe-rich interior emission since these objects are too faint to allow spatially resolved spectral analysis. In addition, the spectral resolution of the current generation CCD detectors cannot resolve the individual lines in the Fe L-shell complex and spectral analysis is hampered by continuing uncertainties in the atomic data for Fe L-shell lines. Spatially resolved, high spectral resolution studies would reveal in detail the plasma conditions in the Fe-rich interior, shedding light on the possible progenitor systems of these objects, as well as providing a test of the Fe L-shell atomic data. The Fe L-shell line complex is known to be a powerful temperature, density, and ionisation condition diagnostic, and the effective area of Athena, coupled with the high spectral resolution of the X-IFU, provide access to this science space. The detections of such objects has grown significantly in recent years due to the XMM-Newton Very Large Programme survey of the Large Magellanic Cloud (LMC) and our ROSAT LMC SNR candidate follow-up programme. In this talk I will review the current sample of centrally peaked Fe-rich SNRs observed with XMM-Newton and illustrate how the Athena X-IFU can allow an unprecedented probe into the Fe-rich plasmas in these objects.

  20. Characterizing Supernova Remnant and Molecular Cloud Interaction Sites Using Methanol (CH3OH) Masers

    Science.gov (United States)

    McEwen, Bridget; Pihlstrom, Ylva; Sjouwerman, Lorant

    2016-01-01

    Astronomical masers are useful probes of the physical conditions of the gas in which they are formed. Masers form under specific physical conditions and therefore, can be used to trace distinct environments. In particular, collisionally excited 36 and 44 GHz methanol (CH3OH) and 1720 MHz hydroxl (OH) masers are found associated with shocked gas produced by the interaction between supernova remnants (SNRs) and molecular clouds (MCs). The overall goal of my thesis research is to combine modeling and observations to characterize the properties and formation of CH3OH masers in these SNR/MC interaction regions. More accurate information of the density (and density gradients) could, for example, be used as inputs or constraints for models of SNR cosmic ray acceleration. In this talk, I will present results from calculations of the physical conditions necessary for the occurence of 36.169, 44.070, 84.521, and 95.169 GHz CH3OH maser lines near SNRs, using a coupled radiative transfer and level population code. The modeling shows that given a sufficient CH3OH abundance, CH3OH maser emission arises over a wide range of densities and temperatures, with optimal conditions at n ~ 104 to 106 cm-3 and T > 60 K, overlapping with masing conditions for OH masers. Furthermore, the 36 and 44 GHz transitions display more significant maser optical depths compared to the 84 and 95 GHz transitions over the majority of the physical conditions. The line intensity ratios between multiple transitions significantly change with altering physical conditions and can be used to constrain the physical parameters of the gas where CH3OH masers are detected. I use the modeling results as a diagnostic tool to interpret the observational results of a sample of SNRs with previous and recent CH3OH maser detections (G1.4-0.1, W28, Sgr A East, G5.7-0.0, W44 and W51C). I will also discuss the close spatial and kinematic correlation of CH3OH masers and ammonia (NH3 (3,3)) emission peaks, which is a reliable method for locating CH3OH masers and may help determine the density structure in SNRs. By combining modeling and observations of different molecular species, I aim to develop a comprehensive picture of the gas structure in an SNR/MC interaction region.

  1. G332.5-5.6, a new Galactic supernova remnant

    OpenAIRE

    Reynoso, E. M.; Green, A.J.

    2006-01-01

    We present radio observations of the source G332.5-5.6, a candidate supernova remnant (SNR). Observations have been performed with the Australia Telescope Compact Array (ATCA) at two frequencies, at 1.4 and 2.4 GHz. Our results confirm that G332.5-5.6 is an SNR, with a spectral index equal to -0.7 +/- 0.2 for the whole source and an average fractional polarization of ~35% at 2.4 GHz. The central component is coincident with extended X-ray emission and the distance to the SNR...

  2. Supernova Remnants in the Sedov Expansion Phase: Thermal X-Ray Emission

    OpenAIRE

    Borkowski, K. J.; Lyerly, W. J.; Reynolds, S. P

    2000-01-01

    Improved calculations of X-ray spectra for supernova remnants (SNRs) in the Sedov-Taylor phase are reported, which for the first time include reliable atomic data for Fe L-shell lines. This new set of Sedov models also allows for a partial collisionless heating of electrons at the blast wave and for energy transfer from ions to electrons through Coulomb collisions. X-ray emission calculations are based on the updated Hamilton-Sarazin spectral model. The calculated X-ray spec...

  3. Submillimeter/millimeter observations of the molecular clouds associated with the Tycho' Supernova Remnant

    OpenAIRE

    Xu, Jin-Long; Jun-jie WANG; Miller, Martin

    2010-01-01

    We have carried out CO J=2-1 and CO J=3-2 observations toward Tycho's supernova remnant (SNR) using the KOSMA 3m-Telescope. From these observations we identified three molecular clouds (MCs) around the SNR. The small cloud in the southwest was discovered for the first time. In the north and east, two MCs (cloud A and cloud B) adjacent in space display a bow-shaped morphology, and have broad emission lines, which provide some direct evidences of the SNR-MCs interaction. The MCs is revealed at ...

  4. Chandra and XMM Observations of the Composite Supernova Remnant G327.1-1.1

    OpenAIRE

    Temim, Tea; Slane, Patrick; Gaensler, B.M.; Hughes, John P.; van der Swaluw, Eric

    2008-01-01

    We present new X-ray imaging and spectroscopy of a composite supernova remnant G327.1-1.1 using the Chandra and XMM-Newton X-ray observatories. G327.1-1.1 has an unusual morphology consisting of a symmetric radio shell and an off center nonthermal component that indicates the presence of a pulsar wind nebula (PWN). Radio observations show a narrow finger of emission extending from the PWN structure towards the northwest. X-ray studies with ASCA, ROSAT, and BeppoSAX revealed ...

  5. Electron acceleration in supernova remnants and diffuse gamma rays above 1 GeV

    DEFF Research Database (Denmark)

    Pohl, M.; Esposito, J.A.

    1998-01-01

    The recently observed X-ray synchrotron emission from four supernova remnants (SNRs) has strengthened the evidence that cosmic-ray electrons are accelerated in SNRs. We show that if this is indeed the case, the local electron spectrum will be strongly time-dependent, at least above roughly 30 Ge......V. The time dependence stems from the Poisson fluctuations in the number of SNRs within a certain volume and within a certain time interval. As far as cosmic-ray electrons are concerned, the Galaxy looks like actively bubbling Swiss cheese rather than a steady, homogeneously filled system. Our finding...

  6. On the population of X-ray supernova remnants in the Large Magellanic Cloud

    OpenAIRE

    P Maggi; Haberl, F.; Kavanagh, P.J.; Sasaki, M.; Bozzetto, L. M.; Filipovi?, M. D.; Vasilopoulos, G.; Pietsch, W.; Points, S. D.; Chu, Y.-H.; Dickel, J.; Ehle, M; Williams, R.; Greiner, J.

    2015-01-01

    We present a comprehensive X-ray study of the population of supernova remnants (SNRs) in the LMC. Using primarily XMM-Newton, we conduct a systematic spectral analysis of LMC SNRs to gain new insights on their evolution and the interplay with their host galaxy. We combine all the archival XMM observations of the LMC with those of our Very Large Programme survey. We produce X-ray images and spectra of 51 SNRs, out of a list of 59. Using a careful modeling of the background, w...

  7. An optical search for supernova remnants in the nearby spiral galaxy NGC 2903

    CERN Document Server

    Sonbas, E; Balman, S

    2009-01-01

    We present the results of an optical search for supernova remnants (SNRs) in the nearby spiral galaxy NGC 2903. Interference filter images and spectral data were taken in March 2005 with the f/7.7 1.5 m Russian Turkish Telescope (RTT150) at TUBITAK National Observatory (TUG). Spectral data were obtained with the 6 m BTA (Bolshoi Azimuthal Telescope, Russia). We used the SNR identification criterion that consists of constructing the continuum-subtracted H$\\alpha$ and continuum-subtracted [SII]$\\lambda

  8. Soft x-ray emission from the Lupus Loop and SN 1006 supernova remnants

    International Nuclear Information System (INIS)

    X-ray maps of the Lupus region have been obtained in a raster scan observation from SAS 3. These show the Lupus Loop to be a faint, extended source of soft x-rays with a temperature about 2.5 x 106 K. The most prominent feature of the region is the A.D. 1006 supernova remnant, which is unexpectedly bright at 0.2--1.0 keV. One speculative interpretation of the low-energy flux from SN 1006 is as blackbody radiation from a hot neutron star

  9. Secondary Accceleration of Cosmic Rays by Supernova Shocks

    OpenAIRE

    Wandel, Amri

    1997-01-01

    In the common model supernova shock-acceleration of cosmic rays there are two open questions: 1. where does the high energy cosmic rays below the knee (10$^4-10^6$ Gev) come from, and 2. are cosmic ray accelerated only at their origin or contineuosly during their residence in the Galaxy. We show that $10^15$ eV light nuclei are probably accelerted by associations of supernovae. The ratio of the spectra of secondary to primary cosmic rays would be affected by repeated acceler...

  10. A Spatially Resolved Study of the Synchrotron Emission and Titanium in Tycho’s Supernova Remnant Using NuSTAR

    Science.gov (United States)

    Lopez, Laura A.; Grefenstette, Brian W.; Reynolds, Stephen P.; An, Hongjun; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Eriksen, Kristoffer A.; Fryer, Chris L.; Hailey, Charles J.; Harrison, Fiona A.; Madsen, Kristin K.; Stern, Daniel K.; Zhang, William W.; Zoglauer, Andreas

    2015-12-01

    We report results from deep observations (˜750 ks) of Tycho's supernova remnant (SNR) with NuSTAR. Using these data, we produce narrow-band images over several energy bands to identify the regions producing the hardest X-rays and to search for radioactive decay line emission from 44Ti. We find that the hardest (>10 keV) X-rays are concentrated in the southwest of Tycho, where recent Chandra observations have revealed high emissivity “stripes” associated with particles accelerated to the knee of the cosmic-ray spectrum. We do not find evidence of 44Ti, and we set limits on its presence and distribution within the SNR. These limits correspond to an upper-limit 44Ti mass of M44 < 2.4 × 10-4 M? for a distance of 2.3 kpc. We perform a spatially resolved spectroscopic analysis of 66 regions across Tycho. We map the best-fit rolloff frequency of the hard X-ray spectra, and we compare these results to measurements of the shock expansion and ambient density. We find that the highest energy electrons are accelerated at the lowest densities and in the fastest shocks, with a steep dependence of the rolloff frequency with shock velocity. Such a dependence is predicted by models where the maximum energy of accelerated electrons is limited by the age of the SNR rather than by synchrotron losses, but this scenario requires far lower magnetic field strengths than those derived from observations in Tycho. One way to reconcile these discrepant findings is through shock obliquity effects, and future observational work is necessary to explore the role of obliquity in the particle acceleration process.

  11. Spitzer IMAGING AND SPECTRAL MAPPING OF THE OXYGEN-RICH SUPERNOVA REMNANT G292.0+1.8

    International Nuclear Information System (INIS)

    We present mid-infrared continuum and emission line images of the Galactic oxygen-rich supernova remnant (SNR) G292.0+1.8, acquired using the MIPS and IRS instruments on the Spitzer Space Telescope. The MIPS 24 ?m and 70 ?m images of G292.0+1.8 are dominated by continuum emission from a network of filaments encircling the SNR. The morphology of the SNR, as seen in the mid-infrared, resembles that seen in X-rays with the Chandra X-Ray Observatory. Most of the mid-infrared emission in the MIPS images is produced by circumstellar dust heated in the non-radiative shocks around G292.0+1.8, confirming the results of earlier mid-IR observations with AKARI. In addition to emission from hot dust, we have also mapped atomic line emission between 14 ?m and 36 ?m using IRS spectral maps. The line emission is primarily associated with the bright oxygen-rich optical knots, but is also detected from fast-moving knots of ejecta. We confirm our earlier detection of 15-25 ?m emission characteristic of magnesium silicate dust in spectra of the radiatively shocked ejecta. We do not detect silicon line emission from any of the radiatively shocked ejecta in the southeast of the SNR, possibly because the reverse shock has not yet penetrated most of the Si-rich ejecta in that region. This may indicate that G292.0+1.8 is less evolved in the southeast than the rest of the SNR, and may be further evidence in favor of an asymmetric SN explosion as proposed in recent X-ray studies of G292.0+1.8.

  12. Observational study of ion-electron equilibration and of cloud evaporation in supernova remnants under the HEAO-2 guest investigator program. Final project report, 1 June 1985-30 September 1986

    International Nuclear Information System (INIS)

    Observations of three selected supernovae remnants (Cygnus Loop, IC 443, and Puppis A) were made in the forbidden coronal iron lines (Fe X) lambda 6374 and (Fe XIV) lambda 5303. The resulting data was compared quantitatively with Einstein images of the same objects, and an attempt was made to determine (a) the process by which ion and electron energies are equilibrated behind the shock front in the ISM and (b) whether cloud evaporation occurs within the hot remnant interiors. Spatially-resolved x-ray emission were modeled for Sedov-Taylor blast wave models of supernovae remnants (SNR) under conditions of non-equlibrium ionization. The computations are intended to provide results that can be directly compared with Einstein high resolution image (HRI) and imaging proportional counter (IPS) data. The computer program for predicting the spatial distribution of HRI and IPS counting rates was completed, and final testing of it had begun

  13. Optical detection and spectroscopic confirmation of supernova remnant G213.0-0.6 (now re-designated as G213.3-0.4)

    CERN Document Server

    Stupar, M

    2011-01-01

    During a detailed search for optical counterparts of known Galactic supernova remnants (SNRs) using the Anglo Australian Observatory/United Kingdom Schmidt Telescope (AAO/UKST) HAlpha survey of the southern Galactic plane we have found characteristic optical HAlpha filaments and associated emission in the area of SNR G213.0-0.6. Although this remnant was previously detected in the radio as a non-thermal source, we also confirm emission at 4850 MHz in the Parkes-MIT-NRAO (PMN) survey and at 1400 MHz in the NRAO/VLA Sky Survey (NVSS). There is an excellent match in morphological structure between the optical (HAlpha) and radio emission. We subsequently obtained optical spectroscopy of selected HAlpha filaments using the South African Astronomical Observatory 1.9-m telescope which confirmed shock excitation typical of supernova remnants. Our discovery of HAlpha emission and the positional match with several radio frequency maps led us to reassign G213.0-0.6 as G213.3-0.4 as these co-ordinates more accurately ref...

  14. SWIFT/BAT DETECTION OF HARD X-RAYS FROM TYCHO'S SUPERNOVA REMNANT: EVIDENCE FOR TITANIUM-44

    Energy Technology Data Exchange (ETDEWEB)

    Troja, E.; Baumgartner, W.; Markwardt, C.; Barthelmy, S.; Gehrels, N. [NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Segreto, A.; La Parola, V.; Cusumano, G. [INAF—IASF Palermo, Via Ugo La Malfa, I-90146 Palermo (Italy); Hartmann, D., E-mail: eleonora.troja@nasa.gov [Department of Physics and Astronomy, Clemson University, Clemson, SC 29631-0978 (United States)

    2014-12-10

    We report Swift/Burst Alert Telescope survey observations of the Tycho's supernova remnant, performed over a period of 104 months since the mission's launch. The remnant is detected with high significance (>10σ) below 50 keV. We detect significant hard X-ray emission in the 60-85 keV band, above the continuum level predicted by a simple synchrotron model. The location of the observed excess is consistent with line emission from radioactive titanium-44, so far reported only for Type II supernova explosions. We discuss the implications of these results in the context of the galactic supernova rate, and nucleosynthesis in Type Ia supernova.

  15. SWIFT/BAT DETECTION OF HARD X-RAYS FROM TYCHO'S SUPERNOVA REMNANT: EVIDENCE FOR TITANIUM-44

    International Nuclear Information System (INIS)

    We report Swift/Burst Alert Telescope survey observations of the Tycho's supernova remnant, performed over a period of 104 months since the mission's launch. The remnant is detected with high significance (>10σ) below 50 keV. We detect significant hard X-ray emission in the 60-85 keV band, above the continuum level predicted by a simple synchrotron model. The location of the observed excess is consistent with line emission from radioactive titanium-44, so far reported only for Type II supernova explosions. We discuss the implications of these results in the context of the galactic supernova rate, and nucleosynthesis in Type Ia supernova

  16. OBSERVATION OF EXTENDED VERY HIGH ENERGY EMISSION FROM THE SUPERNOVA REMNANT IC 443 WITH VERITAS

    International Nuclear Information System (INIS)

    We present evidence that the very high energy (VHE, E > 100 GeV) gamma-ray emission coincident with the supernova remnant IC 443 is extended. IC 443 contains one of the best studied sites of supernova remnant/molecular cloud interaction and the pulsar wind nebula CXOU J061705.3+222127, both of which are important targets for VHE observations. VERITAS observed IC 443 for 37.9 hr during 2007 and detected emission above 300 GeV with an excess of 247 events, resulting in a significance of 8.3 standard deviations (?) before trials and 7.5? after trials in a point-source search. The emission is centered at 6h16m51s + 22030'11'' (J2000) ±0.003stat ± 0.008sys, with an intrinsic extension of 0.016 ± 0.003stat ± 0.004sys. The VHE spectrum is well fit by a power law (dN/dE = N 0 x (E/TeV)-?) with a photon index of 2.99 ± 0.38stat ± 0.3sys and an integral flux above 300 GeV of (4.63 ± 0.90stat ± 0.93sys) x 10-12 cm-2 s-1. These results are discussed in the context of existing models for gamma-ray production in IC 443.

  17. Near-Infrared Spectroscopy of the Cassiopeia A and Kepler Supernova Remnants

    CERN Document Server

    Gerardy, C L

    2001-01-01

    Near-infrared spectra (0.95 - 2.4 micron) of the Cassiopeia A and Kepler supernova remnants (SNRs) are presented. Low-dispersion (R = 700) spectra were obtained for five bright fast-moving ejecta knots (FMKs) at two locations on the main shell and for three bright circumstellar knots (QSFs) near the southwest rim of Cas A. The main shell FMKs in Cas A exhibit a sparse near-infrared spectrum dominated by [S II] 1.03 micron emission with a handful of other, fainter emission lines. Among these are two high-ionization silicon lines, [Si VI] 1.96 micron and [Si X] 1.43 micron, which have been detected in AGNs and novae but never before in a supernova remnant. The near-infrared spectra of circumstellar QSFs in Cas A show a much richer spectrum, with strong He I 1.083 micron emission and over a dozen bright [Fe II] lines. Observed [Fe II] line ratios indicate electron densities of 5 - 9 * 10^4 cm^-3 in the QSFs. The Cas A QSF data are quite similar to the observed spectrum of a bright circumstellar knot along the no...

  18. Observation of Extended VHE Emission from the Supernova Remnant IC 443 with VERITAS

    CERN Document Server

    Acciari, V A; Arlen, T; Aune, T; Bautista, M; Beilicke, M; Benbow, W; Bradbury, S M; Buckley, J H; Bugaev, V; Butt, Y; Byrum, K; Cannon, A; Celik, O; Cesarini, A; Chow, Y C; Ciupik, L; Cogan, P; Colin, P; Cui, W; Daniel, M K; Dickherber, R; Duke, C; Dwarkadas, V V; Ergin, T; Fegan, S J; Finley, J P; Finnegan, G; Fortin, P; Fortson, L; Furniss, A; Gall, D; Gibbs, K; Gillanders, G H; Godambe, S; Grube, J; Guenette, R; Gyuk, G; Hanna, D; Hays, E; Holder, J; Horan, D; Hui, C M; Humensky, T B; Imran, A; Kaaret, Philip; Karlsson, N; Kertzman, M; Kieda, D; Kildea, J; Konopelko, A; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Maier, G; McCann, A; McCutcheon, M; Millis, J; Moriarty, P; Ong, R A; Otte, A N; Pandel, D; Perkins, J S; Pohl, M; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Roache, E; Rose, H J; Schroedter, M; Sembroski, G H; Smith, A W; Steele, D; Swordy, S P; Theiling, M; Toner, J A; Valcarcel, L; Varlotta, A; Vasilev, V V; Vincent, S; Wagner, R G; Wakely, S P; Ward, J E; Weekes, T C; Weinstein, A; Weisgarber, T; Williams, D A; Wissel, S; Wood, M; Zitzer, B

    2009-01-01

    We present evidence that the very-high-energy (VHE, E > 100 GeV) gamma-ray emission coincident with the supernova remnant IC 443 is extended. IC 443 contains one of the best-studied sites of supernova remnant/molecular cloud interaction and the pulsar wind nebula CXOU J061705.3+222127, both of which are important targets for VHE observations. VERITAS observed IC 443 for 37.9 hours during 2007 and detected emission above 300 GeV with an excess of 247 events, resulting in a significance of 8.3 standard deviations (sigma) before trials and 7.5 sigma after trials in a point-source search. The emission is centered at 06 16 51 +22 30 11 (J2000) +- 0.03_stat +- 0.08_sys degrees, with an intrinsic extension of 0.16 +- 0.03_stat +- 0.04_sys degrees. The VHE spectrum is well fit by a power law (dN/dE = N_0 * (E/TeV)^-Gamma) with a photon index of 2.99 +- 0.38_stat +- 0.3_sys and an integral flux above 300 GeV of (4.63 +- 0.90_stat +- 0.93_sys) * 10^-12 cm^-2 s^-1. These results are discussed in the context of existing ...

  19. Chandra and H.E.S.S. observations of the Supernova Remnant CTB 37B

    CERN Document Server

    Aharonian, F; Barresde Almeida, U; Bazer-Bachi, A R; Behera, B; Beilicke, M; Benbow, W; Bernlöhr, K; Boisson, C; Borrel, V; Braun, I; Brion, E; Brucker, J; Buhler, R; Bulik, T; Büsching, I; Boutelier, T; Carrigan, S; Chadwick, P M; Chaves, R C G; Chounet, L M; Clapson, A C; Coignet, G; Cornils, R; Costamante, L; Dalton, M; Degrange, B; Dickinson, H J; Djannati-Ata, A; Domainko, W; O'Connor-Drury, L; Dubois, F; Dubus, G; Dyks, J; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Funk, S; Fuling, M; Gabici, S; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, Y A; Gallant, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; De Jager, O C; Jung, I; Katarzynski, K; Kaufmann, S; Kendziorra, E; Kerschhaggl, M; Khangulyan, D; Khelifi, B; Keogh, D; Komin, Nu; Kosack, K; Lamanna, G; Latham, I J; Lemoine-Goumard, M; Lenain, J P; Lohse, T; Martin, J M; Martineau-Huynh, O; Marcowith, A; Masterson, C; Maurin, D; McComb, T J L; Moderski, R; Moulin, E; Naumann-Godo, M; De Naurois, Mathieu; Nedbal, D; Nekrassov, D; Nolan, S J; Ohm, S; Olive, J P; de Ona Wilhelmi, E; Orford, K J; Osborne, J L; Ostrowski, M; Panter, M; Pedaletti, G; Pelletier, G; Petrucci, P O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, Andreas G; Raubenheimer, B C; Raue, M; Rayner, S M; Renaud, M; Rieger, F; Reimer, O; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Ruppel, J; Sahakian, V V; Santangelo, A; Schlickeiser, R; Schock, F M; Schroder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Skilton, J L; Sol, H; Spangler, D; Stawarz, L; Steenkamp, R; Stegmann, C; Superina, G; Tam, P H; Tavernet, J P; Terrier, R; Van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

    2008-01-01

    The >100 GeV gamma-ray source, HESS J1713-381, apparently associated with the shell-type supernova remnant (SNR) CTB 37B, was discovered using H.E.S.S. in 2006. X-ray follow-up observations with Chandra were performed in 2007 with the aim of identifying a synchrotron counterpart to the TeV source and/or thermal emission from the SNR shell. These new Chandra data, together with additional TeV data, allow us to investigate the nature of this object in much greater detail than was previously possible. The new X-ray data reveal thermal emission from a ~4' region in close proximity to the radio shell of CTB 37B. The temperature of this emission implies an age for the remnant of ~5000 years (assuming a spherical Sedov expansion), disfavouring a suggested association with the supernova of AD 373. A bright (approx 7 x10^-13erg cm^-2 s^-1) and unresolved (<1'') source (CXOU J171405.7-381031) with a soft (Gamma ~ 3.3) non -thermal spectrum is also detected in coincidence with the radio shell. Absorption indicates a ...

  20. The Search for Faint Radio Supernova Remnants in the Outer Galaxy: Five New Discoveries

    CERN Document Server

    Gerbrandt, Stephanie; Kothes, Roland; Geisbuesch, Joern; Tung, Albert

    2014-01-01

    High resolution and sensitivity large-scale radio surveys of the Milky Way are critical in the discovery of very low surface brightness supernova remnants (SNRs), which may constitute a significant portion of the Galactic SNRs still unaccounted for (ostensibly the Missing SNR problem). The overall purpose here is to present the results of a systematic, deep data-mining of the Canadian Galactic Plane Survey (CGPS) for faint, extended non-thermal and polarized emission structures that are likely the shells of uncatalogued supernova remnants. We examine 5$\\times$5 degree mosaics from the entire 1420 MHz continuum and polarization dataset of the CGPS after removing unresolved point sources and subsequently smoothing them. Newly revealed extended emission objects are compared to similarly-prepared CGPS 408 MHz continuum mosaics, as well as to source-removed mosaics from various existing radio surveys at 4.8 GHz, 2.7 GHz, and 327 MHz, to identify candidates with non-thermal emission characteristics. We integrate fl...