WorldWideScience

Sample records for supernova remnant shock

  1. Reverse-Shock in Tycho's Supernova Remnant

    OpenAIRE

    Lu, F. J.; Ge, M. Y.; Zheng, S. J.; Zhang, S. N.; Long, X.; Aschenbach, B.

    2015-01-01

    Thermal X-ray emission from young supernova remnants (SNRs) is usually dominated by the emission lines of the supernova (SN) ejecta, which are widely believed being crossed and thus heated by the inwards propagating reverse shock (RS). Previous works using imaging X-ray data have shown that the ejecta are heated by the RS by locating the peak emission region of the most recently ionized matter, which is found well separated towards the inside from the outermost boundary. Her...

  2. 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...

  3. Reverse-Shock in Tycho's Supernova Remnant

    CERN Document Server

    Lu, F J; Zheng, S J; Zhang, S N; Long, X; Aschenbach, B

    2015-01-01

    Thermal X-ray emission from young supernova remnants (SNRs) is usually dominated by the emission lines of the supernova (SN) ejecta, which are widely believed being crossed and thus heated by the inwards propagating reverse shock (RS). Previous works using imaging X-ray data have shown that the ejecta are heated by the RS by locating the peak emission region of the most recently ionized matter, which is found well separated towards the inside from the outermost boundary. Here we report the discovery of a systematic increase of the Sulfur (S) to Silicon (Si) K$\\alpha$ line flux ratio with radius in Tycho's SNR. This allows us, for the first time, to present continuous radial profiles of the ionization age and, furthermore, the elapsed ionization time since the onset of the ionization, which tells the propagation history of the ionization front into the SNR ejecta.

  4. New insights on hadron acceleration at supernova remnant shocks

    OpenAIRE

    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 scatte...

  5. Effects of Neutral Particles on Modified Shocks at Supernova Remnants

    OpenAIRE

    Ohira, Yutaka; Takahara, Fumio

    2009-01-01

    H-alpha emission from supernova remnants (SNRs) implies the existence of neutral hydrogens in the ambient medium. In the precursor of an SNR shock modified by cosmic rays (CRs), upstream plasmas are pushed by the CR pressure, but neutral particles are not, so that the relative velocity appears and some neutral particles become pickup ions by the charge exchange process in the precursor. We investigate how the pickup ions generated in the precursor affect the shock structure ...

  6. 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.

  7. Grain Destruction in a Supernova Remnant Shock Wave

    CERN Document Server

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

    2013-01-01

    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. Destruction of Interstellar Dust in Evolving Supernova Remnant Shock Waves

    CERN Document Server

    Slavin, Jonathan D; Jones, Anthony P

    2015-01-01

    Supernova generated shock waves are responsible for most of the destruction of dust grains in the interstellar medium (ISM). Calculations of the dust destruction timescale have so far been carried out using plane parallel steady shocks, however that approximation breaks down when the destruction timescale becomes longer than that for the evolution of the supernova remnant (SNR) shock. In this paper we present new calculations of grain destruction in evolving, radiative SNRs. To facilitate comparison with the previous study by Jones et al. (1996), we adopt the same dust properties as in that paper. We find that the efficiencies of grain destruction are most divergent from those for a steady shock when the thermal history of a shocked gas parcel in the SNR differs significantly from that behind a steady shock. This occurs in shocks with velocities >~ 200 km/s for which the remnant is just beginning to go radiative. Assuming SNRs evolve in a warm phase dominated ISM, we find dust destruction timescales are incre...

  9. Grain destruction in a supernova remnant shock wave

    International Nuclear Information System (INIS)

    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. Supernova Remnants

    Science.gov (United States)

    Blair, William P.

    The FUSE Team Project on supernova remnants includes an absorption study of the young Type 1a SN remnant SN1006 and studies of selected filamentary emission regions in evolved galactic SNRs. Observations of the "Schweizer-Middleditch" star behind SN1006 will be used to search for a broad absorption from Fe III 1123, using FUSE's high dispersion to resolve contaminating stellar photospheric lines from the broad line. The presence of this line would indicate iron in the cool ejecta of the supernova. Observations of key, well-studied SNR emission filaments will be used to study different kinds of shock wave-ISM interactions, including nonradiative and radiative shocks, and thermally unstable regions. FUSE coverage of a range of ions and ionization stages at high spectral resolution will provide a unique capability to diagnose the thermal, chemical, and kinematic properties of these interactions. Observations of an X-ray bright region will be used to search for faint, high-ionization lines never observed previously in spectra of SNRs.

  13. 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...

  14. 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...

  15. On cosmic-ray production efficiency at supernova remnant shocks propagating into realistic diffuse interstellar medium

    CERN Document Server

    Shimoda, Jiro; Ohira, Yutaka; Yamazaki, Ryo; Bamba, Aya; Vink, Jacco

    2014-01-01

    Using three-dimensional magnetohydrodynamics simulations, we show that the efficiency of cosmic-ray (CR) production at supernova remnants (SNRs) is over-predicted if it is estimated based on proper motion measurements of H$\\alpha$ filaments in combination with shock-jump conditions. Density fluctuations of upstream medium make shock waves rippled and oblique almost everywhere. The kinetic energy of the shock wave is transfered into that of downstream turbulence as well as thermal energy which is related to the shock velocity component normal to the shock surface. In our case, the apparent efficiency goes up as high as $10\\sim40\\ \\%$ in spite of no CR acceleration.

  16. Supernova remnants and their supernovae

    International Nuclear Information System (INIS)

    Observing supernova remnants provides important clues to the nature of supernova explosions. Conversely, the late stages of stellar evolution and the mechanism of supernova explosions affect supernova remnants through circumstellar matter, stellar remnants, and nucleosynthesis. The elements of supernova classification and the connection between supernova type and remnant properties are explored. A special emphasis is placed on SN 1987a which provides a unique opportunity to learn the connection between the star that exploded and the remnant that will develop in this lifetime

  17. An Integral View of Balmer-dominated Shocks in Supernova Remnants

    CERN Document Server

    Nikoli?, Sladjana; Heng, Kevin; Kupko, Daniel; Méndez-Abreu, Jairo; Aguerri, J Alfonso L; Serra, Joan Font; Beckman, John

    2013-01-01

    We present integral-field spectroscopic observations with the VIMOS-IFU at the VLT of fast (2000-3000 km/s) Balmer-dominated shocks surrounding the northwestern rim of the remnant of supernova 1006. The high spatial and spectral resolution of the instrument enable us to show that the physical characteristics of the shocks exhibit a strong spatial variation over few atomic scale lengths across 133 sky locations. Our results point to the presence of a population of non-thermal protons (10-100 keV) which might well be the seed particles for generating high-energy cosmic rays. We also present observations of Tycho's supernova remnant taken with the narrow-band tunable filter imager OSIRIS at the GTC and the Fabry-Perot interferometer GHaFaS at the WHT to resolve respectively the broad and narrow H\\alpha\\ lines across a large part of the remnant.

  18. Progenitors of Recombining Supernova Remnants

    CERN Document Server

    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 time of the supernova explosion. If the circumstellar medium is dense enough, collisional ionization equilibrium can be established in the early stage of the evolution of the supernova remnant and subsequent adiabatic cooling which occurs after the shock wave gets out of the dense circumstellar medium makes the electron temperature lower than the ionization temperature. We study the circumstellar medium around several supernova progenitors and show which supernova progenitors can have a circumstellar medium which is dense enough to establis...

  19. On Cosmic-ray Production Efficiency at Supernova Remnant Shocks Propagating into Realistic Diffuse Interstellar Medium

    Science.gov (United States)

    Shimoda, Jiro; Inoue, Tsuyoshi; Ohira, Yutaka; Yamazaki, Ryo; Bamba, Aya; Vink, Jacco

    2015-04-01

    Using three-dimensional magnetohydrodynamics simulations, we show that the efficiency of cosmic-ray (CR) production in supernova remnants is over-predicted if it could be estimated based on proper motion measurements of H? filaments in combination with shock-jump conditions. Density fluctuations of the upstream medium cause shock waves to be rippled and oblique almost everywhere. The kinetic energy of the shock wave is transferred into downstream turbulence as well as thermal energy related to the shock velocity component normal to the shock surface. Our synthetic observation shows that the CR acceleration efficiency, as estimated from a lower downstream plasma temperature, is overestimated by 10%–40% because a rippled shock does not immediately dissipate all of the upstream kinetic energy.

  20. PROGENITORS OF RECOMBINING SUPERNOVA REMNANTS

    Energy Technology Data Exchange (ETDEWEB)

    Moriya, Takashi J., E-mail: takashi.moriya@ipmu.jp [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8583 (Japan)

    2012-05-01

    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 ionization temperature higher than the electron temperature, has been recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the supernova explosion. If the circumstellar medium is dense enough, collisional ionization equilibrium can be established in the early stage of the evolution of the supernova remnant and subsequent adiabatic cooling, which occurs after the shock wave gets out of the dense circumstellar medium, makes the electron temperature lower than the ionization temperature. We study the circumstellar medium around several supernova progenitors and show which supernova progenitors can have a circumstellar medium dense enough to establish collisional ionization equilibrium soon after the explosion. We find that the circumstellar medium around red supergiants (especially massive ones) and the circumstellar medium dense enough to make Type IIn supernovae can establish collisional ionization equilibrium soon after the explosion and can evolve to become recombining supernova remnants. Wolf-Rayet stars and white dwarfs have the possibility to be recombining supernova remnants but the fraction is expected to be very small. As the occurrence rate of the explosions of red supergiants is much higher than that of Type IIn supernovae, the major progenitors of recombining supernova remnants are likely to be red supergiants.

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

    OpenAIRE

    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-qual...

  3. Electron acceleration due to high frequency instabilities at supernova remnant shocks

    CERN Document Server

    Dieckmann, M E; Chapman, S C; Dendy, R O; O'Connor-Drury, L

    2000-01-01

    Observations of synchrotron radiation across a wide range of wavelengthsprovide clear evidence that electrons are accelerated to relativistic energiesin supernova remnants (SNRs). However, a viable mechanism for thepre-acceleration of such electrons to mildly relativistic energies has not yetbeen established. In this paper an electromagnetic particle-in-cell (PIC) codeis used to simulate acceleration of electrons from background energies to tensof keV at perpendicular collisionless shocks associated with SNRs. Free energyfor electron energization is provided by ions reflected from the shock front,with speeds greater than the upstream electron thermal speed. The PICsimulation results contain several new features, including: the acceleration,rather than heating, of electrons via the Buneman instability; the accelerationof electrons to speeds exceeding those of the shock-reflected ions producingthe instability; and strong acceleration of electrons perpendicular to themagnetic field. Electron energization takes p...

  4. 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...

  5. Electron Heating, Magnetic Field Amplification, and Cosmic Ray Precursor Length at Supernova Remnant Shocks

    CERN Document Server

    Laming, J Martin; Ghavamian, Parviz; Rakowski, Cara

    2014-01-01

    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 may be quenched either by 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 $10^{17} - 10^{18}$ 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 ...

  6. 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 ...

  7. Reverse and Forward Shock X-Ray Emission in an Evolutionary Model of Supernova Remnants Undergoing Efficient Diffusive Shock Acceleration

    Science.gov (United States)

    Lee, Shiu-Hang; Patnaude, Daniel J.; Ellison, Donald C.; Nagataki, Shigehiro; Slane, Patrick O.

    2014-08-01

    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.

  8. Can diffusive shock acceleration in supernova remnants account for high-energy galactic cosmic rays?

    International Nuclear Information System (INIS)

    Diffusive shock acceleration at the outer front of expanding supernova remnants has provided by far the most popular model for the origin of galactic cosmic rays, and has been the subject of intensive theoretical investigation. But several problems loomed at high energies-how to explain the smooth continuation of the cosmic-ray spectrum far beyond 1014 eV, the very low level of TeV gamma-ray emission from several supernova remnants, and the very low anisotropy of cosmic rays (seeming to conflict with the short trapping times needed to convert a E-2 source spectrum into the observed E-2.7 spectrum of cosmic rays). However, recent work on the cosmic ray spectrum (especially at KASCADE) strongly indicates that about half of the flux does turn down rather sharply near 3 x 1015 V rigidity, with a distinct tail extending to just beyond 1017 V rigidity; whilst a plausible description (Bell and Lucek) of the level of self-generated magnetic fields at the shock fronts of young supernova remnants implies that many SNRs in varying environments might very well generate spectra extending smoothly to just this 'knee' position, and a portion of the exploding red supergiants could extend the spectrum approximately as needed. At low energies, recent progress in relating cosmic ray compositional details to modified shock structure also adds weight to the belief that the model is working on the right lines, converting energy into cothe right lines, converting energy into cosmic rays very efficiently where injection can occur. The low level of TeV gamma-ray flux from many young SNRs is a serious challenge, though it may relate to variations in particle injection efficiency with time. The clear detection of TeV gamma rays from SNRs has now just begun, and predictions of a characteristic curved particle spectrum give a target for new tests by TeV observations. However, the isotropy seriously challenges the assumed cosmic-ray trapping time and hence the shape of the spectrum of particles released from SNRs. There is otherwise enough convergence of model and observation to encourage belief that the outline of the model is right, but there remains the possibility that the spectral shape of particles actually released is not as previously predicted. (topical review)

  9. Electron acceleration due to high frequency instabilities at supernova remnant shocks

    Science.gov (United States)

    Dieckmann, M. E.; Chapman, S. C.; McClements, K. G.; Dendy, R. O.; Drury, L. O'C.

    2000-04-01

    Observations of synchrotron radiation across a wide range of wavelengths provide clear evidence that electrons are accelerated to relativistic energies in supernova remnants (SNRs). However, a viable mechanism for the pre-acceleration of such electrons to mildly relativistic energies has not yet been established. In this paper an electromagnetic particle-in-cell (PIC) code is used to simulate acceleration of electrons from background energies to tens of keV at perpendicular collisionless shocks associated with SNRs. Free energy for electron energization is provided by ions reflected from the shock front, with speeds greater than the upstream electron thermal speed. The PIC simulation results contain several new features, including: the acceleration, rather than heating, of electrons via the Buneman instability; the acceleration of electrons to speeds exceeding those of the shock-reflected ions producing the instability; and strong acceleration of electrons perpendicular to the magnetic field. Electron energization takes place through a variety of resonant and non-resonant processes, of which the strongest involves stochastic wave-particle interactions. In SNRs the diffusive shock process could then supply the final step required for the production of fully relativistic electrons. The mechanisms identified in this paper thus provide a possible solution to the electron pre-acceleration problem.

  10. 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...

  11. 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...

  12. KINEMATICS OF SHOCKED MOLECULAR GAS ADJACENT TO THE SUPERNOVA REMNANT W44

    International Nuclear Information System (INIS)

    We mapped molecular gas toward the supernova remnant W44 in the HCO+ J = 1-0 line with the Nobeyama Radio Observatory 45 m telescope and in the CO J = 3-2 line with the Atacama Submillimeter Telescope Experiment 10 m telescope. High-velocity emission wings were detected in both lines over the area where the radio shell of W44 overlaps with the molecular cloud in the plane of the sky. We found that the average velocity distributions of the wing emission can be fit by a uniform expansion model. The best-fit expansion velocities are 12.2 ± 0.3 km s–1 and 13.2 ± 0.2 km s–1 in HCO+ and CO, respectively. The non-wing CO J = 3-2 component is also fit by the same model with an expansion velocity of 4.7 ± 0.1 km s–1. This component might be dominated by a post-shock higher-density region where the shock velocity had slowed down. The kinetic energy of the shocked molecular gas is estimated to be (3.5 ± 1.3) × 1049 erg. Adding this and the energy of the previously identified H I shell, we conclude that (1.2 ± 0.2) × 1050 erg has been converted into gas kinetic energy from the initial baryonic energy of the W44 supernova. We also found ultra-high-velocity CO J = 3-2 wing emission with a velocity width of ?100 km s–1 at (l, b) = (+34.°73, –0.°47). The origin of this extremely high velocity wing is a mystery

  13. 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.

  14. TWO-STEP ACCELERATION MODEL OF COSMIC RAYS AT MIDDLE-AGED SUPERNOVA REMNANTS: UNIVERSALITY IN SECONDARY SHOCKS

    International Nuclear Information System (INIS)

    Recent gamma-ray observations of middle-aged supernova remnants revealed a mysterious broken power-law spectrum. Using three-dimensional magnetohydrodynamic simulations, we show that the interaction between a supernova blast wave and interstellar clouds formed by thermal instability generates multiple reflected shocks. The typical Mach numbers of the reflected shocks are shown to be M? 2 depending on the density contrast between the diffuse intercloud gas and clouds. These secondary shocks can further energize cosmic-ray particles originally accelerated at the blast-wave shock. This 'two-step' acceleration scenario reproduces the observed gamma-ray spectrum and predicts the high-energy spectral index ranging approximately from 3 to 4.

  15. Supernovae and supernova remnants at low frequencies

    Science.gov (United States)

    Chevalier, Roger A.

    1990-01-01

    The importance of low-frequency observations of the intrinsic radio emission from supernovae and their remnants is discussed, with special attention given to an example of a peculiarity at low frequencies of the 38-MHz 'flare' observed from Cas A in the mid-1970s. It is suggested that, for explosions from supernovae in a low-density wind, it may be possible to follow the absorption over a large range of shock front radii. Absorption local to the remnants can occur in H II regions created by the supernovae or their progenitors and in the cooling layers of radiative shock fronts, or in the ionized interstellar medium. Observations of emission as well as of absorption are necessary to determine the location of the ionized gas.

  16. 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.

  17. 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.

  18. Electron acceleration due to high frequency instabilities at supernova remnant shocks

    OpenAIRE

    Dieckmann, M. E.; Mcclements, K. G.; Chapman, S. C.; Dendy, R. O.; Drury, L. O. C.

    2000-01-01

    Observations of synchrotron radiation across a wide range of wavelengths provide clear evidence that electrons are accelerated to relativistic energies in supernova remnants (SNRs). However, a viable mechanism for the pre-acceleration of such electrons to mildly relativistic energies has not yet been established. In this paper an electromagnetic particle-in-cell (PIC) code is used to simulate acceleration of electrons from background energies to tens of keV at perpendicular ...

  19. 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...

  20. 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.

  1. 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.

  2. Rapid cosmic-ray acceleration at perpendicular shocks in supernova remnants

    CERN Document Server

    Takamoto, Makoto

    2015-01-01

    Perpendicular shocks are shown to be rapid particle accelerators that perform optimally when the ratio $u_{\\rm s}$ of the shock speed to the particle speed roughly equals the ratio $1/\\eta$ of the scattering rate to the gyro frequency. We use analytical methods and Monte-Carlo simulations to solve the kinetic equation that governs the anisotropy generated at these shocks, and find, for $\\eta u_{\\rm s}\\approx1$, that the spectral index softens by unity and the acceleration time increases by a factor of two compared to the standard result of diffusive shock acceleration theory. These results provide a theoretical basis for the thirty-year-old conjecture that a supernova exploding into the wind of a Wolf-Rayet star may accelerate protons to an energy exceeding $10^{15}\\,$eV.

  3. DUSTY BLAST WAVES OF TWO YOUNG LARGE MAGELLANIC CLOUD SUPERNOVA REMNANTS: CONSTRAINTS ON POST-SHOCK COMPRESSION

    International Nuclear Information System (INIS)

    We present results from mid-IR spectroscopic observations of two young supernova remnants (SNRs) in the Large Magellanic Cloud made with the Spitzer Space Telescope. We imaged SNRs B0509-67.5 and B0519-69.0 with 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 Spitzer Infrared Spectrograph (IRS) data to estimate the density of the post-shock 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 composition assumed, and we explore the effects of differing grain porosity on the model fits. We also analyze archival 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 medium. We use model fits to IRS spectra to predict X-ray O line strengths for various grain models and values of the shock compression ratio. For 0509-67.5, we find that compact (solid) grain models require nearly all O lines in X-ray spectra to originate in reverse-shocked ejecta. Porous dust grains would lower the strength of ejecta lines relative to those arising in the shocked ambient medium. In 0519-69.0, we find significant evidence for a higher than standard ccant evidence for a higher than standard compression ratio of 12, implying efficient cosmic-ray acceleration by the blast wave. A compact grain model is favored over porous grain models. We find that the dust-to-gas mass ratio of the ambient medium is significantly lower than what is expected in the interstellar medium.

  4. 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...

  5. Missing supernova remnants

    International Nuclear Information System (INIS)

    The discrepancy between supernova explosion rates estimated from statistics of pulsars and of supernova remnants (SNRs) is well conciliated, if we consider that a considerable fraction of SNRs is missing. As the causes of missing SNRs, we have examined two cases, i.e., the supernova explosions have occurred in a hot, rarefied ambient matter or within stellar wind bubbles. For both cases, usual shell-forming radio SNRs are not expected at the stage, when their radii are smaller than --30 pc. From these, we predict the supernova rate would be (2 -- 5) x r sub(SN)sup(ob), with r sub(SN)sup(ob) being the rate determined from the counts of radio SNRs. This rate is not inconsistent with the one determined from pulsar statistics. Some other problems on missing SNRs will also be discussed. (author)

  6. 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.

  7. What Shapes Supernova Remnants?

    CERN Document Server

    Lopez, Laura A

    2013-01-01

    Evidence has mounted that Type Ia and core-collapse (CC) supernovae (SNe) can have substantial deviations from spherical symmetry; one such piece of evidence is the complex morphologies of supernova remnants (SNRs). However, the relative role of the explosion geometry and the environment in shaping SNRs remains an outstanding question. Recently, we have developed techniques to quantify the morphologies of SNRs, and we have applied these methods to the extensive X-ray and infrared archival images available of Milky Way and Magellanic Cloud SNRs. In this proceeding, we highlight some results from these studies, with particular emphasis on SNR asymmetries and whether they arise from "nature" versus "nurture".

  8. 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.

  9. Efficient Collisionless Electron Heating at the Reverse Shocks of Young Supernova Remnants Revealed by Fe-K Emission Diagnostics

    Science.gov (United States)

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

    2014-08-01

    Although collisionless shocks are ubiquitous in astrophysics, their fundamental properties are still poorly understood. In particular, the process known as collisionless electron heating is one of the main open issues in shock physics. Here we present Suzaku deep observations of the supernova remnants (SNRs) Tycho and 0509-67.5, showing the first robust evidence for efficient collisionless heating of electrons at their reverse shocks. We detect Fe K-beta (3p->1s) fluorescence emission at ~7.1 keV, which is expected only from low-ionization plasma where Fe ions still have many 3p electrons, and so key to diagnosing the plasma state of the immediate postshock ejecta. For Tycho SNR, we reveal that the K-beta emission peaks at a smaller radius than Fe K-alpha (2p->1s) fluorescence dominated by a relatively highly-ionized component. This updates the reverse shock radius of this SNR previously determined using the high-resolution Chandra image. Comparison with our hydrodynamical simulations requires the electron temperature at the reverse shock front to be more than 10 keV, about 1000 times higher than expected from Coulomb collisions alone.

  10. Supernova remnants: the X-ray perspective

    Science.gov (United States)

    Vink, Jacco

    2012-12-01

    Supernova remnants are beautiful astronomical objects that are also of high scientific interest, because they provide insights into supernova explosion mechanisms, and because they are the likely sources of Galactic cosmic rays. X-ray observations are an important means to study these objects. And in particular the advances made in X-ray imaging spectroscopy over the last two decades has greatly increased our knowledge about supernova remnants. It has made it possible to map the products of fresh nucleosynthesis, and resulted in the identification of regions near shock fronts that emit X-ray synchrotron radiation. Since X-ray synchrotron radiation requires 10-100 TeV electrons, which lose their energies rapidly, the study of X-ray synchrotron radiation has revealed those regions where active and rapid particle acceleration is taking place. In this text all the relevant aspects of X-ray emission from supernova remnants are reviewed and put into the context of supernova explosion properties and the physics and evolution of supernova remnants. The first half of this review has a more tutorial style and discusses the basics of supernova remnant physics and X-ray spectroscopy of the hot plasmas they contain. This includes hydrodynamics, shock heating, thermal conduction, radiation processes, non-equilibrium ionization, He-like ion triplet lines, and cosmic ray acceleration. The second half offers a review of the advances made in field of X-ray spectroscopy of supernova remnants during the last 15 year. This period coincides with the availability of X-ray imaging spectrometers. In addition, I discuss the results of high resolution X-ray spectroscopy with the Chandra and XMM-Newton gratings. Although these instruments are not ideal for studying extended sources, they nevertheless provided interesting results for a limited number of remnants. These results provide a glimpse of what may be achieved with future microcalorimeters that will be available on board future X-ray observatories. In discussing the results of the last 15 years I have chosen to discuss a few topics that are of particular interest. These include the properties of Type Ia supernova remnants, which appear to be regularly shaped and have stratified ejecta, in contrast to core collapse supernova remnants, which have patchy ejecta distributions. For core collapse supernova remnants I discuss the spatial distribution of fresh nucleosynthesis products, but also their properties in connection to the neutron stars they contain. For the mature supernova remnants I focus on the prototypal supernova remnants Vela and the Cygnus Loop. And I discuss the interesting class of mixed-morphology remnants. Many of these mature supernova remnants contain still plasma with enhanced ejecta abundances. Over the last five years it has also become clear that many mixed-morphology remnants contain plasma that is overionized. This is in contrast to most other supernova remnants, which contain underionized plasmas. This text ends with a review of X-ray synchrotron radiation from shock regions, which has made it clear that some form of magnetic-field amplification is operating near shocks, and is an indication of efficient cosmic-ray acceleration.

  11. 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...

  12. The Outer Shock of the Oxygen-Rich Supernova Remnant G292.0+1.8: Evidence for the Interaction with the Stellar Winds from its Massive Progenitor

    OpenAIRE

    Lee, Jae-joon; Park, Sangwook; Hughes, John P.; Slane, Patrick O.; Gaensler, B. M.; Ghavamian, Parviz; Burrows, David N.

    2010-01-01

    We study the outer-shock structure of the oxygen-rich supernova remnant G292.0+1.8, using a deep observation with the Chandra X-ray Observatory. We measure radial variations of the electron temperature and emission measure that we identify as the outer shock propagating into a medium with a radially decreasing density profile. The inferred ambient density structure is consistent with models for the circumstellar wind of a massive progenitor star rather than for a uniform int...

  13. Superposition of supernovae remnant imagery

    International Nuclear Information System (INIS)

    The superposition of the X-ray, optical, and radio imagery of supernova remnants in the Cygnus Loop region is described. The radio data of the region was obtained using the Westerbork interferometer, and the optical image was recorded by the NASA Wide Field Camera. The X-ray imagery was obtained using the High Resolution Imager. The mechanisms by which the supernova ejecta and the swept-up material shock the interstellar medium are studied by the resampling of the imagery onto a common celestial grid. The initial results indicate a radio arc in the northeastern portion of the region that is along the faintest outermost filaments, and a separate radio arc along the brightest filaments

  14. 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...

  15. Probing the Reverse Shock in an Oxygen-Rich Supernovae Remnant

    Science.gov (United States)

    Gaetz, Terrance (Principal Investigator); Sonneborn, George (Technical Monitor)

    2005-01-01

    The purpose of this investigation is to examine the O VI emission from the X-ray bright ring of the supernova remnant 1 E0102.2-729 in the small Magellanic cloud. Three pointings were positioned tangent to the ring, north (N), northeast (NE), and southeast (SE), to examine a range of X-ray emitting regions overlapping a range of optical [O III] nebulosity and to examine the velocity structure. One background pointing was also obtained, but it was contaminated by a star. The background levels in the pointings on the remnant were low enough that the background pointing was not required for the remaining analysis. The SE pointing was reobserved in August, 2004, in order to bring the total exposure up to the originally requested 15 ks. The archive notified us of the data's availability in mid September. Significant broad O VI 1032 and O VI 1038 emission was found, brightest in the NE and SE pointings. In the NE and SE pointings, the FWHM of the broad O VI component is approx.800-1000 km/s, while in the N pointing, the line is approx.1500 km/s wide. The O VI is redshifted in the N (approx.380 km/s) and NE (approx.60 km/s) but is blueshifted in the SE (approx. -160 km/s). These FUSE O VI velocity dispersions can be compared to the X-ray gas velocities inferred from Doppler distortions in the Chandra X-ray data as reported by Flanagan et al. 2004 (ApJ 605, 230). The bulk velocities in the X-ray bright ring of order +/- 1000 km/s, comparable to the velocity dispersion seen in the FUSE data. However, the X-ray data indicates a redshift of approx.1000 km/s in the SE, while the FUSE data show a blueshift of approx.160 km/s, underscoring the complex velocity structure in this remnant. The O VI fluxes estimated from the fits to the FUSE data were combined with X-ray (XMM- Newton) O VI1 and O VIII fluxes and compared with predictions from a plasma nonequilibrium ionization model in a "line-based" analysis. We found that the plasma departs significantly from collisional ionization equilibrium, particularly in the SE, and that the plasma excitation conditions vary among the pointings: the O plasma sees different conditions than the Ne and Mg plasmas.

  16. Localized SiO Emission Triggered by the Passage of the W51C Supernova Remnant Shock

    Science.gov (United States)

    Dumas, G.; Vaupré, S.; Ceccarelli, C.; Hily-Blant, P.; Dubus, G.; Montmerle, T.; Gabici, S.

    2014-05-01

    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 H13CO+(1-0) and DCO+(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.

  17. Infrared Studies of Molecular Shocks in the Supernova Remnant HB21: I. Thermal Admixture of Shocked H_2 Gas in the North

    CERN Document Server

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

    2008-01-01

    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 AKARI satellite and the Wide InfraRed Camera (WIRC) at the Palomar 5 m telescope. The IRC 7 um (S7), 11 um (S11), and 15 um (L15) band images and the WIRC H2 v = 1 -> 0 S(1) 2.12 um 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, dN ~ T^-b dT--with n(H2) ~ 10^3 cm^-3, b ~ 3, and N(H2 ;T > 100K) ~ 3x10^20 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-sc...

  18. Antiprotons Produced in Supernova Remnants

    CERN Document Server

    Berezhko, E G

    2014-01-01

    We present the energy spectrum of antiproton cosmic ray (CR) component calculated on the basis of the nonlinear kinetic model of CR production in supernova remnants (SNR). The model includes reacceleration of already existing in interstellar medium antiprotons as well as creation of antiprotons in nuclear collisions of accelerated protons with gas nuclei and their subsequent acceleration by SNR shock. It is shown that antiprotons production in SNRs produces 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 five. Calculated antiproton spectrum is well 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 positrons and secondary nuclei and show that the measured boron-to-carbon and positron-to-electron ratios are consistent with the significant SNR contribution.

  19. 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)

  20. Non Parametric Determination of Acceleration Characteristics in Supernova Shocks Based on Spectra of Cosmic Rays and Remnant Radiation

    Science.gov (United States)

    Petrosian, Vahe; Chen, Qingrong

    2014-06-01

    We have developed an inversion method for determination of the characteristics of the acceleration mechanism directly and non-parametrically from observations, in contrast to the usual forward fitting of parametric model variables to observations. This is done in the frame work of the so-called leaky box model of acceleration, valid for isotropic momentum distribution and for volume integrated characteristics in a finite acceleration site. We consider both acceleration by shocks and stochastic acceleration where turbulence plays the primary role to determine the acceleration, scattering and escape rates. Assuming a knowledge of the background plasma the model has essentially two unknown parameters, namely the momentum and pitch angle scattering diffusion coefficients, which can be evaluated given two independent spectral observations. These coefficients are obtained directly from the spectrum of radiation from the supernova remnants (SNRs), which gives the spectrum of accelerated particles, and the observed spectrum of cosmic rays (CRs), which are related to the spectrum of particles escaping the SNRs. The results obtained from application of this method will be presented.

  1. Supernovae, supernova remnants, and superbubbles

    Science.gov (United States)

    Shull, J. Michael

    1995-01-01

    Supernovae, supernova remmants, and superbubbles in the interstellar medium are reviewed, with an emphasis on infrared studies of these phenomena. Superbubbles are likely to be relevant for understanding such Galactic and extragalactic issues as the photoionization of gas in the Galactic halo, 'superwinds,' and the contribution of 'starbursts' to photoionization of the intergalactic medium.

  2. Molecules and dust in Cassiopeia A. I. Synthesis in the supernova phase and processing by the reverse shock in the clumpy remnant

    Science.gov (United States)

    Biscaro, Chiara; Cherchneff, Isabelle

    2014-04-01

    Aims: We study the chemistry of the type IIb supernova ejecta, which led to the Cas A supernova remnant, to assess the chemical type and quantity of dust that forms and evolves in the remnant phase. We later model a dense oxygen-rich ejecta knot, which is crossed by the reverse shock in Cas A, to study the evolution of the clump gas phase and the possibility to reform dust clusters in the post-reverse shock gas. Methods: The chemistry is described by a chemical network that includes all possible processes that are efficient at high gas temperatures and densities. The formation of key bimolecular species (e.g., CO and SiO) and dust clusters of silicates, alumina, silica, metal carbides and sulphides, pure metals, and amorphous carbon is considered. A set of stiff, coupled ordinary differential equations is solved for the conditions pertaining to both the SN ejecta and the post-reverse shock gas. Results: We find that the ejecta of type IIb SNe are unable to form large amounts of molecules and molecular clusters that are precursors to dust grains, when compared to their type II-P counterparts, because of their diffuse ejecta. The ejecta gas density needs to be increased by several orders of magnitude to allow for the formation of dust clusters. We show that the chemical composition of the dust clusters that form changes drastically and gains in chemical complexity with increasing gas density. Hence, the ejecta of the Cas A supernova progenitor must have been in the form of dense clumps to account for the dust chemical composition and masses that have been inferred from infrared observations of Cas A. As for the impact of the reverse shock on dense ejecta clumps, we show that the ejecta molecules that are destroyed by the shock reform in the post-reverse shock gas with lower abundances than those of the initial ejecta clump, except for SiO. These molecules include CO, SiS, and O2. On the other hand, dust clusters are destroyed by the reverse shock and do not reform in the post-reverse shock gas, even for the highest gas density. These results indicate that the synthesis of dust grains out of the gas phase in the dense knots of Cas A and in other supernova remnants is unlikely.

  3. On the radio spectra of supernova remnants

    OpenAIRE

    Uros?evic?, 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 acce...

  4. Pulsar-supernova remnant associations

    Science.gov (United States)

    Manchester, R. N.

    1994-04-01

    Pulsars and supernova remnants (SNRs) are both believed to be formed in the supernova explosions of massive stars. Therefore one might expect to see associations between the two classes of object. In fact, up until a couple of years ago, there was only a handful of believable associations and even now there are only nine or ten. It is relatively easy to explain why such a small fraction of the 600 or so known pulsars are associated with supernova remnants. The average pulsar lifetime is of the order of 106 years, whereas the average supernova remnant is detectable for about 104 years. Therefore, one would expect only about one percent of pulsars to be still associated, as is observed. It is somewhat more difficult to explain why so few of the 150 known supernova remnants have associated pulsars. The main factor is that supernova remnants are seen throughout the Galaxy whereas most pulsars are detectable only relatively close to the Sun, within a few kiloparsec. Another factor is that pulsar emission is beamed, so even if a pulsar exists in a relatively nearby supernova remnant, it may be undetectable. The most believable of the suggested associations are listed. Associations which are possible but by no means certain are indicated by question mark. For the more certain associations, the pulsar position is within the SNR boundaries (an exception is 'The Duck', where the pulsar is at the tip of the 'beak'), the distance estimates for the pulsar and SNR are compatible, and the age estimates are likewise compatible. References to most of these associations may be found in the pulsar catalog of Taylor, Manchester and Lyne (1993, Astrophys. J. Suppl., 88, 529). Recent references not included in the catalog are for PSR B1706-44 (McAdam, Osborne and Parkinson, 1993, Nature, 361, 516) and PSR B2334+61 (Kulkarni et al., 1993, Nature, 362, 135).

  5. Turbulence and particle acceleration in collisionless supernovae remnant shocks: I-Anisotropic spectra solutions

    CERN Document Server

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

    2006-01-01

    This paper investigates the nature of the MHD turbulence excited by the streaming of accelerated cosmic rays in a shock wave precursor. The two recognised regimes (non-resonant and resonant) of the streaming instability are taken into account. We show that the non-resonant instability is very efficient and saturates through a balance between its growth and non-linear transfer. The cosmic-ray resonant instability then takes over and is quenched by advection through the shock. The level of turbulence is determined by the non-resonant regime if the shock velocity $V_{\\rm sh}$ is larger than a few times $\\xi_{\\rm CR} c$, where $\\xi_{\\rm CR}$ is the ratio of the cosmic-ray pressure to the shock kinetic energy. The instability determines the dependence of the spectrum with respect to $k_\\parallel$ (wavenumbers along the shock normal). The transverse cascade of Alfv\\'en waves simultaneously determines the dependence in $k_{\\perp}$. We also study the redistribution of turbulent energy between forward and backward wav...

  6. The Remnants of Intergalactic Supernovae

    OpenAIRE

    Maoz, Dan; Waxman, Eli; Loeb, Abraham

    2005-01-01

    Intergalactic type-Ia supernovae (SNe-Ia) have been discovered recently in rich galaxy clusters, likely the descendants of an intergalactic stellar population found in recent years through a variety of tracers. We estimate the observational signatures of the associated SN remnants (SNRs) in the unusual intracluster medium (ICM) environment. If SNe-Ia still have a circumstellar medium (CSM) at the time of explosion, then their remnants are visible in the optical for ~100-1000...

  7. Molecules and dust in Cas A: I - Synthesis in the supernova phase and processing by the reverse shock in the clumpy remnant

    CERN Document Server

    Biscaro, Chiara

    2014-01-01

    Aims: We study the chemistry of the Type IIb supernova ejecta that led to the Cas A supernova remnant to assess the chemical type and quantity of dust that forms and evolves in the remnant phase. We later model a dense oxygen-rich ejecta knot that is crossed by the reverse shock in Cas A to study the evolution of the clump gas phase and the possibility to reform dust clusters in the post-reverse shock gas. Methods: A chemical network including all processes efficient at high gas temperatures and densities is considered. The formation of key bimolecular species (CO, SiO) and dust clusters is described. Stiff, coupled, ordinary, differential equations are solved for the conditions pertaining to both the SN ejecta and the post-reverse shock gas. Results: We find that the ejecta of Type IIb SNe are unable to form large amounts of molecules and dust clusters as opposed to their Type II-P counterparts because of their diffuse ejecta. The gas density needs to be increased by several orders of magnitude to allow the ...

  8. Multiwavelength Signatures of Cosmic Ray Acceleration by Young Supernova Remnants

    OpenAIRE

    Vink, Jacco

    2008-01-01

    An overview is given of multiwavelength observations of young supernova remnants, with a focus on the observational signatures of efficient cosmic ray acceleration. Some of the effects that may be attributed to efficient cosmic ray acceleration are the radial magnetic fields in young supernova remnants, magnetic field amplification as determined with X-ray imaging spectroscopy, evidence for large post-shock compression factors, and low plasma temperatures, as measured with h...

  9. 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 remnantclouds, 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

  10. Hydrodynamic simulations of the interaction of supernova shock waves with a clumpy environment: the case of the RX J0852.0-4622 (Vela Jr) supernova remnant

    CERN Document Server

    Obergaulinger, M; Müller, E; Smoot, G F

    2014-01-01

    Observations in all electromagnetic bands show that many supernova remnants (SNRs) have a very aspherical shape. This can be the result of asymmetries in the supernova explosion or a clumpy circumstellar medium. We study the generation of inhomogeneities and the mixing of elements arising from these two sources in multidimensional hydrodynamic simulations of the propagation of a supernova blast wave into a cloudy environment. We model a specific SNR, Vela Jr (RX J0852.0-4622). By comparing our results with recent observations, we can constrain the properties of the explosion. We find that a very energetic explosion of several 10^{51} erg occurring roughly about 800 years ago is consistent with the shape and emission of the SNR, as well as a supernova with an energy closer to the canonical value of 10^{51} erg a few thousand years ago.

  11. The Outer Shock of the Oxygen-Rich Supernova Remnant G292.0+1.8: Evidence for the Interaction with the Stellar Winds from its Massive Progenitor

    CERN Document Server

    Lee, Jae-Joon; Hughes, John P; Slane, Patrick O; Gaensler, B M; Ghavamian, Parviz; Burrows, David N

    2010-01-01

    We study the outer-shock structure of the oxygen-rich supernova remnant G292.0+1.8, using a deep observation with the Chandra X-ray Observatory. We measure radial variations of the electron temperature and emission measure that we identify as the outer shock propagating into a medium with a radially decreasing density profile. The inferred ambient density structure is consistent with models for the circumstellar wind of a massive progenitor star rather than for a uniform interstellar medium. The estimated wind density n_H = 0.1 ~ 0.3 cm^-3) at the current outer radius (~7.7 pc) of the remnant is consistent with a slow wind from a red supergiant (RSG) star. The total mass of the wind is estimated to be ~ 15 - 40 solar mass (depending on the estimated density range), assuming that the wind extended down to near the surface of the progenitor. The overall kinematics of G292.0+1.8 are consistent with the remnant expanding through the RSG wind.

  12. THE OUTER SHOCK OF THE OXYGEN-RICH SUPERNOVA REMNANT G292.0+1.8: EVIDENCE FOR THE INTERACTION WITH THE STELLAR WINDS FROM ITS MASSIVE PROGENITOR

    International Nuclear Information System (INIS)

    We study the outer-shock structure of the oxygen-rich supernova remnant G292.0+1.8 using a deep observation with the Chandra X-ray Observatory. We measure radial variations of the electron temperature and emission measure that we identify as the outer shock propagating into a medium with a radially decreasing density profile. The inferred ambient density structure is consistent with models for the circumstellar wind of a massive progenitor star rather than for a uniform interstellar medium. The estimated wind density (nH = 0.1-0.3 cm-3) at the current outer radius (? 7.7 pc) of the remnant is consistent with a slow wind from a red supergiant (RSG) star. The total mass of the wind is estimated to be ?15-40 Msun (depending on the estimated density range), assuming that the wind extended down to near the surface of the progenitor. The overall kinematics of G292.0+1.8 are consistent with the remnant expanding through the RSG wind.

  13. An X-Ray Pulsar, Metal-rich Ejecta, and Shocked Ambient Medium in the Supernova Remnant G292.0+1.8

    CERN Document Server

    Hughes, J P; Park, S; Slane, P O; Friedman, Robert B.; Hughes, John P.; Park, Sangwook; Slane, Patrick

    2004-01-01

    We report the discovery of pulsed X-ray emission from the compact object CXOU J112439.1-591620 within the Galactic supernova remnant G292.0+1.8 using the High Resolution Camera on the Chandra X-Ray Observatory. The X-ray period is consistent with the extrapolation of the radio period and spindown rate of PSR J1124-5916. The X-ray pulse is single peaked and broad. There is no optical counterpart to a limit of M_V ~ 26. The pressure in the pulsar wind nebula is considerably less than that in the reverse-shock-heated ejecta and circumstellar medium, indicating that the reverse shock has not yet begun to interact with the nebula.

  14. Ortho-to-Para Ratio Studies of Shocked H2 Gas in the Two Supernova Remnants IC 443 and HB 21

    CERN Document Server

    Shinn, Jong-Ho; Moon, Dae-Sik

    2012-01-01

    We present near-infrared (2.5-5.0 {\\mu}m) spectral studies of shocked H2 gas in the two supernova remnants IC 443 and HB 21, which are well known for their interactions with nearby molecular clouds. The observations were performed with Infrared Camera (IRC) aboard the AKARI satellite. At the energy range 7000 K <= E(v,J) <= 20000 K, the shocked H2 gas in IC 443 shows an ortho-to-para ratio (OPR) of 2.4+0.3-0.2, which is significantly lower than the equilibrium value 3, suggesting the existence of non-equilibrium OPR. The shocked gas in HB 21 also indicates a potential non-equilibrium OPR in the range of 1.8-2.0. The level populations are well described by the power-law thermal admixture model with a single OPR, where the temperature integration range is 1000-4000 K. We conclude that the obtained non-equilibrium OPR probably originates from the reformed H2 gas of dissociative J-shocks, considering several factors such as the shock combination requirement, the line ratios, and the possibility that H2 gas ...

  15. 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...

  16. The Blast Wave of Tycho's Supernova Remnant

    Science.gov (United States)

    Cassam-Chenaï, Gamil; Hughes, John P.; Ballet, Jean; Decourchelle, Anne

    2007-08-01

    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 back-reaction that accounts for the observed ratio of radii between the blast wave and contact discontinuity. Two different assumptions were made about the postshock 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 postshock region (synchrotron losses limited rim case), and another where the amplified magnetic field is rapidly damped behind the blast wave (magnetic damping case). Both cases fairly well describe the X-ray data; however, both fail to explain the observed radio profile. The projected synchrotron emission leaves little room for the presence of thermal emission from the shocked ambient medium. This can only be explained if the preshock ambient medium density in the vicinity of the Tycho supernova remnant is below 0.6 cm-3.

  17. 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.

  18. 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.

  19. Measuring the cosmic ray acceleration efficiency of a supernova remnant

    CERN Document Server

    Helder, E A; Bassa, C G; Bamba, A; Bleeker, J A M; Funk, S; Ghavamian, P; Van der Heyden, K J; Verbunt, F; Yamazaki, R; 10.1126/science.1173383

    2009-01-01

    Cosmic rays are the most energetic particles arriving at earth. Although most of them are thought to be accelerated by supernova remnants, the details of the acceleration process and its efficiency are not well determined. Here we show that the pressure induced by cosmic rays exceeds the thermal pressure behind the northeast shock of the supernova remnant RCW 86, where the X-ray emission is dominated by synchrotron radiation from ultra-relativistic electrons. We determined the cosmic-ray content from the thermal Doppler broadening measured with optical spectroscopy, combined with a proper-motion study in X- rays. The measured post-shock proton temperature in combination with the shock velocity does not agree with standard shock heating, implying that >50% of the post-shock pressure is produced by cosmic rays.

  20. Acoustic waves in supernova remnants

    International Nuclear Information System (INIS)

    When the Mach number of a supernova shock wave, propagating through the hot interstellar gas, is less than the critical value 2.76, the interaction of the shock with an interstellar cloud produces a reflected pressure pulse that propagates away from the cloud as an acoustic wave. A preliminary analysis indicates that about 4% of the energy of an exploding supernova shell is converted into such waves. When the postshock gas temperature exceeds 2 x 106 K, waves as short as 6 pc are damped in less than a wavelength, returning the energy to the hot gas. Longer waves, especially at later stages, are less strongly damped, and are superposed in the hot gas to create a fluctuating magnetoacoustic field, with typical periods of about 105 years. In the warm neutral clouds at temperatures of about 8000 K these waves are rapidly damped by plasma slip (ambipolar diffusion), providing a heat source that may account for the temperatures of thse clouds

  1. Spitzer Observations of Molecular Hydrogen in Interacting Supernova Remnants

    OpenAIRE

    Hewitt, John W.; Rho, Jeonghee; Andersen, Morten; Reach, William T.

    2009-01-01

    With Spitzer IRS we have obtained sensitive low-resolution spectroscopy from 5 to 35 microns for six supernova remnants (SNRs) that show evidence of shocked molecular gas: Kes 69, 3C 396, Kes 17, G346.6-0.2, G348.5-0.0 and G349.7+0.2. Bright, pure-rotational lines of molecular hydrogen are detected at the shock front in all remnants, indicative of radiative cooling from shocks interacting with dense clouds. We find the excitation of H2 S(0)-S(7) lines in these SNRs requires ...

  2. 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.

  3. X-ray imaging: supernova remnants

    International Nuclear Information System (INIS)

    The Einstein Observatory has provided astronomers with the first opportunity to obtain optical quality images of extended X-ray sources. Such pictures of supernova remnants, for example, yield a wealth of information on the dynamics and evolution of the expanding blast wave, the possible collapsed remnants of the exploded star, and the structure of the interstellar medium. The author reviews imaging observation of over 50 supernova remnants obtained during the first year of the Observatory's operation. Although analysis of these results is still in its infancy, it is already possible to draw important conclusions regarding models for stellar explosions, remnant evolution, neutron star formation, and the interstellar medium. (Auth.)

  4. 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...

  5. Spectra of supernova remnants in M33

    International Nuclear Information System (INIS)

    Spectral data are presented confirming the classification of three nebulae in M33 as supernova remnants, a result supported by available radio data. A comparison with other supernova remnants and model calculations has been made. Several lines of evidence indicate a nitrogen abundance slightly lower than that in the Galaxy, and consistent with the abundance trends in H II regions at similar radial distance in M33 reported previously. Discrepancies still exist, however, between the observed spectra and model calculations. (author)

  6. Hadronic Gamma Rays from Supernova Remnants

    CERN Document Server

    Moskalenko, I V; Malkov, M A; Diamond, P H

    2007-01-01

    A gas cloud near a supernova remnant (SNR) provides a target for pp-collisions leading to subsequent gamma-ray emission through neutral pion decay. The assumption of a power-law ambient spectrum of accelerated particles with index near -2 is usually built into models predicting the spectra of very-high energy (VHE) gamma-ray emission from SNRs. However, if the gas cloud is located at some distance from the SNR shock, this assumption is not necessarily correct. In this case, the particles which interact with the cloud are those leaking from the shock and their spectrum is approximately monoenergetic with the injection energy gradually decreasing as the SNR ages. The gamma-ray spectrum resulting from particle interactions with the gas cloud will be flatter than expected, with the cutoff defined by the pion momentum distribution in the laboratory frame. We evaluate the flux of particles escaping from a SNR shock and apply the results to the VHE diffuse emission detected by the HESS at the Galactic centre.

  7. The Structure of the Oxygen-rich Supernova Remnant G292.0+1.8 from Chandra X-ray Images Shocked Ejecta and Circumstellar Medium

    CERN Document Server

    Park, S; Hughes, J P; Slane, P O; Burrows, D N; Garmire, G P; Nousek, J A; Park, Sangwook; Roming, Peter W. A.; Hughes, John P.; Slane, Patrick O.; Burrows, David N.; Garmire, Gordon P.; Nousek, John A.

    2001-01-01

    We present results from the observation of the young Galactic supernova remnant (SNR) G292.0+1.8 with the Advanced CCD Imaging Spectrometer (ACIS) on board the {\\it Chandra X-ray Observatory}. In the 0.3 $-$ 8 keV band, the high resolution ACIS images reveal a complex morphology consisting of knots and filaments, as well as the blast wave around the periphery of the SNR. We present equivalent width (EW) maps for the elemental species O, Ne, Mg, and Si, which allow us to identify regions of enhanced metallicity in the SNR. G292.0+1.8 is bright in O, Ne, and Si; weaker in S and Ar; with little Fe. The EW and broad-band images indicate that the metal-rich ejecta are distributed primarily around the periphery of the SNR. The central belt-like structure has normal solar-type composition, strongly suggesting that it is primarily emission from shocked circumstellar medium rather than metal-rich ejecta. We propose that the belt traces its origin to enhanced mass loss in the star's equatorial plane during the slow, re...

  8. Pulsar Wind Nebulae in Evolved Supernova Remnants

    CERN Document Server

    Blondin, J M; Frierson, D M; Blondin, John M.; Chevalier, Roger A.; Frierson, Dargan M.

    2001-01-01

    For pulsars similar to the one in the Crab Nebula, most of the energy input to the surrounding wind nebula occurs on a timescale of less than 1000 years; during this time, the nebula expands into freely expanding supernova ejecta. On a timescale 10,000 years, the interaction of the supernova with the surrounding medium drives a reverse shock front toward the center of the remnant, where it crushes the PWN (pulsar wind nebula). One- and two-dimensional, two-fluid simulations of the crushing and re-expansion phases of a PWN show that (1) these phases are subject to Rayleigh-Taylor instabilities that result in the mixing of thermal and nonthermal fluids, and (2) asymmetries in the surrounding interstellar medium give rise to asymmetries in the position of the PWN relative to the pulsar and explosion site. These effects are expected to be observable in the radio emission from evolved PWN because of the long lifetimes of radio emitting electrons. The scenario can explain the chaotic and asymmetric appearance of th...

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

    OpenAIRE

    Inoue, Tsuyoshi; Yamazaki, Ryo; 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 f...

  10. X-Ray Measured Dynamics of Tycho's Supernova Remnant

    Science.gov (United States)

    Katsuda, Satoru; Petre, Robert; Hughes, John; Hwang, Una; Yamaguchi, Hiroya; Hayato, Asami; Mori, Koji; Tsunemi, Hiroshi

    2010-01-01

    We present X-ray proper-motion measurements of the forward shock and reverse-shocked ejecta in Tycho's supernova remnant, based on three sets of archival Chandra data taken in 2000, 2003, and 2007. We find that the proper motion of the edge of the remnant (i.e., the forward shock and protruding ejecta knots) varies from 0.''20 yr-1 (expansion index m = 0.33, where R = tm ) to 0.''40 yr-1 (m = 0.65) with azimuthal angle in 2000-2007 measurements, and 0.''14 yr-1 (m = 0.26) to 0.''40 yr-1 (m = 0.65) in 2003-2007 measurements. The azimuthal variation of the proper motion and the average expansion index of [approx]0.5 are consistent with those derived from radio observations. We also find proper motion and expansion index of the reverse-shocked ejecta to be 0.''21-0.''31 yr-1 and 0.43-0.64, respectively. From a comparison of the measured m-value with Type Ia supernova evolutionary models, we find a pre-shock ambient density around the remnant of [less, similar]0.2 cm-3.

  11. The acceleration of cosmic rays in supernova remnants

    International Nuclear Information System (INIS)

    The idea that the bulk of cosmic rays below 10 GeV are accelerated in supernova remnants suggests that cosmic rays should also exhibit intensity variations on a scale comparable with the linear size of a representative remnant. Following the general spirit of shock-wave acceleration models, here Monte Carlo simulations are carried out to predict what this scale should be and then corroborative evidence is presented from an autocorrelation analysis of the COS B and SAS II ?-ray data for the latitude range |b|=10-200 ('near Galaxy') and |b| 0 ('far Galaxy'). (author)

  12. CARBON MONOXIDE IN THE CASSIOPEIA A SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    We report the likely detection of near-infrared 2.29 ?m first overtone carbon monoxide (CO) emission from the young supernova (SN) remnant Cassiopeia A (Cas A). The continuum-subtracted CO filter map reveals CO knots within the ejecta-rich reverse shock. We compare the first overtone CO emission with that found in the well studied supernova SN 1987A and find ?30 times less CO in Cas A. The presence of CO suggests that molecule mixing is small in the SN ejecta and that astrochemical processes and molecule formation may continue at least ?300 yr after the initial explosion.

  13. Evolution of multiple supernova remnants

    Science.gov (United States)

    Vasiliev, Evgenii O.; Nath, Biman B.; Shchekinov, Yuri

    2015-01-01

    Heating of the interstellar medium (ISM) by multiple supernova (SN) explosions is at the heart of producing galaxy-scale outflows in starburst galaxies. Standard models of outflows assume a high efficiency of SNe in heating the gas to X-ray emitting temperatures and filling the central region of starburst with hot gas, in order to launch vigorous outflows. We use hydrodynamical simulations to study the efficiency of multiple SNe in heating the ISM and filling the volume with gas of high temperatures. We argue that it is important for SN remnants to have a large filling factor and a large heating efficiency. For this, they have to be clustered in space and time, and keep exploding until the hot gas percolates through the whole region, in order to compensate for the radiative loss. In the case of a limited number of SNe, we find that although the filling factor can be large, the heating efficiency declines after reaching a large value. In the case of a continuous series of SNe, the hot gas (T ? 3 × 106 K) can percolate through the whole region after the total volume filling factor reaches a threshold of ˜0.3. The efficiency of heating the gas to X-ray temperatures can be ?0.1 after this percolation epoch, which occurs after a period of ?10 Myr for a typical starburst SN rate density of ?SN ? 10-9 pc-3 yr-1 and gas density of n ? 10 cm-3 in starburst nuclei regions. This matches the recent observations of a time delay of similar order between the onset of star formation and galactic outflows. The efficiency to heat gas up to X-ray temperatures (?106.5 K) roughly scales as ? _SN^{0.2} n^{-0.6}. For a typical SN rate density and gas density in starburst nuclei, the heating efficiency is ˜0.15, also consistent with previous interpretations from X-ray observations. We discuss the implications of our results with regard to observational diagnostics of ionic ratios and emission measures in starburst nuclei regions.

  14. Nonuniform abundances in young supernova remnants

    International Nuclear Information System (INIS)

    In a young SNR, the possible variation in composition should not be ignored in interpreting observational data. As an example, it is explicitly shown that the Becker et al. observations of Tycho's supernova remnant with HEAO 2 (Einstein) Observatory are consistent with a previously calculated numerical model of a Type I supernova explosion incorporating decay of 56Ni. In young SNRs it may be possible to detect directly the compositions characteristic of the layered structure of the presupernova, not merely the average abundance

  15. 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.

  16. 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...

  17. Ultra High Energy Neutrinos from Supernova Remnants

    OpenAIRE

    Roy, Mou

    1999-01-01

    In this paper we discuss possible ultra high energy ($\\ge$ TeV) neutrino emission from Supernova Remnants (SNRs), specifically the hadronic gamma ray production models. Recent very high energy (VHE) $\\gamma$ ray observation from SNRs is the main motivation behind this study.

  18. 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.

  19. Supernovae and supernova remnants at high energies

    Science.gov (United States)

    Chevalier, Roger A.

    1990-01-01

    The physical phenomena that are observable with X- and gamma-ray observations of supernovae are discussed with respect to possible high-energy astrophysics experiments. Prompt photospheric emission and its echo are discussed, supernova radioactivity and neutron star effects are examined, and circumstellar and interstellar interaction are reviewed. The primary uncertainties are found to be the hardening of the spectrum by non-LTE effects and the amount of absorption of the radiation from the initial soft X-ray burst. The radioactivity in supernovae is theorized to lead to gamma-ray lines and continuum emission unless the event is low-mass type II. Gamma-ray observations are proposed to examine the efficiency of particle acceleration, and high-resolution spectroscopy can provide data regarding ionization, temperature, composition, and velocities of the X-ray-emitting gas.

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

    Energy Technology Data Exchange (ETDEWEB)

    Uchiyama, Y.; Aharonian, F.A.; Tanaka, T.; Takahashi, T.; Maeda, Y.; /JAERI, Tokai /Dublin Inst. /Heidelberg, Max Planck Inst. /SLAC

    2007-10-23

    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 (10{sup 15} eV) and beyond in young supernova remnants.

  1. High Energy Processes in Supernova Remnants Studied From Multiwawvelength Observations

    Science.gov (United States)

    Dickel, J. R.

    2002-05-01

    Supernova remnants release about 1051 ergs of mechanical energy into the circumstellar and interstellar medium. The expanding material slows as it sweeps up surrounding matter and amplifies any irregularities in its environs. Optical spectroscopy can be used to measure velocities and densities of the accumulated gas. Because the expansion is highly supersonic, shock waves quickly form. These shocks heat the gas to millions of kelvins producing bright thermal X-rays in both lines and the continuum. In turn, a major source of cooling of SNRs is in infrared spectral lines of excited ions. Surrounding dust can also be heated by the hot gas to produce infrared continuum emission. The strong shocks accelerate electrons to relativistic speeds, resulting in radio synchrotron emission. Rayleigh-Taylor instabilities at the interface of the ejected and swept-up material can further amplify the magnetic fields and particle energies to enhance the synchrotron radiation. Combination of multi-wavelength results is needed to fully characterize the energy budgets of supernova remnants. Core collapse supernovae from massive stars also leave a compact central object, either a neutron star or a black hole. These objects can eject a variety of rings and jets. The spin-down energy of the compact object can excite the pulsar wind nebula that grows around it and it is often powerful enough to produce even X-ray synchrotron radiation.

  2. Spitzer Observations of Molecular Hydrogen in Interacting Supernova Remnants

    CERN Document Server

    Hewitt, John W; Andersen, Morten; Reach, William T

    2009-01-01

    With Spitzer IRS we have obtained sensitive low-resolution spectroscopy from 5 to 35 microns for six supernova remnants (SNRs) that show evidence of shocked molecular gas: Kes 69, 3C 396, Kes 17, G346.6-0.2, G348.5-0.0 and G349.7+0.2. Bright, pure-rotational lines of molecular hydrogen are detected at the shock front in all remnants, indicative of radiative cooling from shocks interacting with dense clouds. We find the excitation of H2 S(0)-S(7) lines in these SNRs requires two non-dissociative shock components: a slow, 10 km/s C- shock through clumps of density 10^6 cm^-3, and a faster, 40-70 km/s C- shock through a medium of density 10^4 cm^-3. The ortho-to-para ratio for molecular hydrogen in the warm shocked gas is typically found to be much less than the LTE value, suggesting that these SNRs are propagating into cold quiescent clouds. Additionally a total of thirteen atomic fine-structure transitions of Ar+, Ar++, Fe+, Ne+, Ne++, S++, and Si+ are detected. The ionic emitting regions are spatially segrega...

  3. An atlas of confirmed and candidate supernova remnants in M33

    International Nuclear Information System (INIS)

    Thirty emission nebulae in M33 have been discovered which, on the basis of strong forbidden S II compared with H-alpha, are almost certainly supernova remnants. The total number of known supernova remnants in M33 is now about 50. The cumulative number versus diameter relationship for the nebulae in the sample appears to show evidence of shock deceleration. The number of supernova remnants in M33 is consistent with a supernova rate of one per 26-300 yr. The observations are described and positions, diameters, line ratios, and images of the new candidates are presented, as well as 10 previously known and two suggested supernova remnants in M33 that were in the survey region. 57 refs

  4. Forbidden Fe+ Emission from Supernovae Remnants in M33

    OpenAIRE

    Lumsden, S. L.; Puxley, P. J.

    1995-01-01

    Supernovae remnants are known to be luminous sources of infrared [FeII] emission. By studying how the luminosity scales with age, environment and other relevant factors, we can construct an [FeII] luminosity function for supernovae remnants. This will enable us to predict supernovae rates in starburst galaxies that are too distant for individual remnants to be resolved. First, however, we require accurate luminosities for a sample of remnants of varying ages, and in varying ...

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

    OpenAIRE

    W. P. Blair

    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...

  6. 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 offents. 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.

  7. A Supernova Remnant Collision with a Stellar Wind

    CERN Document Server

    Velazquez, P F; Raga, A C; Velazquez, Pablo F.; Koenigsberger, Gloria; Raga, Alejandro C.

    2003-01-01

    Numerical simulations of the interaction between supernova ejecta and a stellar wind are presented. We follow the temporal evolution of the shock fronts that are formed through such an interaction and determine the velocities, temperatures and densities. We model the X-ray emission from the SNR-stellar wind collision region and we compare it with recent results from X-ray observations carried out with the Chandra satellite of the SMC supernova remnant SNR 0057-7226 which could be interacting with the wind of the Wolf-Rayet system HD 5980. The simulations predict the presence of shell-like regions of enhanced X-ray emission which are consistent with the presence of X-ray emitting arcs in the Chandra image. Also the observed X-ray luminosity is comparable to the X-ray luminosities we obtain from the simulations for a supernova with an initial energy in the (1-5)E50 erg range.

  8. Rayleigh-Taylor Instabilities in Young Supernova Remnants Undergoing Efficient Particle Acceleration

    OpenAIRE

    Blondin, John M.; Ellison, Donald C.

    2001-01-01

    We employ hydrodynamic simulations to study the effects of high shock compression ratios, as expected for fast shocks with efficient particle acceleration, on the convective instability of driven waves in supernova remnants. We find that the instability itself does not depend significantly on the compression ratio, but because the width of the interaction region between the forward and reverse shocks can shrink significantly with increasing shock compression, we find that co...

  9. Dynamics of radiative supernova remnants

    International Nuclear Information System (INIS)

    A high-resolution numerical simulation is used to study the evolution of a SNR evolving in a homogeneous uniform medium. Emphasis is placed on the transition from the adiabatic stage to the radiative pressure-driven snowplow stage, along with the possible further establishment of a momentum-conserving snowplow state. In most cases the momentum-conserving snowplow is found to be delayed beyond the merger of the remnant with the interstellar medium. 39 references

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

    Energy Technology Data Exchange (ETDEWEB)

    Funk, S.; /KIPAC, Menlo Park

    2007-09-26

    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.

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

    CERN Document Server

    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 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 betwee...

  12. Toward Connecting Core-Collapse Supernova Explosions with Observations of their Supernova Remnants

    Science.gov (United States)

    Handy, Timothy; Plewa, Tomasz; Gawryszczak, Artur

    2014-03-01

    We study the process of collapse of a massive star and the following explosion process until the formation of a young supernova remnant in a single simulation. These new models are critically evaluated against a database of core-collapse supernovae (ccSNe) explosion models obtained with a standard supernova code. We develop a multiphysics hydrocode capable of accounting for physics from before collapse occurs until the supernova remnant phase. This enables ccSNe studies with a single code without the need of remapping or transferring data between multiple codes. The code uses a new algorithm to account for the effects of neutrino-matter interaction in the collapsing stellar core. The algorithm uses ray-casting in three dimensions and enables performing collapse and explosion simulations on AMR meshes, including non-radial discretizations. Heating due to radioactive decay, and magnetization of the ejecta are included in the model. The asymmetry of the explosion continues to play a role well beyond the shock breakout phase. In particular, the lateral momentum deposited in the process of shock revival helps shape the supernova ejecta. Another important contributing factor shaping the ejecta is due to radioactive decay of nucleosynthetic products of the explosion.

  13. The Origin of Kepler's Supernova Remnant

    CERN Document Server

    Patnaude, Daniel J; Park, Sangwook; Laming, J Martin

    2012-01-01

    It is now well established that Kepler's supernova remnant is the result of a Type Ia explosion. With an age of 407 years, and an angular diameter of ~ 4', Kepler is estimated to be between 3.0 and 7.0 kpc distant. Unlike other Galactic Type Ia supernova remnants such as Tycho and SN 1006, and SNR 0509-67.5 in the Large Magellanic Cloud, Kepler shows evidence for a strong circumstellar interaction. A bowshock structure in the north is thought to originate from the motion of a mass-losing system through the interstellar medium prior to the supernova. We present results of hydrodynamical and spectral modeling aimed at constraining the circumstellar environment of the system and the amount of 56Ni produced in the explosion. Using models that contain either 0.3 M_sun (subenergetic) or 1 M_sun (energetic) of 56Ni, we simulate the interaction between supernova Ia ejecta and various circumstellar density models. Based on dynamical considerations alone, we find that the subenergetic models favor a distance to the SNR...

  14. Origin of Kepler's supernova remnant

    International Nuclear Information System (INIS)

    A bow shock model for Kepler's SNR is presented and the motion of the progenitor star with respect to the interstellar medium is examined. The runaway nature of the progenitor is discussed as well as similarities with known runaway objects. It is maintained that binary Wolf-Rayet stars, P Cygni stars, and some binary pulsars could belong to the same evolutionary track leading to Keppler's SNR. 52 references

  15. Eruption of supernova shock waves

    International Nuclear Information System (INIS)

    The initial burst of radiation from a supernova occurs as the shock wave which was generated by the explosion in the stellar core propagates into the photosphere. It is shown that the radiative hydrodynamics in the photospheric region should not be very sensitive to whether ordinary diffusion or flux-limited diffusion is used. Examination of the published numerical studies indicates that the radiation from the erupting supernova shock wave accelerates the matter in front of the shock so that the velocity discontinuity vanishes; a gas-viscous shock does not form, and there is no intense burst of hard X-rays above several keV. The published estimates of the softer X-ray emission from supernova shock waves are unaffected by the considerations presented here

  16. Influence of an Internal Magnetar on Supernova Remnant Expansion

    OpenAIRE

    M. P. Allen; Horvath, J E

    2003-01-01

    Most of the proposed associations between magnetars and supernova remnant suffer from age problems. Usually, supernova remnants ages are determined from an approximation of the Sedov-Taylor phase relation between radius and age, for a fixed energy of the explosion ~ 10^{51} erg. Those ages do not generally agree with the characteristic ages of the (proposed) associated magnetars. We show quantitatively that, by taking into account the energy injected on the supernova remnant...

  17. Kinematics of Supernova Remnants: Status of X-Ray Observations

    CERN Document Server

    Dewey, Daniel

    2010-01-01

    A supernova (SN) explosion drives stellar debris into the circumstellar material (CSM) filling a region on a scale of parsecs with X-ray emitting plasma. The velocities involved in supernova remnants (SNRs), thousands of km/s, can be directly measured with medium and high-resolution X-ray spectrometers and add an important dimension to our understanding of the last stages of the progenitor, the explosion mechanism, and the physics of strong shocks. After touching on the ingredients of SNR kinematics, I present a summary of the still-growing measurement results from SNR X-ray observations. Given the advances in 2D/3D hydrodynamics, data analysis techniques, and especially X-ray instrumentation, it is clear that our view of SNRs will continue to deepen in the decades ahead.

  18. 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

  19. VHE Gamma-ray Supernova Remnants

    Energy Technology Data Exchange (ETDEWEB)

    Funk, Stefan; /KIPAC, Menlo Park

    2007-01-22

    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 summarizes the current status of {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 GLAST satellite in the energy regime above 100 MeV are given.

  20. 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...

  1. Infrared [Fe II] and Dust Emissions from Supernova Remnants

    CERN Document Server

    Koo, Bon-Chul

    2013-01-01

    Supernova remnants (SNRs) are strong thermal emitters of infrared radiation. The most prominent lines in the near-infrared spectra of SNRs are [Fe II] lines. The [Fe II] lines are from shocked dense atomic gases, so they trace SNRs in dense environments. After briefly reviewing the physics of the [Fe II] emission in SNR shocks, I describe the observational results which show that there are two groups of SNRs bright in [Fe II] emission: middle-aged SNRs interacting with molecular clouds and young core-collapse SNRs in dense circumstellar medium. The SNRs belonging to the former group are also bright in near-infrared H$_2$ emission, indicating that both atomic and molecular shocks are pervasive in these SNRs. The SNRs belonging to the latter group have relatively small radii in general, implying that most of them are likely the remnants of SN IIL/b or SN IIn that had strong mass loss before the explosion. I also comment on the "[Fe II]-H$_2$ reversal" in SNRs and on using the [Fe II]-line luminosity as an indic...

  2. A New Optical Sample of Supernova Remnants in M33

    Science.gov (United States)

    Gordon, Shawn M.; Kirshner, Robert P.; Long, Knox S.; Blair, William P.; Duric, Nebojsa; Smith, R. Chris

    1998-07-01

    We present a new and larger sample of supernova remnants in the nearby spiral galaxy M33. The sample is based upon CCD interference filter observations obtained with the Kitt Peak 4 m telescope and spectroscopic observations obtained with the Multiple Mirror Telescope. Using optical emission-line ratios, supplemented by a radio continuum map of M33 (Duric et al.; Gordon et al.), we have identified 98 supernova remnant (SNR) candidates, of which 53 were previously unknown. We have obtained spectra of 27 SNR candidates, bringing the total number of M33 SNRs for which spectra are available to 72. All the spectra show the characteristic signature of shock-heated gas, which leads us to believe that the rest of the candidates are also supernova remnants. The large sample provides a useful database to investigate the global properties of SNRs. In this paper, we present a new cumulative number-diameter [N(

  3. 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...

  4. An X-ray study of the supernova remnant G20.0-0.2 and its surroundings

    OpenAIRE

    Petriella, Alberto; Paron, Sergio; Giacani, Elsa

    2013-01-01

    Aims: We study the supernova remnant G20.0-0.2 and its surroundings in order to look for the high energy counterpart of the radio nebula and to find evidence of interaction between the shock front and the interstellar medium. Methods: We used Chandra archival observations to analyze the X-ray emission from the supernova remnant. The surrounding gas was investigated using data extracted from the Galactic Ring Survey, the VLA Galactic Plane Survey, the Galactic Legacy Infrared...

  5. Physical Structure and Nature of Supernova Remnants in M101

    CERN Document Server

    Franchetti, N A; Chu, Y -H; Dunne, B C; Pannuti, T G; Kuntz, K D; Chen, C -H R; Grimes, C K; Aldridge, T M

    2012-01-01

    Supernova remnant (SNR) candidates in the giant spiral galaxy M101 have been previously identified from ground-based H-alpha and [SII] images. We have used archival Hubble Space Telescope (HST) H-alpha and broad-band 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 ultra-luminous 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, ~16% are likely remnants of Type Ia SNe and ~45% are remnants of core-collapse SNe. In addition, about ~36% are large candidates which we sugg...

  6. ASCA observations of the Large Magellanic Cloud supernova remnant sample: Typing supernovae from their remnants

    Science.gov (United States)

    Hughes, John P.; Hayashi, Ichizo; Helfand, David; Hwang, Una; Itoh, Masayuki; Kirshner, Robert; Koyama, Katsuji; Markert, Thomas; Tsunemi, Hiroshi; Woo, Jonathan

    1995-01-01

    We present our first results from a study of the supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using data from ASCA. The three remnants we have analyzed to date, 0509-67.5, 0519-69.0, and N103B, are among the smallest, and presumably also the youngest, in the Cloud. The X-ray spectra of these SNRs show strong K alpha emission lines of silicon, sulfur, argon, and calcium with no evidence for corresponding lines of oxygen, neon, or magnesium. The dominant feature in the spectra is a broad blend of emission lines around 1 keV which we attribute to L-shell emission lines of iron. Model calculations (Nomoto, Thielemann, & Yokoi 1984) show that the major products of nucleosynthesis in Type Ia supernovae (SNs) are the elements from silicon to iron, as observed here. The calculated nucleosynthetic yields from Type Ib and II SNs are shown to be qualitatively inconsistent with the data. We conclude that the SNs which produced these remnants were of Type Ia. This finding also confirms earlier suggestions that the class of Balmer-dominated remnants arise from Type Ia SN explosions. Based on these early results from the LMC SNR sample, we find that roughly one-half of the SNRs produced in the LMC within the last approximately 1500 yr came from Type Ia SNs.

  7. Improved optical spectrophotometry of supernova remnants in M33

    Science.gov (United States)

    Blair, W. P.; Kirshner, R. P.

    1985-01-01

    Optical spectra of SNRs in M33 have been used to investigate abundance gradients and SNR evolution in this galaxy. Abundances of O, N, and S are derived from the spectra using new shock models by Dopita et al. (1984). The results for N and S show abundance gradients similar to those in NGC 300 and the Galaxy. The O abundances may be affected by possible contamination from H II regions and low-velocity shocks. Electron densities derived from the forbidden S II 6717 A/6731 A line ratio are used with a pressure equilibrium argument to estimate the initial explosion energy for each SNR. Evolutionary models for the remnants are investigated, and the distribution of the number of remnants with diameter is found to be consistent with free expansion of the SNRs to diameters of about 26 pc. The results may also be consistent with Sedov evolution if the ranges of initial supernova energies and surrounding interstellar medium densities are large enough.

  8. Resolved structure in M33 supernova remnants

    Science.gov (United States)

    Blair, William P.; Davidsen, Arthur F.

    1993-01-01

    We present WF/PC narrow band forbidden S II 6725-wavelength images of two M33 supernova remnants obtained with the Wide Field/Planetary Camera on the HST. Comparison of these images with ground-based CCD data indicates that HST has resolved the nebular structures into shells or partial shells, permitting improved measurements of the diameters of these objects. Ground-based echelle spectra obtained at Kitt Peak with the 4-m telescope show profiles with half-width zero-intensity velocities of 163 and 275 km/sec for the two objects, indicating rapid bulk motions of the emitting filaments. The morphology of the emission seen in the WF/PC images allows the non-Gaussian shapes of the integrated echelle profiles to be understood. We briefly compare the predicted WF/PC count rates with those actually realized and discuss the reason for the discrepancy.

  9. New supernova remnants in M33

    International Nuclear Information System (INIS)

    Existing catalogues of supernova remnants (SNRs) in external galaxies are very incomplete. Potentially however, such examples are of great importance in understanding SNRs, since the distances to objects in a given sample are essentially the same and since absorption is small (compared to galactic SNRs). The authors present H? + [NII], H?, [SII], [OIII], and 6100 angstrom continuum CCD images of nine selected areas in M33 using the KPNO 4m. In addition to the six SNRs already known to exist in the fields we have surveyed, we have identified 21 other nebulae with [SII]:H? + [NII] ratios which may be SNRs. Spectra of seven of these nebulae were obtained subsequently and show that the majority are indeed SNRs

  10. 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.

  11. Optical spectrum of the unusual supernova remnant G109.1 - 1.0

    International Nuclear Information System (INIS)

    Similarities in the x-ray and radio spectra of the new supernova remnant G109.1 - 1.0 and the SS433 - W50 pair have been investigated. A spectrum of the faint optical filaments associated with the large shell-like radio source has been obtained showing strong [S II] lambdalambda 6,717,6,731 emission relative to H?, which is characteristic of shock-heated gas and which confirms that the filaments are part of the supernova remnant, and is generally similar to spectra of the Cygnus Loop. By assuming pressure equilibrium between the optical filaments and the interior of the remnant an initial energy of 3 x 1051 erg is found, which is higher than that found from x-ray measurements. When compared with W50, the G109.1 - 1.0 remnant has filaments of higher density, and weaker [N II] emission. (U.K.)

  12. Radio emission from young supernova remnants - Effects of an inhomogeneous circumstellar medium

    International Nuclear Information System (INIS)

    The evolution of young supernova remnants has been modeled using a one-dimensional hydrodynamics code. Rayleigh-Taylor instabilities and the growth of Rayleigh-Taylor fingers have been included in the code. Turbulent dynamo amplification of magnetic fields and both turbulent and shock acceleration of relativistic electrons have been included macroscopically. From this, the distribution of synchrotron luminosity in the remnant has been calculated. It is found that the radio morphology of model remnants expanding into a homogeneous medium does not agree with observations. Expansion into a circumstellar medium with many small cloudlets does produce radio shells which agree with observations. It is suggested that supernova remnants reflect the interaction of ejected matter with a cloudy circumstellar medium. 77 refs

  13. Spallative Nucleosynthesis in Supernova Remnants; 1, Analytical Estimates

    CERN Document Server

    Parizot, E; Parizot, Etienne; Drury, Luke

    1999-01-01

    Spallative nucleosynthesis is thought to be the only process capable of producing significant amount of Beryllium (Be) in the universe. Therefore, both energetic particles (EPs) and nuclei to be spalled (most efficiently C, N and O nuclei in this case) are required, which indicates that supernovae (SNe) may be directly involved in the synthesis of the Be nuclei observed in the halo stars of the Galaxy. We apply current knowledge relating to supernova remnant (SNR) evolution and particle shock acceleration to calculate the total Be yield associated with a SN explosion in the interstellar medium, focusing on the first stages of Galactic chemical evolution (i.e. when metallicity Z < 0.01 Z_odot) We show that dynamical aspects must be taken into account carefully, and present analytical calculations of the spallation reactions induced by the EPs accelerated at both the forward and the reverse shocks following the SN explosion. Our results show that the production of Be in the early Galaxy is still poorly under...

  14. 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)

  15. Cygnus Superbubble as the remnant of a peculiar supernova

    International Nuclear Information System (INIS)

    An analytic solution is obtained for the evolution of a supernova remnant during the radiative-cooling phase. The Cygnus Superbubble x-ray source could have been formed by the explosion of a single supernova releasing an energy of 1052--1053 erg. Analysis of the light curve of the NGC 1058 supernova 1961v demonstrates that it represents a roughly-equal2 x 1052 erg outburst of a supermassive (roughly-equal103 M/sub sun/) star. Giant shell sources may form an evolutionary sequence, exemplified by R136a as the presupernova, supernova 1961v, and the Superbubble as the remnant

  16. PAH Detection In The Supernova Remnant N132D

    Science.gov (United States)

    Tappe, Achim; Rho, J.; Reach, W. T.

    2006-06-01

    We report the detection of polycyclic aromatic hydrocarbon (PAH) bands associated with the oxygen-rich supernova remnant N132D (SNR 0525-69.6) in the Large Magellanic Cloud. We observed N132D with all instruments onboard the Spitzer Space Telescope, IRS, IRAC, and MIPS (Infrared Spectrograph, Infrared Array Camera, Multiband Imaging Photometer for Spitzer). The 5-40?m IRS spectra toward the southeastern shell of the remnant show a steeply rising continuum with [NeIII] and [OIV] as well as PAH emission. We interpret the continuum as thermal emission from shocked, heated dust grains in its expanding shell, which is clearly visible in the MIPS 24?m image. Superposed on the dust continuum, we detect 15-20?m features, including the 16.4 and 17.4?m lines, which are considered to be PAH C-C-C bending modes. We also detect the well-known 11.3?m PAH C-H bending feature, and find the integrated strength of the 15-20?m features about a factor of five stronger than the 11.3?m band. This ratio is higher than commonly observed in reflection/planetary nebulae or young stellar objects, and similar to HII-regions, suggesting that large and/or dehydrogenated/ionized PAHs dominate the material close to the blast wave of N132D. Smaller PAHs and very small grains may have been destroyed through thermal sputtering in the hot plasma. IRAC 3-9?m images do not show clear evidence of large-scale, shell-like emission from the remnant, partly due to confusion with the ambient ISM material. However, we identified several knots of shocked interstellar gas also seen at optical wavelengths, based on their distinct infrared colors, which suggest the presence of continuum emission from heated silicate/graphite dust grains. We discuss the bright infrared continuum and the polycyclic aromatic hydrocarbon features with respect to dust processing in young supernova remnants.This work is based on observations made with the Spitzer Space Telescope. Support was provided by the NASA LTSA program.

  17. DUST IN A TYPE Ia SUPERNOVA PROGENITOR: SPITZER SPECTROSCOPY OF KEPLER'S SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    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 ?m infrared (IR) spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 ?m, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the asymptotic giant branch 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 Infrared Spectrograph and Infrared Array Camera data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally heated dust emission from fast shocks (>1000 km s–1) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are ?80-100 K, but fail to account for the highest temperatures detected, in e highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km s–1) into moderate density material (n0 ? 50-250 cm–3) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

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

    OpenAIRE

    Reynolds, S. P.; Gaensler, B. M.; 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 ...

  19. Supernova Remnants as the Sources of Galactic Cosmic Rays

    OpenAIRE

    Vink, Jacco

    2012-01-01

    The origin of cosmic rays holds still many mysteries hundred years after they were first discovered. Supernova remnants have for long been the most likely sources of Galactic cosmic rays. I discuss here some recent evidence that suggests that supernova remnants can indeed efficiently accelerate cosmic rays. For this conference devoted to the Astronomical Institute Utrecht I put the emphasis on work that was done in my group, but placed in a broader context: efficient cosmic-...

  20. Long slit echelle spectroscopy of supernova remnants IN M33

    International Nuclear Information System (INIS)

    The authors have obtained long slit echelle spectroscopy for 10 of the brightest supernova remnants in M33 using the KPNO 4 m telescope. The profiles at II? indicate bulk motions in the range 100--350 km s-1 in these remnants. Nearly all of the objects show signs of contamination by low velocity II II emission at some level. This affects the line intensities measured from low resolution data and may affect diameter measurements of these remnants

  1. 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 H? + [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 ?m and 22 ?m 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] ?? 6716/6731 ratio indicates that the electron densities are below 240 cm-3, while the H? 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.

  2. Fermi-LAT Observations of Supernova Remnant Kesteven 79

    CERN Document Server

    Auchettl, Katie; Castro, Daniel

    2014-01-01

    In this paper we report on the detection of $\\gamma$-ray emission coincident with the Galactic supernova remnant Kesteven 79 (Kes 79). We analysed approximately 52 months of data obtained with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. Kes 79 is thought to be interacting with adjacent molecular clouds based on the presence of strong $^{12}$CO J = 1 $\\rightarrow$ 0 and HCO$^{+}$ J = 1 $\\rightarrow$ 0 emission and the detection of 1720 MHz line emission towards the east of the remnant. Acceleration of cosmic rays is expected to occur at SNR shocks, and SNRs interacting with dense molecular clouds provide a good testing ground for detecting and analysing the production of $\\gamma$-rays from the decay of $\\pi^0$ into two $\\gamma$-ray photons. This analysis investigates $\\gamma$-ray emission coincident with Kes 79, which has a detection significance of $\\sim 7 \\sigma$. Additionally we present an investigation of the spatial and spectral characteristics of Kes 79 using multiple arc...

  3. Expansion of the Optical Remnant from Tycho’s Supernova

    Science.gov (United States)

    Putko, Joseph; Winkler, P. Frank; Blair, William P.

    2015-01-01

    Tycho's supernova remnant (SNR) is the expanding remnant from SN 1572, the penultimate Galactic supernova to have been recorded by contemporary observers. Its optical light is almost exclusively faint hydrogen Balmer emission around the periphery of the SNR, produced where fast nonradiative shocks encounter partly neutral preshock interstellar material. A variety of filaments, presumably thin sheets oriented tangentially, surround about one-third of the radio/X-ray shell. We have used CCD images, taken from KPNO over seven epochs from 1986 to 2009, to give the first optical expansion measurement of Tycho's SNR of the CCD era. Thirty filaments were identified and measured; the majority of them are at or near the remnant's outer rim and have proper motions from 0.19?? ± 0.01?? yr-1 to 0.26?? ± 0.02?? yr-1. The associated expansion indices, defined as the ratio of the current expansion rate to the historical mean, range from 0.35 ± 0.03 to 0.52 ± 0.05. Our measurements are consistent with those from the classic study by Kamper & van den Bergh (1978, ApJ, 224, 851) for the same filaments, but the CCD measurements have higher precision, and we have measured several additional fainter filaments. For direct comparison with X-ray and radio measurements, we selected the subset of optical filaments lying exactly at the outer rim, as identified in Chandra and VLA images. Considering only these filaments, virtually all have expansion indices greater than 0.40, the Sedov value. In addition to the rim filaments, there are several seen in the interior (in projection) that have smaller proper motions; these may have been decelerated, and/or they could be directed non-tangentially. Our final epoch of images, taken from the 3.5m WIYN telescope in 2009, reveals previously undetected extremely faint optical emission surrounding well over half of the remnant shell. This newly detected faint emission agrees well with the limb as defined in X-ray and radio images.This work has been supported in part by NSF grant AST-098566.

  4. Suzaku Observations of Tycho's Supernova Remnant

    CERN Document Server

    Tamagawa, T; Nakamura, S; Terada, Y; Bamba, A; Hiraga, J S; Hughes, J P; Hwang, U; Kataoka, J; Kinugasa, K; Kunieda, H; Tanaka, T; Tsunemi, H; Ueno, M; Holt, S S; Kokubun, M; Miyata, E; Szymkowiak, A; Takahashi, T; Tamura, K; Ueno, D; Makishima, K

    2008-01-01

    Tycho's supernova remnant was observed by the XIS and HXD instruments onboard the Suzaku satellite on 2006 June 26-29 for 92 ks. The spectrum up to 30 keV was well fitted with a two-component model, consisting of a power-law with photon index of 2.7 and a thermal bremsstrahlung model with temperature of 4.7 keV. The former component can alternatively be modeled as synchrotron emission from a population of relativistic electrons with an estimated roll-off energy of around 1 keV. In the XIS spectra, in addition to the prominent Fe K_alpha line (6.445 keV), we observe for the first time significant K_alpha line emission from the trace species Cr and Mn at energies of 5.48 keV and 5.95 keV, respectively. Faint K_beta lines from Ca (4.56 keV) and Fe (7.11 keV) are also seen. The ionization states of Cr and Mn, based on their line centroids, are estimated to be similar to that of Fe K_alpha (Fe XV or XVI).

  5. 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 ...

  6. MODIFIED EQUIPARTITION CALCULATION FOR SUPERNOVA REMNANTS

    International Nuclear Information System (INIS)

    Determination of the magnetic field strength in the interstellar medium is one of the more 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 the Zeeman effect and Faraday rotation, the equipartition or 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 its approximate character, it remains a useful tool, especially when there are no other data about the magnetic field in a source. In this paper, we give a modified calculation that we think is more appropriate for estimating magnetic field strengths and energetics in supernova remnants (SNRs). 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 magnetic field strengths of SNRs is available at http://poincare.matf.bg.ac.rs/?arbo/eqp/.

  7. 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

  8. Dense molecular cloud impacted by the W28 supernova remnant

    International Nuclear Information System (INIS)

    Molecular spectra and an infrared survey of a dense molecular cloud obscuring a part of the optical nebulosity associated with the supernova remnant W28 have been obtained. The spectra reveal a warm dense core in a region of substantial line broadening near a maximum of nonthermal radio emission from the remnant. A small (approx.2 km s-1) shift in the velocity of peak molecular emission also occurs in this region. No embedded infrared source capable of heating the cloud appears to be present. The cloud appears to have been impacted by the expanding supernova remnant. The cloud appears to be an ambient cloud only recently compressed and heated by the nearby remnant; no evidence for star formation has been found. The remarkably broad HCO+ lines found near the cloud core originate in a region of enhanced ionization in the cloud, quite possibly resulting from penetration of the cloud by energetic radiation from the remnant

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

    CERN Document Server

    Carlton, A K; Reynolds, S P; Hwang, U; Petre, R; Green, D A; Krishnamurthy, K; Willett, R

    2011-01-01

    We present a measurement of the expansion and brightening of G1.9+0.3, the youngest Galactic supernova remnant, comparing Chandra X-ray images obtained in 2007 and 2009. A simple uniform expansion model describes the data well, giving an expansion rate of 0.642 +/- 0.049 % yr^-1, and a flux increase of 1.7 +/- 1.0 % yr^-1. Without deceleration, the remnant age would then be 156 +/- 11 yr, consistent with earlier results. Since deceleration must have occurred, this age is an upper limit; we estimate an age of about 110 yr, or an explosion date of about 1900. The flux increase is comparable to reported increases at radio wavelengths. G1.9+0.3 is the only Galactic supernova remnant increasing in flux, with implications for the physics of electron acceleration in shock waves

  10. X-ray surface brightness of Kepler's supernova remnant

    International Nuclear Information System (INIS)

    We have observed Kepler's supernova remnant (SNR) with the imaging instruments on board the Einstein Observatory. The 0.15-4.5 keV flux incident on the Earth is 1.2 x 10-10 ergs cm-2 s-1; the flux corrected for interstellar absorption is 3.4 x 10-10 ergs cm-2 s-1 (L/sub x/ = 1.0 x 1036 ergs s-1 at D = 5 kpc) if the absorbing column density is N/sub H/ = 2.8 x 1021 cm-2. The remnant is circular and shows a strong shell which is at least 5 times brighter in the north than in the south. The X-ray observations do not unambiguously determine whether the remnant is in the adiabatic or the free expansion phase. If the remnant is in the adiabatic phase, the density of the interstellar medium (ISM) (2/sub e/>/sup 1/2/) surrounding Kepler's SNR must be about 5 cm-3. If the remnant is in the free expansion phase, where most of the emission arises from shock-heated ejecta, the ISM density must still be relatively high, n/sub i/> or approx. =0.1 cm-3. Even if the ISM is very inhomogeneous, with very many small, dense clouds, we show that the mean density of the ISM must be greater than approx.0.1 cm-3. In any case, the density of the x-ray emitting gas must be high (2/sub e/>/sup 1/2/ > or approxn2/sub e/>/sup 1/2/ > or approx. =10 cm-3), and the temperature must be fairly low (T/sub e/7 K). The relatively high ISM density which is required is surprising in view of Kepler's distance above the galactic plane, approx.600 pc. Possibly the ISM around Kepler's SNR and around other type i SNRs is dominated by the mass lost from the presupernova star

  11. X-RAY EMISSION FROM STRONGLY ASYMMETRIC CIRCUMSTELLAR MATERIAL IN THE REMNANT OF KEPLER'S SUPERNOVA

    International Nuclear Information System (INIS)

    Kepler's supernova remnant resulted from a thermonuclear explosion, but is interacting with circumstellar material (CSM) lost from the progenitor system. We describe a statistical technique for isolating X-ray emission due to CSM from that due to shocked ejecta. Shocked CSM coincides well in position with 24 ?m emission seen by Spitzer. We find most CSM to be distributed along the bright north rim, but substantial concentrations are also found projected against the center of the remnant, roughly along a diameter with position angle ?100°. We interpret this as evidence for a disk distribution of CSM before the supernova, with the line of sight to the observer roughly in the disk plane. We present two-dimensional hydrodynamic simulations of this scenario in qualitative agreement with the observed CSM morphology. Our observations require Kepler to have originated in a close binary system with an asymptotic giant branch star companion.

  12. An Integral View of Fast Shocks around Supernova 1006

    CERN Document Server

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

    2013-01-01

    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 km/s 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\\alpha\\ 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.

  13. DISCOVERY OF X-RAY EMISSION FROM SUPERNOVA 1970G WITH CHANDRA: FILLING THE VOID BETWEEN SUPERNOVAE AND SUPERNOVA REMNANTS

    Science.gov (United States)

    Immler, Stefan; Kuntz, K. D.

    2005-01-01

    We report the discovery of X-ray emission from SN 1970G in M101, 35 yr after its outburst, using deep X-ray imaging with the Chundra X-Ray Observatory. The Chandra ACIS spectrum shows that the emission is soft (52 keV) and characteristic of the reverse-shock region. The X-ray luminosity, Lo,,, = (1.1 3 0.2) x lo3# ergs s-1, is likely caused by the interaction of the supernova shock with dense circumstellar matter. If the material was deposited by the stellar wind from the progenitor, a mass-loss rate of M = (2.6 ? 0.4) x M, yr-I (v,/lO km s-I) is inferred. Utilizing the high-resolution Chandra ACIS data of SN 1970G and its environment, we reconstruct the X-ray lightcurve from previous ROSAT HRI, PSPC, and XMM-Newton EPIC observations, and find a best-fit linear rate of decline of L cc t-# with index s = 2.7 t 0.9 over a period of -20-35 yr after the outburst. As the oldest supernova detected in X-rays, SN 1970G allows, for the first time, direct observation of the transition from a supenova to its supernova remnant phase.

  14. 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 t...

  15. Spitzer observations of supernova remnants: II. Physical conditions and comparison with HH7 and HH54

    OpenAIRE

    YUAN, YUAN; Neufeld, David A.

    2010-01-01

    We have studied the shock-excited molecular regions associated with four supernova remnants (SNRs) - IC443C, W28, W44 and 3C391 - and two Herbig-Haro objects, HH7 and HH54, using Spitzer's Infrared Spectrograph (IRS). The physical conditions within the observed areas are inferred from spectroscopic data obtained from IRS and from SWS and LWS onboard ISO, together with photometric data from Spitzer's Infrared Array Camera (IRAC). Adopting a power-law distribution for the gas ...

  16. 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

  17. 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...

  18. 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.

  19. Self-consistent models for the X-ray emission from supernova remnants

    International Nuclear Information System (INIS)

    A novel solution to the problem of time dependent ionization in shock heated plasmas has been developed and incorporated into a standard, spherically symmetric hydrodynamic shock code. The approach to the ionization calculation is to use the eigenvalue method of solution for the matrix formed from the coupled system of rate equations expressing the time development of the ionization structure. An important tool for studying the evolution of supernova remnants has been developed. As a first application all of the available observations of the remnant of Kepler's supernova (SN 1604) obtained with the imaging and spectral instruments of the Einstein Observatory have been fitted. Two classes of models adequately describe the data: (1) a Sedov model, requiring near solar abundances, and (2) a reverse-shock model, which requires significant heavy element overabundances. The implications of this result are discussed. The distributions of luminosity, spectrum, and diameter were examined for an X-ray selected sample of supernovae remnants in the Large Magellanic Cloud

  20. 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...

  1. Are Models for Core-collapse Supernova Progenitors Consistent with the Properties of Supernova Remnants?

    Science.gov (United States)

    Patnaude, Daniel J.; Lee, Shiu-Hang; Slane, Patrick O.; Badenes, Carles; Heger, Alexander; Ellison, Donald C.; Nagataki, Shigehiro

    2015-04-01

    The recent discovery that the Fe–K line luminosities and energy centroids observed in nearby supernova remnants are a strong discriminant of both progenitor type and circumstellar environment has implications for our understanding of supernova progenitor evolution. Using models for the chemical composition of core-collapse supernova (CCSN) ejecta, we model the dynamics and thermal X-ray emission from shocked ejecta and circumstellar material, modeled as an {{r}-2} wind, to ages of 3000 yr. We compare the X-ray spectra expected from these models to observations made with the Suzaku satellite. We also model the dynamics and X-ray emission from Type Ia progenitor models. We find a clear distinction in Fe–K line energy centroid between core-collapse and Type Ia models. The CCSN models predict higher Fe–K line centroid energies than the Type Ia models, in agreement with observations. We argue that the higher line centroids are a consequence of the increased densities found in the circumstellar environment created by the expansion of the slow-moving wind from the massive progenitors.

  2. Radio and Optical Properties of Supernova Remnants in M33

    Science.gov (United States)

    Gordon, S.; Kirshner, R.; Duric, N.; Long, K.

    1993-12-01

    Although the properties and evolution of supernova remnants (SNRs) are generally understood, there are important questions concerning the interaction of SNRs with the interstellar medium. These include the role of SNRs in regulating the relativistic gas (cosmic rays) in galaxies and the degree to which the ISM affects the evolution of SNRs. Statistically significant samples of SNRs observed at several wavelengths have the potential for yielding valuable insight into these questions. To this end, we are carrying out a search for SNRs in the galaxy M33 at optical, radio and X-ray wavelengths. M33 is ideally suited for a study of this nature. Remnants will all be at essentially the same distance and, because M33 is nearly face on, the effects due to interstellar absorption are reduced. Furthermore, M33 is a spiral galaxy, allowing for comparisons with the Milky Way. We have undertaken new radio, X-ray and optical observations of M33, and, here, we present the sample of radio selected and optically confirmed SNRs and discuss some of the results. We have identified ~ 100 non-thermal radio sources within 20arcmin of the center of M33. Many of these sources are likely to be SNRs, and we have made followup spectroscopic observations of these candidates with the MMT and have found many to be associated with shock-heated gas. This radio-selected sample has the advantage over previous optical samples of M33 in that it can detect remnants in highly optically confused regions. As an example, we have identified a SNR located in the giant HII region NGC-592 in M33 (Gordon et al., 1993 Ap. J., in press). This is a particularly interesting HII region because a soft X-ray source is located in it. We found a knot of non-thermal radio emission at the site of the X-ray source and detected shock-heated gas at optical wavelengths thus showing that the X-ray emission is associated with an embedded SNR.

  3. 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 ...

  4. The youngest known X-ray binary: Circinus X-1 and its natal supernova remnant

    International Nuclear Information System (INIS)

    Because supernova remnants are short-lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: none were known to exist in our Galaxy. We report the discovery of the natal supernova remnant of the accreting neutron star Circinus X-1, which places an upper limit of t < 4600 yr on its age, making it the youngest known X-ray binary and a unique tool to study accretion, neutron star evolution, and core-collapse supernovae. This discovery is based on a deep 2009 Chandra X-ray observation and new radio observations of Circinus X-1. Circinus X-1 produces type I X-ray bursts on the surface of the neutron star, indicating that the magnetic field of the neutron star is small. Thus, the young age implies either that neutron stars can be born with low magnetic fields or that they can rapidly become de-magnetized by accretion. Circinus X-1 is a microquasar, creating relativistic jets that were thought to power the arcminute-scale radio nebula surrounding the source. Instead, this nebula can now be attributed to non-thermal synchrotron emission from the forward shock of the supernova remnant. The young age is consistent with the observed rapid orbital evolution and the highly eccentric orbit of the system and offers the chance to test the physics of post-supernova orbital evolution in X-ray binaries in detail for the first time.

  5. Observations of the remnants of three historical supernovae

    International Nuclear Information System (INIS)

    Radio maps are presented of the supernova remnants G11.2-0.3, G348.5+0.1 and G348.7+0.3, all three of which have been suggested as candidates for the remnants of supernovae in the 4th century AD. An HRI X-ray image of G11.2-0.3 is also shown. G11.2-0.3 is a bright, symmetric shell remnant which looks very like Tycho's or Kepler's SNRs. Its parameters are consistent with an (undetected) supernovae explosion 300-500 yr ago, but an alternative interpretation, that it is the remnant of the explosion of a massive star in AD 386, cannot be excluded. G348.5+0.1 and G348.7+0.3 have weaker, more ragged shells than does G11.2-0.3 and are probably much older. This would be consistent with one of these two remnants being the relic of the AD 393 explosion. (author)

  6. Exploring the supernova remnant G308.4-1.4

    CERN Document Server

    Prinz, Tobias

    2012-01-01

    Aims: We present a detailed X-ray and radio wavelength study of G308.4-1.4, a candidate supernova remnant (SNR) in the ROSAT All Sky Survey and the MOST supernova remnant catalogue. Methods: The SNR candidate and its central point sources were studied using observations from the Chandra X-ray Observatory, SWIFT, the Australian Telescope Compact Array (ATCA) at 1.4 and 2.5 GHz and WISE infrared observation at 24 $\\mu$m. Results: We conclude that G308.4-1.4 is indeed a supernova remnant by means of its morphology matching at X-ray, radio and infrared wavelength, its spectral energy distribution in the X-ray band and its emission characteristics in the radio band. G308.4-1.4 is a shell-type SNR. X-ray, radio and infrared emission is seen only in the eastern part of the remnant due to a strong spatial density variation of the interstellar medium around the remnant. The X-ray emission can best be described by an absorbed non-equilibrium collisional plasma with a hydrogen density of $n_\\text{H}=(1.02\\pm 0.04)$ cm$^...

  7. A multi-wavelength study of Supernova Remnants in six nearby galaxies. II. New optically selected Supernova Remnants

    CERN Document Server

    Leonidaki, I; Zezas, A

    2012-01-01

    We present results from a study of optically emitting Supernova Remnants (SNRs) in six nearby galaxies (NGC 2403, NGC 3077, NGC 4214, NGC 4395, NGC 4449 and NGC 5204) based on deep narrow band H{\\alpha} and [SII] images as well as spectroscopic observations. The SNR classification was based on the detected sources that fulfill the well-established emission line flux criterion of [SII]/H{\\alpha} > 0.4. This study revealed ~400 photometric SNRs down to a limiting H{\\alpha} flux of 10^(-15) erg sec^(-1) cm^(-2). Spectroscopic observations confirmed the shock-excited nature of 56 out of the 96 sources with ([SII]/H{\\alpha})$_{phot}$> 0.3 (our limit for an SNR classification) for which we obtained spectra. 11 more sources were spectroscopically identified as SNRs although their photometric [SII]/H{\\alpha} ratio was below 0.3. We discuss the properties of the optically-detected SNRs in our sample for different types of galaxies and hence different environments, in order to address their connection with the surround...

  8. Radiation hydrodynamics of supernova shock breakouts

    Science.gov (United States)

    Blinnikov, S.; Tolstov, A.; Sorokina, E.; Dolgov, A.

    2013-03-01

    The first powerful burst of photon radiation in a supernova appears when the shock front is a few photon mean-free paths below the star photosphere. This is called "shock breakout" and it is the first observable event after the neutrino and gravitational wave bursts in core-collapsing supernovae. Any early information about collapse is vitally important for understanding the physics of explosion, constraining speed of neutrino propagation etc. Direct observations of shock breakouts have been carried out in a few supernovae. We discuss some puzzles related to those objects. Finally, we describe our current understanding of the most luminous (hyper-)supernovae. Their long living radiative shocks pause many interesting problems in numerical and laboratory astrophysics and may have important applications in cosmology.

  9. Properties of Optically Selected Supernova Remnant Candidates in M33

    Science.gov (United States)

    Lee, Jong Hwan; Lee, Myung Gyoon

    2014-10-01

    Narrowband images covering strong emission lines are efficient for surveying supernova remnants (SNRs) in nearby galaxies. Using the narrowband images provided by the Local Group Galaxy Survey, we searched for SNRs in M33. Culling the objects with enhanced [S II]/H? and round morphology in the continuum-subtracted H? and [S II] images, we produced a list of 199 sources. Among them, 79 are previously unknown. Their progenitor and morphology types were classified. A majority of the sample (170 objects) are likely remnants of core-collapse supernovae (SNe), and 29 are remnants of Type Ia SNe. The cumulative size distribution of these objects is found to be similar to that of the M31 remnants derived in a similar way. We obtain a power-law slope, ? = 2.38 ± 0.05. Thus, a majority of the sources are considered to be in the Sedov-Taylor phase, consistent with previous findings. The histogram of the emission-line ratio ([S II]/H?) of the remnants has two concentrations at [S II]/H? ~ 0.55 and ~0.8, as in M31. Interestingly, L X (and L 20 cm) of the compact center-bright objects are correlated with their optical luminosity. The remnants with X-ray emission have brighter optical surface brightnesses and smaller diameters than those without X-ray emission.

  10. Is there a hidden hole in Type Ia supernova remnants?

    CERN Document Server

    García-Senz, Domingo; Serichol, Nuria

    2011-01-01

    In this paper we report on the bulk features of the hole carved by the companion star in the material ejected during a Type Ia supernova explosion. In particular we are interested in the long term evolution of the hole as well as in its fingerprint in the geometry of the supernova remnant after several centuries of evolution, which is a hot topic in current Type Iasupernovae studies. We use an axisymmetric smoothed particle hydrodynamics code to characterize the geometric properties of the supernova remnant resulting from the interaction of this ejected material with the ambient medium. Our aim is to use supernova remnant observations to constrain the single degenerate scenario for Type Ia supernova progenitors. Our simulations show that the hole will remain open during centuries, although its partial or total closure at later times due to hydrodynamic instabilities is not excluded. Close to the edge of the hole, the Rayleigh-Taylor instability grows faster, leading to plumes that approach the edge of the for...

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

    International Nuclear Information System (INIS)

    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–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–1 that has cooled and begun to recombine. The post-shock region has a swept-up column density of about 1.3 × 1018 cm–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.

  12. Tests for supernova explosion models: from light curves to X-ray emission of supernova remnants

    OpenAIRE

    Sorokina, Elena; Blinnikov, Sergey

    2003-01-01

    The successful theoretical supernova explosion models should be able to explain any features of the emission from supernovae at any evolutionary stage. We check several models from two different points of view. With the multi-frequency radiation hydro code STELLA we calculate gamma-ray, bolometric and broad-band UBVI light curves. Then we use the same models to calculate the emission from young supernova remnants. Here we present new plots for gamma-ray luminosity from seve...

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

    CERN Document Server

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

    2013-01-01

    G1.9+0.3 is the youngest known Galactic supernova remnant (SNR), with an estimated supernova (SN) explosion date of about 1900, and most likely located near the Galactic Center. Only the outermost ejecta layers with free-expansion velocities larger than about 18,000 km/s 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 Kalpha 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 tha...

  14. No cold dust within the supernova remnant Cassiopeia A

    Science.gov (United States)

    Krause, Oliver; Birkmann, Stephan M.; Rieke, George H.; Lemke, Dietrich; Klaas, Ulrich; Hines, Dean C.; Gordon, Karl D.

    2004-12-01

    A large amount (about three solar masses) of cold (18K) dust in the prototypical type II supernova remnant Cassiopeia A was recently reported. It was concluded that dust production in type II supernovae can explain how the large quantities (~ 108 solar masses) of dust observed in the most distant quasars could have been produced within only 700 million years after the Big Bang. Foreground clouds of interstellar material, however, complicate the interpretation of the earlier submillimetre observations of Cas A. Here we report far-infrared and molecular line observations that demonstrate that most of the detected submillimetre emission originates from interstellar dust in a molecular cloud complex located in the line of sight between the Earth and Cas A, and is therefore not associated with the remnant. The argument that type II supernovae produce copious amounts of dust is not supported by the case of Cas A, which previously appeared to provide the best evidence for this possibility.

  15. No cold dust within the supernova remnant Cassiopeia A

    CERN Document Server

    Krause, O; Rieke, G H; Lemke, D; Klaas, U; Hines, D C; Gordon, K D

    2004-01-01

    A large amount (about three solar masses) of cold (18 K) dust in the prototypical type II supernova remnant Cassiopeia A was recently reported. It was concluded that dust production in type II supernovae can explain how the large quantities (10^8 solar masses) of dust observed in the most distant quasars could have been produced within only 700 million years after the Big Bang. Foreground clouds of interstellar material, however, complicate the interpretation of the earlier submillimetre observations of Cas A. Here we report far-infrared and molecular line observations that demonstrate that most of the detected submillimetre emission originates from interstellar dust in a molecular cloud complex located in the line of sight between the Earth and Cas A, and is therefore not associated with the remnant. The argument that type II supernovae produce copious amounts of dust is not supported by the case of Cas A, which previously appeared to provide the best evidence for this possibility.

  16. 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.

  17. 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.

  18. Validating the Supernova Remnant Hypothesis of the Cosmic Ray Origin

    Science.gov (United States)

    Malkov, Mikhail

    The century-old problem of the origin and acceleration of cosmic rays (CR) could soon be resolved. However, as it is impossible to trace CR back to their accelerators because of orbit scrambling in the galactic magnetic field, the solution will not be easy. Also the direct observations of a secondary gamma emission from supernova remnant (SNR) shocks, long suspected to be the main source of galactic CRs, are complicated by the contaminating electron emission. Therefore, the SNR hypothesis of the CR origin can be proven beyond a reasonable doubt only if the acceleration theory is fully consistent with the observations. However, the complexity of plasma dynamics in SNR shocks makes the validation of the SNR hypothesis very difficult. A study of the crucial plasma processes in SNR shocks is proposed. It will determine the three-way partitioning of the shock energy between accelerated particles (protons and electrons), turbulent magnetic fields and thermal plasma. The project includes a comparative analysis of three instabilities, arguably crucial to the diffusive shock acceleration (DSA) mechanism: i.) the cyclotron resonance CR instability, ii.) the non- resonant CR-current driven (kink-type) instability and iii.) the acoustic CR-pressure gradient driven instability. By identifying the dominant instability depending on the local SNR environment, the spectra of different species of accelerated particles, their losses, and the broadband radiation will be calculated and compared to both direct observations of the secondary emission from major SNRs and to the measurements of the background CRs. The comparison will show whether the DSA mechanism production of CR in SNR is consistent with the observed emission. The remnants most visible in gamma rays expand into weakly ionized, dense gases. The physics of the CR production in such environments based on the three instabilities will be studied. The proposer's previous work has shown that the propagation of CRs in a dense SNR surrounding should result in a break in the particle and gamma-ray emission spectra, now frequently observed in such SNRs. The theoretical studies and modeling of the breaks, resulting from interactions of CR with a self-driven wave turbulence, will be carried out for conditions relevant to the observed SNRs. The problem of disentangling electron and proton emissions will be addressed. To this end, a new mechanism of electron injection into the DSA will be examined. This mechanism is based on a macroscopic electric field generated by the current-driven turbulence and penetration of CR into weakly ionized gas upstream. The electric field can accelerate electrons, leading to runaway. This process is well known from laboratory plasma research, so the proposer’s expertise in magnetic confinement studies will be utilized. The escape of accelerated particles into the SNR surroundings are studied separately from this proposal and may also become useful for the purpose of electron/proton differentiation. This will be based, in particular but not exclusively, on the fact that the proton high energy emission pattern is correlated with the ambient dense gas distribution, as opposed to the inverse Compton electron emission. CRs play a fundamental role in our understanding of the structure and evolution of the universe and the mystery of their origin is longstanding and difficult to solve. Very recent revolutionary improvements in SNR observations and CR measurements, including such NASA missions as Fermi and Chandra offer a unique chance for a theoretical breakthrough in validating the SNR hypothesis of the origin of galactic CRs. The proposers will be able to analytically predict CR spectral features, such as breaks and spectral slope variations among different elements. As these features are unique to the DSA, their comparison with the data will help to determine whether the DSA mechanism is indeed responsible for the production of galactic CR in SNRs.

  19. Acceleration of cosmic rays by young core-collapse supernova remnants

    CERN Document Server

    Telezhinsky, I; Pohl, M

    2012-01-01

    Context. Supernova Remnants (SNRs) are thought to be the primary candidates for the sources of Galactic cosmic rays. According to Diffusive Shock Acceleration theory, SNR shocks produce a power-law spectrum with index s = 2, perhaps non-linearly modified to harder spectra at high energy. Observations of SNRs often indicate particle spectra that are softer than that and show features not expected from classical theory. Known drawbacks of the standard approach are the assumption that SNRs evolve in a uniform environment, and that the reverse shock does not accelerate particles. Relaxing those assumptions increases the complexity of the problem, because one needs reliable hydrodynamical data for the plasma flow as well as good estimates for the magnetic field at the reverse shock. Aims. We show that these two factors are especially important when modeling young core-collapse SNRs that evolve in a complicated circumstellar medium shaped by the winds of progenitor stars. Methods. We use high-resolution numerical s...

  20. A Newly Recognized Very Young Supernova Remnant in M83

    Science.gov (United States)

    Blair, William P.; Winkler, P. Frank; 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 Halpha, [O I] 6300, and [O III] 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 not observed. Using photometry of nearby stars from the HST data, we suggest the precursor was at least 17 M(sun), and the presence of broad Halpha in the spectrum makes a type II supernova likely. The supernova must predate the 1983 VLA radio detection of the object. We suggest examination of archival images of M83 to search for evidence of the supernova event that gave rise to this object, and thus provide a precise time since the explosion.We acknowledge STScI grants under the umbrella program ID GO-12513 to Johns Hopkins University, STScI, and Middlebury College. PFW acknowledges additional support from the National Science Foundation through grant AST-0908566.

  1. Infrared Echoes near the Supernova Remnant Cassiopeia A

    CERN Document Server

    Krause, O; Birkmann, S M; Le Floc'h, E; Gordon, K D; Egami, E; Bieging, J H; Hughes, J P; Young, E T; Hinz, J L; Quanz, S P; Hines, D C

    2005-01-01

    Two images of Cassiopeia A obtained at 24 micrometer with the Spitzer Space Telescope over a one year time interval show moving structures outside the shell of the supernova remnant to a distance of more than 20 arcmin. Individual features exhibit apparent motions of 10 to 20 arcsec per year, independently confirmed by near-infrared observations. The observed tangential velocities are at roughly the speed of light. It is likely that the moving structures are infrared echoes, in which interstellar dust is heated by the explosion and by flares from the compact object near the center of the remnant.

  2. 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...

  3. 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...

  4. EVIDENCE FOR PARTICLE ACCELERATION TO THE KNEE OF THE COSMIC RAY SPECTRUM IN TYCHO'S SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    Supernova remnants (SNRs) have long been assumed to be the source of cosmic rays (CRs) up to the 'knee' of the CR spectrum at 1015 eV, accelerating particles to relativistic energies in their blast waves by the process of diffusive shock acceleration (DSA). Since CR nuclei do not radiate efficiently, their presence must be inferred indirectly. Previous theoretical calculations and X-ray observations show that CR acceleration significantly modifies 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 1014-1015 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 amplification of magnetic fields produce structure on the scale of the gyroradius of the highest energy CRs present, but they do not predict the highly ordered pattern we observe. We interpret the stripes as evidence for acceleration of particles to near the knee of the CR spectrum in regions of enhanced magnetic turbulence, while the observed highly ordered pattern of these features provides a new challenge to models of DSA.ge to models of DSA.

  5. 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.

  6. The 7Li/6Li Isotope Ratio Near the Supernova Remnant IC 443

    CERN Document Server

    Taylor, C J; Federman, S R; Lambert, D L

    2012-01-01

    We present an analysis of 7Li/6Li isotope ratios along four sight lines that probe diffuse molecular gas near the supernova remnant IC 443. Recent gamma-ray observations have revealed the presence of shock-accelerated cosmic rays interacting with the molecular cloud surrounding the remnant. Our results indicate that the 7Li/6Li ratio is lower in regions more strongly affected by these interactions, a sign of recent Li production by cosmic rays. We find that 7Li/6Li ~ 7 toward HD 254755, which is located just outside the visible edge of IC 443, while 7Li/6Li ~ 3 along the line of sight to HD 43582, which probes the interior region of the supernova remnant. No evidence of 7Li synthesis by neutrino-induced spallation is found in material presumably contaminated by the ejecta of a core-collapse supernova. The lack of a neutrino signature in the 7Li/6Li ratios near IC 443 is consistent with recent models of Galactic chemical evolution, which suggest that the nu-process plays only a minor role in Li production.

  7. Three-dimensional simulations of the non-thermal broadband emission from young supernova remnants including efficient particle acceleration

    International Nuclear Information System (INIS)

    Supernova remnants are believed to be 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 (1) modify the flow structure and (2) 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 three dimensions, 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 similar modifications of the shock structure, although to very different configurations of the field and particles. We show how this affects the emission patterns in different energy bands, from radio to X-rays and ?-rays. High magnetic fields (>100 ?G) directly impact the synchrotron emission from electrons, by restricting their emission to thin rims, and indirectly impact the inverse Compton emission from electrons and also the pion decay emission from protons, mostly by shifting their cut-off energies to respectively lower and higher energies.

  8. 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.

  9. Understanding hadronic gamma-ray emission from supernova remnants

    International Nuclear Information System (INIS)

    We aim to test the plausibility of a theoretical framework in which the gamma-ray emission detected from supernova remnants may be of hadronic origin, i.e., due to the decay of neutral pions produced in nuclear collisions involving relativistic nuclei. In particular, we investigate the effects induced by magnetic field amplification on the expected particle spectra, outlining a phenomenological scenario consistent with both the underlying Physics and the larger and larger amount of observational data provided by the present generation of gamma experiments, which seem to indicate rather steep spectra for the accelerated particles. In addition, in order to study to study how pre-supernova winds might affect the expected emission in this class of sources, the time-dependent gamma-ray luminosity of a remnant with a massive progenitor is worked out. Solid points and limitations of the proposed scenario are finally discussed in a critical way

  10. Properties of Optically Selected Supernova Remnant Candidates in M33

    OpenAIRE

    Lee, Jong Hwan; Lee, Myung Gyoon

    2014-01-01

    Narrow band images covering strong emission lines are efficient to survey supernova remnants (SNRs) in nearby galaxies. Using the narrow band images provided by the Local Group Galaxy Survey we searched for SNRs in M33. Culling the objects with enhanced [SII]/Ha and round morphology in the continuum-subtracted Ha and [SII] images, we produce a list of 199 sources. Among them 79 are previously unknown. Their progenitor and morphology types were classified. A majority of the s...

  11. Radio emission from supernova remnants in the galaxy M33

    International Nuclear Information System (INIS)

    A new 21-cm map of M33 with a resolution of 25 x 49 arcsec (RA, Dec) and an rms noise of 0.2 mJy per beam area has been used to search for radio emission at the positions of optically identified supernova remnants (SNR). Five well-established and three probable radio identifications are found. In the surface brightness-diameter diagram, the M33 radio remnants agree well with galactic objects. Using the galactic relation as a reference an average distance to M33 of 830 +- 100 kpc is derived. It is estimated that most of the radio remnants in M33 with flux densities > 1 mJy at 21 cm have been optically identified. (author)

  12. Modelling Hard $\\gamma$-Ray Emission From Supernova Remnants

    CERN Document Server

    Baring, M G

    1999-01-01

    The observation by the CANGAROO experiment of TeV emission from SN 1006, in conjunction with several instances of non-thermal X-ray emission from supernova remnants, has led to inferences of super-TeV electrons in these extended sources. While this is sufficient to propel the theoretical community in their modelling of particle acceleration and associated radiation, the anticipated emergence in the next decade of a number of new experiments probing the TeV and sub-TeV bands provides further substantial motivation for modellers. In particular, the quest for obtaining unambiguous gamma-ray signatures of cosmic ray ion acceleration defines a ``Holy Grail'' for observers and theorists alike. This review summarizes theoretical developments in the prediction of MeV-TeV gamma-rays from supernova remnants over the last five years, focusing on how global properties of models can impact, and be impacted by, hard gamma-ray observational programs, thereby probing the supernova remnant environment. Properties of central c...

  13. Particle Acceleration, Magnetic Field Generation and Emission from Relativistic Jets and Supernova Remnants

    Science.gov (United States)

    Nishikawa, K.-I.; Hartmann, D. H.; Hardee, P.; Hededal, C.; Mizunno, Y.; Fishman, G. J.

    2006-01-01

    We performed numerical simulations of particle acceleration, magnetic field generation, and emission from shocks in order to understand the observed emission from relativistic jets and supernova remnants. The investigation involves the study of collisionless shocks, where the Weibel instability is responsible for particle acceleration as well as magnetic field generation. A 3-D relativistic particle-in-cell (RPIC) code has been used to investigate the shock processes in electron-positron plasmas. The evolution of theWeibe1 instability and its associated magnetic field generation and particle acceleration are studied with two different jet velocities (0 = 2,5 - slow, fast) corresponding to either outflows in supernova remnants or relativistic jets, such as those found in AGNs and microquasars. Slow jets have intrinsically different structures in both the generated magnetic fields and the accelerated particle spectrum. In particular, the jet head has a very weak magnetic field and the ambient electrons are strongly accelerated and dragged by the jet particles. The simulation results exhibit jitter radiation from inhomogeneous magnetic fields, generated by the Weibel instability, which has different spectral properties than standard synchrotron emission in a homogeneous magnetic field.

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

    Energy Technology Data Exchange (ETDEWEB)

    Temim, Tea [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Slane, Patrick; Plucinsky, Paul P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Castro, Daniel [MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Gelfand, Joseph [New York University Abu Dhabi (United Arab Emirates); Dickel, John R., E-mail: tea.temim@nasa.gov [Physics and Astronomy Department, University of New Mexico, MSC 07-4220, Alburquerque, NM 87131 (United States)

    2013-05-01

    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 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.

  15. 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.

  16. 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%.

  17. 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...

  18. Spitzer Observations of Supernova Remnant IC 443

    CERN Document Server

    Noriega-Crespo, A; Gordon, K; Marleau, F R; Rieke, G H; Rho, J; Latter, W B

    2008-01-01

    We present Spitzer observations of IC 443 obtained with MIPS and IRS as part of our GTO program on the astrophysics of ejecta from evolved stars. We find that the overall morphology at mid/far IR wavelengths resembles even more closely a loop or a shell than the ground based optical and/or near IR images.The dust temperature map, based on the 70/160micron ratio, shows a range from 18 to 30 K degrees. The IRS spectra confirm the findings from previous near+mid IR spectroscopic observations of a collisionally excited gas, atomic and molecular, rich in fine structure atomic and pure H2 rotational emission lines, respectively. The spectroscopic shock indicator, [Ne II] 12.8micron, suggests shock velocities ranging from 60-90 km/s, consistent with the values derived from other indicators.

  19. The Neutron Star Born in the Antlia Supernova Remnant

    CERN Document Server

    Tetzlaff, Nina; Neuhaeuser, Ralph; Hohle, Markus Matthias

    2013-01-01

    Among all known young nearby neutron stars, we search for the neutron star that was born in the same supernova event that formed the Antlia supernova remnant (SNR). We also look for a runaway star that could have been the former companion to the neutron star (if it exists) and then got ejected due to the same supernova. We find the pulsar PSR J0630-2834 to be the best candidate for a common origin with the Antlia SNR. In that scenario the SNR is ~1.2 Myr old and is presently located at a distance of ~138 pc. We consider the runaway star HIP 47155 a former companion candidate to PSR J0630-2834. The encounter time and place is consistent with both stars being ejected from the Antlia SNR. We measured the radial velocity of HIP 47155 as 32.42 +/- 0.70km/s.

  20. 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....

  1. A high sensitivity search for X-rays from supernova remnants in Aquila

    Science.gov (United States)

    Schwartz, D. A.; Bleach, D. A.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.

    1972-01-01

    A high sensitivity scan of the galactic plane was performed to search for 2-20 keV X-rays from supernova remnants. The spectra of five X-ray sources detected between 44 deg and 31 deg longitude, of which only two might be associated with suggested supernova remnants, are reported on. Upper limits are presented for the 19 possible supernova remnants scanned in this survey.

  2. A high-sensitivity search for X-rays from supernova remnants in Aquila.

    Science.gov (United States)

    Schwartz, D. A.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Bleach, R. D.

    1972-01-01

    A high-sensitivity scan of the galactic plane from 70 to 30 deg was performed to search for 2-20-keV X rays from supernova remnants. The spectra of five X-ray sources detected between 44 and 31 deg longitude are presented, of which only two might be associated with suggested supernova remnants. Upper limits are given for the 19 possible supernova remnants scanned.

  3. Simulations of Supernova Remnants in Diffuse Media. II. Three Remnants and Their X-Ray Emission

    OpenAIRE

    Shelton, R L

    1999-01-01

    This paper describes the X-ray emission from supernova remnants evolving in warm, low density, nonthermal pressure dominated regions. Non-equilibrium ionization hydrocode simulations are used to predict the high resolution spectra, ROSAT PSPC countrates, spatial appearance, color temperatures, and the O VII and O VIII emission line fluxes as a function of time. For comparisons with observations, this paper also applies the standard observational analyses for determining th...

  4. Simulations of Supernova Remnants in Diffuse Media; 2, Three Remnants and Their X-Ray Emission

    CERN Document Server

    Shelton, R L

    1999-01-01

    This paper describes the X-ray emission from supernova remnants evolving in warm, low density, nonthermal pressure dominated regions. Non-equilibrium ionization hydrocode simulations are used to predict the high resolution spectra, ROSAT PSPC countrates, spatial appearance, color temperatures, and the O VII and O VIII emission line fluxes as a function of time. For comparisons with observations, this paper also applies the standard observational analyses for determining the color temperature, electron density, and thermal pressure to ROSAT ``observations'' of one of the simulated remnants, thus providing a map between observational results and physical conditions. The simulated remnants' C IV, N V, and O VI column densities are also reported. The simulations are applied to studies of the Galactic halo and Local Bubble and additionally may be of interest to studies of external galaxies and Galactic interarm regions.

  5. 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...

  6. 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.

  7. Cosmic Ray Electron Evolution in the Supernova Remnant RX J1713.7-3946

    CERN Document Server

    Finke, Justin D

    2012-01-01

    A simple formalism to describe nonthermal electron acceleration, evolution, and radiation in supernova remnants (SNRs) is presented. The electron continuity equation is analytically solved assuming that the nonthermal electron injection power is proportional to the rate at which the kinetic energy of matter swept up in an adiabatically expanding SNR shell. We apply this model to \\fermi\\ and HESS data from the SNR \\rxj, and find that a one-zone leptonic model with Compton-scattered cosmic microwave background (CMB) and interstellar infrared photons has difficulty providing a good fit to its spectral energy distribution, provided the source is at a distance $\\sim 1\\ \\kpc$ from the Earth. However, the inclusion of multiple zones, as hinted at by recent {\\em Chandra} observations, does provide a good fit, but requires a second zone of compact knots with magnetic fields $B\\sim 16\\ \\mu$G, comparable to shock-compressed fields found in the bulk of the remnant.

  8. Tests for supernova explosion models: from light curves to X-ray emission of supernova remnants

    CERN Document Server

    Sorokina, E; Sorokina, Elena; Blinnikov, Sergey

    2003-01-01

    The successful theoretical supernova explosion models should be able to explain any features of the emission from supernovae at any evolutionary stage. We check several models from two different points of view. With the multi-frequency radiation hydro code STELLA we calculate gamma-ray, bolometric and broad-band UBVI light curves. Then we use the same models to calculate the emission from young supernova remnants. Here we present new plots for gamma-ray luminosity from several SN Ia models and recomputations of bolometric and UBVRI light curves of model 13C for SN 1993J.

  9. 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...

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

    CERN Document Server

    Obergaulinger, M; Aloy, M A; Iyudin, A

    2014-01-01

    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 of the right order of magnitude, allowing for further use in more extended sets of models.

  11. 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...

  12. The relativistic ISM in M33: Role of the supernova remnants

    Science.gov (United States)

    Duric, N.; Gordon, S. M.; Goss, W. M.; Viallefond, F.; Lacey, C.

    1995-05-01

    The role of supernova remnants in producing and maintaining the relativistic interstellar medium is investigated for the case of the nearby galaxy M33. Analysis of a radio continuum sample of supernova remnants (SNRs) has led to the following results. (1) The SNRs use roughly 1%-10% of their blast energy to produce relativistic particles. (2) The currently observed SNR population contains between 0.1% and 1% of the relativistic particle energy of the entire interstellar medium of M33, which leads to reasonable values of the particle residence time in the disk. (3) The distribution of synchrotron spectral indices indicates that the particle populations of the observed SNRs have energy spectra with power-law indices of 2.2 +/- 0.4, consistent with values predicted by diffusive shock acceleration theory. Taken together, the three results favor the hypothesis that SNRs account for the bulk of M33's relativistic medium. It is further shown that, as a consequence of these results, the predicted SN rate is 1 per 140-250 yr, in general agreement with independent estimates of the SN rate and the absence of historical supernovae.

  13. Spitzer Observations of Dust Destruction in the Puppis A Supernova Remnant

    Science.gov (United States)

    Arendt, Richard G.; Dweek, Eli; Blair, William P.; Ghavamian, Parviz; Hwang, Una; Long, Knox X.; Petre, Robert; Rho, Jeonghee; Winkler, P. Frank

    2010-01-01

    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 micrometers 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.

  14. High-resolution radio observations of five supernova remnants

    International Nuclear Information System (INIS)

    Five supernova remnants have been mapped with high resolution using the Fleurs synthesis radio telescope. Four of the sources (G33.6 + 0.1, G309.2 - 0.6., G315.4 - 0.3 and G320.4 - 1.2) possess shell structures, albeit with considerable distortion; the fifth source, G308.7 + 0.0, has a centrally concentrated brightness distribution reminiscent of the Crab nebula but considerably more elongated. In the general direction of G320.4 - 1.2 there is considerable optical emission but only the brightest features seem to be associated with the radio source; currently available sky survey photographs show no associated optical nebulosity in the direction of the other four remnants. (author)

  15. Radio maps revealing shell structures in five supernova remnants

    International Nuclear Information System (INIS)

    Five southern supernova remnants (SNRs) of small angular diameter (5 - 10 arcmins) have been mapped with the Fleurs synthesis telescope; at the resolution used (better than 1 arcmin) a shell structure can be seen in each remnant. One of the SNRs, G342.0 - 0.2, is a faint source which we confirm as an SNR for the first time. This source and three others, G340.4 + 0.4, G340.6 + 0.3 and G341.9 - 0.3, lie close together on the sky; they have similar distance estimates of approx. 16 kpc and they all may be located in one of the spiral arms on the far side of the Galaxy. The fifth SNR, G352.7 - 0.1, although displaced from the others by more than 10 deg, is at a similar distance and is possibly in the same arm. (author)

  16. Supernova remnant evolution in an inhomogeneous medium. I. Numerical models

    International Nuclear Information System (INIS)

    We present the first numerical simulations of supernova remnant evolution in an inhomogeneous gas. Evolution in the lowest density substrate (the intercloud) is assumed to be spherically symmetric with a large intercloud filling factor and many dense regions (clouds) within the remnant; however, mass momentum and energy transfer between cloud and intercloud are included and the position and morphology of individual clouds tracked. We consider evolution in several different models of the interstellar medium, both those in which the intercloud gas is diffuse (10-3 to 10-2 cm-3) and those in which it is relatively dense (napprox.0.3 cm-3) under a variety of assumptions about the efficiency of thermal evaporation from the clouds into the intercloud medium

  17. A Chandra X-Ray Survey of Ejecta in the Cassiopeia A Supernova Remnant

    Science.gov (United States)

    Hwang, Una; Laming, J. Martin

    2011-01-01

    We present a survey of the X-ray emitting ejecta in the Cassiopeia A supernova remnant based on an extensive analysis of over 6000 spectral regions extracted on 2.5-10" angular scales using the Chandra 1 Ms observation. We interpret these results in the context of hydrodynamical models for the evolution of the remnant. The distributions of fitted temperature and ionization age are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks. Based on the fitted emission measure and element abundances, and an estimate of the emitting volume, we derive masses for the X-ray emitting ejecta as well as showing the distribution of the mass of various elements over the remnant. The total shocked Fe mass appears to be roughly 0.14 Solar Mass, which accounts for nearly all of the mass expected in Fe ejecta. We find two populations of Fe ejecta, that associated with normal Si-burning and that associated with alpha-rich freeze-out, with a mass ratio of approximately 2:1. Surprisingly, essentially all of this Fe (both components) is well outside the central regions of the SNR, presumably having been ejected by hydrodynamic instabilities during the explosion. We discuss this, and its implications for the neutron star kick.

  18. Radio interferometer observations of compact sources in supernova remnants

    International Nuclear Information System (INIS)

    The remains of the progenitor stars of supernovae are likely to have compact radio structure and steep radio spectra. The radio-linked interferometer comprising the MK IA 76m telescope and the Defford 25m telescope situated 127 km to the south has a resolution of approx. 1 arcsec at 408 MHz and is ideal for searching for new objects. A list of sources which are interesting either because of unusual spectra or by virtue of their position in the remnant, is given. (Auth.)

  19. Radio observations of three supernova remnants in M33

    International Nuclear Information System (INIS)

    Discrete sources in the southern spiral arm of M33 have been observed with the Westerbork Synthesis Radio Telescope at 49 and 21 cm and the Very Large Array at 6 cm. The three optically confirmed supernova remnants were detected with the WSRT and were found to have non-thermal spectral indices. Two of these SNR were detected with the VLA with a resolution of approximately 1.5 arcsec (5 pc). If it is assumed that these M33 SNR are similar to galactic SNR, the surface-brightness-diameter relationship proposed by Caswell and Lerche indicates a distance of 860 +- 200 kpc for M33. (author)

  20. Revealing the Supernova Remnant Population of M33 with Chandra

    OpenAIRE

    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 ...

  1. 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.

  2. Radio and X-ray emission from supernova remnants

    International Nuclear Information System (INIS)

    In this paper it was studied the statistical correlation between radio and X-ray emissions from shell-type supernova remnants (SNR). The primary aim of this work is to test the model of radio emission of shell-type SNRs presented by one of the authors. Based on this model of radio emission, by using the Monte Carlo techniques it was simulated statistical relations radio-X-ray luminosities which then were compared with the observations. X-ray emission is assumed to be thermal. To have a uniform statistical material it was used observational data on the SNRs in Magellanic Clouds

  3. RADIO EMISSION FROM YOUNG SUPERNOVAE AND SUPERNOVA REMNANTS IN Arp 299

    International Nuclear Information System (INIS)

    We have made sensitive milliarcsecond-resolution radio images of the nearby merger galaxy Arp 299 at four epochs spread over 18 months between 2003 and 2005. The combined data revealed a total of 30 point sources in the two primary merger nuclei. Twenty-five of these are found in the northeastern nucleus (component 'A' = IC 694) over a region ?100 pc in diameter, while five are in the southwestern nucleus (component 'B1' = NGC 3690) within a region ?30 pc in size. These objects are interpreted as young supernovae and supernova remnants; the ratio of the source counts in nuclei A and B1 is approximately equal to the ratio of their predicted supernova rates. An approximate luminosity function has been derived for nucleus A, and indicates that it might contain as many as 500-1000 compact radio sources more powerful than Cassiopeia A; the integrated flux density of these sources would be about 20% of the total flux density seen at lower resolution. A new supernova occurred in nucleus B1 in the first half of 2005, having a peak radio power at least 2000 times the present power of Cas A. This supernova is located within 0.4 pc (projected distance) of an apparently older supernova remnant, making it very likely that this indicates the presence of a massive super star cluster within nucleus B1. Comparison of the typical radio flux densities of our compact radio sources to the observed X-ray luminosities of nuclei A and B1 indicates that it is possible that one radio sourcat it is possible that one radio source in each nucleus actually could be associated with an active galactic nucleus rather than being a supernova remnant.

  4. HFPK 334: An unusual Supernova Remnant in the Small Magellanic Cloud

    CERN Document Server

    Crawford, E J; McEntaffer, R L; Brantseg, T; Heitritter, K; Roper, Q; Haberl, F; Urosevi?, D

    2014-01-01

    We present new Australia Telescope Compact Array (ATCA) radio-continuum and XMM-Newton/Chandra X-ray Observatory (CXO) observations of the unusual supernova remnant HFPK 334 in the Small Magellanic Cloud (SMC). The remnant follows a shell type morphology in the radio-continuum and has a size of $\\sim$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 powerlaw with a photon index of $\\Gamma = 2.7 \\pm 0.5$. 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 point toward a younger SNR with an age of $\\lesssim 1800$ years. With an average radio spectral index of $\\alpha=-0.59\\pm0.09$ we find that an equipartition magnetic field for the remnant is $\\sim$90~$\\mu$G, a value typical of younger SNRs in low-density env...

  5. Spherization of remnants of an asymmetrical supernova explosion in the homogeneous medium

    International Nuclear Information System (INIS)

    The spherization of the shock wave is considered, which propagates in the uniform interstellar medium in the presence of the initial asymmetry of the shape and velocity. The calculations have been made in the approximation of 1.5-dimensional hydrodynamics. Three different models have been considered with the preference given to the 'snow-plough'' model. The characteristic time of the spherization is found for different values of the density of the medium and the parameters of the explosion. It is obtained that when the initial asymmetry is large, by the moment of the spherization in the shape of the shock, the large difference of the surface density on the pole and equator remains. This may explain the observed features of the supernova remnant Cas A

  6. 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.

  7. 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

  8. Effect of stellar structure on supernova remnant evolution

    Energy Technology Data Exchange (ETDEWEB)

    Jones, E.M.; Smith, B.W.; Straka, W.C.

    1980-01-01

    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.

  9. High-velocity iron absorption lines in supernova remnant 1006

    International Nuclear Information System (INIS)

    The International Ultraviolet Explorer spectrum of the Schweizer-Middleeditch star projected near the center of supernova remnant SNR 1006 shows an sdOB Star continuum, with very strong, broad absorption lines. Strong Fe+ resonance absorption lines are present. Their centers show zero radial velocity, while their profiles are broadened by approx.5-6 x 103 km s-1. Redshifted Si/sup +,+2,+3/ lines at #betta#/sub r/approx.5 x 103 km s-1 have also been tentatively identified. We argue that the absorptions must occur in the ejecta of the supernova. The strength and symmetric width of the Fe+ lines suggests that the bulk of ejecta is iron, in agreement with the current theory for the origin of Type I supernovae. The previous failure to detect strong Fe emission lines in the X-ray spectrum of this and other young Type I SNRs suggests that the ejecta may not have had time to interact significantly with the ambient medium. The presence of redshifted absorption lines due to supernova ejecta in its spectrum indicates that this star is located behind the SNR and is not physically associated with it

  10. HESS J1818-154, a new composite supernova remnant discovered in TeV gamma rays and X-rays

    OpenAIRE

    Collaboration, H. E. S. S.; Abramowski, A.; Aharonian, F.; Benkhali, F. Ait; Akhperjanian, A. G.; Angu?ner, E.; Anton, G.; Balenderan, S.; Balzer, A.; Barnacka, A.; Becherini, Y.; Tjus, J. Becker; Bernlo?hr, K.; Birsin, E.; Bissaldi, E.

    2013-01-01

    Composite supernova remnants (SNRs) constitute a small subclass of the remnants of massive stellar explosions where non-thermal radiation is observed from both the expanding shell-like shock front and from a pulsar wind nebula (PWN) located inside of the SNR. These systems represent a unique evolutionary phase of SNRs where observations in the radio, X-ray, and $\\gamma$-ray regimes allow the study of the co-evolution of both these energetic phenomena. In this article, we rep...

  11. 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)...

  12. Supernova Remnants and the Interstellar Medium of M83: Imaging & Photometry with WFC3 on HST

    CERN Document Server

    Dopita, Michael A; Long, Knox S; Mutchler, Max; Whitmore, Bradley C; Kuntz, Kip D; Balick, Bruce; Bond, Howard E; Calzetti, Daniela; Carollo, Marcella; Disney, Michael; Frogel, Jay A; O'Connell, Robert; Hall, Donald; Holtzman, Jon A; Kimble, Randy A; MacKenty, John; McCarthy, Patrick; Paresce, Francesco; Saha, Abhijit; Silk, Joe; Sirianni, Marco; Trauger, John; Walker, Alistair R; Windhorst, Rogier; Young, Erick

    2010-01-01

    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$\\alpha$, [\\SII], H$\\beta$, [\\OIII] and [\\OII] filters, we have identified 60 supernova remnant candidates, as well as a handful of young ejecta-dominated candidates. A catalog of these remnants, their sizes and, where possible their H$\\alpha$ fluxes are given. Radiative ages and pre-shock densities are derived from those SNR which have good photometry. The ages lie in the range $2.62 < log(\\tau_{\\rm rad}/{\\rm yr}) < 5.0$, and the pre-shock densities at the blast wave range over $0.56 < n_0/{\\rm cm^{-3}} < 1680$. Two populations of SNR have been discovered. These divide into a nuclear and spiral arm group and an inter-arm population. We infer an arm to inter-arm density contrast of 4. The surface flux in diffuse X-rays is correlated with the inferred pre-shock density, indicati...

  13. Dust Formation Observed in Young Supernova Remnants with Spitzer

    CERN Document Server

    Rho, J; Tappe, A; Rudnick, L; Kozasa, T; Hwang, U; Andersen, M; Gomez, H; DeLaney, T; Dunne, L; Slavin, J

    2009-01-01

    We present dust features and masses observed in young supernova remnants (SNRs) with Spitzer IRS mapping and staring observations of four youngest supernova remnants: SNR 1E102.2-7219 (E0102) in the SMC, Cas A and G11.2-0.3 in our Galaxy, and N132D in the LMC. The spectral mapping data revealed a number of dust features which include 21 micron-peak dust and featureless dust in Cas A and 18-micron peak dust in E0102 and N132D. The 18 micron-peak feature is fitted by a mix of MgSiO$_3$ and solid Si dust grains, while the 21-micron peak dust is by a mix of silicates and FeO; we also explore dust fitting using Continuous Distribution of Ellipsoid grain models. We report detection of CO fundamental band from Cas A in near-infrared. We review dust features observed and identified in other SNRs. The dust emission is spatially correlated with the ejecta emission, showing dust is formed in SN ejecta. The spectra of E0102 show rich gas lines from ejecta including strong ejecta lines of Ne and O, including two [Ne III] ...

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

    CERN Document Server

    Zhou, Xin; Fang, Min; Su, Yang

    2014-01-01

    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....

  15. Properties of Optically Selected Supernova Remnant Candidates in M33

    CERN Document Server

    Lee, Jong Hwan

    2014-01-01

    We present a sample of supernova remnant (SNR) candidates in M33 based on optical narrow band images in the Local Group Survey. We identify emission line objects that have enhanced [SII]:H{\\alpha} (> 0.4) and circular shapes using continuum-subtracted H{\\alpha}and [SII] images and produce a list of 199 SNR candidates, of which 79 are previously unknown. We classify them considering two types of criteria: their progenitor type (Type Ia and core-collapse (CC) SNRs) and their morphological type. Of the total sample, 170 are likely remnants of CC SNe and 29 are likely remnants of Type Ia SNe. We obtain a cumulative size distribution of the SNR candidates, showing that it follows a power law with an index,{\\alpha}= 2.38{\\pm}0.05 (17 < D < 50 pc). This indicates that most of the M33 SNR candidates found in this study are in the Sedov-Taylor phase, consistent with previous findings. The [SII]:H{\\alpha} distribution of the SNR candidates shows two peaks at [SII]:H{\\alpha} ~0.55 and ~0.8. Interestingly X-ray and...

  16. 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...

  17. 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.

  18. 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.

  19. Analytical methods for the hydrodynamical evolution of supernova remnants

    International Nuclear Information System (INIS)

    We present haere an analytical method for computing the hydrodynamical structure and evolution of supernova remnants (SNRs). We show that simple approximations can be derived by using Lagrangian coordinates, rather than Eulerian; in particular, the pressure distribution is obtained as an almost linear function of the mass, M (r); this constitutes the first order of our approximation. The set of the three fundamental hydrodynamic equations, which are partial derivative equations, is reduced to an ordinary differential equation for a function of only one variable. A further simplification characteristic of this method is that the velocity field does not appear explicitly in our equations, and need not be computed. The results obtained in this manner are very accurate in cases of self-similar expansion, and remain satisfactory in more general cases.We also give a rapidly converging development of the exact solution, and explicitly calculate the second-order terms. The accuracy of the second-order expansion is high, and seems comparable to that given by fully numerical calculations.We have tested this analytical method by comparison with self-similar solutions, and also by comparing our results with earlier calculations on the early phases of expansion (pre-Sedov), when the mass of ejecta has not yet become negligible in comparison with the swept-up mass. We also present results on the expansion of a supernova remnant through a hot interstellar medium (ISM), which should t interstellar medium (ISM), which should be applicable to SNRs of large radius; recent work has shown that the ISM pressure cannot be neglected for such remnants.We hope to generalize this method of solution to more complex, e.g., non-spherically symmetric cases; the complexity of the fully numerical treatment should make analytical methods most useful in such cases

  20. Swift Observations of Supernovae during and after Shock Breakout

    Science.gov (United States)

    Immler, Stefan

    2008-01-01

    Over the past few years, space-based observatories have allowed detailed studies of energetic supernova explosions in previously unexplored time domains and wavelength regimes. NASA's Swift observatory is playing an important role in probing the early emission of SNe during and after shock breakout due to its fast response, flexible scheduling capabilities, and large wavelength band coverage, ranging from the optical, W, and X-ray to the Gamma-ray bands. By studying the outgoing SN shocks with material in its surroundings, the explosion physics and nature of progenitor stars can be studied. Furthermore, monitoring the X-ray emission of SNe with space-based X-ray observatories is being used to map the density structure in SN environments out to large radii from the sites of the explosions (>E20 cm), the transition of a SN into an old supernova remnant can be studied, and the mass-loss rates of the progenitor stars are being probed over significant timescales (>E4 years) in the stellar wind history. In combination, these observations give unprecedented insights into the nature of energetic explosions and their environments. During this talk, I will present highlights from recent observations, among them the first observation of a SN DURING the actual explosion with Swift, and I will discuss the "naked eye" burst at a redshift of -1, which was the most distant object humans could ever see with their own eyes.

  1. 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.

  2. 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 ...

  3. A multi-wavelength look at the young plerionic supernova remnant 0540-69.3

    International Nuclear Information System (INIS)

    We present a study of the plerionic supernova remnant 0540-69.3 in the LMC in X-ray, radio, optical, and infrared. We find that the shell of 0540-69.3 is characterized in the X-ray by thermal nonequilibrium plasma with depleted Mg and Si abundances and a temperature of kT ? 0.7 keV. This thermal emission is superimposed with synchrotron emission in several regions. Based on X-ray spectra and on morphological considerations in all surveyed wavebands, we conclude that the shell is expanding into a clumpy and highly inhomogeneous medium. In one region of the shell we find an overabundance of Ne, suggesting the presence of ejecta near the edge of the remnant. We also see evidence for reheating of material via a reverse shock originating from the interaction of the supernova blast wave with a particularly dense cloud in the surrounding medium. Finally, we perform the first detailed study of the 'halo' region extending 1.2-2.2 pc from the central pulsar. We detect the presence of thermal and nonthermal spectral components but do not find evidence for mixing or ejecta. We conclude that the thermal component is not a counterpart to similar optical and infrared halos and that it is most likely due to the projection of shell material along the line of sight.

  4. An Investigation into PAH Destruction in Nearby Supernova Remnants, North Polar Spur and Cygnus Loop

    Science.gov (United States)

    Burkhart, Sarah M.; Witt, Adolf N.

    2015-01-01

    Our goal in conducting this research was to look at the polycyclic aromatic hydrocarbon (PAH)/large dust grain emission intensity ratio in nearby supernova remnants to find evidence for selective PAH destruction by hot gas and high velocity shock waves within these regions, as predicted by the models of Arendt et al. (2010) and Micelotta et al. (2010a,b). Two supernova remnants were studied- the North Polar Spur (NPS) and the Cygnus Loop. The data for PAHs were obtained from the WISE W3 12 micron all-sky map processed by Meisner & Finkbeiner (2014), and the data for the larger grains come from the IRAS 100 micron all-sky map processed by Schlegel, Finkbeiner & Davis (1998). After obtaining a control PAH/large grain intensity ratio of ~2.8 (DN/px)/(MJy/sr) from two high latitude clouds, MBM 30 and MBM 32, we found that the intensity ratios across the NPS and Cygnus Loop were not far off- ~2.7 (DN/px)/(MJy/sr) and ~3.1 (DN/px)/(MJy/sr), respectively- showing no evidence of selective large-scale PAH destruction in supernova remnants. The individual intensities for both PAHs and large grains do decrease inside the Cygnus Loop, however, suggesting a decrease in abundances of both grain types, which could mean total dust grain destruction with the normal ratios coming from foreground and background dust located in the line of sight of the remnant. In addition, temperature and E(B-V) measurements taken from calibrated IRAS images show that while the dust column density increases in the Eastern Veil of the Cygnus Loop, the dust temperature reaches a local maximum, indicating the heating of large grains by interaction with the hot gas in the remnant. The PAH/large grain ratio in the Eastern Veil does decrease and could be indicative of currently ongoing active grain destruction there, with the PAHs being destroyed on a more rapid timescale than the large grains.We are grateful for financial support from the NSF REU Program grant to the Department of Physics & Astronomy at the University of Toledo.

  5. Radio supernovae, supernova remnants and HII regions in NGC 2146 observed with MERLIN and the VLA

    CERN Document Server

    Tarchi, A; Greve, A; Klein, U; Garrington, S T; Muxlow, T W B; Pedlar, A; Glendenning, B E

    2000-01-01

    We present a high-resolution 5-GHz radio continuum map of the starburst galaxy NGC 2146 made with MERLIN and the VLA, in a search of radio supernovae and supernova remnants expected to be already produced by the most massive stars in the starburst. At 5 GHz, about 20 point sources were detected earlier by Glendenning & Kronberg (1986) in the central 800 pc of NGC 2146. Our observations with higher sensitivity and resolution made with MERLIN and the VLA confirms the detection of 18 sources, and resolves 7 of them. Additional 1.6-GHz MERLIN observations disclose 9 sources coincident in position with those detected at 5 GHz, which allows us to derive their spectral indices. Only 3 sources have indices consistent with synchrotron emission from supernova remnants or radio supernovae, while the others have very steep inverted spectra. We suggest that the sources with positive spectral index are optically thick ultra-compact and/or ultra-dense HII regions with high electron densities and high emission measures (...

  6. 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...

  7. Identification campaign of supernova remnant candidates in the Milky Way. II. X-ray studies of G38.7-1.4

    International Nuclear Information System (INIS)

    We report on XMM-Newton and Chandra observations of the Galactic supernova remnant candidate G38.7-1.4, together with complementary radio, infrared, and ?-ray data. An approximately elliptical X-ray structure is found to be well correlated with a 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 behavior, we suggest that G38.7-1.4 is indeed a supernova remnant belonging to a mix-morphology category.

  8. 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

  9. Hard X-Ray Emission and 44Ti Line Features of the Tycho Supernova Remnant

    Science.gov (United States)

    Wang, Wei; Li, Zhuo

    2014-07-01

    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.

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

    Science.gov (United States)

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

    2015-05-01

    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 us 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 suggest that SNR 0509-67.5 could originate from a delayed detonation explosion and SNR 0519-69.0 from an oxygen-rich merger.

  11. 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.

  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. 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.

  14. 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.

  15. Dynamics of Supernova Remnants with Ejecta and Circumstellar Bubbles

    Science.gov (United States)

    Blondin, M. J.; Featherstone, N.; Borkowski, J. K.; Reynolds, P. S.

    2001-09-01

    Progenitors of core-collapse supernovae (SNe) blow bubbles in the ambient medium and sweep it into shells with their powerful stellar winds. After the explosion, SN ejecta initially collide with the stellar wind, then with the wind-blown bubble, and finally with a dense wind-swept shell. This collision is particularly energetic for SNe whose progenitors lost most of their outer envelopes just prior to explosion: the brightest galactic supernova remnant (SNR), Cas A, is a prime example of such an interaction with the circumstellar medium (CSM). The SN ejecta are far from being smooth for such remnants, because of vigorous turbulence and mixing of heavy-element ejecta immediately after the explosion and subsequent growth of Ni-Fe bubbles powered by the radioactive decay. We study the interaction of ``bubbly'' SN ejecta with a CSM bubble and a swept CSM shell, using hydrodynamical simulations in 2 and 3 dimensions with the VH-1 hydrocode. We compare our simulations with analytic self-similar (Chevalier & Liang 1989) solutions and with our previous simulations of interaction of bubbly ejecta with a uniform ambient medium. When compared with these simulations, the impact of bubbly ejecta with the shell results in a more vigorous turbulence and mixing. Dense and cool ejecta at the boundaries of adjacent bubbles may penetrate the shell, leading to plume-like and ring-like features. We examine whether such an interaction is responsible for the observed morphology of Cas A as seen by the Chandra X-ray Observatory and the Hubble Space Telescope, and for the different expansion rates seen at X-ray and radio wavelengths.

  16. 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

    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.

  17. Extended supernova shock breakout signals from inflated stellar envelopes

    OpenAIRE

    Moriya, Takashi J.; Sanyal, Debashis; 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 diffusio...

  18. Imaging of the Supernova Remnant Cassiopeia A with the Multiband Imaging Photometer for Spitzer (MIPS)

    Science.gov (United States)

    Hines, D. C.; Rieke, G. H.; Gordon, K. D.; Rho, J.; Misselt, K. A.; Woodward, C. E.; Werner, M. W.; Krause, O.; Latter, W. B.; Engelbracht, C. W.; Egami, E.; Kelly, D. M.; Muzerolle, J.; Stansberry, J. A.; Su, K. Y. L.; Morrison, J. E.; Young, E. T.; Noriega-Crespo, A.; Padgett, D. L.; Gehrz, R. D.; Polomski, E.; Beeman, J. W.; Haller, E. E.

    2004-09-01

    We present new images of the supernova remnant (SNR) Cas A observed in the 24 and 70 ?m bands of the Spitzer Space Telescope (Spitzer). The IR emission correlates well with the Si X-ray and optical [S II] emission but poorly with either the synchrotron-dominated radio structure or the continuum X-ray emission. The IR is therefore dominated by thermal emission from dust within the SNR and associated with emission-line gas inside the reverse shock region, confirming earlier IRAS and Infrared Space Observatory results. Supplemented by new photometric measurements from archived Midcourse Space Experiment images, we suggest stochastic heating to model the overall mid- to far-IR spectral energy distribution. The 24 and 70 ?m images also reveal a counterjet to the well-known northeast jet feature imaged previously at X-ray, optical, and radio wavelengths. This IR counterjet corresponds well with (optical) fast-moving knots confirming its outflow nature. The opposing jetlike features define a symmetry axis that bisects the SNR and suggest that the supernova explosion was axisymmetric. The IR images also show a region in which the SNR forward shock appears to be propagating into a ~650 Msolar molecular cloud. The new images also show other details of the surrounding ISM structure, including two groups of knots extending ~6'-12' on either side of the SNR.

  19. DIRECT EVIDENCE FOR HADRONIC COSMIC-RAY ACCELERATION IN THE SUPERNOVA REMNANT IC 443

    International Nuclear Information System (INIS)

    The supernova remnant (SNR) IC 443 is an intermediate-age remnant well known for its radio, optical, X-ray, and gamma-ray energy emissions. In this Letter, we study the gamma-ray emission above 100 MeV from IC 443 as obtained by the AGILE satellite. A distinct pattern of diffuse emission in the energy range 100 MeV-3 GeV is detected across the SNR with its prominent maximum (source 'A') localized in the northeastern shell with a flux F=(47±10)x10-8 photons cm-2s-1 above 100 MeV. This location is the site of the strongest shock interaction between the SNR blast wave and the dense circumstellar medium. Source 'A' is not coincident with the TeV source located 0.4 deg. away and associated with a dense molecular cloud complex in the SNR central region. From our observations, and from the lack of detectable diffuse TeV emission from its northeastern rim, we demonstrate that electrons cannot be the main emitters of gamma rays in the range 0.1-10 GeV at the site of the strongest SNR shock. The intensity, spectral characteristics, and location of the most prominent gamma-ray emission together with the absence of cospatial detectable TeV emission are consistent only with a hadronic model of cosmic-ray acceleration in the SNR. A high-density molecular cloud (cloud 'E') provides a remarkable 'target' for nucleonic interactions of accelerated hadrons; our results show enhanced gamma-ray production near the molecular cloud/shocked shell interactionmolecular cloud/shocked shell interaction site. IC 443 provides the first unambiguous evidence of cosmic-ray acceleration by SNRs.

  20. 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-...

  1. 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 ...

  2. 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 ...

  3. Development of an x-ray imaging proportional counter and an analysis of Tycho's supernova remnant

    International Nuclear Information System (INIS)

    A soft X-ray imaging proportional counter was developed for use in X-ray astronomy. The detector, a drift multiwire proportional counter, determines the position of the site of X-ray absorption in the detector in two orthogonal directions using the center-of-gravity centroid determination technique. Spatial resolutions of 0.2 millimeters full width at half maximum and 0.5 millimeters full width at half maximum have been obtained at X-ray energies of 0.94 and 0.28 kiloelectron volts, respectively. Energy resolutions of 65 percent full width at half maximum and 110 percent full width at half maximum have been obtained at these energies. The detector and processing electronics were integrated into a rocket-borne X-ray telescope payload capable of providing angular resolutions of 1.0 arcminutes full width at half maximum and 1.3 arcminutes full width at half maximum at X-ray energies of 0.94 and 0.28 kiloelectron volts, respectively. X-ray imaging observations of Tycho's supernova remnant were obtained with the Einstein Observatory imaging proportional counter. The remnant appears as an incomplete shell of radius 3.5 parsecs in the adiabatic phase of evolution. The X-ray and radio shells are spatially coincident, although uncorrelated in intensity. The luminosity at a distance of 3 kiloparsecs is (5.3 +- 1.3) x 1036 ergs per second. The current shock velocity is 3400 +- 140 kilometers per second. An initial blast energy is found of 2.5 x 1051 ergs an is found of 2.5 x 1051 ergs and an average ambient density is found in the vicinity of Tycho of approximately 3 atoms per cubic centimeter. The mass swept up by the expanding shock wave is estimated at about 20 solar masses. A range of 0.3 to 3 solar masses has been placed on the supernova ejected mass

  4. 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...

  5. A Multiwavelength Study of Supernova Remnants in M33: The Radio Subsample

    Science.gov (United States)

    Gordon, S.; Kirshner, R.; Duric, N.; Long, K.

    1992-12-01

    M33 is the current focus of a project to identify and study supernova remnantsi (SNRs) using observations in radio, X-ray and optical wavelengths. Here, we present the results from the radio selected sample of SNRs in M33. The radio observations were obtained with the Very Large Array and the Westerbork Synthesis Array at 6 and 20 cm. The flux and spectral index of all sources down to the 3sigma noise level of the maps have been measured. From the resulting catalogue, a list of candidate SNRs has been compiled, where the sample is defined as all radio sources with a non-thermal spectral index. This effectively eliminates most HII regions, but also includes background radio sources. Because of the inclusion of background sources, it is necessary to turn to other wavelengths for confirmation. We have examined the sites of radio emission using interference filter (6100 Angstroms, [SII], H? ) observations taken with the KPNO 4m telescope. Following the method of Long et al. (1990,Ap. J. Suppl. 72,61), we have identified a list of 37 non-thermal radio sources that have a high [SII]/H? ratio, making them probable optical SNR candidates. We have observed 32 of these spectroscopically at the MMT with the Red Channel long-slit spectrograph. The results of these observations will be presented. The multiwavelength approach allows us more than the ability to confirm the existence of new remnants, it also gives us valuable information on the dynamics of the SNR and its interaction with the surrounding medium. As an example, we are studying a particularily interesting remnant in M33 which has been detected in X-ray, radio and optical and is located in the HII region NGC 592. With information from all three wavelengths we are exploring the properties of the shock, the efficiency of conversion of shock energy into relativistic particles, and the state of evolution of the remnant.

  6. Using [FeII] to Search for Supernova Remnants in NGC 6946

    Science.gov (United States)

    Bruursema, Justice; Meixner, M.; Long, K. S.; Otsuka, M.

    2014-01-01

    Supernovae and supernova remnants (SNRs) play an important role in the evolution of the interstellar medium of their host galaxies. A crucial part in gaining a better understanding of this role is in obtaining a large sample of such objects and studying how their properties relate to their physical environment. Usually, SNRs are identified at optical wavelengths as emission nebulae with high [SII]:H? flux ratios compared to HII regions. However, in the IR, shock models indicate and observations show that SNRs emit strongly in [Fe II] at 1.64 ?m. Here we report on an attempt to use the [Fe II] 1.64 ?m line to search for SNRs in the nearby starburst galaxy NGC 6946. For this study we have used the WIYN High Resolution Infrared Camera (WHIRC) on the WIYN 3.5m telescope to image NGC 6946 in broad bands J and H and narrow bands [FeII], [FeII]-4500, Pa? and Pa?-4500 (where -4500 indicates an offset ~4500 km s-1 from the named filter). We processed the images to create a mosaic image of NGC 6946 in each of the six filters and visually searched these mosaics to find potential supernova remnants using the criteria that candidates should show significant [FeII] emission, but little of no emission in the other filters. We have identified 47 supernova remnant candidates (SNRcs). Only one of these objects is coincident with an optically selected SNR. The [FeII] fluxes range from 1.5e-16 to 4.2e-15 erg s-1 cm-2. These fluxes are at the highest end of previously published extragalactic SNR [FeII] fluxes, which suggests there is a much larger population of SNRs in NGC 6946 below the detection threshold of our data. All of the candidates now need to be confirmed spectroscopically. However, the fact that we detect as many objects as we did, suggests that [FeII] can be used as an effective search tool to find extragalactic SNRs.

  7. 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 ?m 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.

  8. Numerical Code for Fitting Radial Emission Profile of a Shell Supernova Remnant

    CERN Document Server

    Arbutina, Bojan

    2012-01-01

    Expressions for surface brightness distribution and for flux density have been theoretically derived in the case of two simple models of a shell supernova remnant. The models are: a homogenous optically thin emitting shell with constant emissivity and a synchrotron shell source with radial magnetic field. Interactive Data Language (IDL) codes for fitting theoretically derived emission profiles assuming these two models to mean profiles of shell supernova remnants obtained from radio observations have been written.

  9. Young Collapsed Supernova Remnants: Similarities and Differences in Neutron Stars, Black Holes, and More Exotic Objects

    OpenAIRE

    Graber, James S.

    2000-01-01

    Type Ia supernovae are thought to explode completely, leaving no condensed remnant, only an expanding shell. Other types of supernovae are thought to involve core collapse and are expected to leave a condensed remnant, which could be either a neutron star or a black hole, or just possibly, something more exotic, such as a quark orstrange star, a naked singularity, a frozen star, a wormhole or a red hole. It has proven surprisingly difficult to determine which type of condens...

  10. X-ray ejecta kinematics of the Galactic core-collapse supernova remnant G292.0+1.8

    CERN Document Server

    Bhalerao, Jayant; Dewey, Daniel; Hughes, John P; Mori, Koji; Lee, Jae-Joon

    2014-01-01

    We report on the results from the analysis of our 114 ks Chandra HETGS observation of the Galactic core-collapse supernova remnant G292.0+1.8. To probe the 3D 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_r <~ 1400 km s^-1. The distribution of ejecta knots in velocity vs. 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 10^51 erg, we est...

  11. Determination of acceleration mechanism characteristics directly and nonparametrically from observations: Application to supernova remnants

    Science.gov (United States)

    Petrosian, Vahé; Chen, Qingrong

    2014-05-01

    We have developed an inversion method for determination of the characteristics of the acceleration mechanism directly and nonparametrically from observations, in contrast to the usual forward fitting of parametric model variables to observations. In two recent papers [V. Petrosian and Q. Chen, Astrophys. J. 712, L131 (2010); Q. Chen and V. Petrosian, Astrophys. J. 777, 33 (2013)], we demonstrated the efficacy of this inversion method by its application to acceleration of electrons in solar flares based on stochastic acceleration by turbulence. Here we explore its application for determining the characteristics of shock acceleration in supernova remnants (SNRs) based on the electron spectra deduced from the observed nonthermal radiation from SNRs and the spectrum of the cosmic ray electrons observed near the Earth. These spectra are related by the process of escape of the electrons from SNRs and energy loss during their transport in the Galaxy. Thus, these observations allow us to determine spectral characteristics of the momentum and pitch angle diffusion coefficients, which play crucial roles in both direct acceleration by turbulence and in high Mach number shocks. Assuming that the average electron spectrum deduced from a few well-known SNRs is representative of those in the solar neighborhood, we find interesting discrepancies between our deduced forms for these coefficients and those expected from well-known wave-particle interactions. This may indicate that the standard assumptions made in the treatment of shock acceleration need revision. In particular, the escape of particles from SNRs may be more complex than generally assumed.

  12. Nonthermal radiation of young supernova remnants: the case of Cas A

    CERN Document Server

    Zirakashvili, V N; Yang, R; Ona-Wilhelmi, E; Tuffs, R J

    2013-01-01

    The processes responsible for the broad-band radiation of the young supernova remnant Cas A are explored using a new code which is designed for a detailed treatment of the diffusive shock acceleration of particles in 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 LAT 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...

  13. 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...

  14. Chandra observation of the Galactic supernova remnant CTB 109 (G109.1-1.0)

    CERN Document Server

    Sasaki, Manami; Gaetz, Terrance J; Bocchino, Fabrizio

    2013-01-01

    Context: We study the X-ray emission of the Galactic supernova remnant (SNR) CTB 109 (G109.1-1.0), which is well-known for its enigmatic half-shell morphology both in radio and in X-rays and is associated with the anomalous X-ray pulsar (AXP) 1E2259+586. Aims: We want to understand the origin of the X-ray bright feature inside the SNR called the Lobe and the details of the interaction of the SNR shock wave with the ambient interstellar medium (ISM). Methods: The Lobe and the northeastern part of the SNR were observed with Chandra ACIS-I. We analysed the spectrum of the X-ray emission by dividing the entire observed emission into small regions. The X-ray emission is best reproduced with one-component or two-component non-equilibrium ionisation models depending on the position. In the two-component model one emission component represents the shocked ISM and the other the shocked ejecta. Results: We detect enhanced element abundances, in particular for Si and Fe, in and around the Lobe. There is one particular r...

  15. 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...

  16. 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.

  17. Radio Emission from Young Supernovae and Supernova Remnants in Arp 299

    CERN Document Server

    Ulvestad, James S

    2009-01-01

    We have made sensitive milliarcsecond-resolution radio images of the nearby merger galaxy Arp 299 at four epochs spread over 18 months between 2003 and 2005. The combined data revealed a total of 30 point sources in the two primary merger nuclei. Twenty-five of these are found in the northeastern nucleus (component "A"=IC 694) over a region ~100 pc in diameter, while five are in the southwestern nucleus (component "B1"=NGC 3690) within a region ~30 pc in size. These objects are interpreted as young supernovae and supernova remnants; the ratio of the source counts in nuclei A and B1 is approximately equal to the ratio of their predicted supernova rates. An approximate luminosity function has been derived for nucleus A, and indicates that it might contain as many as 500-1000 compact radio sources more powerful than Cas A; the integrated flux density of these sources would be about 20% of the total flux density seen at lower resolution. A new supernova occurred in nucleus B1 in the first half of 2005, having a p...

  18. Imaging of the Supernova Remnant Cassiopeia A with the Multiband Imaging Photometer for Spitzer (MIPS)

    Science.gov (United States)

    Hines, D. C.; Rieke, G. H.; Gordon, K. D.; Rho, J.; Misselt, K. A.; Woodward, C. E.; Werner, M. W.; Latter, W. B.; Engelbracht, C. W.; Egami, E.; Kelly, D. M.; Krause, O.; Muzerolle, J.; Stansberry, J. A.; Su, K. Y. L.; Young, E. T.; Noriega-Crespo, A.; Padgett, D. L.; Gehrz, R. D.; Polomski, E.

    2004-05-01

    The supernova remnant (SNR) Cas A has been imaged at 24? m, 70? m and 160? m with the Multiband Imaging Photometer for Spitzer (MIPS). The 24? and 70? m images are well resolved and dominated by thermal emission from dust within the SNR and associated with emission line gas inside the reverse shock region, confirming earlier IRAS and ISO results for ˜ 24? m and extending this result to 70? m. The 160? m image is heavily saturated. Faint 24? m emission is associated with the outermost regions of the X-ray continuum images, which is presumably the location of the forward shock. Therefore, the SNR is beginning to sweep up and heat some ISM dust at this shock front. The 24? m and 70? m images also reveal a structure that appears to be a counter-jet to the well-known North-East jet feature imaged previously at X-ray, optical, and radio wavelengths. This infrared feature corresponds well with optical Fast Moving Knots (FMKs) confirming its outflow nature. The twin jet-like features define a symmetry axis that bisects the SNR, and suggest that the supernova explosion was similar in this regard to SN 1987A. The MIPS maps resolve details of the structure of the ISM surrounding Cas A that may be indicative of interaction between Cas A and the ISM. This work is based [in part] on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Support for this work was provided by NASA through Contract Number 960785 issued by JPL/Caltech.

  19. A Multiwavelength Database of Magellanic Cloud Supernova Remnants

    Science.gov (United States)

    Murphy Williams, Rosa Nina; Dickel, J. R.; Chu, Y.; Points, S.; Winkler, F.; Johnson, M.; Lodder, K.

    2010-01-01

    Supernovae (SNe), through their diffuse supernova remnants (SNRs), are primarily responsible for the injection of energy and heavy elements into the interstellar medium (ISM). SNe provide most of the hot gas component of the ISM, and through collective inputs to structures such as superbubbles and supergiant shells, can transfer hot gas into a galaxy halo. The energy and heavy elements influence future generations of star formation in a galaxy and have a profound effect on galaxy evolution. We have undertaken a long-term multiwavelength study of SNRs in the Magellanic Clouds (MCs). These galaxies contain extraordinary samples of SNRs at a wide variety of types, ages, evolutionary stages, and environments. The known, common distances and low obscuration of the MCs allows their SNRs to be studied as members of an increasingly well-understood population. The current generation of instruments, including the Chandra and XMM X-ray satellites and the Hubble and Spitzer Space Telescopes, have allowed high-resolution examinations of these SNRs at levels comparable to those for Galactic objects. Crucially, new surveys of the MCs with the Australia Telescope Compact Array in radio, and the Magellanic Clouds Emission-Line Survey at CTIO, have providded a wealth of data on each of these objects. We have used these resources to build up a database of information on the Magellanic Cloud SNRs, in order to make the data and findings easily accessible to other researchers. We here present the current state of the database and future plans for the inclusion of more information. The authors thank NASA's LTSA grant NNX08AM54G for support of this long-term project.

  20. 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

  1. Broad-band Observations and Modeling of the Shell-Type Supernova Remnant G347.3-0.5

    OpenAIRE

    Ellison, Donald C.; Slane, Patrick; Gaensler, Bryan M.

    2001-01-01

    The supernova remnant G347.3--0.5 emits a featureless power-law in X-rays, thought to indicate shock-acceleration of electrons to high energies. We here produce a broad-band spectrum of the bright NW limb of this source by combining radio observations from the Australia Telescope Compact Array (ATCA), X-ray observations from the Advanced Satellite for Cosmology and Astrophysics (ASCA), and TeV gamma-ray observations from the CANGAROO imaging Cerenkov telescope. We assume thi...

  2. A Chandra View Of Nonthermal Emission In The Northwestern Region Of Supernova Remnant RCW 86: Particle Acceleration And Magnetic Fields

    CERN Document Server

    Castro, Daniel; Slane, Patrick O; Yamaguchi, Hiroya; Ramirez-Ruiz, Enrico; Figueroa-Feliciano, Enectali

    2013-01-01

    The shocks of supernova remnants (SNRs) are believed to accelerate particles to cosmic ray (CR) energies. The amplification of the magnetic field due to CRs propagating in the shock region is expected to have an impact on both the emission from the accelerated particle population, as well as the acceleration process itself. Using a 95 ks observation with the Advanced CCD Imaging Spectrometer (ACIS) onboard the Chandra X-ray Observatory, we map and characterize the synchrotron emitting material in the northwestern region of RCW 86. We model spectra from several different regions, filamentary and diffuse alike, where emission appears dominated by synchrotron radiation. The fine spatial resolution of Chandra allows us to obtain accurate emission profiles across 3 different non-thermal rims in this region. The narrow width (l = 10''-30'') of these filaments constrains the minimum magnetic field strength at the post-shock region to be approximately 80 {\\mu}G.

  3. The X-ray structure and mass of the Cassiopeia A supernova remnant

    International Nuclear Information System (INIS)

    The X-ray images of the Cassiopeia supernova remnant from the Einstein Observatory have been processed by a maximum-entropy algorithm. The emission appears to originate in two concentric thin shells. The image of highest resolution (about 4 arcsec) has been used to derive temperature and density maps of the remnant assuming that the X-ray emission is thermal and from an optically thin hot gas. These maps are consistent with both pressure equilibrium and the overall X-ray spectrum. The mass of X-ray emitting gas is found to be at least 15 solar masses, which is considerably more than observed directly at other wavelengths. The X-ray structure and dynamics of Cas A are consistent with it being in a 'free-expansion' phase of evolution, with the bulk of the emission from a reverse shock in the ejecta. The progenitor star is likely to have been massive, as seems to be required by the element abundances of the optical knots. (author)

  4. $^{44}Ti Its Effective Decay Rate in Young Supernova Remnants, and its Abundance in Cas A

    CERN Document Server

    Mochizuki, Y; Janka, H T; Hillebrandt, W; Diehl, R

    1999-01-01

    Radioactive isotopes such as 44Ti offer probably the most direct probe into nucleosynthesis environments in the interior of exploding stars, when the associated gamma-ray activities in the explosion remnant are detected and translated back to the isotopic abundances at the time of the explosion. In this paper, we assert that the procedure may not necessarily be straightforward, at least in the case of 44Ti, an orbital-electron capture decay isotope. Using the analytic model of McKee and Truelove (1995) for young supernova remnants, and assuming the existence of overdense 56Fe-dominated clumps that contain also 44Ti, we show that a high degree of ionization may be caused by the reverse shock so that the electron-capture rate of 44Ti could be significantly reduced from its laboratory value. When applied to Cas A, this increases under certain conditions the current 44Ti-activity by a factor 1.5 - 2.5, which yields a better compatibility between the COMPTEL observation of the 1.16 MeV line activity associated wit...

  5. THE BROADBAND EMISSION FROM SUPERNOVA REMNANT RX J0852.0-4622

    International Nuclear Information System (INIS)

    We study the nonthermal emission from SNR RX J0852.0-4622 based on a self-consistent kinetic method that describes the nonlinear shock acceleration of cosmic rays in supernova remnants (SNRs). In this method, the spectrum of accelerated protons in the SNR can be self-consistently calculated, where a proton's maximum momentum is determined by equating the SNR's age with the acceleration time of the proton. At the same time, the spectrum of accelerated electrons is similar to the proton's spectrum if the electron's momentum is much less than the electron's maximum momentum (pe,max), which is estimated by equating the synchrotron loss time to the acceleration time of the electrons, but the cutoff shapes around pe,max are assumed to be exponential. Using the accelerated particle's spectra, we calculate nonthermal photon spectra for different values of some main model parameters such as the SNR's age, an injection parameter, and a background magnetic field. Moreover, we study possible (hadronic or leptonic) origins of very high energy (VHE) ?-ray emission from SNR RX J0852.0-4622. Our results indicate that a hadronic origin of VHE ?-rays from SNR RX J0852.0-4622 seems to be more reasonable although a leptonic origin cannot be ruled out. We suggest that the observations of Fermi LAT for this remnant will help us find the evidence to determine the main emission mechanism.

  6. 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.

  7. Unveiling the true age of the 'Vela Junior' supernova remnant

    International Nuclear Information System (INIS)

    The supernova remnant G266.1-1.2 has attracted considerable interest owing to its possible detection in the 1.156 MeV line of 44Ti by COMPTEL. If this controversial result is confirmed, G266.1-1.2 well deserves the 'Vela Junior' nickname, since the observed gamma-ray line flux implies a very small age (?700 years) and distance (?200 pc). We discuss the implications of recent X-ray observations on the SNR distance and age. Two sources were detected with BeppoSAX close to the geometrical center of G266.1-1.2. Independent of which one is the neutron star associated to G266.1-1.2, their properties imply an age of a few 10,000 years and a distance greater than one kpc. We also present a preliminary analysis of the brightest portion of the SNR shell, in which significant upper limits on the presence of X-ray emission lines are derived

  8. Pulsar Wind Nebulae, Space Velocities and Supernova Remnant

    Science.gov (United States)

    2005-01-01

    The original proposal for this LTSA grant was for X-ray studies of pulsars, and especially pulsar wind nebulae and what they could tell us about pulsar properties, especially their space velocities. By any metric, this program has been very successful. No fewer than 14 papers on directly related topics (and several dozen more on related topics) have been published in refereed journals with the PI as lead or co-author, all observational results that have had significant impact on the field. These include the first X-ray detection of the "Duck" pulsar, a clear demonstration that estimated pulsar ages can be off by over an order of magnitude (via observations of the young supernova remnant G11.2-0.3) and the detection of the first pulsar wind nebula around a millisecond pulsar. These publications have also resulted in 4 press releases. Moreover, they also represent the thesis work of two PhD students at MIT (Froney Crawford and Mike Pivovaroff) and one postdoctoral fellow, Bryan Gaensler, now Assistant Professor at Harvard.

  9. Magnetic field decay of magnetars in supernova remnants

    CERN Document Server

    Gao, Z F; Wang, N; Yuan, J P

    2013-01-01

    In this paper, we modify our previous research carefully, and derive a new expression of electron energy density in superhigh magnetic fields. Based on our improved model, we re-compute the electron capture rates and the magnetic fields' evolutionary timescales $t$ of magnetars. According to the calculated results, the superhigh magnetic fields may evolve on timescales $\\sim (10^{6}-10^{7})$ yrs for common magnetars, and the maximum timescale of the field decay, $t\\approx 2.9507 \\times 10^{6}$ yrs, corresponding to an initial internal magnetic field $B_{\\rm 0}= 3.0 \\times 10^ {15}$ G and an initial inner temperature $T_{\\rm 0}= 2.6 \\times 10^ {8}$ K. Motivated by the results of the neutron star-supernova remnant(SNR) association of Zhang $\\&$ Xie(2011), we calculate the maximum $B_{\\rm 0}$ of magnetar progenitors, $B_{\\rm max}\\sim (2.0\\times 10^{14}-2.93 \\times 10^{15})$ G when $T_{\\rm 0}= 2.6 \\times 10^ {8}$ K. When $T_{\\rm 0}\\sim 2.75 \\times 10^ {8}-~1.75 \\times 10^ {8}$ K, the maximum $B_{\\rm 0}$ will ...

  10. Dust Cooling in Supernova Remnants in the Large Magellanic Cloud

    CERN Document Server

    Seok, Ji Yeon; Hirashita, Hiroyuki

    2015-01-01

    The infrared-to-X-ray (IRX) flux ratio traces the relative importance of dust cooling to gas cooling in astrophysical plasma such as supernova remnants (SNRs). We derive IRX ratios of SNRs in the LMC using Spitzer and Chandra SNR survey data and compare them with those of Galactic SNRs. IRX ratios of all the SNRs in the sample are found to be moderately greater than unity, indicating that dust grains are a more efficient coolant than gas although gas cooling may not be negligible. The IRX ratios of the LMC SNRs are systematically lower than those of the Galactic SNRs. As both dust cooling and gas cooling pertain to the properties of the interstellar medium, the lower IRX ratios of the LMC SNRs may reflect the characteristics of the LMC, and the lower dust-to- gas ratio (a quarter of the Galactic value) is likely to be the most significant factor. The observed IRX ratios are compared with theoretical predictions that yield IRX ratios an order of magnitude larger. This discrepancy may originate from the dearth ...

  11. Updated radio $\\Sigma-D$ relation for Galactic supernova remnants

    CERN Document Server

    Pavlovi?, M Z; Vukoti?, B; Uroševi?, D

    2014-01-01

    We present updated empirical radio surface-brightness-to-diameter ($\\Sigma-D$) relation for supernova remnants (SNRs) in our Galaxy. Our original calibration sample of Galactic SNRs with independently determined distances (Pavlovi\\'c et al. 2013, hereafter Paper I) is reconsidered and updated with data which became available in the past two years. The orthogonal fitting procedure and probability-density-function-based (PDF) method are applied to the calibration sample in the $\\log \\Sigma - \\log D$ plane. Orthogonal regression keeps $\\Sigma-D$ and $D-\\Sigma$ relations invariant. Our previous Monte Carlo simulations verified that the slopes of the empirical $\\Sigma-D$ relation should be determined by using orthogonal regression. Updated calibration sample contains 65 shell SNRs. 6 new Galactic SNRs are added to the sample from Paper I, one is omitted and distances are changed for 10 SNRs. The slope derived here is slightly steeper ($\\beta \\approx 5.2$) than $\\Sigma-D$ slope in Paper I ($\\beta \\approx 4.8$). The...

  12. Photoionization of Galactic Halo Gas by Old Supernova Remnants

    CERN Document Server

    Slavin, J D; Hollenbach, D J; Slavin, Jonathan D.; Kee, Christopher F. Mc; Hollenbach, David J.

    2000-01-01

    We present new calculations on the contribution from cooling hot gas to the photoionization of warm ionized gas in the Galaxy. We show that hot gas in cooling supernova remnants (SNRs) is an important source of photoionization, particularly for gas in the halo. We find that in many regions at high latitude this source is adequate to account for the observed ionization so there is no need to find ways to transport stellar photons from the disk. The flux from cooling SNRs sets a floor on the ionization along any line of sight. Our model flux is also shown to be consistent with the diffuse soft X-ray background and with soft X-ray observations of external galaxies. We consider the ionization of the clouds observed towards the halo star HD 93521, for which there are no O stars close to the line of sight. We show that the observed ionization can be explained successfully by our model EUV/soft X-ray flux from cooling hot gas. In particular, we can match the H alpha intensity, the S++/S+ ratio, and the C+* column. F...

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

    CERN Document Server

    Arendt, Richard G; Kober, Gladys; Rho, Jeonghee; Hwang, Una

    2014-01-01

    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. Using low resolution Spitzer IRS spectra (5-35 $\\mu$m), and broad-band Herschel PACS imaging (70, 100, and 160 $\\mu$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 $\\sim9$ and 21 $\\mu$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$_2$O$_3$ 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 e...

  14. 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...

  15. 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...

  16. Galactic supernova remnants: dependence of radio brightness on galactic height and its implications

    International Nuclear Information System (INIS)

    The variation of radio brightness across individual shell supernova remnants has been investigated; on the average, the brightness decreases with increasing distance from the galactic plane (z), with a scale height of 110 pc. Part of the brightness gradient results from a dependence of diameter (D) on the density of the interstellar medium, but much of the gradient represents a z-dependence intrinsic to the radio emission process. It is concluded that the relation ? varies as D-3 exp (-| z |/175) describes the typical evolution of the mean brightness (?) of supernova remnants at different z. The applicability of this relation extends to the faintest observable remnants and entails considerable revision of the diameters, distances and ages for some remnants; in particular, a long-standing anomaly concerning the faint (but young) remnant of AD 1006 is now explained. Estimates of the galactic distribution of supernovae are also affected by the z-dependence of ?; corrected values of 200 pc are derived for the scale height of supernovae producing shell remnants, and 80 years for the mean interval between such supernovae. (author)

  17. SUPERNOVA REMNANT KES 17: AN EFFICIENT COSMIC RAY ACCELERATOR INSIDE A MOLECULAR CLOUD

    International Nuclear Information System (INIS)

    The 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 ?-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 concluding that the strong magnetic field, turbulence, and clumpy nature of molecular clouds enhance 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

  18. 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.

  19. Theory of cosmic ray production in the supernova remnant RX J1713.7-3946

    CERN Document Server

    Berezhko, E G

    2006-01-01

    A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants (SNRs) is employed to investigate the properties of SNR RX J1713.7-3946. Observations of the nonthermal radio and X-ray emission spectra as well as the H.E.S.S. measurements of the very high energy gamma-ray emission are used to constrain the astronomical and the particle acceleration parameters of the system. Under the assumptions that RX J1713.7-3946 was a core collapse supernova (SN) of type II/Ib with a massive progenitor, has an age of \\approx 1600 yr and is at a distance of \\approx 1 kpc, the theory gives indeed a consistent description for all the existing observational data. Specifically it is shown that an efficient production of nuclear CRs, leading to strong shock modification, and a large downstream magnetic field strength B_d ~ 100 mkG can reproduce in detail the observed synchrotron emission from radio to X-ray frequencies together with the gamma-ray spectral characteristics as observed by the H.E.S.S. telescopes. S...

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

    OpenAIRE

    Patricia Ambrocio-Cruz; Margarita Rosado; Eduardo de la Fuente

    2006-01-01

    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.

  1. 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.

  2. Evolution of supernova remnants in different galactic environments, and its effects on supernova statistics

    International Nuclear Information System (INIS)

    By examining the interaction between supernova (SJ) ejecta and the various environments in which the explosive event might occur, we conclude that only a small fraction of the many SNs produce observable supernova remnants (SNRs). This fraction, which is found to depend weakly upon the lower mass limit of the Sn progenitors, and more strongly on the specific characteristics of the associated interstellar medium, decreases from approximately 15% near the galactic center to 10% at R/sub gal/ approx.10 kpc and drops nearly to zero for R/sub gal/>15 kpc. Generally, whether a SNR is detectable is determined by the density of the ambient interstellar medium in which it is embedded. We find that SNRs are only detectable above some critical density (napprox.0.1 cm-3). The presence of large, low-density superbubble cavities around stellar associations due to the combined effects of stellar winds and supernova shells strongly suggests that a large portion of the detectable SNRs must have runaway stars as their progenitors. These results explain the differences between the substantially larger SN rates in the Galaxy derived both from pulsar statistics and from observations of SN events in external galaxies, when compared to the substantially smaller SN rates derived from galactic SNR statistics. These results also explain the very large number of SNRs observed toward the galactic center in comparison to few SNRs found in the anticenter directionnticenter direction

  3. 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 evidensub>sun. Finally, we give evidence for the likely detection of the remnant of the historical supernova, SN1968L.

  4. Radio observations of the supernova remnant G 109.1 - 1.0

    International Nuclear Information System (INIS)

    The supernova remnant G 109.1-1.0, which contains a periodic X-ray point source, has been observed with the Effelsberg 100-m telescope at 2.7 GHz. The remnant has shell structure at both radio and X-ray wave-lengths and the radio and X-ray maps show similar large-scale emission. No linearly polarized radio emission was detected. G 109.1-1.0 is one of three shell remnants in which the probable stellar remnant has now been found. (author)

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

    International Nuclear Information System (INIS)

    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–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.

  6. The mass of Tycho's supernova remnant as determined from a high-resolution X-ray map

    Science.gov (United States)

    Seward, F.; Gorenstein, P.; Tucker, W.

    1983-01-01

    High resolution Einstein Observatory X ray images of Tycho's supernova remnant (SNR) are discussed. The object has features of a shock heated shell in the interstellar medium, accompanied by an inner shell with clumped ejecta. The measurements were made for 22 hr on Feb. 8, 1979, revealing a circular SNR, a thin emission shelf at the outer edge of the remnant, no emission in the central object, and most emissions concentrated in small, clumpy objects within a spherical shell. Three components of the X ray emission were identified, and calculations of the swept-up mass, the diffuse component of the ejecta shell, and the clumpy ejecta are reported to be 2.2, 1.2, and 0.7 solar mass, respectively. The SNR is concluded to be at an evolutionary stage between uniform expansion and adiabatic changes.

  7. Gamma-Ray Emission from Supernova Remnant Interaction with Molecular Clumps

    CERN Document Server

    Tang, Xiaping

    2014-01-01

    Observations of the middle-aged supernova remnants IC 443, W28 and W51C indicate that the brightnesses at GeV and TeV energies are correlated with each other and with regions of molecular clump interaction, but not with the radio synchrotron brightness. We suggest that the radio emission is primarily associated with a radiative shell in the interclump medium of a molecular cloud, while the gamma-ray emission is primarily associated with the interaction of the radiative shell with molecular clumps. The shell interaction produces a high pressure region, so that the gamma-ray luminosity can be approximately reproduced even if shock acceleration of particles is not efficient, provided that energetic particles are trapped in the cooling region. In this model, the spectral shape \\ga 2 GeV is determined by the spectrum of cosmic ray protons. Models in which diffusive shock acceleration determines the spectrum tend to underproduce TeV emission because of the limiting particle energy that is attained.

  8. Dense Gas Towards the RXJ1713.7-3946 Supernova Remnant

    CERN Document Server

    Maxted, Nigel I; Dawson, Bruce R; Burton, Michael G; Fukui, Yasuo; Lazendic, Jasmina; Kawamura, Akiko; Horachi, Hirotaka; Sano, Hidetoshi; Walsh, Andrew J; Yoshiike, Satoshi; Fukuda, Tatsuya

    2013-01-01

    We present results from a Mopra 7mm-wavelength survey that targeted the dense gas-tracing CS(1-0) transition towards the young gamma-ray-bright supernova remnant, RXJ1713.7-3946 (SNR G347.3-0.5). In a hadronic gamma-ray emission scenario, where cosmic ray protons interact with gas to produce the observed gamma-ray emission, the mass of potential cosmic ray target material is an important factor. We summarise newly-discovered dense gas components, towards Cores G and L, and Clumps N1, N2, N3 and T1, which have masses of 1-10^4 solar masses. We argue that these components are not likely to contribute significantly to gamma-ray emission in a hadronic gamma-ray emission scenario. This would be the case if RXJ1713.7-3946 were at either the currently favoured distance of ~1kpc or an alternate distance (as suggested in some previous studies) of ~6kpc. This survey also targeted the shock-tracing SiO molecule. Although no SiO emission corresponding to the RXJ1713.7-3946 shock was observed, vibrationally-excited SiO(1-...

  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. An Extreme Pulsar Tail Protruding from the Frying Pan Supernova Remnant

    CERN Document Server

    Ng, C -Y; Gaensler, B M; Camilo, F; Chatterjee, S; Bouchard, A

    2011-01-01

    The Frying Pan (G315.9-0.0) is a radio supernova remnant with a peculiar linear feature extending 10' radially outward from the rim of the shell. We present radio imaging and polarization observations with the Molonglo Observatory Synthesis Telescope and the Australia Telescope Compact Array, confirming the linear structure as a bow-shock pulsar wind nebula powered by the young pulsar J1437-5959. Extending over 20pc, this is the longest pulsar tail observed. We found a stand-off distance of 0.002pc, smallest among any bow-shock systems, suggesting a large pulsar velocity over 1000km/s and a high Mach number ~200. The magnetic field geometry inferred from radio polarimetry shows a good alignment with the tail orientation, which could be a result of high flow speed. There are also hints that the postshock wind has a low magnetization and is dominated by electrons and positrons in energy. This study shows that pulsar wind nebulae can offer a powerful probe of the pulsar environment, particularly for the case of ...

  11. Dust Formation in the young core-collapse supernova remnant E0102

    CERN Document Server

    Rho, J; Tappe, A; Hwang, U; Slavin, J D; Kozasa, T; Dunne, L

    2009-01-01

    We present Spitzer IRS and IRAC observations of the young supernova remnant E0102 (SNR 1E0102.2-7219) in the Small Magellanic Cloud. The infrared spectra show strong ejecta lines of Ne and O, with the [Ne II] line at 12.8 microns having a large velocity dispersion of 2,000-4,500 km/s indicative of fast-moving ejecta. Unlike the young Galactic SNR Cas A, E0102 lacks emission from Ar and Fe. Diagnostics of the observed [Ne III] line pairs imply that [Ne III] emitting ejecta have a low temperature of 650 K, while [Ne V] line pairs imply that the infrared [Ne V] emitting ejecta have a high density of ~10^4/cm3. We have calculated radiative shock models for various velocity ranges including the effects of photoionization. The shock model indicates that the [Ne V] lines come mainly from the cooling zone, which is hot and dense, whereas [Ne II] and [Ne III] come mainly from the photoinization zone, which has a low temperature of 400-1000 K. We estimate an infrared emitting Ne ejecta mass of 0.04 Msun from the infrar...

  12. 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...

  13. 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...

  14. The Sizes of 1720 MHz OH Masers VLBA and MERLIN Observations of the Supernova Remnants W44 and W28

    CERN Document Server

    Claussen, M J; Frail, D A; Desai, K V

    1999-01-01

    We have used the NRAO Very Long Baseline Array (VLBA) to image OH(1720 MHz) masers in the supernova remnants W28 and W44 at a resolution of 40 mas. We also used MERLIN to observe the same OH(1720 MHz) masers in W44 at a resolution of 290 x 165 mas. All the masers are resolved by these VLBA and MERLIN observations. The measured sizes range from 50 to 180 mas and yield brightness temperature estimates from 0.3--20 x 10**8 K. We investigate whether these measured angular sizes are intrinsic and hence originate as a result of the physical conditions in the supernova remnant shock, or whether they are scatter broadened sizes produced by the turbulent ionized gas along the line of sight. While the current data on the temporal and angular broadening of pulsars, masers and extragalactic soures toward W44 and W28 can be understood in terms of scattering, we cannot rule out that these large sizes are intrinsic. Recent theoretical modeling by Lockett et al. suggests that the physical parameters in the shocked region are...

  15. Dense Iron Ejecta and Core-collapse Supernova Explosion in the Young Supernova Remnant G11.2-0.3

    CERN Document Server

    Moon, Dae-Sik; Lee, Ho-Gyu; Matthews, Keith; Lee, Jae-Joon; Pyo, Tae-Soo; Seok, Ji Yeon; Hayashi, Masahiko

    2009-01-01

    We present the results of near-infrared spectroscopic observations of dense ($\\simgt$ 10$^3$ cm$^{-3}$) iron ejecta in the young core-collapse supernova remnant G11.2-0.3. Five ejecta knots projected to be close to its center show a large dispersion in their Doppler shifts: two knots in the east are blueshifted by more than 1,000 \\kms, while three western knots have relatively small blueshifts of 20-60 \\kms. This velocity discrepancy may indicate that the western knots have been significantly decelerated or that there exists a systematic velocity difference among the knots. One ejecta filament in the northwestern boundary, on the other hand, is redshifted by $\\simgt$ 200 \\kms, while opposite filament in the southeastern boundary shows a negligible radial motion. Some of the knots and filaments have secondary velocity components, and one knot shows a bow shock-like feature in the velocity structure. The iron ejecta appear to be devoid of strong emission from other heavy elements, such as S, which may attest to...

  16. 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.

  17. 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

  18. AKARI Detection of the Infrared-Bright Supernova Remnant B0104-72.3 in the Small Magellanic Cloud

    CERN Document Server

    Koo, Bon-Chul; Moon, Dae-Sik; Lee, Jae-Joon; Seok, Ji Yeon; Lee, Hyung Mok; Hong, Seung Soo; Lee, Myung Gyoon; Kaneda, Hidehiro; Ita, Yoshifusa; Jeong, Woong-Seob; Onaka, Takashi; Sakon, Itsuki; Nakagawa, Takao; Murakami, Hiroshi

    2007-01-01

    We present a serendipitous detection of the infrared-bright supernova remnant (SNR) B0104-72.3 in the Small Magellanic Cloud by the Infrared Camera (IRC) onboard AKARI. An elongated, partially complete shell is detected in all four observed IRC bands covering 2.6-15 um. The infrared shell surrounds radio, optical, and X-ray emission associated with the SNR and is probably a radiative SNR shell. This is the first detection of a SNR shell in this near/mid-infrared waveband in the Small Magellanic Cloud. The IRC color indicates that the infrared emission might be from shocked H2 molecules with some possible contributions from ionic lines. We conclude that B0104-72.3 is a middle-aged SNR interacting with molecular clouds, similar to the Galactic SNR IC 443. Our results highlight the potential of AKARI IRC observations in studying SNRs, especially for diagnosing SNR shocks.

  19. 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.

  20. Reconstructing supernova explosions from X-ray observations of their remnants

    Science.gov (United States)

    Laming, J. M.

    Imaging spectroscopy with Chandra ACIS has opened a rich new field of investigation in the field of young supernova remnants The combination of sub-arcsecond imaging and CCD resolution spectroscopy has proved to be very powerful I will describe some of the novel methods that have been developed to analyze and interpret such data Concentrating mainly on Cassiopeia A as an example of a core-collapse remnant I will show how careful spectral analysis of its knotty ejecta will allow one to build up a 3D picture of its ejecta composition and energy Then time and energy permitting I will review an orthogonal approach to the remnants of Type Ia supernovae where one proceeds from an explosion scenario to calculate forward models of the remnant emission to compare with data Work supported by the NASA LTSA program and by basic research funds of the Office of Naval Research

  1. Multifrequency study of SNR J0533-7202, a new supernova remnant in the LMC

    CERN Document Server

    Bozzetto, L M; Crawford, E J; Sasaki, M; Maggi, P; Haberl, F; Uroševi?, D; Payne, J L; De Horta, A Y; Stupar, M; Gruendl, R; Dickel, J

    2013-01-01

    We present a detailed study of Australia Telescope Compact Array (ATCA) observations of a newly discovered Large Magellanic Cloud (LMC) supernova remnant (SNR), SNR J0533-7202. This object follows a horseshoe morphology, with a size 37 pc x 28 pc (1-pc uncertainty in each direction). It exhibits a radio spectrum with the intrinsic synchrotron spectral index of alpha= -0.47+-0.06 between 73 and 6 cm. We report detections of regions showing moderately high fractional polarisation at 6 cm, with a peak value of 36+-6% and a mean fractional polarisation of 12+-7%. We also estimate an average rotation measure across the remnant of -591 rad m^-2. The current lack of deep X-ray observation precludes any conclusion about high-energy emission from the remnant. The association with an old stellar population favours a thermonuclear supernova origin of the remnant.

  2. 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

  3. On the Amplification of Magnetic Field by a Supernova Blast Shock Wave in a Turbulent Medium

    Science.gov (United States)

    Guo, Fan; Li, Shengtai; Li, Hui; Giacalone, Joe; Jokipii, J. R.; Li, David

    2012-03-01

    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.

  4. Optical Spectroscopy of Supernova Remnants in M81 and M82

    Science.gov (United States)

    Lee, Myung Gyoon; Sohn, Jubee; Lee, Jong Hwan; Lim, Sungsoon; Jang, In Sung; Ko, Youkyung; Koo, Bon-Chul; Hwang, Narae; Kim, Sang Chul; Park, Byeong-Gon

    2015-05-01

    We present spectroscopy of 28 supernova remnant (SNR) candidates as well as one H ii region in M81 and two SNR candidates in M82. Twenty-six of the M81 candidates turn out to be genuine SNRs, and two in M82 may be shocked condensations in the galactic outflow or SNRs. The distribution of [N ii]/H? ratios of M81 SNRs is bimodal. M81 SNRs are divided into two groups in the spectral line ratio diagrams: an [O iii]-strong group and an [O iii]-weak group. The latter are larger and may have faster shock velocities. [N ii]/H? ratios of the SNRs show a strong correlation with [S ii]/H? ratios. They show a clear radial gradient in their [N ii]/H? and [S ii]/H? ratios: dLog ([N ii]/H?)/dLog R = ?0.018 ± 0.008 dex kpc?1 and dLog ([S ii]/H?)/dLog R = ?0.016 ± 0.008 dex kpc?1, where R is the deprojected galactocentric distance. We estimate the nitrogen and oxygen abundances of the SNRs from comparison with shock-ionization models. We obtain a value for the nitrogen radial gradient of dLog(N/H)/dLog R= ?0.023 ± 0.009 dex kpc?1, and find little evidence for an oxygen gradient. This nitrogen abundance shows a gradient that is a few times flatter than those of the planetary nebulae and H ii regions. We find that five SNRs are matched with X-ray sources. Their X-ray hardness colors are consistent with thermal SNRs.

  5. 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)

  6. Are Models for Core-Collapse Supernova Progenitors Consistent with the Properties of Supernova Remnants?

    CERN Document Server

    Patnaude, Daniel J; Slane, Patrick O; Badenes, Carles; Heger, Alexander; Ellison, Donald C; Nagataki, Shigehiro

    2015-01-01

    The recent discovery that the Fe-K line luminosities and energy centroids observed in nearby SNRs are a strong discriminant of both progenitor type and circumstellar environment has implications for our understanding of supernova progenitor evolution. Using models for the chemical composition of core-collapse supernova ejecta, we model the dynamics and thermal X-ray emission from shocked ejecta and circumstellar material, modeled as an $r^{-2}$ wind, to ages of 3000 years. We compare the X-ray spectra expected from these models to observations made with the Suzaku satellite. We also model the dynamics and X-ray emission from Type Ia progenitor models. We find a clear distinction in Fe-K line energy centroid between core-collapse and Type Ia models. The core-collapse supernova models predict higher Fe-K line centroid energies than the Type Ia models, in agreement with observations. We argue that the higher line centroids are a consequence of the increased densities found in the circumstellar environment create...

  7. Thermal X-ray emission of the remnants of ashperical Supernova explosions

    OpenAIRE

    Petruk, O.

    2001-01-01

    Evolution of adiabatic remnants of an aspherical supernova explosion in uniform medium are considered. Thermal X-ray emission of such remnants are investigated. It is shown that integral thermal X-ray characteristics (X-ray luminosity and spectrum) of the objects do not allow us to reveal the assymetry in the explosion because these characteristics are close to their Sedov counterparts. Surface distribution of X-ray emission is sensitive to anisotropy of the explosion and no...

  8. Highly Clumpy Structure of the Thermal Composite Supernova Remnant 3C391 Unveiled by Chandra

    OpenAIRE

    Chen, Yang; Su, Yang; Slane, Patrick O.; Wang, Q. Daniel

    2005-01-01

    The nature of the internal thermal X-ray emission seen in ``thermal composite" supernova remnants is still uncertain. Chandra observation of the 3C391 shows a southeast-northwest elongated morphology and unveils a highly clumpy structure of the remnant. Detailed spatially resolved spectral analysis for the small-scale features reveals normal metal abundance and uniform temperature for the interior gas. The properties of the hot gas comparatively favor the cloudlet evaporatio...

  9. 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...

  10. The Discovery of a Supernova Remnant Embedded in a Giant H II Region of M33

    Science.gov (United States)

    Gordon, Shawn M.; Kirshner, Robert P.; Duric, Nebojsa; Long, Knox S.

    1993-12-01

    We have combined radio, optical, and X-ray data to discover a new supernova remnant (SNR) in M33. This remnant is embedded in the giant H II region NGC 592. Our VLA-WSRT radio survey of M33 showed that NGC 592 has a nonthermal component to its radio emission. Optical images of the H II region at the KPNO 4 m allowed us to subtract the thermal source to reveal the nonthermal source. NGC 592 had also been identified in Einstein data as a soft X-ray source. Our ROSAT observation, combined with the radio and optical data, provides evidence that the X-ray source is a supernova remnant. A knot of [S II] emission was isolated in the H II region, and MMT spectra confirm that the knot has the spectrum of a supernova remnant. We use these observations to investigate the properties of the remnant and its environment. We find that this SNR is a typical middle-aged remnant except that it is expanding into dense gas of the H II region NGC 592. We also find that there is a pressure difference between the hot postshock region and the cool recombination zone. This difference may be a sign that nonthermal particles and magnetic fields provide significant pressure support in the recombination zone.

  11. Updated radio ??D relation for galactic supernova remnants

    Directory of Open Access Journals (Sweden)

    Pavlovi? M.Z.

    2014-01-01

    Full Text Available We present the updated empirical radio surface-brightness-to-diameter (? ? D relation for supernova remnants (SNRs in our Galaxy. Our original calibration sample of Galactic SNRs with independently determined distances (Pavlovi? et al. 2013, hereafter Paper I is reconsidered and updated with data which became available in the past two years. The orthogonal fitting procedure and probability-density-function-based (PDF method are applied to the calibration sample in the log? ? logD plane. Non-standard orthogonal regression keeps the ??D and D?? relations invariant within estimated uncertainties. Our previous Monte Carlo simulations verified that the slopes of the empirical ??D relation should be determined by using the orthogonal regression, because of its good performances for data sets with severe scatter. The updated calibration sample contains 65 shell SNRs. 6 new Galactic SNRs are added to the sample from Paper I, one is omitted and distances are changed for 10 SNRs. The slope derived is here slightly steeper (? ? 5.2 than the ??D slope in Paper I (? ? 4.8. The PDF method relies on data points density maps which can provide more reliable calibrations that preserve more information contained in the calibration sample. We estimate distances to five new faint Galactic SNRs discovered for the first time by Canadian Galactic Plane Survey, and obtained distances of 2.3, 4.0, 1.3, 2.9 and 4.7 kiloparsecs for G108.5+11.0, G128.5+2.6, G149.5+3.2, G150.8+3.8 and G160.1?1.1, respectively. The updated empirical relation is used to estimate distances of 160 shell Galactic SNRs and new results change their distance scales up to 15 per cent, compared to the results from Paper I. The PDF calculation can provide even few times higher or lower values in comparison with the orthogonal fit, as it uses a totally different approach. However, on average, this difference is 32, 24 and 18 per cent for mode, median and mean distances. [Projekat Ministarstva nauke Republike Srbije, br. 176005: Emission nebulae: structure and evolution’. B.V. also acknowledges financial support through the Project i br. 176021: Visible and invisible matter in nearby galaxies: theory and observations

  12. Supernova remnants and diffuse ionized gas in M31

    International Nuclear Information System (INIS)

    Researchers have compiled an initial list of radio/optical supernova remnants (SNRs) in M31, by searching for radio identifications of emission-line sources with a high (SII)/H alpha ratio (greater than 0.60). The (SII) filter included both sulfur lines and the H alpha filter did not include (NII). This search revealed 11 SNRs, of which only two were known. In addition, researchers detected radio emission from 3 SNRs that were identified in previous optical surveys (D'Odorico et al., 1980), but that were outside the charge coupled device (CCD) fields. The 14 objects only include the most obvious candidates, but a full search is in progress and the researchers expect to find several more SNRs. Also not all optical SNRs show detectable radio emission and a pure optical list of SNR candidates based only on the ratio of (SII)/H alpha emission contains many more objects. Two conclusions are apparent. First, the radio properties of the SNRs in M31 are quite similar to those of Galactic SNRs as is illustrated. The brightnesses are not systematically lower as has been suggested in the past (Dickel and D'Odorico, 1984). Second, the slope of the relation is close to -2; this slope is expected from the intrinsic dependence between surface brightness and diameter. The radio luminosity of the SNRs does not seem to depend strongly on diameter, or age, contrary to model predictions. Selection effects, however, play an important role in these plots. The CCD images show widespread dif plots. The CCD images show widespread diffuse ionized gas with a ratio of (SII)/H alpha that is higher than that of discrete HII regions. Discrete HII regions typically show ratios between 0.2 to 0.3, while the diffuse gas in the arms consistently shows ratios of 0.5. Researchers can trace this gas across the spiral arms to emission measures below 5 pc cm (-6). Its properties seem to be similar to that of the diffuse gas in the solar neighborhood

  13. X-ray Spectroscopy of Potential Small Magellanic Cloud Type Ia Supernova Remnants and Their Environments

    Science.gov (United States)

    Roper, Q.; McEntaffer, R. L.; DeRoo, C.; Filipovic, M.; Wong, G. F.; Crawford, E. J.

    2015-04-01

    We examine three supernova remnants in the SMC, IKT 5 (supernova remnant (SNR) 0047-73.5), IKT 25 (SNR 0104-72.3), and DEM S 128 (SNR 0103-72.4), which are designated as Type Ia in the literature due to their spectra and morphology. This is troublesome because of their asymmetry, a trait not usually associated with young Type Ia remnants. We present Chandra X-ray Observatory data on these three remnants and perform a maximum likelihood analysis on their spectra. We find that the X-ray emission is dominated by interactions with the interstellar medium. In spite of this, we find a significant Fe overabundance in all three remnants. Through examination of radio, optical, and infrared data, we conclude that these three remnants are likely not Type Ia SNRs. We detect potential point sources that may be members of the progenitor systems of both DEM S 128 and IKT 5, which could suggest these could be Fe-rich core-collapse remnants.

  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. 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,...

  16. Neutral pion emission from accelerated protons in the supernova remnant W44

    CERN Document Server

    Giuliani, A; Tavani, M; Fukui, Y; Yoshiike, S; Torii, K; Dubner, G; Castelletti, G; Barbiellini, G; Bulgarelli, A; Caraveo, P; Costa, E; Cattaneo, P W; Chen, A; Contessi, T; Del Monte, E; Donnarumma, I; Evangelista, Y; Feroci, M; Gianotti, F; Lazzarotto, F; Lucarelli, F; Longo, F; Marisaldi, M; Mereghetti, S; Pacciani, L; Pellizzoni, A; Piano, G; Picozza, P; Pittori, C; Pucella, G; Rapisarda, M; Rappoldi, A; Sabatini, S; Soffitta, P; Striani, E; Trifoglio, M; Trois, A; Vercellone, S; Verrecchia, F; Vittorini, V; Colafrancesco, S; Giommi, P; Bignami, G

    2011-01-01

    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 (20, 000 years) and its ejecta expand in a dense medium as shown by a prominent radio shell, nearby molecular clouds, and bright [SII] 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 mod...

  17. Submillimeter/millimeter observations of the molecular clouds associated with the Tycho' Supernova Remnant

    CERN Document Server

    Xu, Jin-Long; 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 -69~-59 km \\s, well coincident with the Tycho's SNR. The MCs associated with Tycho's SNR have a mass of ~2130 sun masses. Position-velocity diagrams show the two clouds adjacent in velocity which means possible cloud-cloud collision in this region. The maximum value (0.66) of integrated CO line intensity ratio I(CO J=3-2/CO J=2-1) for the three MCs agrees well with the previous measurement of individual Galactic MCs, implying that the SNR shock just drove into the MCs. The two MCs have a line intensity ratio gradient. The...

  18. Spitzer observations of supernova remnants: II. Physical conditions and comparison with HH7 and HH54

    CERN Document Server

    Yuan, Yuan

    2010-01-01

    We have studied the shock-excited molecular regions associated with four supernova remnants (SNRs) - IC443C, W28, W44 and 3C391 - and two Herbig-Haro objects, HH7 and HH54, using Spitzer's Infrared Spectrograph (IRS). The physical conditions within the observed areas are inferred from spectroscopic data obtained from IRS and from SWS and LWS onboard ISO, together with photometric data from Spitzer's Infrared Array Camera (IRAC). Adopting a power-law distribution for the gas temperature in the observed region, the H2 S(0) to S(7) spectral line maps obtained with IRS were used to constrain the gas density, yielding estimated n(H2) in the range 2-4*10^3 cm^-3. The excitation of H2 S(9) to S(12) and high-J CO pure rotational lines, however, require environments several times denser. The inconsistency among the best-fit densities estimated from different species can be explained by density fluctuations within the observed regions. The best-fit power-law index b is smaller than the value 3.8 predicted for a parabol...

  19. GeV Gamma Rays from Supernova Remnants Interacting with Molecular Clouds

    CERN Document Server

    Uchiyama, Yasunobu

    2011-01-01

    We report the current status of the observations of supernova remnants (SNRs) with the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope, focusing on middle-aged SNRs that appear to be interacting with molecular clouds. Observations with the Fermi LAT in an energy range from 0.2 to ~100 GeV have unveiled the presence of luminous GeV gamma-ray emission in middle-aged SNRs, providing a new insight into the shock-acceleration theory and the origin of galactic cosmic rays. The middle-aged SNRs detected by the Fermi LAT are generally much brighter in GeV than in TeV in terms of energy flux, which emphasizes the importance of the GeV observations. Spectral steepening in the Fermi-LAT band is commonly found for the GeV-luminous SNRs. Remarkably, most (if not all) of them are known to be interacting with molecular clouds, and they are also the strong sources of synchrotron radio emission. We discuss possible scenarios to explain the enhanced GeV gamma-ray emission in the cloud-interacting SNRs. Pa...

  20. Supernova Remnant Kesteven 27: Interaction with A Neighbor HI Cloud Viewed by Fermi

    Science.gov (United States)

    Xing, Yi; Wang, Zhongxiang; Zhang, Xiao; Chen, Yang

    2015-05-01

    We report on the likely detection of ?-ray emission from the supernova remnant (SNR) Kesteven 27 (Kes 27). We analyze 5.7 yr Fermi Large Area Telescope data of the SNR region and find an unresolved source at a position consistent with the radio brightness peak and the X-ray knot of Kes 27, which is located in the eastern region of the SNR and caused by its interaction with a nearby Hi cloud. The source’s emission is best fit with a power-law spectrum with a photon index of 2.5 ± 0.1 and a >0.2 GeV luminosity of 5.8× {{10}34} erg s?1 assuming a distance of 4.3 kpc, as derived from radio observations of the nearby Hi cloud. Comparing the properties of the source with that of other SNRs that are known to be interacting with nearby high-density clouds, we discuss the origin of the source’s emission. The spectral energy distribution of the source can be described by a hadronic model that considers the interaction of energetic protons escaping from the shock front of Kes 27 with a high-density cloud.

  1. Kinematics of the Galactic Supernova Remnant G206.9+2.3

    Science.gov (United States)

    Ambrocio-Cruz, P.; Rosado, M.; Le Coarer, E.; Bernal, A.; Gutiérrez, L.

    2014-10-01

    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 km s^{-1} and a linear diameter of 18 pc. Finally, we calculated the energy deposited in the interstellar medium by the SN explosion as 1.7×10^{49} ergs and concluded that the SNR is in the radiative phase of evolution with an age of 6.4×10^{4} years.

  2. 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...

  3. Some properties of synchrotron radio and inverse-Compton gamma-ray images of supernova remnants

    Science.gov (United States)

    Petruk, O.; Beshley, V.; Bocchino, F.; Orlando, S.

    2009-05-01

    The synchrotron radio maps of supernova remnants (SNRs) in a uniform interstellar medium and interstellar magnetic field (ISMF) are analysed, allowing for different `sensitivity' of the injection efficiency to the obliquity of the shock. The very-high-energy ?-ray maps arising from inverse Compton processes are also synthesized. The properties of images in these different wavelength bands are compared, with particular emphasis on the location of the bright limbs in bilateral SNRs. Recent High-Energy Stereoscopic System (HESS) observations of SN 1006 show that the radio and inverse Compton ?-ray limbs coincide, and we found that this may happen if (i) injection is isotropic but the variation of the maximum energy of electrons is rather fast to compensate for differences in the magnetic field, or (ii) the obliquity dependence of injection (either quasi-parallel or quasi-perpendicular) and the electron maximum energy are strong enough to dominate the magnetic field variation. In the latter case, the obliquity dependences of the injection and the maximum energy should not be opposite. We argue that the position of the limbs alone, and even their coincidence in radio, X-rays and ?-rays, as discovered by HESS in SN 1006, cannot be conclusive as regards the dependence of the electron injection efficiency, the compression/amplification of the ISMF and the electron maximum energy on the obliquity angle.

  4. The supernova remnant W50: understanding the magnetic fields in a unique outflow-driven object

    Science.gov (United States)

    Farnes, J. S.; Gaensler, B. M.

    We present new radio observations of the nebula W50 (G39.7-2.0), using the Australia Telescope Compact Array (ATCA). Our understanding of this enigmatic object has previously been hindered by the large angular extent of the nebulae (2x1 degrees), with the Western edge dipping into the Galactic plane. Such large objects are typically poorly studied due to the considerable number of separate pointings required for full imaging. The nebula is also entirely unique in that it appears to be interacting with the central compact source and first known Galactic microquasar, SS433. Our mosaiced, spectropolarimetric ATCA observations of this field are centred at 2.1 GHz, using a large bandwidth of 2 GHz. This allows us to measure the polarised fraction, rotation measure, depolarisation, and spectral index of W50's emission, and to detect diffuse linearly polarised emission which 'lights up' the large-scale ordered magnetic fields in the object. The challenge of processing such wide-field, wide-band, spectropolarimetric observations is a significant technical issue that is currently being faced by the upcoming Square Kilometre Array (SKA) pathfinders and will be faced by the SKA itself. We therefore analyse the data using techniques that are fundamental to understanding cosmic magnetism - such as Rotation Measure Synthesis - and that allow us to probe Faraday rotation along the line of sight towards W50. Through these methods it is possible to distinguish between magnetic effects arising in the nebula itself, and those arising along the line of sight in intervening Faraday screens. While W50 is typically considered to be a supernova remnant, the contribution from the initial explosion that presumably preceded formation of the compact object SS433, has not previously been convincingly distinguished from the impact of the jet and wind activity of the central system. We shall discuss how we are able to put constraints on the formation of the object through our discovery of a 'ring' of ordered magnetic fields that surrounds SS433 - consistent with field compression from a shock wave, and evidence in favour of the supernova remnant hypothesis.

  5. 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

  6. Acceleration of cosmic rays and gamma-ray emission from supernova remnant/molecular cloud associations

    CERN Document Server

    Gabici, S; Morlino, G; Nava, L

    2015-01-01

    The gamma-ray observations of molecular clouds associated with supernova remnants are considered one of the most promising ways to search for a solution of the problem of cosmic ray origin. Here we briefly review the status of the field, with particular emphasis on the theoretical and phenomenological aspects of the problem.

  7. VizieR Online Data Catalog: Supernova remnants in M33 (Gordon+, 1999)

    Science.gov (United States)

    Gordon, S. M.; Duric, N.; Kirshner, R. P.; Goss, W. M.; Viallefond, F.

    1999-05-01

    Using radio data to identify and optical data to confirm, we have established the largest and most complete sample of extragalactic radio-bright supernova remnants (SNRs) in the nearby spiral galaxy M33. We have identified 53 radio SNRs, doubling the size of the earlier survey by Duric et al. (1993A&AS...99..217D). (2 data files).

  8. A morphological criterion for distinguishing between supernova remnants and H II regions

    International Nuclear Information System (INIS)

    A variant of the vector discriminant pattern recognition technique is applied to UK Schmidt telescope images of nebulae in the Large Magellanic Cloud. A criterion is thereby obtained which may be applied generally to distinguish between supernova remnants (SNRs) and H II regions from their optical images. Furthermore, two nebulae previously identified as H II regions are now interpreted as SNRs. (author)

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

    International Nuclear Information System (INIS)

    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%) consistent with the hypothesis that SNRs are the sources of Galactic CRs. In particular, we quantitatively work out the details of instantaneous and cumulative CR spectra during the evolution of a typical SNR, also stressing the implications of the observed levels of magnetization on both the expected maximum energy and the predicted CR acceleration efficiency. The latter naturally turns out to saturate around 10-30%, almost independently of the fraction of particles injected into the acceleration process as long as this fraction is larger than about 10?4

  10. 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 ...

  11. X-ray emission from young supernova remnants: nonionization equilibrium abundances and emissivities

    International Nuclear Information System (INIS)

    X-ray line emission from hot, low-density plasma in young supernova remnants is strongly enhanced by departures from ionization equilibrium. We have calculated the X-ray emission from a Sedov blast wave, a nonequilibrium evolutionary treatment of the ionization structure, and have fitted the resulting spectrum to HEAO 2 SSS data for Tycho's remnant. These models yield dramatically different elemental abundances for heavy elements (Ne, Mg, Si, S, Ar, Ca, and Fe), compared with two-temperature component equilibrium models of Becker et al. Nonequilibrium broad-band X-ray emissivities result in lower mass determinations for the supernova ejecta. Areas of further improvement of remnant X-ray modeling are suggested

  12. XMM-Newton observations of the thermal X-ray emitting plasma in the supernova remnant IC443

    Science.gov (United States)

    Troja, E.; Bocchino, F.; Reale, F.

    We present a spatially resolved analysis of XMM-Newton observations of the Galactic supernova remnant SNR IC443 and a comparison with results obtained at other wavelengths This remnant is a classical example of SNR interacting with ambient molecular clouds MCs and it has been considered a member of the mixed morphology class Our data unveil for the first time a partial limb-brightened very soft X-ray shell corresponding to the interaction with a neutral cloud in the NE We have also measured the MCs absorption effects on the X-ray emission of the remnant confirming the presence of a tilted torus of very dense material partially hit by SNR shock Our spatially resolved spectral analysis points out heavy-element enhanced abundances mostly distributed in a previously unknown ring of ejecta around the pulsar wind nebula We finally discuss our results on the light of other recent detections of enhanced abundances in thermal composite X-ray SNRs

  13. Suzaku Results of SN 1006: Chemical Abundances of the ''youngest'' Galactic Type Ia Supernova Remnant

    International Nuclear Information System (INIS)

    SN 1006 is one of the supernova remnants (SNR) recorded in the Japanese diary 'Meigetsuki'. From the historical records including Meigetsuki, we conclude that SN 1006 was the brightest type Ia supernova remnant. We report on the observations of SN 1006 with the X-ray Imaging Spectrometers (XIS) on board the 5-th Japanese X-ray satellite Suzaku. We found that the ionization age of SN 1006 is the youngest among any Galactic SNRs, hence is the best SNR to study early phase of type Ia. In the X-ray spectrum, we found the K-shell emission lines from heavy elements, in particular that from iron, for the first time. The X-ray emitting plasma is highly overabundant in heavy elements, hence are likely due to ejecta. The abundance pattern agrees well to the theoretical prediction of type Ia supernova

  14. 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.)

  15. How Do The Properties of Light Help Us To Study Supernovae and Their Remnants?

    Science.gov (United States)

    This resource describes special properties of light that can help us to understand objects that are millions and billions of light years away. Students explore some of these properties and how they can use them to understand our universe. They will understand that superheated material created by the supernova explosion gives off X-rays and gamma-rays. They will find the answers to questions such as what electromagnetic (EM) radiation is and what units are used to characterize it. They also learn that it pays to make multiple observations of astronomical objects, since they emit light of different energies, that supernovae remnants can give off visible light, ultraviolet light, radio waves and X-rays, and that each observation of a supernovae remnant can give us different information about it. The site also includes a student exercise and links to more information.

  16. Discrete sources of gamma radiation, supernova remnants and pulsars

    International Nuclear Information System (INIS)

    An attempt to identify detected by present discrete gamma radiation sources (Esub(?) approximately equal to 108 eV) with known residuals of supernova flares is undertaken. An analysis of gamma source catalogue shows that most part (70%) of detected discrete gamma radiation sources may be identified with known residuals of sUpernova flares. Supernova residuals being identified have a low spectral index ? < or approximately 0.3. Such objects, probably, contain a pulsar with a relatively large magnetic field. It is possible that supernovae 185g and 393g are related to gamma sources. There are not less than 150 similar gamma sources in Galaxy which contribute significantly into diffuse gamma radiation of a galactic disc

  17. 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) ...

  18. ROLE OF EJECTA CLUMPING AND BACK-REACTION OF ACCELERATED COSMIC RAYS IN THE EVOLUTION OF TYPE Ia SUPERNOVA REMNANTS

    International Nuclear Information System (INIS)

    We investigate the role played by initial clumping of ejecta and by efficient acceleration of cosmic rays (CRs) in determining the density structure of the post-shock region of a Type Ia supernova remnant (SNR) through detailed three-dimensional MHD modeling. Our model describes the expansion of an SNR through a magnetized interstellar medium, including the initial clumping of ejecta and the effects on shock dynamics due to back-reaction of accelerated CRs. The model predictions are compared to the observations of SN 1006. We found that the back-reaction of accelerated CRs alone cannot reproduce the observed separation between the forward shock and the contact discontinuity unless the energy losses through CR acceleration and escape are very large and independent of the obliquity angle. On the contrary, the clumping of ejecta can naturally reproduce the observed small separation and the occurrence of protrusions observed in SN 1006, even without the need of accelerated CRs. We conclude that forward shock-contact discontinuity separation is a probe of the ejecta structure at the time of explosion rather than a probe of the efficiency of CR acceleration in young SNRs.

  19. 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.

  20. 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

  1. Extended supernova shock breakout signals from inflated stellar envelopes

    Science.gov (United States)

    Moriya, Takashi J.; Sanyal, Debashis; Langer, Norbert

    2015-03-01

    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 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 on the order of the solar radius can have shock breakout signals that are longer than ~100 s. 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 physical properties of these enigmatic structures.

  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. Chandra Observations and Models of the Mixed Morphology Supernova Remnant W44: Global Trends

    Science.gov (United States)

    Shelton, R. L.; Kuntz, K. D.; Petre, R.

    2004-01-01

    We report on the Chandra observations of the archetypical mixed morphology (or thermal composite) supernova remnant, W44. As with other mixed morphology remnants, W44's projected center is bright in thermal X-rays. It has an obvious radio shell, but no discernable X-ray shell. In addition, X-ray bright knots dot W44's image. The spectral analysis of the Chandra data show that the remnant s hot, bright projected center is metal-rich and that the bright knots are regions of comparatively elevated elemental abundances. Neon is among the affected elements, suggesting that ejecta contributes to the abundance trends. Furthermore, some of the emitting iron atoms appear to be underionized with respect to the other ions, providing the first potential X-ray evidence for dust destruction in a supernova remnant. We use the Chandra data to test the following explanations for W44's X-ray bright center: 1.) entropy mixing due to bulk mixing or thermal conduction, 2.) evaporation of swept up clouds, and 3.) a metallicity gradient, possibly due to dust destruction and ejecta enrichment. In these tests, we assume that the remnant has evolved beyond the adiabatic evolutionary stage, which explains the X-ray dimness of the shell. The entropy mixed model spectrum was tested against the Chandra spectrum for the remnant's projected center and found to be a good match. The evaporating clouds model was constrained by the finding that the ionization parameters of the bright knots are similar to those of the surrounding regions. While both the entropy mixed and the evaporating clouds models are known to predict centrally bright X-ray morphologies, their predictions fall short of the observed brightness gradient. The resulting brightness gap can be largely filled in by emission from the extra metals in and near the remnant's projected center. The preponderance of evidence (including that drawn from other studies) suggests that W44's remarkable morphology can be attributed to dust destruction and ejecta enrichment within an entropy mixed, adiabatic phase supernova remnant. The Chandra data prompts a new question - by what astrophysical mechanisms are the metals distributed so inhomogeneously in the supernova remnant.

  4. A THOROUGH INVESTIGATION OF THE DISTANCE TO THE SUPERNOVA REMNANT CTB109 AND ITS PULSAR AXP J2301+5852

    International Nuclear Information System (INIS)

    CTB109 is one of only three Galactic supernova remnants (SNRs) known to harbor an anomalous X-ray pulsar or magnetar. That makes this SNR an object of great importance and a prime target for high-energy astrophysics studies. Those studies rely heavily on the assumed distance to CTB109. There have been three major distance determinations over the last decade, all of which report completely different results. While chaotic distance determinations in the literature are not uncommon for SNRs as a class of object, the wild discrepancy in the distance to CTB109 makes it especially important to revisit and firmly resolve once and for all. In this Letter we bring to bear all available observational information and present a synthesis of evidence that consistently locates CTB109 within or close to the Perseus arm spiral shock, at a distance of 3.2 ± 0.2 kpc.

  5. The Youngest Known X-ray Binary: Circinus X-1 and its Natal Supernova Remnant

    CERN Document Server

    Heinz, S; Fender, R P; Jonker, P G; Brandt, W N; Calvelo-Santos, D E; Tzioumis, A K; Nowak, M A; Schulz, N S; Wijnands, R; van der Klis, M

    2013-01-01

    Because supernova remnants are short lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: none were known to exist in our Galaxy. We report the discovery of the natal supernova remnant of the accreting neutron star Circinus X-1, which places an upper limit of t < 4, 600 years on its age, making it the youngest known X-ray binary and a unique tool to study accretion, neutron star evolution, and core collapse supernovae. This discovery is based on a deep 2009 Chandra X-ray observation and new radio observations of Circinus X-1. Circinus X-1 produces type I X-ray bursts on the surface of the neutron star, indicating that the magnetic field of the neutron star is small. Thus, the young age implies either that neutron stars can be born with low magnetic fields or that they can rapidly become de-magnetized by accretion. Circinus X-1 is a microquasar, creating relativistic jets which we...

  6. 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...

  7. 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.

  8. 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.

  9. ON THE RADIO POLARIZATION SIGNATURE OF EFFICIENT AND INEFFICIENT PARTICLE ACCELERATION IN SUPERNOVA REMNANT SN 1006

    International Nuclear Information System (INIS)

    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 utheastern 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.

  10. 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.

  11. SEARCH FOR GAMMA-RAY EMISSION FROM THE SUPERNOVA REMNANT IC 443 WITH THE MAGIC TELESCOPE

    Directory of Open Access Journals (Sweden)

    R. J. Garc\\u00EDa L\\u00F3pez

    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.

  12. Fermi Large Area Telescope observations of the supernova remnant HESS J1731-347

    OpenAIRE

    Yang, Rui-zhi; Zhang, Xiao; Yuan, Qiang; Liu, Siming

    2014-01-01

    Context: HESS J1731-347 has been identified as one of the few TeV-bright shell-type supernova remnants (SNRs). These remnants are dominated by nonthermal emission, and the nature of TeV emission has been continuously debated for nearly a decade. Aims: We carry out the detailed modeling of the radio to gamma-ray spectrum of HESS J1731-347 to constrain the magnetic field and energetic particles sources, which we compare with those of the other TeV-bright shell-type SNRs e...

  13. H.E.S.S. upper limits for Kepler's supernova remnant

    OpenAIRE

    Hess, Collaboration; Aharonian, F.

    2008-01-01

    Observations of Kepler's supernova remnant (G4.5+6.8) with the H.E.S.S. telescope array in 2004 and 2005 with a total live time of 13 h are presented. Stereoscopic imaging of Cherenkov radiation from extensive air showers is used to reconstruct the energy and direction of the incident gamma rays. No evidence for a very high energy (VHE: >100 GeV) gamma-ray signal from the direction of the remnant is found. An upper limit (99% confidence level) on the energy flux in the range...

  14. 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.

  15. H.E.S.S. observations of the supernova remnant RCW 86

    OpenAIRE

    Hoppe, S.; Lemoine-goumard, M.; Collaboration, For The H. E. S. S.

    2007-01-01

    The shell-type supernova remnant (SNR) RCW 86 - possibly associated with the historical supernova SN 185 - was observed during the past three years with the High Energy Stereoscopic System (H.E.S.S.), an array of four atmospheric-Cherenkov telescopes located in Namibia. The multi-wavelength properties of RCW 86, e.g. weak radio emission and North-East X-ray emission almost entirely consisting of synchroton radiation, resemble those of two very-high energy (VHE; > 100 GeV) ga...

  16. Nonthermal Electron Acceleration at Supernova Shocks: Relativistic Shock Surfing Mechanism

    Science.gov (United States)

    Hoshino, Masahiro; Shimada, N.

    2003-07-01

    A nonthermal electron acceleration mechanism in high Mach number shocks is studied. We find that the relativistic shock surfing/surfatron acceleration occurs in the shock transition region, where a series of large amplitude electrostatic soliton-like waves (ESWs) are excited by Buneman instability under the interaction between the reflected ions and the incoming electrons. It is shown that the electrons are likely to be trapped by ESWs, and during the trapping phase they can be effectively accelerated by the shock motional/convection electric field. When Alfven Mach number exceeds several tens, the nonthermal electrons are efficiently produced, and their maximum energy reaches up to the shock potential energy determined by the global shock size.

  17. Laboratory simulations of supernova shockwaves: Formation of a second shock ahead of a radiative shock

    Science.gov (United States)

    Hansen, J. F.; Edwards, M. J.; Froula, D.; Gregori, G.; Edens, A.; Ditmire, T.

    2005-09-01

    Supernovae launch spherical shocks into the circumstellar medium (CSM). These shocks may interact with both the intergalactic magnetic field (IGM) and local mass accumulations (possibly with their own local magnetic fields). The latter interaction may trigger star formation. The shocks have high Mach numbers and may be radiative. We have created similar shocks in the laboratory by focusing laser pulses onto the tip of a solid pin surrounded by ambient gas; ablated material from the pin rapidly expands and launches a shock through the surrounding gas. The shock may then be allowed to interact with (a) mass accumulations, (b) magnetic fields, or (c) allowed to expand freely. We will present examples of each type of experiment, but mainly discuss a new phenomena observed first in (c) at the edge of the radiatively heated gas ahead of the shock, a second shock forms. The two expanding shocks are simultaneously visible for a time, until the original shock stalls from running into the heated gas. The second shock remains visible and continues to expand. A minimum condition for the formation of the second shock is that the original shock is super-critical, i.e., the temperature distribution ahead of the original shock has an inflexion point. In a non-radiative control experiment the second shock does not form.

  18. Laboratory simulations of supernova shockwaves: Formation of a second shock ahead of a radiative shock

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, J F; Edwards, M J; Froula, D; Gregori, G; Edens, A; Ditmire, T

    2005-01-28

    Supernovae launch spherical shocks into the circumstellar medium (CSM). These shocks may interact with both the intergalactic magnetic field (IGM) and local mass accumulations (possibly with their own local magnetic fields). The latter interaction may trigger star formation. The shocks have high Mach numbers and may be radiative. We have created similar shocks in the laboratory by focusing laser pulses onto the tip of a solid pin surrounded by ambient gas; ablated material from the pin rapidly expands and launches a shock through the surrounding gas. The shock may then be allowed to interact with (a) mass accumulations, (b) magnetic fields, or (c) allowed to expand freely. We will present examples of each type of experiment, but mainly discuss a new phenomena observed first in (c); at the edge of the radiatively heated gas ahead of the shock, a second shock forms. The two expanding shocks are simultaneously visible for a time, until the original shock stalls from running into the heated gas. The second shock remains visible and continues to expand. A minimum condition for the formation of the second shock is that the original shock is super-critical, i.e., the temperature distribution ahead of the original shock has an inflexion point. In a non-radiative control experiment the second shock does not form.

  19. Discovery of molecular shells associated with supernova remnants. (II) Kesteven 75

    CERN Document Server

    Su, Yang; Yang, Ji; Koo, Bon-Chul; Zhou, Xin; Jeong, Il-Gyo; Zhang, Chun-Guang

    2008-01-01

    The young composite supernova remnant (SNR) Kesteven 75, with a pulsar wind nebula at its center, has an unusual morphology with a bright southern half-shell structure in multiwavelengths. The distance to Kes 75 has long been uncertain. Aiming to address these issues, we have made millimeter spectroscopic observations of the molecular gas toward the remnant. The V_{LSR}~83--96 km/s molecular clouds (MCs) are found to overlap a large north-western region of the remnant and are suggested to be located in front of the SNR along the line of sight. Also in the remnant area, the V_{LSR}= 45--58 km/s MC shows a blue-shifted broadening in the 12CO (J=1-0) line profile and a perturbed position-velocity structure near the edge of the remnant, with the intensity centroid sitting in the northern area of the remnant. In particular, a cavity surrounded by a molecular shell is unveiled in the intensity map in the broadened blue wing (45--51 km/s), and the southern molecular shell follows the bright partial SNR shell seen in...

  20. Neutral hydrogen in the vicinity of galactic radio sources: the supernova remnant W28

    International Nuclear Information System (INIS)

    The H I line in the vicinity of the radio source W28 has been observed in absorption and emission with the RATAN-600 radio telescope at a resolution of 2'.4 x 45' x 6.3 km/sec. The absorption line yields a distance of roughly-equal3 kpc to the supernova remnant; the compact H II regions observed there are located at the same distance. In emission, an expanding H I envelope 82 pc in diameter has been detected around W28; its mass is 6.9 x 104 M/sub sun/ and it is expanding at roughly-equal20 km/sec. The supernova remnant is 5.8 x 105 yr old and the energy of the original explosion was 8.4 x 1051 erg. Some conclusions are reached as to the possible genetic relation between the H II zones and the SNR

  1. 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.

  2. 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...

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

    OpenAIRE

    Milisavljevic, Dan; Robert A. Fesen

    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...

  4. Interaction of Supernovae remnants: From the circumstellar medium to the terrestrial laboratory

    OpenAIRE

    Velarde, P; García Senz, Domingo; Bravo Guil, Eduardo; Ogando, F; Relaño, A.; E. Oliva

    2006-01-01

    The evolution of supernova remnants (SNRs) represents a useful and natural laboratory for gasdynamics studies. In this paper the results of several hydrodynamical simulations of the propagation and early phases of interaction of two SNRs embedded in a homogeneous interstellar environment are shown. In particular, the hydrodynamic evolution and collision of twin SNRs during their self-similar stage has been simulated using a two-dimensional Lagrangian hydrocode. In addition, the results of a d...

  5. The Search for Faint Radio Supernova Remnants in the Outer Galaxy: Five New Discoveries

    OpenAIRE

    Gerbrandt, Stephanie; Foster, Tyler J.; 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 structu...

  6. The Interaction of Supernova Remnant G357.7+0.3 with the Interstellar Medium

    OpenAIRE

    J. P.; Phillips; 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 th...

  7. H.E.S.S. observations of the supernova remnant RX J0852.0-4622

    OpenAIRE

    Collaboration, H. E. S. S.; 3; Lemoine-goumard, M.; Aharonian, F.; Degrange, B.; Drury, L.; Schwanke, U.

    2007-01-01

    The shell-type supernova remnant RX J0852.0-4622 was detected in 2004 and re-observed between December 2004 and May 2005 with the High Energy Stereoscopic System (H.E.S.S.), an array of four Imaging Cherenkov Telescopes located in Namibia and dedicated to the observations of gamma-rays above 100 GeV. The angular resolution of

  8. 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.

  9. Diffuse neutrinos from extragalactic supernova remnants: Dominating the 100 TeV IceCube flux

    Science.gov (United States)

    Chakraborty, Sovan; Izaguirre, Ignacio

    2015-05-01

    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.

  10. A View of Supernova Remnant CTB 37A with the Fermi Gamma-ray Space Telescope

    CERN Document Server

    Brandt, T J

    2013-01-01

    Supernovae and their remnants have long been favored as cosmic ray ac- celerators. Recent data from the Fermi Gamma-ray Space Telescope has given us an improved window into such sources, including the remnant CTB 37A. Using the Fermi Large Area Telescope, we found significant gamma-ray emission coincident with the remnant, which also emits in radio, X-ray, and very high energy gamma-rays. We modeled the multiwavelength spectrum using a combination of hadronic and leptonic emission with reasonable parameter values and determined that CTB 37A is a potential cosmic ray accelerator commensurate with direct observations. By assembling statistically significant populations of such objects, we will be able to more fully illuminate the mystery of cosmic ray origins.

  11. New radio observations of the composite supernova remnant G29.7-0.3

    Science.gov (United States)

    Becker, R. H.; Helfand, D. J.

    1984-01-01

    The galactic supernova remnant G29.7-0.3, recently identified as a new member of the class of composite remnants, has been imaged with the VLA at three wavelengths: 2, 6, and 20 cm. Two spectrally distinct components, a flat-spectrum core surrounded by a shell with alpha of about -0.7, suggested by early observations, have been confirmed. Neutral hydrogen absorption measurements of these two components confirm their physical association and place the remnant at a distance of about 21 kpc. A radio polarization map of the Crab-like core and results of an examination of existing X-ray data for evidence of emission from the shell component are also presented. A comparison of the radio and X-ray properties of G29.7-0.3 and other composite SNRs concludes the report.

  12. Non-equilibrium ionisation in supernova remnants: the case of Tycho

    International Nuclear Information System (INIS)

    We present a detailed numerical study of the X-ray emission of Tycho's supernova remnant which, at an age of ? 430 years, has not yet reached its adiabatic phase of expansion. The carbon deflagration of a C + 0 white dwarf, which seems to be the most plausible model for type Ia supernova explosions, results in a highly non-solar abundance distribution, which influences the hydrodynamical evolution of the remnant considerably. Using Nomoto's W7 model of an exploding white dwarf as initial condition we follow simultaneously the hydrodynamical and ionisational evolution for different densities of the interstellar medium and compare the emitted spectra with EXOSAT GSPC observations. To match the fluxes of the observed X-ray lines a partial mixing the ejecta is required. The results indicate that the density of the ambient medium is 0.5 o -3, the distance to Tycho is then about 3 kpc. Finally, we discuss the actual physical uncertainties in modelling supernova remnants and relate them to the magnitude of possible errors of the derived parameters

  13. CO J=2-1 Observations toward the Supernova Remnant G54.1+0.3

    CERN Document Server

    Lee, Jung-Won; Lee, Jeong-Eun

    2012-01-01

    We present 12CO J = 2-1 line observations of G54.1+0.3, a composite supernova remnant with a mid-infrared (MIR) loop surrounding the central pulsar wind nebula (PWN). We mapped an area of 12' x 9' around the PWN and its associated MIR loop. We confirm two velocity components that had been proposed to be possibly interacting with the PWN/MIR-loop; the +53 km/s cloud that appears in contact with the eastern boundary of the PWN and the +23 km/s cloud that has CO emission coincident with the MIR loop. We have not found a direct evidence for the interaction in either of these clouds. Instead, we detected an 5'-long arc-like cloud at +15-+23 km/s with a systematic velocity gradient of ~3 km/s/arcmin and broad-line emitting CO gas having widths (FWHM) of <7 km/s in the western interior of the supernova remnant. We discuss their association with the supernova remnant.

  14. Locating the Periodic Transient GRO J1849-03; Gamma-Ray Luminous Supernovae Remnants

    Science.gov (United States)

    Kaaret, P.; White, Nicholas (Technical Monitor)

    2000-01-01

    We obtained one 50 ks observation of the Monoceros supernova remnant under this proposal. This supernova remnant was selected because it overlaps the error box of a gamma-ray source. Much to our surprise, we discovered a hard x-ray point source instead of the diffuse hard x-ray emission we expected from the supernova remnant. A paper on the discovery of the hard x-ray source and on follow-up optical observations identifying a likely Bestar companion was published in the Astrophysical Journal. Subsequently, a reanalysis of the same data yielded the detection of pulsations from the x-ray source. These results were also published in the Astrophysical Journal. Subsequent x-ray observations, which we performed under later proposals, have shown that the x-ray pulsar has a characteristic spin-down age of less than 1400 years in a binary system. The system is likely the first discovered very young, highly-energetic, rotation-powered pulsar in a binary system and offers an exciting opportunity to study the infancy and early evolution of neutron-star binaries.

  15. Discriminating the Progenitor Type of Supernova Remnants with Iron K-Shell Emission

    CERN Document Server

    Yamaguchi, Hiroya; Petre, Robert; Nakano, Toshio; Castro, Daniel; Enoto, Teruaki; Hiraga, Junko S; Hughes, John P; Maeda, Yoshitomo; Nobukawa, Masayoshi; Safi-Harb, Samar; Slane, Patrick O; Smith, Randall K; Uchida, Hiroyuki

    2014-01-01

    Supernova remnants (SNRs) retain crucial information about both their parent explosion and circumstellar material left behind by their progenitor. However, the complexity of the interaction between supernova ejecta and ambient medium often blurs this information, and it is not uncommon for the basic progenitor type (Ia or core-collapse) of well-studied remnants to remain uncertain. Here we present a powerful new observational diagnostic to discriminate between progenitor types and constrain the ambient medium density of SNRs solely using Fe K-shell X-ray emission. We analyze all extant Suzaku observations of SNRs and detect Fe K alpha emission from 23 young or middle-aged remnants, including five first detections (IC 443, G292.0+1.8, G337.2-0.7, N49, and N63A). The Fe K alpha centroids clearly separate progenitor types, with the Fe-rich ejecta in Type Ia remnants being significantly less ionized than in core-collapse SNRs. Within each progenitor group, the Fe K alpha luminosity and centroid are well correlate...

  16. Photoionization of galactic halo gas by old supernova remnants

    OpenAIRE

    Slavin, Jonathan D.

    2000-01-01

    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 medi...

  17. Discovery of X-Ray-Emitting O-Ne-Mg-Rich Ejecta in the Galactic Supernova Remnant Puppis A

    Science.gov (United States)

    Katsuda, Satoru; Hwang, Una; Petre, Robert; Park, Sangwook; Mori, Koji; Tsunemi, Hiroshi

    2010-01-01

    We report on the discovery of X-ray-emitting O-Ne-Mg-rich ejecta in the middle-aged Galactic O-rich supernova remnant Puppis A with Chandra and XMM-Newton. We use line ratios to identify a low-ionization filament running parallel to the northeastern edge of the remnant that requires super-solar abundances, particularly for O, Ne, and Mg, which we interpret to be from O-Ne-Mg-rich ejecta. Abundance ratios of Ne/O, Mg/O, and Fe/O are measured to be [approx]2, [approx]2, and <0.3 times the solar values. Our spatially resolved spectral analysis from the northeastern rim to the western rim otherwise reveals sub-solar abundances consistent with those in the interstellar medium. The filament is coincident with several optically emitting O-rich knots with high velocities. If these are physically related, the filament would be a peculiar fragment of ejecta. On the other hand, the morphology of the filament suggests that it may trace ejecta heated by a shock reflected strongly off the dense ambient clouds near the northeastern rim.

  18. Simulated morphologies of non-thermal emission from the supernova remnant RX J0852.0-4622 in a turbulent medium

    Science.gov (United States)

    Fang, Jun; Yu, Huan; Zhang, Li

    2014-12-01

    The morphologies of the X-rays from synchrotron radiation and the ?-rays produced via either inverse Compton scattering or proton-proton interaction for the supernova remnant RX J0852.0-4622 are investigated using a three-dimensional magnetohydrodynamic simulation. The simulation is initiated with the supernova ejecta imbedded in the turbulent environment, and the distributions of the density and the magnetic field within the shock wave can be obtained. Assuming that the number of the protons accelerated by the forward shock is proportional to the local density since more protons can be injected into the diffusive shock acceleration process with a higher density, the morphology of the emission produced via the inelastic collisions between the accelerated protons with the ambient matter is achieved. Furthermore, the X-ray map of the synchrotron radiation and the ?-ray image of the inverse Compton scattering can be obtained with the assumption that the relativistic electrons have a similar spatial distribution as the protons. The results show that the shock front is distorted by the turbulent medium, and the morphologies of the non-thermal emission from RX J0852.0-4622, which shows a broken shell with bright rims at the shock in the observed images both in the X-ray band and in the TeV ?-ray band, can be generally reproduced using the model. It can be concluded that the observed broken morphologies of the non-thermal emission with bright regions along the shock are the result of the remnant evolving in a turbulent plasma.

  19. To what type of supernovae do old galactic remnants belong; the evolution of envelopes in the interstellar medium

    International Nuclear Information System (INIS)

    Investigation of the evolution of supernova remnants in the Galaxy medium is carried out. The investigation of the kinematics of old optical Supernova remnants allows to estimate the mean initial energy of the envelopes, E0=(3.7+-1.5)x1050 erg; this gives the mass ejected approximately equal to 0.3 Msub(Sun) for the type 1 (V0=104 km/s), and 1-2 Msub(Sun) for the type 2. Supernovae (V0=(5-7)x103 km/s.) For determining the Supernova type, the physical association of the remnants with gas-and-dust complexes and OB-associations is considered. It is shown that the optical remnants IC443, the Monoceros Loop, the weak envelope of W1, W28, Vela X, and possibly HB3, may have been formed in the type 2 Supernovae explosion; the late stage of the evolution was accompanied by an intense mass loss. The problem of the ''plerions'' evolution is considered. It is suggested that as far as their central sources damp, they turn into classical envelope radio Supernova remnants

  20. a Chandra Survey for Compact Objects in Supernova Remnants

    Science.gov (United States)

    Kulkarni, Shri

    2001-09-01

    It has become increasingly clear that the natal properties of young neutron stars exhibit a rich diversity --- dramatically illustrated by the enigmatic central object in Cas A and hinted at by early 3D modeling of core-collapse. We propose a survey of an objectively constructed sample of nearby SNRs which, when combined with archival data and our vigorous multi-wavelength observation program, will give us a reliable view of the true variety of neutron stars. The ensuing statistics and studies of the central objects will advance our understanding of core-collapse and have bearing on related topics (supernova energetics, natal kicks, etc). We believe that this comprehensive effort, a census of such objects within 5 kpc, will be one of the enduring legacies of the Chandra mission.

  1. Probing X-ray Absorption and Optical Extinction in the Interstellar Medium Using Chandra Observations of Supernova Remnants

    CERN Document Server

    Foight, Dillon; Ozel, Feryal; Slane, Patrick

    2015-01-01

    We present a comprehensive study of interstellar X-ray extinction using the extensive Chandra supernova remnant archive and use our results to refine the empirical relation between the hydrogen column density and optical extinction. In our analysis, we make use of the large, uniform data sample to assess various systematic uncertainties in the measurement of the interstellar X-ray absorption. Specifically, we address systematic uncertainties that originate from (i) the emission models used to fit supernova remnant spectra, (ii) the spatial variations within individual remnants, (iii) the physical conditions of the remnant such as composition, temperature, and non-equilibrium regions, and (iv) the model used for the absorption of X-rays in the interstellar medium. Using a Bayesian framework to quantify these systematic uncertainties, and combining the resulting hydrogen column density measurements with the measurements of optical extinction toward the same remnants, we find the empirical relation NH = (2.87+/-...

  2. Supernova envelope shock origin of cosmic rays: a review

    Energy Technology Data Exchange (ETDEWEB)

    Colgate, S.A.

    1984-01-01

    The hydrodynamic shock origin of cosmic rays in the envelope of a Type I presupernova star is reviewed. The possibility of accelerating ultrahigh energy particles to greater than or equal to 10/sup 18/ eV is unique to the shock mechanism and currently no other suggested galactic or extragalactic site is likely. In this paper a review of the work leading to a renewed commitment to the origin of cosmic rays in the shock ejected envelope of supernova is given. The degree to which this interpretation applies to the origin of all cosmic rays is certainly uncertain and does not exclude the possibility of a fraction of the lower energy cosmic rays being accelerated in collisionless plasma shocks in the interstellar medium. 45 references, 3 figures.

  3. Supernova envelope shock origin of cosmic rays: a review

    International Nuclear Information System (INIS)

    The hydrodynamic shock origin of cosmic rays in the envelope of a Type I presupernova star is reviewed. The possibility of accelerating ultrahigh energy particles to greater than or equal to 1018 eV is unique to the shock mechanism and currently no other suggested galactic or extragalactic site is likely. In this paper a review of the work leading to a renewed commitment to the origin of cosmic rays in the shock ejected envelope of supernova is given. The degree to which this interpretation applies to the origin of all cosmic rays is certainly uncertain and does not exclude the possibility of a fraction of the lower energy cosmic rays being accelerated in collisionless plasma shocks in the interstellar medium. 45 references, 3 figures

  4. An expanded HST/WFC3 survey of M83: Project overview and targeted supernova remnant search

    International Nuclear Information System (INIS)

    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.

  5. 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.

  6. Self-consistent models for the X-ray emission from supernova remnants - an application to Kepler's remnant

    International Nuclear Information System (INIS)

    A tool for exploring the evolution of X-ray emission from young SNRs is presented which employs a novel approach to the problem of time-dependent ionization in a shock-heated plasma. The solution of this problem is coupled to a spherically symmetric hydrodynamic calculation for the evolution of a point explosion in a uniform medium. The method is applied to Kepler's SNR, and two narrowly constrained classes of models which can simultaneously fit the spectral and morphological features of the object are found. One of these is a Sedov model in which the emission arises from shocked ambient gas, and the other is a reverse-shock model in which the SN ejecta is the dominant source of radiation. The emission from one specific model in each class is compared with the radial surface brightness profile, the 0.2-4.5 keV broadband spectrum, and the 1-3 keV moderate-resolution spectrum of the remnant. Reasonable fits are obtained in both cases. 48 references

  7. Nucleosynthesis in The Oxygen-Rich Supernova Remnant G292.0+1.8 from Chandra X-Ray Spectroscopy

    CERN Document Server

    Park, S; Slane, P O; Burrows, D N; Roming, P W A; Nousek, J A; Garmire, G P; Park, Sangwook; Hughes, John P.; Slane, Patrick O.; Burrows, David N.; Roming, Peter W. A.; Nousek, John A.; Garmire, Gordon P.

    2004-01-01

    We continue our analysis of the Galactic oxygen-rich supernova remnant (SNR) G292.0+1.8, which was observed with the {\\it Chandra X-ray Observatory}. The high angular resolution {\\it Chandra} data resolve metal-rich ejecta knots as well as the shocked circumstellar medium. X-ray emission from the ejecta material in G292.0+1.8 is dominated by highly ionized O, Ne and Mg. Measured abundance ratios suggest that this material was produced during the hydrostatic evolution of the massive progenitor star. In contrast to Cassiopeia A, there is little evidence for X-ray-emitting ejecta from explosive nucleosynthesis, i.e., material enriched in Si, S, and particularly, Fe. This limits the amount of mixing or overturning of deep ejecta material in G292.0+1.8 and suggests that the ejecta are strongly stratified by composition and that the reverse shock has not propagated to the Si/S or Fe-rich zones. On the other hand, the bright equatorial belt is dominated by X-ray emission with normal chemical composition, which suppo...

  8. 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.

  9. 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.

  10. 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

  11. Discovery of TeV Gamma Ray Emission from Tycho's Supernova Remnant

    CERN Document Server

    Acciari, V A; Arlen, T; Aune, T; Beilicke, M; Benbow, W; Bradbury, S M; Buckley, J H; Bugaev, V; Byrum, K; Cannon, A; Cesarini, A; Ciupik, L; Collins-Hughes, E; Cui, W; Dickherber, R; Duke, C; Errando, M; Finley, J P; Finnegan, G; Fortson, L; Furniss, A; Galante, N; Gall, D; Gillanders, G H; Godambe, S; Griffin, S; Grube, J; Guenette, R; Gyuk, G; Hanna, D; Holder, J; Hughes, J P; Hui, C M; Humensky, T B; Kaaret, P; Karlsson, N; Kertzman, M; Kieda, D; Krawczynski, H; Krennrich, F; Lang, M J; LeBohec, S; Madhavan, A S; Maier, G; Majumdar, P; McArthur, S; McCann, A; Moriarty, P; Mukherjee, R; Ong, R A; Orr, M; Otte, A N; Pandel, D; Park, N; Perkins, J S; Pohl, M; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Roache, E; Rose, H J; Saxon, D B; Schroedter, M; Sembroski, G H; Senturk, G Demet; Slane, P; Smith, A W; Teši?, G; Theiling, M; Thibadeau, S; Tsurusaki, K; Varlotta, A; Vassiliev, V V; Vincent, S; Vivier, M; Wakely, S P; Ward, J E; Weekes, T C; Weinstein, A; Weisgarber, T; Williams, D A; Wood, M; Zitzer, B

    2011-01-01

    We report the discovery of TeV gamma-ray emission from the Type Ia supernova remnant (SNR) G120.1+1.4, known as Tycho's supernova remnant. Observations performed in the period 2008-2010 with the VERITAS ground-based gamma-ray observatory reveal weak emission coming from the direction of the remnant, compatible with a point source located at $00^{\\rm h} \\ 25^{\\rm m} \\ 27.0^{\\rm s},\\ +64^{\\circ} \\ 10^{\\prime} \\ 50^{\\prime\\prime}$ (J2000). The TeV photon spectrum measured by VERITAS can be described with a power-law $dN/dE = C(E/3.42\\;\\textrm{TeV})^{-\\Gamma}$ with $\\Gamma = 1.95 \\pm 0.51_{stat} \\pm 0.30_{sys}$ and $C = (1.55 \\pm 0.43_{stat} \\pm 0.47_{sys}) \\times 10^{-14}$ cm$^{-2}$s$^{-1}$TeV$^{-1}$. The integral flux above 1 TeV corresponds to $\\sim 0.9%$ percent of the steady Crab Nebula emission above the same energy, making it one of the weakest sources yet detected in TeV gamma rays. We present both leptonic and hadronic models which can describe the data. The lowest magnetic field allowed in these models ...

  12. 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...

  13. MODELING THE MULTI-WAVELENGTH EMISSION OF THE SHELL-TYPE SUPERNOVA REMNANT RX J1713.7-3946

    International Nuclear Information System (INIS)

    Emission mechanisms of the shell-type supernova remnant (SNR) RX J1713.7-3946 are studied with multi-wavelength observational data from the radio, X-ray, GeV ?-ray, and TeV ?-ray bands. A Markov Chain Monte Carlo method is employed to explore the high-dimensional model parameter space systematically. Three scenarios for the ?-ray emission are investigated: the leptonic, the hadronic, and a hybrid. Thermal emission from the background plasma is also included to constrain the gas density, assuming ionization equilibrium, and a 2? upper limit of about 0.03 cm-3 is obtained as far as thermal energies account for a significant fraction of the dissipated kinetic energy of the SNR shock. Although systematic errors dominate the ?2 of the spectral fit of all models, we find that (1) the leptonic model has the best constrained model parameters, whose values can be easily accommodated with a typical supernova, but gives a relatively poor fit to the TeV ?-ray data; (2) the hybrid scenario has one more parameter than the leptonic one and improves the overall spectral fit significantly; and (3) the hadronic one, which has three more parameters than the leptonic model, gives the best fit to the overall spectrum with relatively poorly constrained model parameters and very hard spectra of accelerated particles. The uncertainties of the model parameters decrease significantly if the spectral indices of accelerated electrons and protons are the same. The hybrs and protons are the same. The hybrid and hadronic models also require an energy input into high-energy protons, which seems to be too high compared with typical values for a supernova explosion. Further investigations are required to reconcile these observations with SNR theories.

  14. Multi-frequency study of supernova remnants in the Large Magellanic Cloud. Confirmation of the supernova remnant status of DEM L205

    CERN Document Server

    Maggi, P; Bozzetto, L M; Filipovi?, M D; Points, S D; Chu, Y -H; Sasaki, M; Pietsch, W; Gruendl, R A; Dickel, J; Smith, R C; Sturm, R; Crawford, E J; De Horta, A Y

    2012-01-01

    We present new X-ray and radio data of the LMC SNR candidate DEM L205, obtained by XMM-Newton and ATCA, along with archival optical and infrared observations. We use data at various wavelengths to study this object and its complex neighbourhood, in particular in the context of the star formation activity, past and present, around the source. We analyse the X-ray spectrum to derive some remnant's properties, such as age and explosion energy. Supernova remnant features are detected at all observed wavelengths: soft and extended X-ray emission is observed, arising from a thermal plasma with a temperature kT between 0.2 keV and 0.3 keV. Optical line emission is characterised by an enhanced [SII]/Halpha ratio and a shell-like morphology, correlating with the X-ray emission. The source is not or only tentatively detected at near-infrared wavelengths (< 10 microns), but there is a detection of arc-like emission at mid and far-infrared wavelengths (24 and 70 micron) that can be unambiguously associated with the re...

  15. 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...

  16. Radio-continuum study of Large Magellanic Cloud Supernova Remnant J0509-6731

    CERN Document Server

    Bozzetto, L M; Urosevic, D; Kothes, R; Crawford, E J

    2013-01-01

    We present a detailed study of Australia Telescope Compact Array (ATCA) observations of supernova remnant (SNR) J0509-6731 in the Large Magellanic Cloud (LMC). The remnant has a ring morphology with brightened regions towards the south-western limb. We also find a second brightened inner ring which is only seen in the radio-continuum. The SNR exhibits an almost circular shape of $D=8\\times7$ pc (1 pc uncertainty in each direction) and a steep radio spectral index between 36 and 3 cm of $\\alpha=-0.73\\pm0.02$, which is characteristic of younger SNRs. We also report detection of radially orientated polarisation across the remnant at 6 cm, with a mean fractional polarisation level of $P\\cong$ (26 $\\pm$ 13)%. We find that the magnetic field ($\\sim$168 $\\mu$G) and $\\Sigma$ - D (7.35 pc, $1.1\\times 10^{-19}$ W m$^{-2}$ Hz$^{-1}$ Sr$^{-1}$) are consistent with other young remnants.

  17. Suzaku studies of the supernova remnant CTB 109 hosting the magnetar 1E 2259+586

    Science.gov (United States)

    Nakano, Toshio; Murakami, Hiroaki; Makishima, Kazuo; Hiraga, Junoko S.; Uchiyama, Hideki; Kaneda, Hidehiro; Enoto, Teruaki

    2015-02-01

    Ages of the magnetar 1E 2259+586 and the associated supernova remnant CTB 109 were studied. Analyzing the Suzaku data of CTB 109, its age was estimated to be ˜ 14 kyr, which is much younger than the measured characteristic age of 1E 2259+586, 230 kyr. This reconfirms the previously reported age discrepancy of this magnetar/remnant association, and suggests that the characteristic ages of magnetars are generally over-estimated as compared to their true ages. This discrepancy is thought to arise because the former are calculated without considering decay of the magnetic fields. This novel view is supported independently by much stronger Galactic-plane concentration of magnetars than other pulsars. The process of magnetic field decay in magnetars is mathematically modeled. It is implied that magnetars are much younger objects than previously considered, and can dominate new-born neutron stars.

  18. 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.)

  19. BeppoSAX observations of the young pulsar in the Kes 75 Supernova Remnant

    OpenAIRE

    Mereghetti, S.; Bandiera, R.; Bocchino, F.; Israel, G.L.

    2002-01-01

    We present the results of BeppoSAX observations of the young X-ray pulsar PSR J1846-0258, recently discovered at the center of the composite supernova remnant Kes 75. The pulsar (plus nebula) spectrum can be fitted by an absorbed power law with photon index alpha_ph=2.16+/-0.15, N_H=(4.7+/-0.8) x 10^22 cm^-2, and unabsorbed flux ~3.9x10^-11 erg cm^-2 s^-1 (2-10 keV). By joining two observations taken at an interval of two weeks we have been able to obtain a precise measureme...

  20. Cosmic ray positrons from a local, middle-aged supernova remnant

    CERN Document Server

    Erlykin, Anatoly

    2013-01-01

    We argue that the cosmic ray positron excess observed in ATIC-2, Fermi LAT, PAMELA, HESS and recently in the precision AMS-02 experiment can be attributed to the production in a local, middle-aged supernova remnant (SNR). Using the prediction of our model of cosmic ray acceleration in SNR we estimate that the SNR responsible for the observed positron excess is located between 250 and 320pc from the Sun and is 170-380 kyear old. The most probable candidate for such a source is the SNR which gave birth to the well-known Geminga pulsar, but is no longer visible. Other contenders are also discussed.

  1. Class I Methanol (CH$_{3}$OH) Maser Conditions near Supernova Remnants

    OpenAIRE

    McEwen, Bridget C.; Pihlström, Ylva M.; Sjouwerman, Loránt O.

    2014-01-01

    We present results from calculations of the physical conditions necessary for the occurrence of 36.169 ($4_{-1}-3_{0}\\, E$), 44.070 ($7_{0}-6_{1}\\,A^+$), 84.521 ($5_{-1}-4_{0}\\,E$), and 95.169 ($8_{0}-7_{1}\\,A^+$) GHz methanol (CH$_3$OH) maser emission lines near supernova remnants (SNRs), using the MOLPOP-CEP program. The calculations show that given a sufficient methanol abundance, methanol maser emission arises over a wide range of densities and temperatures, with optimal...

  2. 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

  3. A New Optical Survey of Supernova Remnant Candidates in M31

    OpenAIRE

    Lee, Jong Hwan; Lee, Myung Gyoon

    2014-01-01

    We present a survey of optically emitting supernova remnants (SNRs) in M31 based on H$\\alpha$ and [SII] images in the Local Group Survey. Using these images, we select objects that have [SII]:H$\\alpha$ $>$ 0.4 and circular shapes. We find 76 new SNR candidates. We also inspect 234 SNR candidates presented in previous studies, finding that only 80 of them are SNR candidates according to our criteria. Combining them with the new candidates, we produce a master catalog of 156 S...

  4. Optical Imaging and Spectroscopic Observation of the Galactic Supernova Remnant G85.9-0.6

    OpenAIRE

    Gok, F.; Sezer, A.; Aktekin, E.; Guver, T.; Ercan, N.

    2009-01-01

    Optical CCD imaging with H$\\alpha$ and [SII] filters and spectroscopic observations of the galactic supernova remnant G85.9-0.6 have been performed for the first time. The CCD image data are taken with the 1.5m Russian-Turkish Telescope (RTT150) at TUBITAK National Observatory (TUG) and spectral data are taken with the Bok 2.3 m telescope on Kitt Peak, AZ. The images are taken with narrow-band interference filters H$\\alpha$, [SII] and their continuum. [SII]/H$\\alpha$ ratio...

  5. Nonlinear instability of accelerating shock waves with application to supernovae

    Science.gov (United States)

    Luo, Ding; Chevalier, Roger A.

    1994-01-01

    We consider the stability of a planar accelerating shock front in an exponential atmosphere, a situation that can be described by a self-similar solution. A previous linear instability analysis showed that there are three regimes, depending on the wavelength of the perturbation along the direction of the shock front: at long wavelengths the shock is unstable, at intermediate wavelengths it is overstable, and at short wavelenghts it is stable, where the characteristic length is set by the initial density scale height. We have carried out numerical simulations of such an accelerating shock front and have confirmed the results of the semianalytic linear analysis in the linear regime. In the nonlinear regime, the evolution again depends on the three wavelength domains. At long wavelengths, the instability continuously grows but the flow remains smooth, and at short wavelengths, the flow is stable. The intermediate wavelength, overstable regime shows more complex evolution. The growing linear oscillations saturate soon after entering the nonlinear regime and the oscillations continue with the same approximate period. The shock front develops moving points of intersection, which generate weak shock fronts and density and pressure structure in the immediate postshock flow. The density fluctuations, with a contrast of a factor of 2-3, become frozen into the downstream flow. The growth of the instability is slow, so substantial initial perturbations are needed; thesemay be present in Type II supernovae with red supergiant progenitor stars which have outer convective regions. The clumping in the outer supernova atmosphere may affect spectral line formation and may play a role in the formation of fast knots.

  6. Spitzer Spectroscopy of the Galactic Supernova Remnant G292.0+1.8: Structure and Composition of the Oxygen-Rich Ejecta

    CERN Document Server

    Ghavamian, Parviz; Blair, William P; Long, Knox S; Tappe, Achim; Park, Sangwook; Winkler, P Frank

    2009-01-01

    We present mid-infrared (5-40 micron) spectra of shocked ejecta in the Galactic oxygen-rich supernova remnant G292.0+1.8, acquired with the IRS spectrograph on board the Spitzer Space Telescope. The observations targeted two positions within the brightest oxygen-rich feature in G292.0+1.8. Emission lines of [Ne II] 12.8, [Ne III] 15.5, 36.0, [Ne V] 24.3 and [O IV] 25.9 are detected from the shocked ejecta. No discernible mid-IR emission from heavier species such as Mg, Si, S, Ar or Fe is detected in G292.0+1.8. We also detect a broad emission bump between 15 and 28 microns in spectra of the radiatively shocked O-rich ejecta in G292.0+1.8. We suggest that this feature arises from either shock-heated Mg2SiO4 (forsterite) dust in the radiatively shocked O-rich ejecta, or collisional excitation of PAHs in the blast wave of the SNR. If the former interpretation is correct, this would be the first mid-IR detection of ejecta dust in G292.0+1.8. A featureless dust continuum is also detected from non-radiative shocks ...

  7. Sheet description of the emission from middle-aged supernova remnants

    International Nuclear Information System (INIS)

    The hypothesis that sheetlike shock fronts propagating into large clouds immersed in a fairly uniform intercloud medium can provide a consistent picture accounting for essentially all the observational data for the Cygnus Loop SNR is considered. Filaments are interpreted as line-of-sight projections of portions of the sheet. Variations in the projection of the shock velocity along the line of sight lead naturally to turbulent velocities consistent with observation. An analog model of a large, distorted, bumpy shock front is presented and shown to produce the observed morphology of the remnant's prominent optical filaments. Comparison with the observed morphology supports the idea that regions of optical emission lie on the local outer boundary of the shell and have not been engulfed by the blast wave. Bright X-ray emission arises when the blast wave encounters a preshock medium with an intermediate density higher than average for the adiabatic portion of the remnant, but still lower than that required for the shock to become radiative. 43 references

  8. H.E.S.S. observations of the supernova remnant RCW 86

    CERN Document Server

    Hoppe, S

    2007-01-01

    The shell-type supernova remnant (SNR) RCW 86 - possibly associated with the historical supernova SN 185 - was observed during the past three years with the High Energy Stereoscopic System (H.E.S.S.), an array of four atmospheric-Cherenkov telescopes located in Namibia. The multi-wavelength properties of RCW 86, e.g. weak radio emission and North-East X-ray emission almost entirely consisting of synchroton radiation, resemble those of two very-high energy (VHE; > 100 GeV) gamma-ray emitting SNRs RX J1713.7-3946 and RX J0852-4622. The H.E.S.S. observations reveal a new extended source of VHE gamma-ray emission.The morphological and spectral properties of this new source will be presented.

  9. H.E.S.S. observations of the supernovae remnant RCW 86

    Science.gov (United States)

    Hoppe, S.; Lemoine-Goumard, M.

    The shell-type supernova remnant (SNR) RCW 86 - possibly associated with the historical supernova SN 185 - was observed during the past three years with the High Energy Stereoscopic System (H.E.S.S.), an array of four atmospheric-Cherenkov telescopes located in Namibia. The multi-wavelength properties of RCW 86, e.g. weak radio emission and North-East X-ray emission almost entirely consisting of synchroton radiation, resemble those of two VHE emitting SNRs RX J1713.7-3946 and RX J0852-4622. The H.E.S.S. observations reveal a new extended source of VHE (>100 GeV) gamma-ray emission.The morphological and spectral properties of this new source will be presented.

  10. Shock waves in supernovae: New implications on the diffuse supernova neutrino background

    International Nuclear Information System (INIS)

    We investigate shock wave effects upon the diffuse supernova neutrino background using dynamic profiles taken from hydrodynamical simulations and calculating the neutrino evolution in three flavors with the S-matrix formalism. We show that the shock wave impact is significant and introduces modifications of the relic fluxes by about 20% and of the associated event rates at the level of 10%-20%. Such an effect is important since it is of the same order as the rate variation introduced when different oscillation scenarios (i.e., hierarchy or ?13) are considered. In addition, due to the shock wave, the rates become less sensitive to collective effects, in the inverted hierarchy and when sin22?13 is between the Chooz limit and 10-5. We propose a simplified model to account for shock wave effects in future predictions.

  11. LIMITS ON THE NUMBER OF GALACTIC YOUNG SUPERNOVA REMNANTS EMITTING IN THE DECAY LINES OF 44Ti

    International Nuclear Information System (INIS)

    We revise the assumptions of the parameters involved in predicting the number of supernova remnants detectable in the nuclear lines of the decay chain of 44Ti. Specifically, we consider the distribution of the supernova progenitors, the supernova rate in the Galaxy, the ratios of supernova types, the Galactic production of 44Ti, and the 44Ti yield from supernovae of different types to derive credible bounds on the expected number of detectable remnants. We find that, within 1? uncertainty, the Galaxy should contain an average of 5.1+2.4-2.0 remnants detectable to a survey with a 44Ti decay line flux limit of 10–5 photons cm–2 s–1, with a probability of detecting a single remnant of 2.7+10.0-2.4%, and an expected number of detections between two and nine remnants, making the single detection of Cas A unlikely but consistent with our models. Our results show that the probability of detecting the brightest 44Ti flux source at the high absolute Galactic longitude of Cas A or above is ?10%. Using the detected flux of Cas A, we attempt to constrain the Galactic supernova rate and Galactic production of 44Ti, but find the detection to be only weakly informative. We conclude that even future surveys having 200 times more sensitivity than state-of-the-art surveys can be guaranteed to detect only a few new remnants, with an expected number of detections between 8 and 21 at a limiting 44Ti decay flux of 10–7 photons cm–2 s–1

  12. Shock Breakout in Type II Plateau Supernovae: Prospects for High Redshift Supernova Surveys

    OpenAIRE

    Tominaga, N.; Morokuma, T.; Blinnikov, S. I.; Baklanov, P.; Sorokina, E. I.; Nomoto, K.

    2011-01-01

    Shock breakout is the brightest radiative phenomenon in a supernova (SN) but is difficult to be observed owing to the short duration and X-ray/ultraviolet (UV)-peaked spectra. After the first observation from the rising phase reported in 2008, its observability at high redshift is attracting enormous attention. We perform multigroup radiation hydrodynamics calculations of explosions for evolutionary presupernova models with various main-sequence masses $M_{\\rm MS}$, metallic...

  13. Discovery of radio pulsations from the X-ray pulsar in the supernova remnant G32.4-1.2

    International Nuclear Information System (INIS)

    A radio counterpart to the X-ray pulsar discovered by Seward and Harnden in the supernova remnant G320.4-1.2 (MSH 15--52) has been detected. The radio observations confirm the very large period derivative indicated by the X-ray data. This implies that the object is not a member of a binary system and hence is an isolated pulsar similar in some ways to the Crab pulsar. Association of the pulsar and the supernova remnant is supported by the observed pulsar dispersion measure

  14. Measuring Dust Production in the Small Magellanic Cloud Core-Collapse Supernova Remnant 1E 0102.2-7219

    OpenAIRE

    Sandstrom, Karin M.; Bolatto, Alberto D.; Stanimirovic, Snezana; van Loon, Jacco; Smith, J. D. T.

    2008-01-01

    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 (IRS) 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 ej...

  15. Shock Breakout from Type Ia Supernova

    CERN Document Server

    Piro, Anthony L; Weinberg, Nevin N

    2009-01-01

    The mode of explosive burning in Type Ia SNe remains an outstanding problem. It is generally thought to begin as a subsonic deflagration, but this may transition into a supersonic detonation (the DDT). We argue that this transition leads to a breakout shock, which would provide the first unambiguous evidence that DDTs occur. Its main features are a hard X-ray flash (~20 keV) lasting ~0.01 s with a total radiated energy of ~10^{40} ergs, followed by a cooling tail. This creates a distinct feature in the visual light curve, which is separate from the nickel decay. This cooling tail has a maximum absolute visual magnitude of M_V = -9 to -10 at approximately 1 day, which depends most sensitively on the white dwarf radius at the time of the DDT. As the thermal diffusion wave moves in, the composition of these surface layers may be imprinted as spectral features, which would help to discern between SN Ia progenitor models. Since this feature should accompany every SNe Ia, future deep surveys (e.g., m=24) will see i...

  16. Revival of a stalled supernova shock by neutrino heating

    International Nuclear Information System (INIS)

    We analyze the mechanism for revival of a stalled supernova shock found by one of us (J. R. W.) in a computation. Neutrinos from the hot, inner core of the supernova are absorbed in the outer layers, and although only about 0.1% of their energy is so absorbed, this is enough to eject the outer part of the star and leave only enough mass to form a neutron star. The neutrino absorption is independent of the density of material. After the shock recedes to some extent, neutrino heating establishes a sufficient pressure gradient to push the material beyond about 150 km outward, while the material further in falls rapidly toward the core. This makes the density near 150 km decrease spectacularly, creating a quasi-vacuum in which the pressure is mainly carried by radiation. This is a perfect condition to make the internal energy of the matter sufficient to escape from the gravitational attraction of the star. The net energy of the outgoing shock is about 4 x 1050 ergs

  17. 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 ...

  18. BeppoSAX observations of the young pulsar in the Kes 75 Supernova Remnant

    CERN Document Server

    Mereghetti, S; Bocchino, F; Israel, G L

    2002-01-01

    We present the results of BeppoSAX observations of the young X-ray pulsar PSR J1846-0258, recently discovered at the center of the composite supernova remnant Kes 75. The pulsar (plus nebula) spectrum can be fitted by an absorbed power law with photon index alpha_ph=2.16+/-0.15, N_H=(4.7+/-0.8) x 10^22 cm^-2, and unabsorbed flux ~3.9x10^-11 erg cm^-2 s^-1 (2-10 keV). By joining two observations taken at an interval of two weeks we have been able to obtain a precise measurement of the spin period (P=324.818968+/-0.000006 ms). This value, when combined with previous measurements, cannot be fitted by a smooth frequency evolution with a canonical braking index n=3. With the hypothesis of no glitches and/or significant timing noise, the braking index would be n=1.86+/-0.08 and, assuming a short initial period, the pulsar age would be \\~1700 years, closer to that of the supernova remnant than the simple estimate \\tau=P/2\\pdot=723 years. Other likely possibilities involve the presence of glitches and lead to a wide ...

  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...

  1. Far Ultraviolet Spectroscopic Explorer Observations of the Supernova Remnant N49 in the Large Magellanic Cloud

    CERN Document Server

    Blair, W P; Shelton, R; Sembach, K R; Moos, H W; Raymond, J C; York, D G; Feldman, P D; Chayer, P; Murphy, E M; Sahnow, D J; Wilkinson, E; Blair, William P.; Sankrit, Ravi; Shelton, Robin; Sembach, Kenneth R.; Raymond, John C.; York, Donald G.; Feldman, Paul D.; Chayer, Pierre; Murphy, Edward M.; Sahnow, David J.; Wilkinson, Erik

    2001-01-01

    We report a Far Ultraviolet Spectroscopic Explorer satellite observation of the supernova remnant N49 in the Large Magellanic Cloud, covering the 905 -- 1187 A spectral region. A 30'' square aperture was used, resulting in a velocity resolution of ~100 km/s. The purpose of the observation was to examine several bright emission lines expected from earlier work and to demonstrate diffuse source sensitivity by searching for faint lines never seen previously in extragalactic supernova remnant UV spectra. Both goals were accomplished. Strong emission lines of O VI 1031.9 A, 1037.6 A and C III 977.0 A were seen, Doppler broadened to +/- 225 km/s and with centroids red-shifted to 350 km/s, consistent with the LMC. Superimposed on the emission lines are absorptions by C III and O VI 1031.9 at +260 km/s, which are attributed to warm and hot gas (respectively) in the LMC. The O VI 1037.6 A line is more severely affected by overlying interstellar and H2 absorption from both the LMC and our galaxy. N III 989.8 A is not s...

  2. Radio and x-ray observations of compact sources in or near supernova remnants

    International Nuclear Information System (INIS)

    We present VLA multifrequency radio observations of six compact radio sources from the list of nine objects proposed by Ryle et al. [Nature 276, 571 (1978)] as a new class of radio star, possibly the stellar remnants of supernovae. We also present the results of a search for x-ray emission from four of these objects with the Einstein observatory. The radio observations provide information on spectra, polarization, time variability, angular structure, and positions for these sources. The bearing of these new data on the nature of the sources is discussed. One particularly interesting result is that the polarization and angular-size measurements are combined in an astrophysical argument to conclude that one of the sources (2013+370) is extragalactic. No x-ray emission was detected from any of the four objects observed, but an extended x-ray source was found coincident with the supernova remnant G 33.6+0.1 near 1849+005. Our measurements provide no compelling arguments to consider any of the six objects studied as radio stars

  3. DISCOVERY OF TeV GAMMA-RAY EMISSION TOWARD SUPERNOVA REMNANT SNR G78.2+2.1

    International Nuclear Information System (INIS)

    We report the discovery of an unidentified, extended source of very-high-energy gamma-ray emission, VER J2019+407, within the radio shell of the supernova remnant SNR G78.2+2.1, using 21.4 hr of data taken by the VERITAS gamma-ray observatory in 2009. These data confirm the preliminary indications of gamma-ray emission previously seen in a two-year (2007-2009) blind survey of the Cygnus region by VERITAS. VER J2019+407, which is detected at a post-trials significance of 7.5 standard deviations in the 2009 data, is localized to the northwestern rim of the remnant in a region of enhanced radio and X-ray emission. It has an intrinsic extent of 0.23°.23 ± 0.°03stat-0°.02sys+0°.04 and its spectrum is well-characterized by a differential power law (dN/dE = N0 × (E/TeV)–?) with a photon index of ? = 2.37 ± 0.14stat ± 0.20sys and a flux normalization of N0 = 1.5 ± 0.2stat ± 0.4sys × 10–12 photon TeV–1 cm–2 s–1. This yields an integral flux of 5.2 ± 0.8stat ± 1.4sys × 10–12 photon cm–2 s–1 above 320 GeV, corresponding to 3.7% of the Crab Nebula flux. We consider the relationship of the TeV gamma-ray emission with the GeV gamma-ray emission seen from SNR G78.2+2.1 as well as that seen from a nearby cocoon of freshly accelerated cosmic rays. Multiple scultiple scenarios are considered as possible origins for the TeV gamma-ray emission, including hadronic particle acceleration at the SNR shock.

  4. Diffusive propagation of cosmic rays from supernova remnants in the Galaxy. I: spectrum and chemical composition

    International Nuclear Information System (INIS)

    In this paper we investigate the effect of stochasticity in the spatial and temporal distribution of supernova remnants on the spectrum and chemical composition of cosmic rays observed at Earth. The calculations are carried out for different choices of the diffusion coefficient D(E) experienced by cosmic rays during propagation in the Galaxy. In particular, at high energies we assume that D(E)?E?, with ? = 1/3 and ? = 0.6 being the reference scenarios. The large scale distribution of supernova remnants in the Galaxy is modeled following the distribution of pulsars, with and without accounting for the spiral structure of the Galaxy. We find that the stochastic fluctuations induced by the spatial and temporal distribution of supernovae, together with the effect of spallation of nuclei, lead to mild but sensible violations of the simple, leaky-box-inspired rule that the spectrum observed at Earth is N(E)?E?? with ? = ?+?, where ? is the slope of the cosmic ray injection spectrum at the sources. Spallation of nuclei, even with the small rates appropriate for He, may account for small differences in spectral slopes between different nuclei, possibly providing an explanation for the recent CREAM observations. For ? = 1/3 we find that the slope of the proton and helium spectra are ? 2.67 and ? 2.6 respectively (with fluctuations depending on the realization of source distribution) at energies around ? 1 TeV (to be compared with the measured values of 2.66±0.02 and 2.58±0.02). For ? = 0.6 the hardening of the He spectra is not observed. The stochastic effects discussed above cannot be found in ordinary propagation calculations, such as GALPROP, where these effects and the point like nature of the sources are not taken into account. We also comment on the effect of time dependence of the escape of cosmic rays from supernova remnants, and of a possible clustering of the sources in superbubbles. In a second paper we will discuss the implications of these different scenarios for the anisotropy of cosmic rays

  5. The N19 HII Complex in the SMC: Multiple Supernova Remnants Forming a Proto-Superbubble?

    Science.gov (United States)

    Williams, Rosa N.; Chu, Y. H.; Chen, C. H.; Gruendl, R. A.; Points, S. D.; Smith, R. C.

    2006-12-01

    We have analyzed Chandra data for supernova remnants (SNRs) within the N19 HII complex in the Small Magellanic Cloud, supplemented by optical emission-line images and echelle spectroscopy. Our analysis examines the known SNR MCRX J0047.2-7308 (SNR B0045-73.4), confirms the SNR candidate MCRX J0046.6-7308 (SNR B0045-7325), and strengthens the case for a large, extended SNR identified as candidate MCRX J0047.5-7308. We find that the abundances inferred from spectral model fits to the X-ray emission from these SNRs and SNR candidates are consistent in each case with remnants of massive-star progenitors. We observe a possible point source within J0047.2-7308, embedded in a region of hard emission, suggestive of a possible embedded PWN. As these three remnants, all with massive-star origins, appear to be spatially located within the N19 complex, we infer that a small OB association may be the source of these phenomena. To expand on this assessment, we estimate the number of massive stars within N19 and project their energy input to the region. We find that a stellar-wind created superbubble is unlikely to have formed, but that the further expansion of the SNRs in the region may lead to superbubble formation on a timescale of LTSA grant NNG05GC97G.

  6. Supernova Remnants in the N19 Complex of the Small Magellanic Cloud

    Science.gov (United States)

    Williams, R. N. M.; Chu, Y.-H.; Chen, C.-H. R.; Gruendl, R. A.; Points, S. D.; Smith, R. C.

    2005-12-01

    We have analyzed Chandra data for supernova remnants (SNRs) within the N19 H II complex in the Small Magellanic Cloud, supplemented by optical emission-line images and echelle spectroscopy. Our observations include the known SNR MCRX J0047.2-7308 (SNR B0045-73.4), confirm the SNR candidate MCRX J0046.6-7308 (SNR B0045-7325), and strengthen the case for a large, extended SNR identified as candidate MCRX J0047.5-7308. We find that the abundances inferred from spectral model fits to the X-ray emission from these SNRs and SNR candidates are consistent in each case with remnants of massive-star progenitors. We observe a possible point source within J0047.2-7308, embedded in a region of hard emission, suggestive of a possible embedded PWN. As these three remnants, all with massive-star origins, appear to be spatially located within the N19 H II complex, we infer that a small OB association may be the source of these phenomena. To expand on this assessment, we estimate the number of massive stars within N19 and project their energy input to the region. We find that a stellar-wind created superbubble is unlikely to have formed, but that the further expansion of the SNRs in the region may lead to superbubble formation on a timescale of LTSA Program.

  7. A Broadband Study of the Emission from the Composite Supernova Remnant MSH 11-62

    Science.gov (United States)

    Slane, Patrick; Hughes, John P.; Temim, Tea; Rousseau, Romain; Castro, Daniel; Foight, Dillon; Gaensler, B. M.; Funk, Stefan; Lemoine-Goumard, Marianne; Gelfand, Joseph D.; Moffett, David A.

    2012-01-01

    MSH 11-62 (G29U)-Q.1) is a composite supernova remnant for which radio and X-ray observations have identified the remnant shell as well as its central pulsar wind nebula. The observations suggest a relatively young system expanding into a low-density region. Here, we present a study of MSH ll-62 using observations with the Chandra, XMM-Newton, and Fermi observatories, along with radio observations from the Australia Telescope Compact Array. We identify a compact X-ray source that appears to be the putative pulsar that powers the nebula, and show that the X-ray spectrum of the nebula bears the signature of synchrotron losses as particles diffuse into the outer nebula. Using data from the Fermi Large Area Telescope, we identify gamma-ray emission originating from MSH 11-62. With density constraints from the new X-ray measurements of the remnant, we model the evolution of the composite system in order to constrain the properties of the underlying pulsar and the origin of the gamma-ray emission.

  8. H.E.S.S. upper limits for Kepler's supernova remnant

    CERN Document Server

    Aharonian, F; Barresde Almeida, U; Bazer-Bachi, A R; Behera, B; Beilicke, M; Benbow, W; Berge, D; Bernlöhr, K; Boisson, C; Bolz, O; Borrel, V; Braun, I; Brion, E; Brucker, J; Buhler, R; Bulik, T; Büsching, I; Boutelier, T; Carrigan, S; Chadwick, P M; Chounet, L M; Clapson, A C; Coignet, G; Cornils, R; Costamante, L; Dalton, M; Degrange, B; Dickinson, H J; Djannati-Ata, A; Domainko, i 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; Fuling, M; Gallant, Y A; Giebels, B; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, G; Henri, G; Hermann, J F Glicenstein G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; De Jager, O C; Jung, I; Katarzynski, K; Kendziorra, E; Kerschhaggl, M; 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; 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; 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; Ward, M; Zdziarski, A A; Wagner, A; Zech, J

    2008-01-01

    Observations of Kepler's supernova remnant (G4.5+6.8) with the H.E.S.S. telescope array in 2004 and 2005 with a total live time of 13 h are presented. Stereoscopic imaging of Cherenkov radiation from extensive air showers is used to reconstruct the energy and direction of the incident gamma rays. No evidence for a very high energy (VHE: >100 GeV) gamma-ray signal from the direction of the remnant is found. An upper limit (99% confidence level) on the energy flux in the range 230 GeV - 12.8 TeV of 8.6 x 10^{-13} erg cm^{-2} s^{-1} is obtained. In the context of an existing theoretical model for the remnant, the lack of a detectable gamma-ray flux implies a distance of at least 6.4 kpc. A corresponding upper limit for the density of the ambient matter of 0.7 cm^{-3} is derived. With this distance limit, and assuming a spectral index Gamma = 2, the total energy in accelerated protons is limited to E_p < 8.6 x 10^{49} erg. In the synchrotron/inverse Compton framework, extrapolating the power law measured by RX...

  9. Fermi Large Area Telescope observations of the supernova remnant HESS J1731-347

    CERN Document Server

    Yang, Rui-zhi; Yuan, Qiang; Liu, Siming

    2014-01-01

    Context: HESS J1731-347 has been identified as one of the few TeV-bright shell-type supernova remnants (SNRs). These remnants are dominated by nonthermal emission, and the nature of TeV emission has been continuously debated for nearly a decade. Aims: We carry out the detailed modeling of the radio to gamma-ray spectrum of HESS J1731-347 to constrain the magnetic field and energetic particles sources, which we compare with those of the other TeV-bright shell-type SNRs explored before. Methods: Four years of data from Fermi Large Area Telescope (LAT) observations for regions around this remnant are analyzed, leading to no detection correlated with the source discovered in the TeV band. The Markov Chain Monte Carlo method is used to constrain parameters of one-zone models for the overall emission spectrum. Results: Based on the 99.9% upper limits of fluxes in the GeV range, one-zone hadronic models with an energetic proton spectral slope greater than 1.8 can be ruled out, which favors a leptonic origin for the ...

  10. Spatially-resolved Thermal Continuum Absorption against the Supernova Remnant W49B

    CERN Document Server

    Lacey, C K; Kassim, N E; Duric, N; Briggs, D S; Dyer, K K; Kassim, Namir E.

    2001-01-01

    We present sub-arcminute resolution imaging of the Galactic supernova remnant W49B at 74 MHz (25") and 327 MHz (6"), the former being the lowest frequency at which the source has been resolved. While the 327 MHz image shows a shell-like morphology similar to that seen at higher frequencies, the 74 MHz image is considerably different, with the southwest region of the remnant almost completely attenuated. The implied 74 MHz optical depth (~ 1.6) is much higher than the intrinsic absorption levels seen inside two other relatively young remnants, Cas A and the Crab Nebula, nor are natural variations in the relativistic electron energy spectra expected at such levels. The geometry of the absorption is also inconsistent with intrinsic absorption. We attribute the absorption to extrinsic free-free absorption by a intervening cloud of thermal electrons. Its presence has already been inferred from the low-frequency turnover in the integrated continuum spectrum and from the detection of radio recombination lines toward...

  11. XMM-Newton detection of the supernova remnant G304.6+0.1 (Kes 17)

    CERN Document Server

    Combi, J A; Sanchez-Ayaso, E; Romero, G E; Marti, J; Luque-Escamilla, P L; Mu?noz-Arjonilla, A J; Sanchez-Sutil, J R; Lopez-Santiago, J

    2010-01-01

    Aims. We report the first detailed X-ray study of the supernova remnant (SNR) G304.6+0.1, achieved with the XMM-Newton mission. Methods. The powerful imaging capability of XMM-Newton was used to study the X-ray characteristics of the remnant at different energy ranges. The X-ray morphology and spectral properties were analyzed. In addittion, radio and mid-infrared data obtained with the Molonglo Observatory Synthesis Telescope and the Spitzer Space Telescope were used to study the association with the detected X-ray emission and to understand the structure of the SNR at differents wavelengths. Results. The SNR shows an extended and arc-like internal structure in the X-ray band with out a compact point-like source inside the remnant. We find a high column density of NH in the range 2.5-3.5x1022 cm-2, which supports a relatively distant location (d $\\geq$ 9.7 kpc). The X-ray spectrum exhibits at least three emission lines, indicating that the X-ray emission has a thin thermal plasma origin, although a non-therm...

  12. A Broadband Study of the Emission from the Composite Supernova Remnant MSH 11-62

    CERN Document Server

    Slane, Patrick; Temim, Tea; Rousseau, Romain; Castro, Daniel; Foight, Dillon; Gaensler, B M; Funk, Stefan; Lemoine-Goumard, Marianne; Gelfand, Joseph D; Moffett, David A; Dodson, Richard G; Bernstein, Joseph P

    2012-01-01

    MSH 11-62 (G291.1-0.9) is a composite supernova remnant for which radio and X-ray observations have identified the remnant shell as well as its central pulsar wind nebula. The observations suggest a relatively young system expanding into a low density region. Here we present a study of MSH 11-62 using observations with the Chandra, XMM-Newton, and Fermi observatories, along with radio observations from the Australia Telescope Compact Array (ATCA). We identify a compact X-ray source that appears to be the putative pulsar that powers the nebula, and show that the X-ray spectrum of the nebula bears the signature of synchrotron losses as particles diffuse into the outer nebula. Using data from the Fermi LAT, we identify gamma-ray emission originating from MSH 11-62. With density constraints from the new X-ray measurements of the remnant, we model the evolution of the composite system in order to constrain the properties of the underlying pulsar and the origin of the gamma-ray emission.

  13. A detailed X-ray investigation of PSR J2021+4026 and $\\gamma$-Cygni supernova remnant

    CERN Document Server

    Hui, C Y; 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

    2014-01-01

    We have investigated the field around the radio-quiet $\\gamma$-ray pulsar, PSR J2021+4026, with a ~140 ks XMM-Newton observation and a ~56 ks archival Chandra data. Through analyzing the pulsed spectrum, we show that the X-ray pulsation is purely thermal in nature which suggests the pulsation is originated from a hot polar cap with $T\\sim3\\times10^{6}$ K on the surface of a rotating neutron star. On the other hand, the power-law 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 bow-shock nebula which extends from the pulsar to 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-Newto...

  14. H.E.S.S. reveals a lack of TeV emission from the supernova remnant Puppis A

    CERN Document Server

    :,; Aharonian, F; Benkhali, F Ait; Akhperjanian, A G; Angüner, E O; Backes, M; Balenderan, S; Balzer, A; Barnacka, A; Becherini, Y; Tjus, J Becker; Berge, D; Bernhard, S; Bernlöhr, K; Birsin, E; Biteau, J; Böttcher, M; Boisson, C; Bolmont, J; Bordas, P; Bregeon, J; Brun, F; Brun, P; Bryan, M; Bulik, T; Carrigan, S; Casanova, S; Chadwick, P M; Chakraborty, N; Chalme-Calvet, R; Chaves, R C G; Chrétien, M; Colafrancesco, S; Cologna, G; Conrad, J; Couturier, C; Cui, Y; Davids, I D; Degrange, B; Deil, C; deWilt, P; Djannati-Ataï, A; Domainko, W; Donath, A; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Edwards, T; Egberts, K; Eger, P; Espigat, P; Farnier, C; Fegan, S; Feinstein, F; Fernandes, M V; Fernandez, D; Fiasson, A; Fontaine, G; Förster, A; Füßling, M; Gabici, S; Gajdus, M; Gallant, Y A; Garrigoux, T; Giavitto, G; Giebels, B; Glicenstein, J F; Gottschall, D; Grondin, M -H; Grudzi?ska, M; Hadasch, D; Häffner, S; Hahn, J; Harris, J; Heinzelmann, G; Henri, G; Hermann, G; Hervet, O; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Ivascenko, A; Jacholkowska, A; Jahn, C; Jamrozy, M; Janiak, M; Jankowsky, F; Jung-Richardt, I; Kastendieck, M A; Katarzy?ski, K; Katz, U; Kaufmann, S; Khélifi, B; Kieffer, M; Klepser, S; Klochkov, D; Klu?niak, W; Kolitzus, D; Komin, Nu; Kosack, K; Krakau, S; Krayzel, F; Krüger, P P; Laffon, H; Lamanna, G; Lefaucheur, J; Lefranc, V; Lemière, A; Lemoine-Goumard, M; Lenain, J -P; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Marx, R; Maurin, G; Maxted, N; Mayer, M; McComb, T J L; Méhault, J; Meintjes, P J; Menzler, U; Meyer, M; Mitchell, A M W; Moderski, R; Mohamed, M; Morå, K; Moulin, E; Murach, T; de Naurois, M; Niemiec, J; Nolan, S J; Oakes, L; Odaka, H; Ohm, S; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Parsons, R D; Arribas, M Paz; Pekeur, N W; Pelletier, G; Petrucci, P -O; Peyaud, B; Pita, S; Poon, H; Pühlhofer, G; Punch, M; Quirrenbach, A; Raab, S; Reichardt, I; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Romoli, C; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Salek, D; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schüssler, F; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sol, H; Spanier, F; Spengler, G; Spies, F; Stawarz, {? }; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Tavernet, J -P; Tavernier, T; Taylor, A M; Terrier, R; Tluczykont, M; Trichard, C; Valerius, K; van Eldik, C; van Soelen, B; Vasileiadis, G; Veh, J; Venter, C; Viana, A; Vincent, P; Vink, J; Völk, H J; Volpe, F; Vorster, M; Vuillaume, T; Wagner, S J; Wagner, P; Wagner, R M; Ward, M; Weidinger, M; Weitzel, Q; White, R; Wierzcholska, A; Willmann, P; Wörnlein, A; Wouters, D; Yang, R; Zabalza, V; Zaborov, D; Zacharias, M; Zdziarski, A A; Zech, A; Zechlin, H -S

    2014-01-01

    Puppis A is an interesting ~4 kyr-old supernova remnant (SNR) that shows strong evidence of interaction between the forward shock and a molecular cloud. It has been studied in detail from radio frequencies to high-energy (HE, 0.1-100 GeV) gamma-rays. An analysis of the Fermi-LAT data has shown an extended HE gamma-ray emission with a 0.2-100 GeV spectrum exhibiting no significant deviation from a power law, unlike most of the GeV-emitting SNRs known to be interacting with molecular clouds. This makes it a promising target for imaging atmospheric Cherenkov telescopes (IACTs) to probe the gamma-ray emission above 100 GeV. Very-high-energy (VHE, E >= 0.1 TeV) gamma-ray emission from Puppis A is for the first time searched for with the High Energy Stereoscopic System (H.E.S.S.). The analysis of the H.E.S.S. data does not reveal any significant emission towards Puppis A. The derived upper limits on the differential photon flux imply that its broadband gamma-ray spectrum must exhibit a spectral break or cutoff. By ...

  15. A Spatially Resolved Study of the Synchrotron Emission and Titanium in Tycho's Supernova Remnant with NuSTAR

    CERN Document Server

    Lopez, Laura A; 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

    2015-01-01

    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 tight limits on its presence which exclude the reported Swift/BAT and INTEGRAL detections and correspond to an upper-limit 44Ti mass of M44 < 8.4e-5 Msun for a distance of 2.3 kpc. We perform spatially resolved spectroscopic analysis of sixty-six 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 energ...

  16. An X-Ray Pulsar in the Oxygen-Rich Supernova Remnant G292.0+1.8

    CERN Document Server

    Hughes, J P; Park, S; Roming, P W A; Burrows, D N; Hughes, John P.; Slane, Patrick O.; Park, Sangwook; Roming, Peter W. A.; Burrows, David N.

    2003-01-01

    We report the discovery of pulsed X-ray emission from the compact object CXOU J112439.1-591620 within the supernova remnant (SNR) G292.0+1.8 using the High Resolution Camera on the Chandra X-ray Observatory. The X-ray period (P=0.13530915 s) is consistent with extrapolation of the radio pulse period of PSR J1124-5916 for a spindown rate of dP/dt=7.6E-13 s/s. The X-ray pulse is single peaked and broad with a FWHM width of 0.23P (83 degrees). The pulse-averaged X-ray spectral properties of the pulsar are well described by a featureless power law model with an absorbing column density, N_H= 3.1E21 atoms/cm^2; photon index, gamma = 1.6; and unabsorbed 0.3-10 keV band luminosity, L_X = 7.2E32 erg/s. We plausibly identify the location of the pulsar's termination shock. Pressure balance between the pulsar wind and the larger synchrotron nebula, as well as lifetime issues for the X-ray-emitting electrons, argues for a particle- dominated PWN that is far from the minimum energy condition. Upper limits on the surface t...

  17. Constraints on cosmic-ray efficiency in the supernova remnant RCW 86 using multi-wavelength observations

    CERN Document Server

    Lemoine-Goumard, M; Vink, J; Allen, G E; Bamba, A; Giordano, F; Uchiyama, Y

    2012-01-01

    Several young supernova remnants (SNRs) have recently been detected in the high-energy and very-high-energy gamma-ray domains. As exemplified by RX J1713.7-3946, the nature of this emission has been hotly debated, and direct evidence for the efficient acceleration of cosmic-ray protons at the SNR shocks still remains elusive. We analyzed more than 40 months of data acquired by the Large Area Telescope (LAT) on-board the Fermi Gamma-Ray Space Telescope in the HE domain, and gathered all of the relevant multi-wavelength (from radio to VHE gamma-rays) information about the broadband nonthermal emission from RCW 86. For this purpose, we re-analyzed the archival X-ray data from the ASCA/Gas Imaging Spectrometer (GIS), the XMM-Newton/EPIC-MOS, and the RXTE/Proportional Counter Array (PCA). Beyond the expected Galactic diffuse background, no significant gamma-ray emission in the direction of RCW 86 is detected in any of the 0.1-1, 1-10 and 10-100 GeV Fermi-LAT maps. In the hadronic scenario, the derived HE upper lim...

  18. ENERGY PARTITION BETWEEN ENERGETIC ELECTRONS AND TURBULENT MAGNETIC FIELD IN SUPERNOVA REMNANT RX J1713.7-3946

    International Nuclear Information System (INIS)

    Current observations of supernova remnant (SNR) RX J1713.7-3946 favor the leptonic scenario for the TeV emission, where the radio to X-ray emission is produced via the synchrotron process and the ?-ray emission is produced via the inverse Comptonization of soft background photons, and the electron distribution can be inferred from the observed ?-ray spectrum with a spectral inversion method. It is shown that the observed correlation between the X-ray and ?-ray brightness of SNR RX J1713.7-3946 can be readily explained with the assumption that the energy density of energetic electrons is proportional to that of the magnetic field in such a scenario. A two-dimensional magnetohydrodynamic simulation is then carried out to model the overall emission spectrum. It is found that the total energy of electrons above ?1 GeV is equal to that of the magnetic field. This is the first piece of observational evidence for energy equipartition between energetic electrons and magnetic field in the downstream of strong collisionless astrophysical shocks of SNRs

  19. Probing Supernova Shock Waves and Matter Density Fluctuations by Neutrino Flavor Conversions

    Science.gov (United States)

    Fogli, G. L.; Lisi, E.; Mirizzi, A.; Montanino, D.

    2007-11-01

    Future detection of a supernova neutrino burst by large underground detectors would give important information about the supernova matter density profile and unknown neutrino properties, due to the effects of flavor oscillations in the supernova envelope. We mainly discuss the detectability of signatures associated to the shock-wave propagation in observable neutrino signals. We also investigate the effects of possible small-scale stochastic matter density fluctuations in the wake of supernova shock waves. We find that such fluctuations can partly erase the shock-wave imprint on the neutrino event spectra.

  20. IDENTIFICATION CAMPAIGN OF SUPERNOVA REMNANT CANDIDATES IN THE MILKY WAY. I. CHANDRA OBSERVATION OF G308.3-1.4

    International Nuclear Information System (INIS)

    ROSAT all-sky survey data have provided another window in which to search for supernova remnants (SNRs). In re-examining this data archive, a list of unidentified extended X-ray objects have been suggested as promising SNR candidates. However, most of these targets have not yet been fully explored by state-of-the-art X-ray observatories. To select a pilot target for a long-term identification campaign, we observed the brightest candidate, G308.3-1.4, with the Chandra X-ray Observatory. An incomplete shell-like X-ray structure that is well correlated with the radio shell emission at 843 MHz has been revealed. The X-ray spectrum suggests the presence of a shock-heated plasma. All these evidences confirm G308.3-1.4 as an SNR. The brightest X-ray point source detected in this field of view is also the one located closest to the geometrical center of G308.3-1.4, which has a soft spectrum. The intriguing temporal variability and the identification of the optical/infrared counterpart rule out the possibility of an isolated neutron star. On the other hand, the spectral energy distribution from the Ks band to the R band suggests a late-type star. Together with a putative periodicity of ?1.4 hr, the interesting excesses in the V and B bands and in H? suggest that this source is a promising candidate for a compact binary that survived a supernova explosion.

  1. Shock Breakout in Type II Plateau Supernovae: Prospects for High Redshift Supernova Surveys

    CERN Document Server

    Tominaga, N; Blinnikov, S I; Baklanov, P; Sorokina, E I; Nomoto, K

    2011-01-01

    Shock breakout is the brightest radiative phenomenon in a supernova (SN) but is difficult to be observed owing to the short duration and X-ray/ultraviolet (UV)-peaked spectra. After the first observation from the rising phase reported in 2008, its observability at high redshift is attracting enormous attention. We perform multigroup radiation hydrodynamics calculations of explosions for evolutionary presupernova models with various main-sequence masses $M_{\\rm MS}$, metallicities $Z$, and explosion energies $E$. We present multicolor light curves of shock breakout in Type II plateau SNe, being the most frequent core-collapse SNe, and predict apparent multicolor light curves of shock breakout at various redshifts $z$. We derive the observable SN rate and reachable redshift as functions of filter $x$ and limiting magnitude $m_{x,{\\rm lim}}$ by taking into account an initial mass function, cosmic star formation history, intergalactic absorption, and host galaxy extinction. We propose a realistic survey strategy ...

  2. The supernova remnant CTB 37B and its associated magnetar CXOU J171405.7-381031: evidence for a magnetar-driven remnant

    International Nuclear Information System (INIS)

    We discuss the association between the candidate magnetar CXOU J171405.7-381031 and the supernova remnant CTB 37B. The recent detection of the period derivative of the object allowed an estimation of a young characteristic age of only ? 1000 yr. This value is too small to be compatible even with the minimum radius of the remnant being ? 10 pc, the value corresponding to the lower limit of the estimated distance of 10.2 ± 3.5 kpc, unless the true distance happens to be even smaller than the lower limit. We argue that a consistent scenario for the remnant's origin, in which the latter is powered by the energy injected by a young magnetar, is indeed more accurate to explain the young age, and demonstrates its non-standard (i.e. magnetar-driven) nature. (letters)

  3. THE CHANDRA ACIS SURVEY OF M33: X-RAY, OPTICAL, AND RADIO PROPERTIES OF THE SUPERNOVA REMNANTS

    International Nuclear Information System (INIS)

    M33 contains a large number of emission nebulae identified as supernova remnants (SNRs) based on the high [S II]:H? ratios characteristic of shocked gas. Using Chandra data from the ChASeM33 survey with a 0.35-2 keV sensitivity of ?2 x 1034 erg s-1, we have detected 82 of 137 SNR candidates, yielding confirmation of (or at least strongly support for) their SNR identifications. This provides the largest sample of remnants detected at optical and X-ray wavelengths in any galaxy, including the Milky Way. A spectral analysis of the seven X-ray brightest SNRs reveals that two, G98-31 and G98-35, have spectra that appear to indicate enrichment by ejecta from core-collapse supernova explosions. In general, the X-ray-detected SNRs have soft X-ray spectra compared to the vast majority of sources detected along the line of sight to M33. It is unlikely that there are any other undiscovered thermally dominated X-ray SNRs with luminosities in excess of ?4 x 1035 erg s-1 in the portions of M33 covered by the ChASeM33 survey. We have used a combination of new and archival optical and radio observations to attempt to better understand why some objects are detected as X-ray sources and others are not. We have also developed a morphological classification scheme for the optically identified SNRs and discussed the efficacy of this scheme as a predictor of X-ray detectability. Finally, we have compared the SNRs found in M33 to those that hthe SNRs found in M33 to those that have been observed in the Galaxy and the Magellanic Clouds. There are no close analogs of Cas A, Kepler's SNR, Tycho's SNR, or the Crab Nebula in the regions of M33 surveyed, but we have found an X-ray source with a power-law spectrum coincident with a small-diameter radio source that may be the first pulsar-wind nebula recognized in M33.

  4. Measuring Dust Production in the Small Magellanic Cloud Core-Collapse Supernova Remnant 1E 0102.2-7219

    CERN Document Server

    Sandstrom, Karin M; Stanimirovic, Snezana; van Loon, Jacco; Smith, J D T

    2008-01-01

    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 (IRS) 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 3x10^-3 solar masses of amorphous carbon dust at 70 K and 2x10^-5 solar masses 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 b...

  5. TOWARD UNDERSTANDING THE COSMIC-RAY ACCELERATION AT YOUNG SUPERNOVA REMNANTS INTERACTING WITH INTERSTELLAR CLOUDS: POSSIBLE APPLICATIONS TO RX J1713.7–3946

    International Nuclear Information System (INIS)

    Using three-dimensional magnetohydrodynamic simulations, we investigate general properties of a blast wave shock interacting with interstellar clouds. The pre-shock cloudy medium is generated as a natural consequence of the thermal instability that simulates realistic clumpy interstellar clouds and their diffuse surrounding. The shock wave that sweeps the cloudy medium generates a turbulent shell through the vorticity generations that are induced by shock-cloud interactions. In the turbulent shell, the magnetic field is amplified as a result of turbulent dynamo action. The energy density of the amplified magnetic field can locally grow comparable to the thermal energy density, particularly at the transition layers between clouds and the diffuse surrounding. In the case of a young supernova remnant (SNR) with a shock velocity ?> 103 km s–1, the corresponding strength of the magnetic field is approximately 1 mG. The propagation speed of the shock wave is significantly stalled in the clouds because of the high density, while the shock maintains a high velocity in the diffuse surrounding. In addition, when the shock wave hits the clouds, reflection shock waves are generated that propagate back into the shocked shell. From these simulation results, many observational characteristics of the young SNR RX J1713.7–3946 that is suggested to be interacting with molecular clouds can be explained as follows. The reflection shocks can accelerate particlection shocks can accelerate particles in the turbulent downstream region where the magnetic field strength reaches 1 mG, which causes short-time variability of synchrotron X-rays. Since the shock velocity is stalled locally in the clouds, the temperature in the shocked cloud is suppressed far below 1 keV. Thus, thermal X-ray line emission would be faint even if the SNR is interacting with molecular clouds. We also find that the photon index of the ?0-decay gamma rays generated by cosmic-ray protons can be 1.5 (corresponding energy flux is ?F???0.5) because the penetration depth of high-energy particles into the clumpy clouds depends on their energy. This suggests that, if we rely only on the spectral study, the hadronic gamma-ray emission is indistinguishable from the leptonic inverse Compton emission. We propose that the spatial correlation of the gamma-ray, X-ray, and CO line-emission regions can be conclusively used to understand the origin of gamma rays from RX J1713.7–3946.

  6. Search for broad absorption lines in spectra of stars in the field of supernova remnant RX J0852.0-4622 (Vela Jr.)

    CERN Document Server

    Iyudin, A F; Chugai, N N; Greiner, J; Axelsson, M; Larsson, S; Ryabchikova, T A

    2010-01-01

    Supernova remnant (SNR) RX J0852.0-4622 is one of the youngest and is most likely the closest among known galactic supernova remnants (SNRs). It was detected in X-rays, the 44Ti gamma-line, and radio. We obtain and analyze medium-resolution spectra of 14 stars in the direction towards the SNR RX J0852.0-4622 in an attempt to detect broad absorption lines of unshocked ejecta against background stars. Spectral synthesis is performed for all the stars in the wavelength range of 3740-4020AA to extract the broad absorption lines of Ca II related to the SNR RX J0852.0-4622. We do not detect any broad absorption line and place a 3-sigma upper limit on the relative depths of <0.04 for the broad Ca II absorption produced by the SNR. We detect narrow low and high velocity absorption components of Ca II. High velocity |V(LSR)|=100-140 km/s components are attributed to radiative shocks in clouds engulfed by the old Vela SNR. The upper limit to the absorption line strength combined with the width and flux of the 44Ti g...

  7. Supernova shock acceleration of cosmic rays in the galaxy

    International Nuclear Information System (INIS)

    The regeneration of galactic cosmic rays by first-order Fermi acceleration due to supernova shock waves traversing interstellar space is investigated. It is shown that if most of the volume of the interstellar medium comprises a low density ''coronal'' phase and supernova blast waves can propagate for more than 100 pc, then reacceleration of existing cosmic rays is important. Model Green's functions describing this redistribution in energy are calculated, and their properties are contrasted with stochastic and source function acceleration schemes. Shcok wave acceleration is incorporated in a model containing simple treatments of escape, ionization, radiation, and spallation loss. The injection of low energy particles treated in an ad hoc fashion. It is shown that it is possible to reproduce the observed cosmic ray spectra for protons, electrons, light, medium and heavy nucleons up to energies -2 Myr-1. The relative importance of direct acceleration of suprathermal particles produced in a shock front and reacceleration of existing cosmic rays may be best gauged by observing the energy dependence of the abundance ratio of light to medium nucleons and the low energy proton and electron spectra. Observational tests for the importance of this acceleration mechanism are proposed

  8. Extinction curves flattened by reverse shocks in supernovae

    CERN Document Server

    Hirashita, Hiroyuki; Takeuchi, Tsutomu T; Kozasa, Takashi

    2008-01-01

    We investigate the extinction curves of young galaxies in which dust is supplied from Type II supernovae (SNe II) and/or pair instability supernovae (PISNe). Since at high redshift (z>5), low-mass stars cannot be dominant sources for dust grains, SNe II and PISNe, whose progenitors are massive stars with short lifetimes, should govern the dust production. Here, we theoretically investigate the extinction curves of dust produced by SNe II and PISNe, taking into account reverse shock destruction induced by collision with ambient interstellar medium. We find that the extinction curve is sensitive to the ambient gas density around a SN, since the efficiency of reverse shock destruction strongly depends on it. The destruction is particularly efficient for small-sized grains, leading to a flat extinction curve in the optical and ultraviolet wavelengths. Such a large ambient density as n_H > 1 cm^{-3} produces too flat an extinction curve to be consistent with the observed extinction curve for SDSS J104845.05+463718...

  9. SHOCK BREAKOUT IN TYPE II PLATEAU SUPERNOVAE: PROSPECTS FOR HIGH-REDSHIFT SUPERNOVA SURVEYS

    International Nuclear Information System (INIS)

    Shock breakout is the brightest radiative phenomenon in a supernova (SN) but is difficult to be observed owing to the short duration and X-ray/ultraviolet (UV)-peaked spectra. After the first observation from the rising phase reported in 2008, its observability at high redshift is attracting enormous attention. We perform multigroup radiation hydrodynamics calculations of explosions for evolutionary presupernova models with various main-sequence masses M MS, metallicities Z, and explosion energies E. We present multicolor light curves of shock breakouts in Type II plateau SNe, being the most frequent core-collapse SNe, and predict apparent multicolor light curves of shock breakout at various redshifts z. We derive the observable SN rate and reachable redshift as functions of filter x and limiting magnitude m x,lim by taking into account an initial mass function, cosmic star formation history, intergalactic absorption, and host galaxy extinction. We propose a realistic survey strategy optimized for shock breakout. For example, the g'-band observable SN rate for m g',lim = 27.5 mag is 3.3 SNe deg-2 day-1 and half of them are located at z ? 1.2. It is clear that the shock breakout is a beneficial clue for probing high-z core-collapse SNe. We also establish ways to identify shock breakout and constrain SN properties from the observations of shock breakout, brightness, timescale, and color. We emphasize that the multe, and color. We emphasize that the multicolor observations in blue optical bands with ?hour intervals, preferably over ?2 continuous nights, are essential to efficiently detect, identify, and interpret shock breakout.

  10. Shock Breakout in Type II Plateau Supernovae: Prospects for High-Redshift Supernova Surveys

    Science.gov (United States)

    Tominaga, N.; Morokuma, T.; Blinnikov, S. I.; Baklanov, P.; Sorokina, E. I.; Nomoto, K.

    2011-03-01

    Shock breakout is the brightest radiative phenomenon in a supernova (SN) but is difficult to be observed owing to the short duration and X-ray/ultraviolet (UV)-peaked spectra. After the first observation from the rising phase reported in 2008, its observability at high redshift is attracting enormous attention. We perform multigroup radiation hydrodynamics calculations of explosions for evolutionary presupernova models with various main-sequence masses M MS, metallicities Z, and explosion energies E. We present multicolor light curves of shock breakouts in Type II plateau SNe, being the most frequent core-collapse SNe, and predict apparent multicolor light curves of shock breakout at various redshifts z. We derive the observable SN rate and reachable redshift as functions of filter x and limiting magnitude m x,lim by taking into account an initial mass function, cosmic star formation history, intergalactic absorption, and host galaxy extinction. We propose a realistic survey strategy optimized for shock breakout. For example, the g'-band observable SN rate for m g',lim = 27.5 mag is 3.3 SNe deg-2 day-1 and half of them are located at z >= 1.2. It is clear that the shock breakout is a beneficial clue for probing high-z core-collapse SNe. We also establish ways to identify shock breakout and constrain SN properties from the observations of shock breakout, brightness, timescale, and color. We emphasize that the multicolor observations in blue optical bands with ~hour intervals, preferably over >=2 continuous nights, are essential to efficiently detect, identify, and interpret shock breakout.

  11. The shocking development of lithium (and boron) in supernovae

    Science.gov (United States)

    Dearborn, David S. P.; Schramm, David N.; Steigman, Gary; Truran, James

    1989-01-01

    It is shown that significant amounts of Li-7 and B-11 are produced in Type 2 supernovae. The synthesis of these rare elements occurs as the supernova shock traverses the base of the hydrogen envelope burning He-3 to masses 7 and 11 via alpha capture. The yields in this process are sufficient to account for the difference in lithium abundance observed between Pop 2 and Pop 1 stars. Since lithium (and boron) would, in this manner, be created in the same stars that produce the bulk of the heavy elements, the lithium abundance even in old Pop 1 stars would be high (as observed). The B-11 production may remedy the long-standing problem of the traditional spallation scenario to account for the observed isotopic ratio of boron. Observational consequences of this mechanism are discussed, including the evolution of lithium and boron isotope ratios in the Galaxy and the possible use of the boron yields to constrain the number of blue progenitor Type 2 supernovae.

  12. Radio-continuum observations of small, radially polarised Supernova Remnant J0519-6902 in the large Magellanic cloud

    Directory of Open Access Journals (Sweden)

    Bozzetto L.M.

    2012-01-01

    Full Text Available We report on new Australian Telescope Compact Array (ATCA observations of SNR J0519-6902. The Supernova Remnant (SNR is small in size (~8 pc and exhibits a typical SNR spectrum with ? = -0.53±0.07, with steeper spectral indices towards the northern limb of the remnant. SNR J0519-6902 contains a low level of radially orientated polarisation at wavelengths of 3 and 6 cm, which is typical of younger SNRs. A fairly strong magnetic field was estimated to ~171µG. The remnant appears to be the result of a typical Type Ia supernova, sharing many properties with another small and young Type Ia LMC SNR, J0509-6731. [Projekat Ministarstva nauke Republike Srbije, br. 176005

  13. Multi-frequency study of a new Fe-rich supernova remnant in the Large Magellanic Cloud, MCSNR J0508-6902

    CERN Document Server

    Bozzetto, L M; Maggi, P; Filipovi?, M D; Stupar, M; Parker, Q A; Reid, W A; Sasaki, M; Haberl, F; Uroševi?, D; Dickel, J; Sturm, R; Williams, R; Ehle, M; Gruendl, R; Chu, Y -H; Points, S; Crawford, E J

    2014-01-01

    We present a detailed radio, X-ray and optical study of a newly discovered Large Magellanic Cloud (LMC) supernova remnant (SNR) which we denote MCSNR J0508-6902. Observations from the Australian Telescope Compact Array (ATCA) and the $\\textit{XMM-Newton}$ X-ray observatory are complemented by deep H$\\alpha$ images and Anglo Australian Telescope AAOmega spectroscopic data to study the SNR shell and its shock-ionisation. Archival data at other wavelengths are also examined. The remnant follows a filled-in shell type morphology in the radio-continuum and has a size of $\\sim$74 pc $\\times$ 57 pc at the LMC distance. The X-ray emission exhibits a faint soft shell morphology with Fe-rich gas in its interior $-$ indicative of a Type Ia origin. The remnant appears to be mostly dissipated at higher radio-continuum frequencies leaving only the south-eastern limb fully detectable while in the optical it is the western side of the SNR shell that is clearly detected. The best-fit temperature to the shell X-ray emission ($...

  14. The Fermi Gamma Ray Space Telescope discovers the Pulsar in the Young Galactic Supernova-Remnant CTA 1

    CERN Document Server

    Abdo, A A; Atwood, W B; 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; Bogaert, G; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Caliandro, G A; Cameron, R A; Caraveo, P A; Carlson, P; Casandjian, J M; Cecchi, C; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Cutini, S; Davis, D S; Dermer, C D; De Angelis, A; de Palma, F; Digel, S W; Dormody, M; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Farnier, C; Focke, W B; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M H; Grove, J E; Guillemot, L; Guiriec, S; Harding, A K; Hartman, R C; Hays, E; Hughes, R E; Jhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Kanai, Y; Kanbach, G; Katagiri, H; Kawai, N; Kerr, M; Kishishita, T; Kiziltan, B; Kndlseder, J; Kocian, M L; Komin*, N; Kühn, F; Kuss, M; Latronico, L; Lemoine-Goumard, M; Longo, F; Lonjou, V; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Marelli, M; Mazziotta, M N; McEnery, J E; McGlynn, S; Meurer, C; Michelson, P F; Mineo, T; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nolan, P L; Nuss, E; Ohno, M; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepé, M; Pesce-Rollins, M; Piano, G; Pieri, L; Piron, F; Porter, T A; Rain, S; Rando, R; Ray, P S; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Romani, R W; Roth, M; Ryde, F; Sadrozinski, H F W; Sánchez, D; Sander, A; Saz-Parkinson, P M; Schalk, T L; Sellerholm, A; Sgr, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Starck, J L; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J B; Thayer, J G; Thompson, D J; Thorsett, S E; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Usher, T L; Van Etten, A; Vilchez, N; Vitale, V; Wang, P; Watters, K; Winer, B L; Wood, K S; Yasuda, H; Ylinen, T; Ziegler, M

    2008-01-01

    Energetic young pulsars and expanding blast waves (supernova remnants, SNRs) are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. The pulsar, discovered through its gamma-ray pulsations, has a period of 316.86 ms, a period derivative of 3.614 x 10-13 s s-1 . Its characteristic age of 104 years is comparable to that estimated for the SNR. It is conjectured that most unidentified Galactic gamma ray sources associated with star-forming regions and SNRs are such young pulsars.

  15. Toward Understanding the Cosmic-Ray Acceleration at Young Supernova Remnants Interacting with Interstellar Clouds: Possible Applications to RX J1713.7-3946

    Science.gov (United States)

    Inoue, Tsuyoshi; Yamazaki, Ryo; Inutsuka, Shu-ichiro; Fukui, Yasuo

    2012-01-01

    Using three-dimensional magnetohydrodynamic simulations, we investigate general properties of a blast wave shock interacting with interstellar clouds. The pre-shock cloudy medium is generated as a natural consequence of the thermal instability that simulates realistic clumpy interstellar clouds and their diffuse surrounding. The shock wave that sweeps the cloudy medium generates a turbulent shell through the vorticity generations that are induced by shock-cloud interactions. In the turbulent shell, the magnetic field is amplified as a result of turbulent dynamo action. The energy density of the amplified magnetic field can locally grow comparable to the thermal energy density, particularly at the transition layers between clouds and the diffuse surrounding. In the case of a young supernova remnant (SNR) with a shock velocity >~ 103 km s-1, the corresponding strength of the magnetic field is approximately 1 mG. The propagation speed of the shock wave is significantly stalled in the clouds because of the high density, while the shock maintains a high velocity in the diffuse surrounding. In addition, when the shock wave hits the clouds, reflection shock waves are generated that propagate back into the shocked shell. From these simulation results, many observational characteristics of the young SNR RX J1713.7-3946 that is suggested to be interacting with molecular clouds can be explained as follows. The reflection shocks can accelerate particles in the turbulent downstream region where the magnetic field strength reaches 1 mG, which causes short-time variability of synchrotron X-rays. Since the shock velocity is stalled locally in the clouds, the temperature in the shocked cloud is suppressed far below 1 keV. Thus, thermal X-ray line emission would be faint even if the SNR is interacting with molecular clouds. We also find that the photon index of the ?0-decay gamma rays generated by cosmic-ray protons can be 1.5 (corresponding energy flux is ?F ?vprop?0.5) because the penetration depth of high-energy particles into the clumpy clouds depends on their energy. This suggests that, if we rely only on the spectral study, the hadronic gamma-ray emission is indistinguishable from the leptonic inverse Compton emission. We propose that the spatial correlation of the gamma-ray, X-ray, and CO line-emission regions can be conclusively used to understand the origin of gamma rays from RX J1713.7-3946.

  16. Modeling W44 as a Supernova Remnant in a Density Gradient, with a Partially Formed Dense Shell and Thermal Conduction in the Hot Interior

    CERN Document Server

    Shelton, R L; Maciejewski, W; Smith, R; Plewa, T; Pawl, A; Rózyczka, M; Cox, Donald P.; Maciejewski, Witold; Smith, Randall; Plewa, Tomasz; Pawl, Andrew; Rozyczka, Michal

    1998-01-01

    (shortened version) We show that many observations of W44, a supernova remnant in the galactic plane at a distance of about 2500 pc, are remarkably consistent with the simplest realistic model. The model remnant is evolving in a smooth ambient medium of fairly high density, about 6 cm^-3 on average, with a substantial density gradient. At the observed time it has an age of about 20,000 years, consistent with the age of the associated pulsar, and a radius of 11 to 13 pc. Over most of the outer surface, radiative cooling has become important in the post shock gas; on the denser end there has been sufficient compression of the cooled gas to develop a very thin dense half shell of about 450 M_sun, supported against further compression by nonthermal pressure. The half shell has an expansion velocity of about 150 km s^-1, and is bounded on the outer surface by a radiative shock with that speed. We provide several analytic tools for the assembly of models of this type. We review the early evolution and shell formati...

  17. Supernova Remnants as a Probe of Dust Grains in the Interstellar Medium

    CERN Document Server

    Williams, Brian J

    2010-01-01

    Interstellar dust grains play a crucial role in the evolution of the galactic interstellar medium (ISM). Despite its importance, however, dust remains poorly understood in terms of its origin, composition, and abundance throughout the universe. Supernova remnants (SNRs) provide a laboratory for studying the evolution of dust grains, as they are one of the only environments in the universe where it is possible to observe grains being both created and destroyed. SNRs exhibit collisionally heated dust, allowing dust to serve as a diagnostic both for grain physics and for the plasma conditions in the SNR. I present theoretical models of collisionally heated dust which calculate grain emission as well as destruction rates. In these models, I incorporate physics such as nonthermal sputtering caused by grain motions through the gas, a more realistic approach to sputtering for small grains, and arbitrary grain compositions porous and composite grains. I apply these models to infrared and X-ray observations of Kepler'...

  18. Detection of the Characteristic Pion-Decay Signature in Supernova Remnants

    CERN Document Server

    :,; Ajello, M; Allafort, A; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Bechtol, K; Bellazzini, R; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bottacini, E; Brandt, T J; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Busetto, G; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Çelik, Ö; Charles, E; Chaty, S; Chaves, R C G; Chekhtman, A; Cheung, C C; Chiang, J; Chiaro, G; Cillis, A N; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Corbel, S; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; Silva, E do Couto e; Drell, P S; Drlica-Wagner, A; Falletti, L; Favuzzi, C; Ferrara, E C; Franckowiak, A; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Germani, S; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M -H; Grove, J E; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hayashi, K; Hays, E; Hewitt, J; Hill, A B; Hughes, R E; Jackson, M S; Jogler, T; Jóhannesson, G; Johnson, A S; Kamae, T; Kataoka, J; Katsuta, J; Knödlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Madejski, G M; Massaro, F; Mayer, M; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mignani, R P; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nemmen, R; Nuss, E; Ohno, M; Ohsugi, T; Omodei, N; Orienti, M; Orlando, E; Ormes, J F; Paneque, D; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Rainò, S; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Ritz, S; Romoli, C; Sánchez-Conde, M; Schulz, A; Sgrò, C; Simeon, P E; Siskind, E J; Smith, D A; Spandre, G; Spinelli, P; Stecker, F W; Strong, A W; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Thorsett, S E; Tibaldo, L; Tibolla, O; Tinivella, M; Troja, E; Uchiyama, Y; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Werner, M; Winer, B L; Wood, K S; Wood, M; Yamazaki, R; Yang, Z; Zimmer, S; 10.1126/science.1231160

    2013-01-01

    Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) are the sources of galactic cosmic rays, unequivocal evidence for the acceleration of protons in these objects is still lacking. When accelerated protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma rays. This offers a compelling way to detect the acceleration sites of protons. The identification of pion-decay gamma rays has been difficult because high-energy electrons also produce gamma rays via bremsstrahlung and inverse Compton scattering. We detected the characteristic pion-decay feature in the gamma-ray spectra of two SNRs, IC 443 and W44, with the Fermi Large Area Telescope. This detection provides direct evidence that cosmic-ray protons are accelerated in SNRs.

  19. Systematic X-ray Mapping of Metal-Rich Ejecta in Bright Supernova Remnants.

    Science.gov (United States)

    Schenck, Andrew; Park, Sangwook; Bhalerao, Jayant; Post, Seth; Alan, Neslihan; Abualfoul, Mujahed

    2015-01-01

    We apply our adaptive mesh technique coupled with simple automated NEI spectral modelings for archival Chandra data of several bright supernova remnants (SNRs) DEML71, N132D, E0102-72.3, G292.0+1.8, G299.2-2.9, Kepler, and Tycho. Based on the chi-square distributions of these model fits, we identify regions in which metal elements are enhanced compared to the circumstellar/interstellar abundances, and thus map over-abundant ejecta regions throughout these SNRs. With these maps we also reveal spatial structures of the individual ejecta elements O, Ne, Mg, Si, and Fe. We find that this simple chi-square mapping is effective to study spatial distributions of ejecta elements without performing extensive spectral model fits for individual sub-regions in SNRs. These ejecta maps may also be useful to reveal global structures such as the contact discontinuity. We present our preliminary results demonstrating the utility of this method.

  20. A study of optical observing techniques for extra-galactic supernova remnants: Case of NGC300

    Directory of Open Access Journals (Sweden)

    Millar W.C.

    2012-01-01

    Full Text Available We present the results of a study of observational and identification techniques used for surveys and spectroscopy of candidate supernova remnants (SNRs in the Sculptor Group galaxy NGC300. The goal of this study was to investigate the reliability of using [Sii]:H? ? 0.4 in optical SNR surveys and spectra as an identifying feature of extra-galactic SNRs (egSNRs, and also to investigate the effectiveness of the observing techniques (which are hampered by seeing conditions and telescope pointing errors using this criterion in egSNR surveys and spectrographs. This study is based on original observations of these objects and archival data obtained from the Hubble Space Telescope which contained images of some of the candidate SNRs in NGC300. We found that the reliability of spectral techniques may be questionable and very high-resolution images may be needed to confirm a valid identification of some egSNRs.

  1. Spectral and morphological analysis of the remnant of Supernova 1987A with ALMA & ATCA

    CERN Document Server

    Zanardo, Giovanna; Indebetouw, Remy; Chevalier, Roger A; Matsuura, Mikako; Gaensler, Bryan M; Barlow, Michael J; Fransson, Claes; Manchester, Richard N; Baes, Maarten; Kamenetzky, Julia R; Lakicevic, Masha; Lundqvist, Peter; Marcaide, Jon M; Marti-Vidal, Ivan; Meixner, Margaret; Ng, C -Y; Park, Sangwook; Sonneborn, George; Spyromilio, Jason; van Loon, Jacco Th

    2014-01-01

    We present a comprehensive spectral and morphological analysis of the remnant of Supernova (SN) 1987A with the Australia Telescope Compact Array (ATCA) and the Atacama Large Millimeter/submillimeter Array (ALMA). The non-thermal and thermal components of the radio emission are investigated in images from 94 to 672 GHz ($\\lambda$ 3.2 mm to 450 $\\mu$m), with the assistance of a high-resolution 44 GHz synchrotron template from the ATCA, and a dust template from ALMA observations at 672 GHz. An analysis of the emission distribution over the equatorial ring in images from 44 to 345 GHz highlights a gradual decrease of the east-to-west asymmetry ratio with frequency. We attribute this to the shorter synchrotron lifetime at high frequencies. Across the transition from radio to far infrared, both the synchrotron/dust-subtracted images and the spectral energy distribution (SED) suggest additional emission beside the main synchrotron component ($S_{\

  2. XMM and Chandra Spectroscopy of the Brightest Supernova Remnants in M33

    Science.gov (United States)

    Plucinsky, Paul

    2014-11-01

    We present a spectral analysis of the X-ray brightest Supernova Remnants (SNRs) in the nearby, spiral galaxy M33 from our deep XMM-Newton survey that complements our previous survey with Chandra (ChASeM33) by covering the entire galaxy. We have simultaneously fit the XMM and Chandra spectra (when available) to better constrain the fitted parameters. We do not find any young (t<1,000 yr) SNRs that could be analogs of Cas A or the Crab, but we find several older SNRs that show evidence of enhanced abundances. These bright X-ray SNRs appear to occur in regions with a higher than average ISM density, assuming they are in the Sedov phase. We include the first detailed spectral analysis of the third most luminous X-ray SNR in M33, which was outside the ChASeM33 survey area.

  3. The second epoch Molonglo Galactic Plane Survey: images and candidate supernova remnants

    CERN Document Server

    Green, A J; Murphy, T

    2014-01-01

    The second epoch Molonglo Galactic Plane Survey (MGPS-2) covers the area bounded by 245deg < Galactic longitude < 365deg and Galactic latitude < |10|deg, at a frequency of 843 MHz and an angular resolution of 45" x 45" cosec(Dec.). The sensitivity varies between 1 - 2 mJy/beam depending on the presence of strong extended sources. This survey is currently the highest resolution and most sensitive large-scale continuum survey of the southern Galactic Plane. In this paper, we present the images of the complete survey, including postage stamps of some new supernova remnant (SNR) candidates and a discussion of the highly structured features detected in the interstellar medium. The intersection of these two types of features is discussed in the context of the "missing" SNR population in the Galaxy.

  4. Detection of class I methanol (CH3OH) maser candidates in supernova remnants

    International Nuclear Information System (INIS)

    We have used the Karl G. Jansky Very Large Array to search for 36 GHz and 44 GHz methanol (CH3OH) lines in a sample of 21 Galactic supernova remnants (SNRs). Mainly the regions of the SNRs with 1720 MHz OH masers were observed. Despite the limited spatial extent covered in our search, methanol masers were detected in both G1.4–0.1 and W28. Additional masers were found in Sgr A East. More than 40 masers were found in G1.4–0.1, which we deduce are due to interactions between the SNR and at least two separate molecular clouds. The six masers in W28 are associated with the molecular cloud that is also associated with the OH maser excitation. We discuss the possibility that the methanol maser may be more numerous in SNRs than the OH maser, but harder to detect due to observational constraints.

  5. The Evolution of Adiabatic Supernova Remnants in a Turbulent, Magnetized Medium

    CERN Document Server

    Balsara, D; Cox, D P; Balsara, Dinshaw; Benjamin, Robert A.; Cox, Donald P.

    2001-01-01

    (Abridged) We present the results of three dimensional calculations for the MHD evolution of an adiabatic supernova remnant in both a uniform and turbulent interstellar medium using the RIEMANN framework of Balsara. In the uniform case, which contains an initially uniform magnetic field, the density structure of the shell remains largely spherical, while the magnetic pressure and synchrotron emissivity are enhanced along the plane perpendicular to the field direction. This produces a bilateral or barrel-type morphology in synchrotron emission for certain viewing angles. We then consider a case with a turbulent external medium as in Balsara & Pouquet, characterized by $v_{A}(rms)/c_{s}=2$. Several important changes are found. First, despite the presence of a uniform field, the overall synchrotron emissivity becomes approximately spherically symmetric, on the whole, but is extremely patchy and time-variable, with flickering on the order of a few computational time steps. We suggest that the time and spatial...

  6. A Study of Optical Observing Techniques for Extra-Galactic Supernova Remnants: Case of NGC 300

    CERN Document Server

    Millar, William C; Filipovic, Miroslav D

    2012-01-01

    We present the results of a study of observational and identification techniques used for surveys and spectroscopy of candidate supernova remnants (SNRs) in the Sculptor Group galaxy NGC 300. The goal of this study was to investigate the reliability of using [Sii]/Halpha > 0.4 in optical SNR surveys and spectra as an identifying feature of extra-galactic SNRs (egSNRs) and also to investigate the effectiveness of the observing techniques (which are hampered by seeing conditions and telescope pointing errors) using this criterion in egSNR surveys and spectrographs. This study is based on original observations of these objects and archival data obtained from the Hubble Space Telescope which contained images of some of the candidate SNRs in NGC 300. We found that the reliability of spectral techniques may be questionable and very high-resolution images may be needed to confirm a valid identification of some egSNRs.

  7. SOFT X-RAY SPECTROSCOPY OF THE CYGNUS LOOP SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    We present the results of a suborbital rocket flight whose scientific target was the Cygnus Loop Supernova Remnant. The payload consists of wire grid collimators, off-plane grating arrays, and gaseous electron multiplier (GEM) detectors. The system is designed for spectral measurements in the 17-107 Å bandpass with a resolution up to ?60 (?/??). The Extended X-ray Off-plane Spectrometer (EXOS) was launched on a Terrier-Black Brant rocket on 2009 November 13 from White Sands Missile Range and obtained 340 s of useable scientific data. The X-ray emission is dominated by O VII and O VIII, including the He-like O VII triplet at ?22 Å. Another emission feature at ?45 Å is composed primarily of Si XI and Si XII. The best-fit model to this spectrum is an equilibrium plasma model at a temperature of log(T) = 6.4 (0.23 keV).

  8. Instabilities and the adiabatic and isothermal blast wave models for supernova remnants

    International Nuclear Information System (INIS)

    Isenberg as well as lerche and Vasyliunas proposed the existence of an instability to radial perturbations in adiabatic and isothermal models of self-similar supernova blast waves. Their derivations fail to impose the physical conservation laws at the shock (i.e., the Rankine-Hugoniot jump conditions) as boundary conditions, and their claim of an instability is unsubstantiated. Although as analytic demonstration of the stability of the adiabatic self-similar solution does not presently exist, the cumulative result of three decades of gas dynamic experimentation and numerical simulation provides unmistakable evidence for the stabilty of self-similar blast waves

  9. Prediction of the diffuse neutrino flux from cosmic ray interactions near supernova remnants

    Science.gov (United States)

    Mandelartz, Matthias; Becker Tjus, Julia

    2015-05-01

    In this paper, we present high-energy neutrino spectra from 21 Galactic supernova remnants (SNRs), derived from gamma-ray measurements in the GeV-TeV range. We find that only the strongest sources, i.e. G40.5-0.5 in the north and Vela Junior in the south could be detected as single point sources by IceCube or KM3NeT, respectively. For the first time, it is also possible to derive a diffuse signal by applying the observed correlation between gamma-ray emission and radio signal. Radio data from 234 supernova remnants listed in Green's catalog are used to show that the total diffuse neutrino flux is approximately a factor of 2.5 higher compared to the sources that are resolved so far. We show that the signal at above 10 TeV energies can actually become comparable to the diffuse neutrino flux component from interactions in the interstellar medium. Recently, the IceCube collaboration announced the detection of a first diffuse signal of astrophysical high-energy neutrinos. Directional information cannot unambiguously reveal the nature of the sources at this point due to low statistics. A number of events come from close to the Galactic center and one of the main questions is whether at least a part of the signal can be of Galactic nature. In this paper, we show that the diffuse flux from well-resolved SNRs is at least a factor of 20 below the observed flux.

  10. SUBARU HIGH-RESOLUTION SPECTROSCOPY OF STAR G IN THE TYCHO SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    It is widely believed that Type Ia supernovae (SNe Ia) originate in binary systems where a white dwarf accretes material from a companion star until its mass approaches the Chandrasekhar mass and carbon is ignited in the white dwarf's core. This scenario predicts that the donor star should survive the supernova (SNe) explosion, providing an opportunity to understand the progenitors of SNe Ia. In this paper, we argue that rotation is a generic signature expected of most nongiant donor stars that is easily measurable. Ruiz-Lapuente et al. examined stars in the center of the remnant of SN 1572 (Tycho SN) and showed evidence that a subgiant star (Star G by their naming convention) near the remnant's center was the system's donor star. We present high-resolution (R ? 40, 000) spectra taken with the High Dispersion Spectrograph on Subaru of this candidate donor star and measure the star's radial velocity as 79 ± 2 km s-1 with respect to the local standard of rest and put an upper limit on the star's rotation of 7.5 km s-1. In addition, by comparing images that were taken in 1970 and 2004, we measure the proper motion of Star G to be ? l = -1.6 ± 2.1 mas yr-1 and ? b = -2.7 ± 1.6 mas yr-1. We demonstrate that all of the measured properties of Star G presented in this paper are consistent with those of a star in the direction of Tycho SN that is not associated with the SN event. However, we discuss an unSN event. However, we discuss an unlikely, but still viable scenario for Star G to be the donor star, and suggest further observations that might be able to confirm or refute it.

  11. NONTHERMAL EMISSION FROM MIDDLE-AGED SUPERNOVA REMNANTS INTERACTING WITH MOLECULAR CLOUDS

    International Nuclear Information System (INIS)

    Supernova remnants (SNRs) interacting with dense molecular clouds (MCs) are proven to be bright ?-ray emitters by recent observations in the GeV-TeV band. We theoretically investigate the multiband radiative properties of the four middle-aged SNRs IC443, W51C, W28, and W44 with a time-dependent injection model. In the model, part of the SNR shell transports into a dense MC, with the other part of the shell evolving in a relatively tenuous interstellar medium. We find a broken power law with a break energy of ?3-40 GeV that must be imposed to reproduce the observed multiwavelength spectra for the four remnants. The results indicate that the observed ?-ray spectra can be reproduced as a p-p interaction of the high-energy protons injected by the shell interacting with the MC with the dense matter, whereas the radio emission is produced via synchrotron radiation of the injected electrons from the other part of the shell for the four middle-aged SNRs.

  12. Radio-continuum emission from the young galactic supernova remnant G1.9+0.3

    Directory of Open Access Journals (Sweden)

    de Horta A.Y.

    2014-01-01

    Full Text Available We present an analysis of a new Australia Telescope Compact Array (ATCA radio-continuum observation of supernova remnant (SNR G1.9+0.3, which at an age of ~181±25 years is the youngest known in the Galaxy. We analysed all available radio-continuum observations at 6-cm from the ATCA and Very Large Array. Using this data we estimate an expansion rate for G1.9+0.3 of 0.563%±0.078% per year between 1984 and 2009. We note that in the 1980's G1.9+0.3 expanded somewhat slower (0.484% per year than more recently (0.641% per year. We estimate that the average spectral index between 20-cm and 6-cm, across the entire SNR is ?={0.72±0.26 which is typical for younger SNRs. At 6-cm, we detect an average of 6% fractionally polarised radio emission with a peak of 17%§3%. The polarised emission follows the contours of the strongest of X-ray emission. Using the new equipartition formula we estimate a magnetic field strength of B?273?G, which to date, is one of the highest magnetic field strength found for any SNR and consistent with G1.9+0.3 being a very young remnant.

  13. Discovery of a VHE gamma-ray source coincident with the supernova remnant CTB 37A

    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; 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; Gallant, Y A; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, 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; Nakajima, H; 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; Reimer, O; Renaud, M; Rieger, F; 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; Tibolla, O; 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 supernova remnant (SNR) complex CTB 37 is an interesting candidate for observations with Very High Energy (VHE) gamma-ray telescopes such as H.E.S.S. In this region, three SNRs are seen. One of them is potentially associated with several molecular clouds, a circumstance that can be used to probe the acceleration of hadronic cosmic rays. This region was observed with the H.E.S.S. Cherenkov telescopes and the data were analyzed with standard H.E.S.S. procedures. Recent X-ray observations with Chandra and XMM-Newton were used to search for X-ray counterparts. The discovery of a new VHE gamma-ray source HESS J1714-385 coincident with the remnant CTB 37A is reported. The energy spectrum is well described by a power-law with a photon index of Gamma =2.30pm0.13 and a differential flux at 1 TeV of Phi_0 = (8.7 pm 1.0_{stat} pm 1.8_{sys})x10^{-13}cm^{-2}s^{-1}TeV^{-1}. The integrated flux above 1 TeV is equivalent to 3% of the flux of the Crab nebula above the same energy. This VHE gamma-ray source is a counterpar...

  14. Evidence of a Curved Synchrotron Spectrum in the Supernova Remnant SN 1006

    CERN Document Server

    Allen, G E; Sturner, S J

    2008-01-01

    A joint spectral analysis of some Chandra ACIS X-ray data and Molonglo Observatory Synthesis Telescope radio data was performed for 13 small regions along the bright northeastern rim of the supernova remnant SN 1006. These data were fitted with a synchrotron radiation model. The nonthermal electron spectrum used to compute the photon emission spectra is the traditional exponentially cut off power law, with one notable difference: The power-law index is not a constant. It is a linear function of the logarithm of the momentum. This functional form enables us to show, for the first time, that the synchrotron spectrum of SN 1006 seems to flatten with increasing energy. The effective power-law index of the electron spectrum is 2.2 at 1 GeV (i.e., radio synchrotron-emitting momenta) and 2.0 at about 10 TeV (i.e., X-ray synchrotron-emitting momenta). This amount of change in the index is qualitatively consistent with theoretical models of the amount of curvature in the proton spectrum of the remnant. The evidence of...

  15. Radio Detection of A Candidate Neutron Star Associated with Galactic Center Supernova Remnant Sagittarius A East

    CERN Document Server

    Zhao, Jun-Hui; Goss, W M

    2013-01-01

    We report the VLA detection of the radio counterpart of the X-ray object referred to as the "Cannonball", which has been proposed to be the remnant neutron star resulting from the creation of the Galactic Center supernova remnant, Sagittarius A East. The radio object was detected both in our new VLA image from observations in 2012 at 5.5 GHz and in archival VLA images from observations in 1987 at 4.75 GHz and in the period from 1990 to 2002 at 8.31 GHz. The radio morphology of this object is characterized as a compact, partially resolved point source located at the northern tip of a radio "tongue" similar to the X-ray structure observed by Chandra. Behind the Cannonball, a radio counterpart to the X-ray plume is observed. This object consists of a broad radio plume with a size of 30\\arcsec$\\times$15\\arcsec, followed by a linear tail having a length of 30\\arcsec. The compact head and broad plume sources appear to have relatively flat spectra ($\\propto\

  16. The properties of non-thermal X-ray filaments in young supernova remnants

    Science.gov (United States)

    Rettig, R.; Pohl, M.

    2012-09-01

    Context. Young supernova remnants (SNRs) exhibit narrow filaments of non-thermal X-ray emission whose widths can be limited either by electron energy losses or damping of the magnetic field. Aims: We want to investigate whether or not different models of these filaments can be observationally tested. Methods: Using observational parameters of four historical remnants, we calculated the filament profiles and compared the spectra of the filaments with those of the total non-thermal emission. For that purpose, we solved a one-dimensional stationary transport equation for the isotropic differential number density of the electrons. Results: We find that the difference between the spectra of filament and total non-thermal emission above 1 keV is more pronounced in the damping model than in the energy-loss model. Conclusions: A considerable damping of the magnetic field can result in an observable difference between the spectra of filament and total non-thermal emission, thus potentially permitting an observational discrimination between the energy-loss model and the damping model of the X-ray filaments.

  17. The properties of non-thermal X-ray filaments in young supernova remnants

    CERN Document Server

    Rettig, Robert

    2012-01-01

    Context. Young supernova remnants (SNRs) exhibit narrow filaments of non-thermal X-ray emission whose widths can be limited either by electron energy losses or damping of the magnetic field. Aims. We want to investigate whether or not different models of these filaments can be observationally tested. Methods. Using observational parameters of four historical remnants, we calculate the filament profiles and compare the spectra of the filaments with those of the total non-thermal emission. For that purpose, we solve an one-dimensional stationary transport equation for the isotropic differential number density of the electrons. Results. We find that the difference between the spectra of filament and total non-thermal emission above 1 keV is more pronounced in the damping model than in the energy-loss model. Conclusions. A considerable damping of the magnetic field can result in an observable difference between the spectra of filament and total non-thermal emission, thus potentially permitting an observational di...

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

    CERN Document Server

    Temim, Tea; 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 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 oriente...

  19. Late-time Evolution of Composite Supernova Remnants: Deep Chandra Observations and Hydrodynamical Modeling of a Crushed Pulsar Wind Nebula in SNR G327.1-1.1

    CERN Document Server

    Temim, Tea; Kolb, Christopher; Blondin, John; Hughes, John P; Bucciantini, Niccolo

    2015-01-01

    In an effort to better understand the evolution of composite supernova remnants (SNRs) and the eventual fate of relativistic particles injected by their pulsars, we present a multifaceted investigation of the interaction between a pulsar wind nebula (PWN) and its host SNR G327.1-1.1. Our 350 ks Chandra X-ray observations of SNR G327.1-1.1 reveal a highly complex morphology; a cometary structure resembling a bow shock, prong-like features extending into large arcs in the SNR interior, and thermal emission from the SNR shell. Spectral analysis of the non-thermal emission offers clues about the origin of the PWN structures, while enhanced abundances in the PWN region provide evidence for mixing of supernova ejecta with PWN material. The overall morphology and spectral properties of the SNR suggest that the PWN has undergone an asymmetric interaction with the SNR reverse shock (RS) that can occur as a result of a density gradient in the ambient medium and/or a moving pulsar that displaces the PWN from the center ...

  20. Equation-of-State Dependent Features in Shock-Oscillation Modulated Neutrino and Gravitational-Wave Signals from Supernovae

    CERN Document Server

    Marek, A; Müller, E

    2008-01-01

    We present 2D hydrodynamic simulations of the long-time accretion phase of a 15 solar mass star after core bounce and before the launch of a supernova explosion. Our simulations are performed with the Prometheus-Vertex code, employing multi-flavor, energy-dependent neutrino transport and an effective relativistic gravitational potential. Testing the influence of a stiff and a soft equation of state for hot neutron star matter, we find that the non-radial mass motions in the supernova core due to the standing accretion shock instability (SASI) and convection impose a time variability on the neutrino and gravitational-wave signals. These variations have larger amplitudes as well as higher frequencies in the case of a more compact nascent neutron star. After the prompt shock-breakout burst of electron neutrinos, a more compact accreting remnant radiates neutrinos with higher luminosities and larger mean energies. The observable neutrino emission in the direction of SASI shock oscillations exhibits a modulation o...