WorldWideScience

Sample records for supernova remnant shock

  1. Reverse-Shock in Tycho's Supernova Remnant

    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.

  2. Particle acceleration by shocks in supernova remnants

    Bell, A R

    2013-01-01

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

  3. Shock Destruction of Dust in Supernova Remnants

    Shull, J.

    2009-07-01

    In this AR-Theory program, we propose to carry out a series of investigations of grain injection, transport, and destruction using hydrodynamical models of reverse-shocked SN ejecta. In a young supernova remnant {SNR} such as Cas A or SN 1987A the outer blast wave strikes surrounding circumstellar matter, and reverse shocks propagate inward toward the interior debris, which may contain large amounts of newly formed dust. Our major theoretical goals are to determine how much dust is destroyed in shocked SNR ejecta, as they are decelerated by the reverse shocks, and to study how these ejecta are lighted up in optical, X-ray, andIR line emission. Numerical codes will be used to study grain destruction in metal-enriched ejecta and to interpret the morphologies, proper motions, and emissivities of these fast-moving ejecta, observed by Hubble in many young SNRs. We intend to undertake the following tasks: {1} Compile the latest gas-grain data {sputtering yields vs projectile energy for H, He, and heavy ions}; {2} Incorporate gas-grain and grain-grain interactions with radiative cooling rates {X-ray, optical, IR line emission} of sputtered atoms and ions; {3} Compute adaptive-mesh hydrodynamical models of ejecta-shock interactions; {4} Use these ejecta models to compute grain destruction, grain heating, plasma cooling, and spectral diagnostics in metal-enriched environments; {5} Apply our results to specific SNRs {Cas A, SN 1987A, G292, etc} to interpret ejecta morphologies, proper motions, and emissivities; {6} assess the net efficiency of supernova dust injection.

  4. Cosmic Ray Spectrum in Supernova Remnant Shocks

    Kang, Hyesung

    2010-01-01

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

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

    T. W. Jones

    2011-12-01

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

  6. Shock evolution in non-radiative supernova remnants

    Tang, Xiaping

    2016-01-01

    We present a new analytical approach to derive approximate solutions describing the shock evolution in non-radiative supernova remnants (SNRs). We focus on the study of the forward shock; applications to the reverse shock are also discussed briefly. The spherical shock evolution of a SNR in both the interstellar medium with a constant density profile and a circumstellar medium with a wind density profile is studied. The new solution is significantly simplified compared to previous analytical models, e.g. Truelove&McKee 1999, as it only depends on the asymptotic behaviors of the remnant during its evolution. We compare our new analytical solution with both numerical simulations and previous analytical models, finding that a few percent accuracy is achieved. For a uniform ambient medium, the accuracy of our analytical approximation is comparable with that in Truelove&McKee 1999. For a wind density profile medium, our solution performs better, especially when the ejecta envelope has a steep density profi...

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

    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.

  8. The Role of Diffusive Shock Acceleration on Nonequilibrium Ionization in Supernova Remnant Shocks II: Emitted Spectra

    Patnaude, Daniel J.; Slane, Patrick; Raymond, John C.; Ellison, Donald C.

    2010-01-01

    We present a grid of nonequilibrium ionization models for the X-ray spectra from supernova remnants undergoing efficient diffusive shock acceleration. The calculation follows the hydrodynamics of the blast wave as well as the time-dependent ionization of the plasma behind the shock. The ionization state is passed to a plasma emissivity code to compute the thermal X-ray emission, which is combined with the emission from nonthermal synchrotron emission to produce a self-consistent model for the...

  9. Supernova remnants and their supernovae

    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

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

    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.

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

    Anderl, S; Güsten, R

    2014-01-01

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

  12. The Role of Diffusive Shock Acceleration on Nonequilibrium Ionization in Supernova Remnant Shocks II: Emitted Spectra

    Patnaude, Daniel J; Raymond, John C; Ellison, Donald C

    2010-01-01

    We present a grid of nonequilibrium ionization models for the X-ray spectra from supernova remnants undergoing efficient diffusive shock acceleration. The calculation follows the hydrodynamics of the blast wave as well as the time-dependent ionization of the plasma behind the shock. The ionization state is passed to a plasma emissivity code to compute the thermal X-ray emission, which is combined with the emission from nonthermal synchrotron emission to produce a self-consistent model for the thermal and nonthermal emission from cosmic-ray dominated shocks. We show how plasma diagnostics such as the G'-ratio of He-like ions, defined as the ratio of the sum of the intercombination, forbidden, and satellite lines to the resonance line, can vary with acceleration efficiency, and discuss how the thermal X-ray emission, when the time-dependent ionization is not calculated self-consistently with the hydrodynamics, can differ from the thermal X-ray emission from models which do account for the hydrodynamics. Finally...

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

    Morlino, G.; P. Blasi(INAF Arcetri); 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 o...

  14. Molecular and Ionic shocks in the Supernova Remnant 3C391

    Reach, William T.; Rho, Jeonghee; Jarrett, T. H.; Lagage, Pierre-Olivier

    2001-01-01

    New observations of the supernova remnant 3C391 are in the H2 2.12 micron and [Fe II] 1.64 micron narrow-band filters at the Palomar 200-inch telescope, and in the 5-15 micron CVF on ISOCAM. Shocked H2 emission was detected from the region 3C391:BML, where broad millimeter CO and CS lines had previously been detected. A new H2 clump was confirmed to have broad CO emission, demonstrating that the near-infrared H2 images can trace previously undetected molecular shocks. The [Fe II] emission has...

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

    Micelotta, Elisabetta R; Slavin, Jonathan D

    2016-01-01

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

  16. H$\\alpha$ Imaging spectroscopy of Balmer-dominated shocks in Tycho's supernova remnant

    Knežević, Sladjana; van de Ven, Glenn; Font, Joan; Raymond, John C; Ghavamian, Parviz; Beckman, John

    2016-01-01

    We present Fabry-P\\'erot interferometric observations of the narrow H$\\alpha$ component in the shock front of the historical supernova remnant Tycho (SN 1572). Using GH$\\alpha$FaS (Galaxy H$\\alpha$ Fabry-P\\'erot Spectrometer) on the William Herschel Telescope, we observed a great portion of the shock front in the northeastern (NE) region of the remnant. The angular resolution of $\\sim$1$^{\\prime\\prime}$ and spectral resolving power of R$\\sim$21 000 together with the large field-of-view (3.4$^{\\prime}$ $\\times$ 3.4$^{\\prime}$) of the instrument allow us to measure the narrow H$\\alpha$-line width in 73 bins across individual parts of the shock simultaneously and thereby study the indicators of several shock precursors in a large variety of shock front conditions. Compared to previous studies, the detailed spatial resolution of the filament also allows us to mitigate possible artificial broadening of the line from unresolved differential motion and projection. Covering one quarter of the remnant's shell, we conf...

  17. Molecular and Ionic shocks in the Supernova Remnant 3C391

    Reach, W T; Jarrett, T H; Lagage, P O; Reach, William T.; Rho, Jeonghee; Lagage, Pierre-Olivier

    2001-01-01

    New observations of the supernova remnant 3C391 are in the H2 2.12 micron and [Fe II] 1.64 micron narrow-band filters at the Palomar 200-inch telescope, and in the 5-15 micron CVF on ISOCAM. Shocked H2 emission was detected from the region 3C391:BML, where broad millimeter CO and CS lines had previously been detected. A new H2 clump was confirmed to have broad CO emission, demonstrating that the near-infrared H2 images can trace previously undetected molecular shocks. The [Fe II] emission has a significantly different distribution, being brightest in the bright radio bar, at the interface between the supernova remnant and the giant molecular cloud, and following filaments in the radio shell. The near-infrared [Fe II] and the mid-infrared 12-18 micron filter images are the first images to reveal the radiative shell of 3C391. The mid-infrared spectrum is dominated by bright ionic lines and H2 S(2) through S(7). There are no aromatic hydrocarbons associated with the shocks, nor is their any mid-infrared continuu...

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

    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...

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

    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 ...

  20. Progress on multi-waveband observations of supernova remnants

    Yang, Xuejuan; Lu, FangJun; Tian, Wenwu

    2008-01-01

    The development of observational techniques has inriched our knowledge of supernova remnants. In this paper, we review the main progresses in the last decade, including new discoveries of supernova remnants and the associated (rare type of) pulsars, nucleosynthesis, the interaction between supernova remnants and molecular clouds, dust in the supernova remnants, shock physics, and cosmic ray accelerations.

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

    Petruk, O; Beshley, V

    2015-01-01

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

  2. Detailed studies of shock-cloud interaction toward the young supernova remnants

    Sano, H.; Fukui, Y.

    2016-06-01

    In young supernova remnants (SNRs; ˜2000 yrs), the study of the interaction between the shock waves and the inhomogeneous interstellar gas is a key element in understanding the SNR evolution, cosmic-ray acceleration, and multi-wavelength emission. In particular, TeV γ-ray and synchrotron X-ray bright SNRs, RX J1713.7-3946, RX J0852.0-4622, and N132D have been considered good candidates for an efficient cosmic-ray accelerator via shock-cloud interaction (Sano et al. 2013, 2015a; Fukui 2013). In RXJ1713, we performed imaging and spectral analysis of the Suzaku X-rays and compared it with the interstellar gas distribution (Sano et al. 2013; 2015b). The shock interaction with dense gas clumps enhances turbulence and magnetic fields up to mG around the clumps, which was observed as limb-brightening of the synchrotron X-rays and hard spectra with photon indexes of less than 2.4. Moreover, turbulence and magnetic field amplifications may promote an additional acceleration of cosmic-ray electrons. In contrast, the synchrotron X-rays also become bright toward diffuse gas regions due to the high shock velocity. In this talk, we introduce the recent results of shock-cloud interaction toward RX J1713.7-3946, RX J0852.0-4622, and N132D using the Suzaku, XMM-Newton, Chandra X-rays, and interstellar gas datasets.

  3. Infrared analysis of supernova remnants

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

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

    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...

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

    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.

  6. Supernova Remnants in High Definition

    Slane, Patrick; Badenes, Carles; Freyer, Chris; Hughes, Jack; Lee, Herman Shiu-Hang; Lopez, Laura; Patnaude, Daniel; Reynolds, Steve; Temim, Tea; Williams, Brian; Wongwathanarat, Annop; Yamaguchi, Hiroya

    2015-01-01

    As the observable products of explosive stellar death, supernova remnants reveal some of the most direct information on the physics of the explosions, the properties of the progenitor systems, and the demographics of compact objects formed in the supernova events. High sensitivity X-ray observations have allowed us to probe the properties of the shocked plasma, providing constraints on abundances and ionization states that connect directly progenitor masses and metallicities, the nature of th...

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

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

    2016-01-01

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

  8. Supernova remnants and the ISM

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

  9. Time dependent diffusive shock acceleration and its application to middle aged supernova remnants

    Tang, Xiaping

    2016-01-01

    Recent gamma-ray observations show that middle aged supernova remnants (SNRs) interacting with molecular clouds (MCs) can be sources of both GeV and TeV emission. Based on the MC association, two scenarios have been proposed to explain the observed gamma-ray emission. In one, energetic cosmic ray (CR) particles escape from the SNR and then illuminate nearby MCs, producing gamma-ray emission, while the other involves direct interaction between the SNR and MC. In the direct interaction scenario, re-acceleration of pre-existing CRs in the ambient medium is investigated while particles injected from the thermal pool are neglected in view of the slow shock speeds in middle aged SNRs. However, standard diffusive shock acceleration (DSA) theory 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 re-acceleration of...

  10. A GENERALIZED MODEL OF NONLINEAR DIFFUSIVE SHOCK ACCELERATION COUPLED TO AN EVOLVING SUPERNOVA REMNANT

    Lee, Shiu-Hang; Nagataki, Shigehiro [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Ellison, Donald C., E-mail: lee@yukawa.kyoto-u.ac.jp, E-mail: nagataki@yukawa.kyoto-u.ac.jp, E-mail: don_ellison@ncsu.edu [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States)

    2012-05-10

    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 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; (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. Our generalized code combines these elements and describes the interplay between CR production and SNR evolution, including the nonlinear coupling of efficient diffusive shock acceleration, based mainly on the work of P. Blasi and coworkers, and a non-equilibrium ionization (NEI) calculation of thermal X-ray line emission. We believe that our generalized model will provide a consistent modeling platform for SNRs, including those interacting with molecular clouds, and improve the interpretation of current and future observations, including the high-quality spectra expected from Astro-H. SNR RX J1713.7-3946 is modeled as an example.

  11. Nonrelativistic Perpendicular Shocks Modeling Young Supernova Remnants: Nonstationary Dynamics and Particle Acceleration at Forward and Reverse Shocks

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

    2016-03-01

    For parameters that are applicable to the conditions at young supernova remnants, we present results of two-dimensional, three-vector (2D3V) particle-in-cell simulations of a non-relativistic plasma shock with a large-scale perpendicular magnetic field inclined at a 45^\\circ angle to the simulation plane to approximate three-dimensional (3D) physics. We developed an improved clean setup that uses the collision of two plasma slabs with different densities and velocities, leading to the development of two distinctive shocks and a contact discontinuity. The shock formation is mediated by Weibel-type filamentation instabilities that generate magnetic turbulence. Cyclic reformation is observed in both shocks with similar period, for which we note global variations due to shock rippling and local variations arising from turbulent current filaments. The shock rippling occurs on spatial and temporal scales produced by the gyro-motions of shock-reflected ions. The drift motion of electrons and ions is not a gradient drift, but is commensurate with {\\boldsymbol{E}}× {\\boldsymbol{B}} drift. We observe a stable supra-thermal tail in the ion spectra, but no electron acceleration because the amplitude of the Buneman modes in the shock foot is insufficient for trapping relativistic electrons. We see no evidence of turbulent reconnection. A comparison with other two-dimensional (2D) simulation results suggests that the plasma beta and the ion-to-electron mass ratio are not decisive for efficient electron acceleration, but the pre-acceleration efficacy might be reduced with respect to the 2D results once 3D effects are fully accounted for. Other microphysical factors may also play a part in limiting the amplitude of the Buneman waves or preventing the return of electrons to the foot region.

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

    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.

  13. FISICA Integral Field Spectroscopy of the Shocked Iron Gas in the Supernova Remnant G11.2--0.3

    Moon, Dae-Sik; Eikenberry, Stephen S.; Koo, Bon-Chul; Raines, S. Nicholas; Gruel, Nicolas

    2006-02-01

    We have recently discovered strong iron line ([Fe II] (lambda)1.644 (mu)m) emission in the young supernova remnant G11.2-0.3. The iron line emission occurs at the south-eastern shell edge of G11.2-0.3, and positionally overlaps with the very strong X-ray and radio emission of the supernova remnant. The iron line emission is most likely caused by the shock acceleration of G11.2-0.3 interacting with the ambient medium. We propose to carry out JH-band integral-field spectroscopy of the two iron line clumps in G11.2-0.3 with FISICA, an image-slicing integral-field unit for FLAMINGOS, which will give us a uniquely comprehensive view of the strong shock acceleration of a SNR.

  14. Radio emission from Supernova Remnants

    Dubner, Gloria

    2015-01-01

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

  15. Progenitors of Recombining Supernova Remnants

    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 superno...

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

    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.

  17. Environmental impact of Supernova Remnants

    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.

  18. Radio Emission from Supernova Remnants: Implications for Post-Shock Magnetic Field Amplification and the Magnetic Fields of Galaxies

    Thompson, Todd A; Murray, Norman

    2009-01-01

    Using observations from the literature, we show that the non-thermal radio luminosity (L) of supernova remnants (SNRs) is a strong function of the average gas surface density (Sigma) of the galaxy in which the remnants reside, from normal spirals to luminous starbursts. We combine a simple theory for electron cooling in SNRs with the observed radio luminosities to estimate the remnant magnetic field strength (B_SNR): the correlation between L and Sigma implies that B_SNR also increases with Sigma. We explore two interpretations of this correlation: (1) B_SNR is generated by post-shock magnetic field amplification, with B_SNR^2 proportional to Sigma and (2) B_SNR results from shock-compression of the ambient ISM magnetic field (B_ISM), with B_ISM being larger in denser galaxies. We find that shock compression is, on average, sufficient to produce the observed radio emission from SNRs in the densest starbursts; amplification of post-shock magnetic fields is not required. By contrast, in normal spirals post-shoc...

  19. Supernova Remnants in High Definition

    Slane, Patrick; Badenes, Carles; Freyer, Chris; Hughes, Jack; Lee, Herman Shiu-Hang; Lopez, Laura; Patnaude, Daniel; Reynolds, Steve; Temim, Tea; Williams, Brian; Wongwathanarat, Annop; Yamaguchi, Hiroya

    2015-10-01

    As the observable products of explosive stellar death, supernova remnants reveal some of the most direct information on the physics of the explosions, the properties of the progenitor systems, and the demographics of compact objects formed in the supernova events. High sensitivity X-ray observations have allowed us to probe the properties of the shocked plasma, providing constraints on abundances and ionization states that connect directly progenitor masses and metallicities, the nature of the explosions (core-collapse vs. thermonuclear), and the physics of shock heating and particle acceleration in fast shocks. Studies of SNRs in the Magellanic Clouds have provided information on source demographics in a low metallicity environment, and deep searches for point sources in Galactic SNRs imply that many remnants contain rapidly cooling neutron stars or black holes. Based on Chandra observations, we know that crucial measurements required to advance our knowledge in these areas are possible only with much more sensitive observations at high angular resolution. From identifying the effects of particle acceleration on the post-shock gas in young SNRs like Tycho to obtaining spatially resolved spectra - and identifying compact objects - for young SNRs in the Magellanic Clouds, the capabilities of a facility like the X-ray Surveyor are required. Here I present a summary of recent advances brought about by spectral investigations of SNRs, and discuss particular examples of new advances that will be enabled by X-ray Surveyor capabilities.

  20. Time-dependent shock acceleration of particles. Effect of the time-dependent injection, with application to supernova remnants

    Petruk, Oleh

    2016-01-01

    Three approaches are considered to solve the equation which describes the time-dependent diffusive shock acceleration of test particles at the non-relativistic shocks. At first, the solution of Drury (1983) for the particle distribution function at the shock is generalized to any relation between the acceleration time-scales upstream and downstream and for the time-dependent injection efficiency. Three alternative solutions for the spatial dependence of the distribution function are derived. Then, the two other approaches to solve the time-dependent equation are presented, one of which does not require the Laplace transform. At the end, our more general solution is discussed, with a particular attention to the time-dependent injection in supernova remnants. It is shown that, comparing to the case with the dominant upstream acceleration time-scale, the maximum momentum of accelerated particles shifts toward the smaller momenta with increase of the downstream acceleration time-scale. The time-dependent injectio...

  1. Forbidden Iron Lines and Dust Destruction in Supernova Remnant Shocks: The Case of N49 in the Large Magellanic Cloud

    Dopita, Michael A.; Seitenzahl, Ivo R.; Sutherland, Ralph S.; Vogt, Frédéric P. A.; Winkler, P. Frank; Blair, William P.

    2016-08-01

    We present the results of a complete integral-field survey of the bright supernova remnant (SNR) N49 in the Large Magellanic Cloud, obtained with the WiFeS instrument mounted on the ANU 2.3 m telescope at Siding Spring Observatory. From theoretical shock modeling with the new MAPPINGS 5.1 code, we have, for the first time, subjected the optical Fe emission line spectrum of an SNR to a detailed abundance and dynamical analysis covering eight separate stages of ionization. This allows us to derive the dust depletion factors as a function of ionization stage. We have shown that there is substantial (30%–90%) destruction of Fe-bearing dust grains in these fast shocks (v s ∼ 250 km s‑1), and we have confirmed that the dominant dust destruction occurs through the non-thermal sputtering and grain–grain collision mechanisms developed in a number of theoretical works.

  2. Forbidden Iron Lines and Dust Destruction in Supernova Remnant Shocks: The Case of N49 in the Large Magellanic Cloud

    Dopita, Michael A; Sutherland, Ralph S; Vogt, Frédéric P A; Winkler, P Frank; Blair, William P

    2016-01-01

    We present results of a complete integral field survey of the bright SNR N49 in the LMC, obtained with the WiFeS instrument mounted on the ANU 2.3m telescope at Siding Spring Observatory. From theoretical shock modelling with the new MAPPINGS 5.1 code we have, for the first time, subjected the optical Fe emission line spectrum of a supernova remnant to a detailed abundance and dynamical analysis covering 8 separate stages of ionisation. This allows us to derive the dust depletion factors as a function of ionisation stage. We have shown that there is substantial (30% - 90%) destruction of Fe-bearing dust grains in these fast shocks ($v_s \\sim 250$ km/s), and we have confirmed that the dominant dust destruction is through the non-thermal sputtering and grain-grain collision mechanisms developed in a number of theoretical works.

  3. Dust Destruction in Fast Shocks of Core-Collapse Supernova Remnants in the Large Magellanic Cloud

    Williams, B J; Reynolds, S P; Blair, W P; Ghavamian, P; Hendrick, S P; Long, K S; Points, S; Raymond, J C; Sankrit, R; Smith, R C; Winkler, P F; Williams, Brian J.

    2006-01-01

    We report observations with the MIPS instrument aboard the {\\it Spitzer Space Telescope} (SST) of four supernova remnants (SNRs) believed to be the result of core-collapse SNe: N132D (0525-69.6), N49B (0525-66.0), N23 (0506-68.0), and 0453-68.5. All four of these SNRs were detected in whole at 24 $\\mu$m and in part at 70 $\\mu$m. Comparisons with {\\it Chandra} broadband X-ray images show an association of infrared (IR) emission with the blast wave. We attribute the observed IR emission to dust that has been collisionally heated by electrons and ions in the hot, X-ray emitting plasma, with grain size distributions appropriate for the LMC and the destruction of small grains via sputtering by ions. As with our earlier analysis of Type Ia SNRs, models can reproduce observed 70/24 $\\mu$m ratios only if effects from sputtering are included, destroying small grains. We calculate the mass of dust swept up by the blast wave in these remnants, and we derive a dust-to-gas mass ratio of several times less than the often a...

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

    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.

  5. Supernova remnant 1987 A

    A dense circumstellar shell, with radius of about 0.5 lt-yr, surrounds SN 1987 A. In 16 yr or less after outburst, the expanding debris of SN 1987 A will strike this shell. When it does, the hot gas and relativistic electrons resulting from the forward and reverse shocks will radiate X-rays, infrared radiation, and nonthermal radio waves. The remnant of SN 1987 A will then become one of the brightest X-ray and radio sources in the LMC. 23 refs

  6. Barrel-shaped supernova remnants

    The authors argue that the majority of radio supernova remnants have a three-dimensional distribution of emissivity which is barrel shaped, with little emission from the end-caps. They examine some mechanisms which could produce this distribution

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

    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

  8. X-ray haloes around supernova remnants

    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)

  9. The blast wave of Tycho's supernova remnant

    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 arcs...

  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

    Obergaulinger, M.; Iyudin, A. F.; Muller, 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 ou...

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

    Petrosian, Vahe

    2016-07-01

    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.

  12. Non-linear diffusive acceleration of heavy nuclei in supernova remnant shocks

    Caprioli, D.; P. Blasi(INAF Arcetri); Amato, E.

    2010-01-01

    Abstract We describe a semi-analytical approach to non-linear diffusive shock acceleration in the case in which nuclei other than protons are also accelerated. The structure of the shock is determined by the complex interplay of all nuclei, and in turn this shock structure determines the spectra of all components. The magnetic field amplification upstream is described as due to streaming instability of all nuclear species. The amplified magnetic field is then taken into account for...

  13. Electron acceleration by young supernova remnant blast waves

    Blandford, R. D.

    1992-01-01

    Some general considerations regarding relativistic particle acceleration by young supernova remnants are reviewed. Recent radio observations of supernova remnants apparently locate the bounding shock and exhibit large electron density gradients which verify the presence of strong particle scattering. The radio 'rim' in Tycho's remnant has been found to contain a predominantly radial magnetic field. This may be attributable to an instability of the shock surface and a progress report on an investigation of the stability of strong shocks in partially ionized media is presented.

  14. Molecular clouds near supernova remnants

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

  15. Plerionic Supernova Remnants

    Safi-Harb, Samar

    2012-01-01

    Plerions represent ideal laboratories for the search for neutron stars, the study of their relativistic winds, and their interaction with their surrounding supernova ejecta and/or the interstellar medium. As well, they are widely believed to represent efficient engines for particle acceleration up to the knee of the cosmic ray spectrum (at about 1E15 eV). Multi-wavelength observations from the radio to the highest TeV energies, combined with modelling, have opened a new window to study these ...

  16. Supernova Remnant in 3-D

    2009-01-01

    [figure removed for brevity, see original site] Click on the image for the movie For the first time, a multiwavelength three-dimensional reconstruction of a supernova remnant has been created. This stunning visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several telescopes: X-ray data from NASA's Chandra X-ray Observatory, infrared data from NASA's Spitzer Space Telescope and optical data from the National Optical Astronomy Observatory 4-meter telescope at Kitt Peak, Ariz., and the Michigan-Dartmouth-MIT 2.4-meter telescope, also at Kitt Peak. In this visualization, the green region is mostly iron observed in X-rays. The yellow region is a combination of argon and silicon seen in X-rays, optical, and infrared including jets of silicon plus outer debris seen in the optical. The red region is cold debris seen in the infrared. Finally, the blue reveals the outer blast wave, most prominently detected in X-rays. Most of the material shown in this visualization is debris from the explosion that has been heated by a shock moving inwards. The red material interior to the yellow/orange ring has not yet encountered the inward moving shock and so has not yet been heated. These unshocked debris were known to exist because they absorb background radio light, but they were only recently discovered in infrared emission with Spitzer. The blue region is composed of gas surrounding the explosion that was heated when it was struck by the outgoing blast wave, as clearly seen in Chandra images. To create this visualization, scientists took advantage of both a previously known phenomenon the Doppler effect and a new technology that bridges astronomy and medicine. When elements created inside a supernova, such as iron, silicon and argon, are heated they emit light at certain wavelengths. Material moving towards the observer will have shorter wavelengths and material moving away will have longer wavelengths. Since the amount

  17. Featured Image: Modeling Supernova Remnants

    Kohler, Susanna

    2016-05-01

    This image shows a computer simulation of the hydrodynamics within a supernova remnant. The mixing between the outer layers (where color represents the log of density) is caused by turbulence from the Rayleigh-Taylor instability, an effect that arises when the expanding core gas of the supernova is accelerated into denser shell gas. The past standard for supernova-evolution simulations was to perform them in one dimension and then, in post-processing, manually smooth out regions that undergo Rayleigh-Taylor turbulence (an intrinsically multidimensional effect). But in a recent study, Paul Duffell (University of California, Berkeley) has explored how a 1D model could be used to reproduce the multidimensional dynamics that occur in turbulence from this instability. For more information, check out the paper below!CitationPaul C. Duffell 2016 ApJ 821 76. doi:10.3847/0004-637X/821/2/76

  18. Formation of supernova remnants: The pre-blast-wave phase

    The effect of stellar structure on supernova remnant formation is studied with a series of computer models of a 1051 erg explosion in a 15 M/sub sun/ star. We find that immediately after the explosion shock wave travels down a steep density gradient, the material in the gradient goes into free expansion, forming a collapsible piston. At the outer edge of such a piston are two shock waves: the expanding supernova shock and a reverse shock moving back into the collapsible piston. Until the piston is completely collapsed it is Rayleigh-Taylor stable, but after collpse the inner material behaves as a massive piston and the interface is R-T unstable. If there is a significant mass in an external density gradient, the material between the supernova shock moving out through the interstellar medium and the reverse shock will be a singificant source of x-rays during the pre--blast-wave phase of remnant formation

  19. Neutron Stars in Supernova Remnants and Beyond

    Gvaramadze, V. V.

    2002-01-01

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

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

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

    2013-01-01

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

  1. Low Frequency Insights Into Supernova Remnants

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

    2000-01-01

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

  2. The peculiar supernova remnant CTB 80

    Mavromatakis, F; Paleologou, E V; Papamastorakis, J

    2001-01-01

    Deep CCD exposures of the peculiar supernova remnant CTB 80 in the light of major optical lines have been obtained. These images reveal significant shock heated emission in the area of the remnant. The sulfur line image shows emission in the north along the outer boundary of the IRAS and HI shells. The comparison between the [OIII] and [OII] line images further suggest the presence of significant inhomogeneities in the interstellar medium. The flux calibrated images do not indicate the presence of incomplete recombination zones, and we estimate that the densities of the preshock clouds should not exceed a few atoms per cm^3. The area covered by the optical radiation along with the radio emission at 1410 MHz suggest that CTB 80 occupies a larger angular extent than was previously known.

  3. OH (1720 MHz) Masers and Mixed-Morphology Supernova Remnants

    Yusef-Zadeh, F.; Wardle, M.; Rho, J.; M. SAKANO

    2002-01-01

    Radio surveys of supernova remnants (SNRs) in the Galaxy have uncovered 19 SNRs accompanied by OH maser emission at 1720 MHz. This unusual class of maser sources is suggested to be produced behind a shock front from the expansion of a supernova remnant running into a molecular cloud. An important ingredient of this model is that X-ray emission from the remnant enhances the production of OH molecule. The role of X-ray emission from maser emitting (ME) SNRs is investigated by comparing the X-ra...

  4. Vivid View of Tycho's Supernova Remnant

    2008-01-01

    This composite image of the Tycho supernova remnant combines infrared and X-ray observations obtained with NASA's Spitzer and Chandra space observatories, respectively, and the Calar Alto observatory, Spain. It shows the scene more than four centuries after the brilliant star explosion witnessed by Tycho Brahe and other astronomers of that era. The explosion has left a blazing hot cloud of expanding debris (green and yellow). The location of the blast's outer shock wave can be seen as a blue sphere of ultra-energetic electrons. Newly synthesized dust in the ejected material and heated pre-existing dust from the area around the supernova radiate at infrared wavelengths of 24 microns (red). Foreground and background stars in the image are white.

  5. Multi-Wavelength Observations of Supernova Remnants

    Williams, B.

    2012-01-01

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

  6. Supernova remnants: the X-ray perspective

    Vink, Jacco

    2011-01-01

    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 fr...

  7. Einstein Observations of Galactic supernova remnants

    Seward, Frederick D.

    1990-01-01

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

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

    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.

  9. Runaway Stars in Supernova Remnants

    Pannicke, Anna; Neuhaeuser, Ralph; Dinçel, Baha

    2016-07-01

    Half of all stars and in particular 70 % of the massive stars are a part of a multiple system. A possible development for the system after the core collapse supernova (SN) of the more massive component is as follows: The binary is disrupted by the SN. The formed neutron star is ejected by the SN kick whereas the companion star either remains within the system and is gravitationally bounded to the neutron star, or is ejected with a spatial velocity comparable to its former orbital velocity (up to 500 km/s). Such stars with a large peculiar space velocity are called runaway stars. We present our observational results of the supernova remnants (SNRs) G184.6-5.8, G74.0-8.5 and G119.5+10.2. The focus of this project lies on the detection of low mass runaway stars. We analyze the spectra of a number of candidates and discuss their possibility of being the former companions of the SN progenitor stars. The spectra were obtained with INT in Tenerife, Calar Alto Astronomical Observatory and the University Observatory Jena. Also we investigate the field stars in the neighborhood of the SNRs G74.0-8.5 and G119.5+10.2 and calculate more precise distances for these SNRs.

  10. The early evolution of supernova remnants

    This paper discusses how the density distribution of the supernova ejecta and that of the surrounding medium are the most important parameters for the early evolution of supernova remnants. The distribution of the ejecta depends on the detailed hydrodynamics of the explosion, but the outer parts of a supernova can probably be represented by a steep power law density distribution with radius. Self-similar solutions are especially useful for modeling the interaction of a supernova with its surroundings. The supernova first interacts with mass loss from the progenitor star. Evidence for circumstellar interaction is present in a number of extra-galactic supernovae, including SN1987a

  11. Supernova remnants in the GC region

    Asvarov, Abdul

    2016-07-01

    Along with the central Black hole the processes of active star formation play very important role in the energetics of the Galactic center region. The SNe and their remnants (SNRs) are the main ingredients of the processes of star formation. SNRs are also the sources of electromagnetic radiation of all wavelengths from the optical to hard gamma rays. In the presented work we consider the physics of supernova remnants evolving in extreme environmental conditions which are typical for the region of the Galactic center. Because of the high density and strong inhomogeneity of the surrounding medium these objects remain practically invisible at almost all wavelengths. We model evolution of SNR taking into account the pressure of the surrounding medium and the gravitational field of the matter (stars, compact clouds, dark matter) inside the remnant. As it is well established, considerable portion of the kinetic energy of the SNR can be converted into the cosmic ray particles by diffusive shock acceleration mechanism. Therefore the effect of particle acceleration is also included in the model (with the effectiveness of acceleration as a free parameter). Using the observed radiation fluxes at different wavelengths we attempt to obtain limits on the parameters of the model of the Galactic Center, namely, the frequency of star birth, the average density of the matter and radiation field, etc.

  12. Extended OH(1720 MHz) Maser Emission from Supernova Remnants

    Hewitt, J W; Wardle, M; Roberts, D A

    2007-01-01

    Compact OH(1720 MHz) masers have proven to be excellent signposts for the interaction of supernova remnants with adjacent molecular clouds. Less appreciated has been the weak, extended OH(1720 MHz) emission which accompanies strong compact maser sources. Recent single-dish and interferometric observations reveal the majority of maser-emitting supernova remnants have accompanying regions of extended maser emission. Enhanced OH abundance created by the passing shock is observed both as maser emission and absorption against the strong background of the remnant. Modeling the observed OH profiles gives an estimate of the physical conditions in which weak, extended maser emission arises. I will discuss how we can realize the utility of this extended maser emission, particularly the potential to measure the strength of the post-shock magnetic field via Zeeman splitting over these large-scales.

  13. Synthesis surveys of southern supernova remnants

    A report is presented detailing observations of supernova remnants (SNRs) with the Fleurs and Molonglo synthesis radio telescopes. Fifty-four remnants have been mapped with at least one of these instruments, eleven with both. Approximately half of the maps have been published and a key to these publications is given

  14. Supernova remnants: the X-ray perspective

    J. Vink

    2012-01-01

    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 i

  15. Young Supernova Remnants: Issues and Prospects

    McKee, Christopher F.

    2001-01-01

    After reviewing recent work on the dynamics of young supernova remnants (YSNRs) and discussing how YSNRs can be used as physics laboratories, I discuss several challenges: Where are the very young SNRs in the Galaxy? Can very young SNRs produce gamma ray bursts? The Connections Challenge: Can one infer the nature of the supernova and its progenitor star from observations of the YSNR?

  16. An infrared survey of galactic supernova remnants

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

  17. Circumstellar Nebulae in Young Supernova Remnants

    Chu, Y.-H.

    2000-01-01

    Supernovae descendent from massive stars explode in media that have been modified by their progenitors' mass loss and UV radiation. The supernova ejecta will first interact with the circumstellar material shed by the progenitors at late evolutionary stages, and then interact with the interstellar material. Circumstellar nebulae in supernova remnants can be diagnosed by their small expansion velocities and high [N II]/H$\\alpha$ ratios. The presence of circumstellar nebulae appears ubiquitous a...

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

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

    2015-01-01

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

  19. Chandra Observations of Tycho’s Supernova Remnant

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

    2002-03-01

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

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

    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...

  1. X-ray images of supernova remnants

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

  2. Nonthermal Emission of Tycho's Supernova Remnant

    TANG Yun-Yong; FANG Jun; ZHANG Li

    2011-01-01

    The time-dependent non-thermal particle and photon spectra are reproduced for a Type Ia SNR Tycho with radio,x-ray,GeV and TeV emission within the framework of the diffusive shock acceleration of the non-thermal particles.TeV photons can come from the inverse Compton scattering of relativistic electrons and from the π0-decay process in proton-proton interaction.The results show that (1) the hadronic case can model the observed multiwavelength spectrum well and,peculiarly,the π0-decay process appears to be necessary to explain the GeV emission;and (2) magnetic field amplification is vital in the SNR.Tycho's supernova remnant (SNR) is a Type Ia SNR with an age of 438 y.At radio band,the images indicate a clear shell-like morphology with enhanced emission along the northeastern edge of the remnant,[1,2] the spectral index and the fiux density at 1.4 GHz are 0.65 and 40.5 Jy,respectively.[3]%The time-dependent non-thermal particle and photon spectra are reproduced for a Type /a SNR Tycho with radio, x-ray, GeV and TeV emission within the framework of the diffusive shock acceleration of the non-thermal particles. TeV photons can come from the inverse Compton scattering of relativistic electrons and from theπ°-decay process in proton-proton interaction. The results show that (1) the hadronic case can model the observed multiwavelength spectrum well and, peculiarly, the π°-decay process appears to be necessary to explain the GeV emission; and (2) magnetic field amplification is vital in the SNR.

  3. OH (1720 MHz) Masers and Mixed-Morphology Supernova Remnants

    Yusef-Zadeh, F; Rho, J; Sakano, M

    2003-01-01

    Radio surveys of supernova remnants (SNRs) in the Galaxy have uncovered 19 SNRs accompanied by OH maser emission at 1720 MHz. This unusual class of maser sources is suggested to be produced behind a shock front from the expansion of a supernova remnant running into a molecular cloud. An important ingredient of this model is that X-ray emission from the remnant enhances the production of OH molecule. The role of X-ray emission from maser emitting (ME) SNRs is investigated by comparing the X-ray induced ionization rate with theory. One aspect of this model is verified: there is a strong association between maser emitting and mixed-morphology (MM) or thermal composite SNRs --center-filled thermal X-ray emission surrounded by shell-like radio morphology. We also present ROSAT and ASCA observations of two maser emitting SNRs: G21.8--0.6 (Kes 69) and G357.7--0.1 (Tornado).

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

    Jun, B I

    1997-01-01

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

  5. Isothermal blast wave model of supernova remnants

    The validity of the ''adiabatic'' assumption in supernova remnant calculations is examined, and the alternative extreme of an isothermal blast wave is explored. It is concluded that, because of thermal conductivity, the large temperature gradients predicted by the adiabatic model probably are not maintained in nature. Self-similar solutions to the hydrodynamic equations for an isothermal blast wave have been found and studied. These solutions are then used to determine the relationship between X-ray observations and inferred parameters of supernova remnants. A comparison of the present results with those for the adiabatic model indicates differences which are less than present observational uncertainties. It is concluded that most parameters of supernova remnants inferred from X-ray measurements are relatively insensitive to the specifics of the blast wave model

  6. Isothermal blast wave model of supernova remnants

    Solinger, A.; Buff, J.; Rappaport, S.

    1975-01-01

    The validity of the 'adiabatic' assumption in supernova-remnant calculations is examined, and the alternative extreme of an isothermal blast wave is explored. It is concluded that, because of thermal conductivity, the large temperature gradients predicted by the adiabatic model probably are not maintained in nature. Self-similar solutions to the hydrodynamic equations for an isothermal blast wave have been found and studied. These solutions are then used to determine the relationship between X-ray observations and inferred parameters of supernova remnants. A comparison of the present results with those for the adiabatic model indicates differences which are less than present observational uncertainties. It is concluded that most parameters of supernova remnants inferred from X-ray measurements are relatively insensitive to the specifics of the blast-wave model.

  7. New supernova remnant results from radio surveys

    Helfand, D. J.

    Our knowledge of the Galactic supernova remnant population is woefully incomplete A total of 231 remnants appear in the latest catalog Green 2004 whereas we expect the total population to be between 500 and 1000 Helfand et al 1989 The current discovery rate of new remnants has averaged about four per year over the past two decades In recent years a number of new Galactic plane radio surveys have been undertaken which offer the possibility of significantly increasing this discovery rate For example the VLA MAGPIS survey Helfand et al 2006 has identified fifty new remnant candidates in a 27-degree swath of Galactic longitude Unsurprisingly this high-resolution survey finds many more small-diameter remnants than past single-dish observations increasing by seven-fold the number of remnants with diameters less than 5 arcmin in this region of the Galaxy Brogan et al report 90 cm observations in this region identifying up to 35 new remnants I will review all published results on new radio remnants highlighting the impact of these discoveries on our understanding of the remnant population and noting the value of observations from the mid-infrared to TeV gamma rays in defining the Galaxy s remnant population This work is supported in part by grant AST 05-07598 from the National Science Foundation

  8. Gamma-Rays from Heavy Nuclei Accelerated in Supernova Remnants

    Caprioli, D.; P. Blasi(INAF Arcetri); Amato, E.

    2010-01-01

    We investigate the theoretical and observational implications of the acceleration of protons and heavier nuclei in supernova remnants (SNRs). By adopting a semi-analytical technique, we study the non-linear interplay among particle acceleration, magnetic field generation and shock dynamics, outlining a self-consistent scenario for the origin of the spectrum of Galactic cosmic rays as produced in this class of sources. Moreover, the inferred chemical abundances suggest nuclei heavier than Hydr...

  9. Outflow from supernovae as a possible cause of the finefibered structure of supernova remnants

    Arguments are given which point out some sort of connection between filaments in supernova remnants and exploded stars in them. A stellar wind from the presupernova which has Wolf-Rayet star parameters is considered as a possible example of this connection. The wind consists, by suggestion, of both rarefied phase and dense clusters. At the stage of the wind deceleration, the clusters cannot be stopped. They throw out the wind and move through the interstellar medium at a large velocity, shocking the gas before them. It is shown that the evolution of the gas disturbed by the cluster leads to formation of a structure similar to the one observed in the supernova remnants. The required wind power is less than that of the Wolf-Rayet stars by an order of magnitude. Slowly expanding HI clouds discovered around some supernova remnants may be the interstellar gas carried away by the wind rarefied component

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

    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. Evolution of magnetic fields in supernova remnants

    Schure, K.M.; Vink, J.; Achterberg, A.; Keppens, R.

    2009-01-01

    Supernova remnants (SNR) are now widely believed to be a source of cosmic rays (CRs) up to an energy of 10(15) eV. The magnetic fields required to accelerate CRs to sufficiently high energies need to be much higher than can result from compression of the circumstellar medium (CSM) by a factor 4, as

  12. Neutron Star/Supernova Remnant Associations

    Kaspi, V. M.

    1998-01-01

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

  13. Transport of magnetic turbulence in Supernova remnants

    Brose, Robert; Pohl, Martin

    2016-01-01

    Context. Supernova remnants are known as sources of galactic cosmic rays for their non-thermal emission of radio waves, X-rays, and gamma-rays. However, the observed soft broken power-law spectra are hard to reproduce within standard acceleration theory based on the assumption of Bohm diffusion and steady-state calculations. Aims. We point out that a time-dependent treatment of the acceleration process together with a self-consistent treatment of the scattering turbulence amplification is necessary. Methods. We numerically solve the coupled system of transport equations for cosmic rays and isotropic Alfvenic turbulence. The equations are coupled through the growth rate of turbulence determined by the cosmic-ray gradient and the spatial diffusion coefficient of cosmic rays determined by the energy density of the turbulence. The system is solved on a co-moving expanding grid extending upstream for dozens of shock radii, allowing for the self-consistent study of cosmic-ray diffusion in the vicinity of their acce...

  14. Gamma-ray Emission from Crushed Clouds in Supernova Remnants

    Uchiyama, Yasunobu; Funk, Stefan; Tajima, Hiroyasu; Tanaka, Takaaki

    2010-01-01

    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 neutral pions 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.

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

    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. Near-Infrared Spectroscopy of Young Galactic Supernova Remnants

    Koo, Bon-Chul

    2015-01-01

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

  17. Transport of magnetic turbulence in supernova remnants

    Brose, R.; Telezhinsky, I.; Pohl, M.

    2016-08-01

    Context. Supernova remnants are known as sources of Galactic cosmic rays for their nonthermal emission of radio waves, X-rays, and gamma rays. However, the observed soft broken power-law spectra are hard to reproduce within standard acceleration theory based on the assumption of Bohm diffusion and steady-state calculations. Aims: We point out that a time-dependent treatment of the acceleration process together with a self-consistent treatment of the scattering turbulence amplification is necessary. Methods: We numerically solve the coupled system of transport equations for cosmic rays and isotropic Alfvénic turbulence. The equations are coupled through the growth rate of turbulence determined by the cosmic-ray gradient and the spatial diffusion coefficient of cosmic rays determined by the energy density of the turbulence. The system is solved on a comoving expanding grid extending upstream for dozens of shock radii, allowing for the self-consistent study of cosmic-ray diffusion in the vicinity of their acceleration site. The transport equation for cosmic rays is solved in a test-particle approach. Results: We demonstrate that the system is typically not in a steady state. In fact, even after several thousand years of evolution, no equilibrium situation is reached. The resulting time-dependent particle spectra strongly differ from those derived assuming a steady state and Bohm diffusion. Our results indicate that proper accounting for the evolution of the scattering turbulence and hence the particle diffusion coefficient is crucial for the formation of the observed soft spectra. In any case, the need to continuously develop magnetic turbulence upstream of the shock introduces nonlinearity in addition to that imposed by cosmic-ray feedback.

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

    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. Supernova Remnant Evolution: from explosion to dissipation

    Leahy, Denis

    2016-01-01

    Here is considered the full evolution of a spherical supernova remnant. We start by calculating the early time ejecta dominated stage and continue through the different phases of interaction with the circumstellar medium, and end with the dissipation and merger phase. The physical connection between the phases reveals new results. One is that the blast wave radius during the adiabatic phase is significantly smaller than it would be, if one does notaccount for the blast wave interaction with the ejecta.

  20. OXYGEN-RICH SUPERNOVA REMNANT IN THE LARGE MAGELLANIC CLOUD

    2002-01-01

    This is a NASA Hubble Space Telescope image of the tattered debris of a star that exploded 3,000 years ago as a supernova. This supernova remnant, called N132D, lies 169,000 light-years away in the satellite galaxy, the Large Magellanic Cloud. A Hubble Wide Field Planetary Camera 2 image of the inner regions of the supernova remnant shows the complex collisions that take place as fast moving ejecta slam into cool, dense interstellar clouds. This level of detail in the expanding filaments could only be seen previously in much closer supernova remnants. Now, Hubble's capabilities extend the detailed study of supernovae out to the distance of a neighboring galaxy. Material thrown out from the interior of the exploded star at velocities of more than four million miles per hour (2,000 kilometers per second) plows into neighboring clouds to create luminescent shock fronts. The blue-green filaments in the image correspond to oxygen-rich gas ejected from the core of the star. The oxygen-rich filaments glow as they pass through a network of shock fronts reflected off dense interstellar clouds that surrounded the exploded star. These dense clouds, which appear as reddish filaments, also glow as the shock wave from the supernova crushes and heats the clouds. Supernova remnants provide a rare opportunity to observe directly the interiors of stars far more massive than our Sun. The precursor star to this remnant, which was located slightly below and left of center in the image, is estimated to have been 25 times the mass of our Sun. These stars 'cook' heavier elements through nuclear fusion, including oxygen, nitrogen, carbon, iron etc., and the titanic supernova explosions scatter this material back into space where it is used to create new generations of stars. This is the mechanism by which the gas and dust that formed our solar system became enriched with the elements that sustain life on this planet. Hubble spectroscopic observations will be used to determine the exact

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

    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...

  2. Evolution of multiple supernova remnants

    Vasiliev, Evgenii O; Bondarev, Roman; Shchekinov, Yuri

    2014-01-01

    Heating of the interstellar medium by multiple supernovae (SNe) 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 to fill the central region of starburst with hot gas, in order to launch vigorous outflows. We study the efficiency of multiple SNe in heating the interstellar medium (ISM) and filling the volume with gas of high temperatures, with 2-D and 3-D hydrodynamic simulations. We argue that SNe have to be clustered in space and time (and be coherent) in order to compensate for the radiative loss. In particular, we find that in coherent cases, the filling factor of gas with $3 \\times 10^6$ K can be at the most $\\le 0.3$ and the total heating efficiency $\\le 0.3$, for gas with density $1$ cm$^{-3}$ and $0.1\\hbox{--}1$ Z$_\\odot$. The heating efficiency and filling factors are much smaller in incoherent cases. Comparing our results to the commonly adopted efficie...

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

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

    2014-11-15

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

  4. Three Supernova Remnants observed by BeppoSAX

    Vink, Jacco

    1998-01-01

    We present the results of three observations of shell-type supernova remnants observed by BeppoSAX. Two of the remnants (N132D and Cas A) are oxygen rich supernova remnants. They were observed during the PV phase. SN1006 was observed during A01. For SN1006 we present preliminary results on the abundance measurements based on the emission from the center of the remnant.

  5. Simulation of the growth of the 3D Rayleigh-Taylor instability in Supernova Remnants using an expanding reference frame

    Fraschetti, Federico; Ballet, Jean; Decourchelle, Anne

    2010-01-01

    Context: The Rayleigh-Taylor instabilities generated by the deceleration of a supernova remnant during the ejecta-dominated phase are known to produce finger-like structures in the matter distribution which modify the geometry of the remnant. The morphology of supernova remnants is also expected to be modified when efficient particle acceleration occurs at their shocks. Aims: The impact of the Rayleigh-Taylor instabilities from the ejecta-dominated to the Sedov-Taylor phase is investigated over one octant of the supernova remnant. We also study the effect of efficient particle acceleration at the forward shock on the growth of the Rayleigh-Taylor instabilities. Methods: We modified the Adaptive Mesh Refinement code RAMSES to study with hydrodynamic numerical simulations the evolution of supernova remnants in the framework of an expanding reference frame. The adiabatic index of a relativistic gas between the forward shock and the contact discontinuity mimics the presence of accelerated particles. Results: The ...

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

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

    2015-01-01

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

  7. Cosmic ray acceleration search in Supernova Remnants

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

    2014-11-15

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

  8. Cosmic ray acceleration search in Supernova Remnants

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

  9. Supernova Remnants In The Magellanic Clouds

    Filipović, Miroslav D.; Bozzetto, Luke M.

    2016-01-01

    We present initial results of an ongoing study of the supernova remnants (SNRs) and candidates in the Magellanic Clouds. Some 108 objects in both Clouds are considered to be either an SNR or a reliable candidate. This represents the most complete sample of known SNRs in any galaxy. therefore, this study allows us to study SNR population properties such as the size and spectral index distribution. Here, we also show 12 known Large Magellanic Cloud SNRs from type Ia SN explosions and briefly co...

  10. Supernova Remnants In The Magellanic Clouds

    Filipović, Miroslav D

    2016-01-01

    We present initial results of an ongoing study of the supernova remnants (SNRs) and candidates in the Magellanic Clouds. Some 108 objects in both Clouds are considered to be either an SNR or a reliable candidate. This represents the most complete sample of known SNRs in any galaxy. therefore, this study allows us to study SNR population properties such as the size and spectral index distribution. Here, we also show 12 known Large Magellanic Cloud SNRs from type Ia SN explosions and briefly comment on their importance.

  11. Approximate supernova remnant dynamics with cosmic ray production

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

  12. Non-thermal acceleration mechanisms in supernova remnant shells

    Decourchelle, Anne

    2008-01-01

    A review of the main issues in the field of particle acceleration in Supernova Remnants is provided in the context of future X-ray observations with Simbol-X. After a summary of the nonthermal acceleration mechanisms at work, I briefly review the observations of supernova remnants in hard X-rays and in gamma rays. Open issues are discussed in this framework.

  13. The First Fermi LAT Supernova Remnant Catalog

    Acero, F.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen, J. M.; Cohen-Tanugi, J.; Cominsky, L. R.; Condon, B.; Conrad, J.; Cutini, S.; D’Ammando, F.; de Angelis, A.; de Palma, F.; Desiante, R.; Digel, S. W.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Favuzzi, C.; Ferrara, E. C.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Grenier, I. A.; Grondin, M.-H.; Guillemot, L.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Harding, A. K.; Hayashida, M.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Hou, X.; Iafrate, G.; Jogler, T.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.; Katagiri, H.; Kataoka, J.; Katsuta, J.; Kerr, M.; Knödlseder, J.; Kocevski, D.; Kuss, M.; Laffon, H.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Marelli, M.; Mayer, M.; Mazziotta, M. N.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Petrosian, V.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Renaud, M.; Reposeur, T.; Rousseau, R.; Saz Parkinson, P. M.; Schmid, J.; Schulz, A.; Sgrò, C.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Strong, A. W.; Suson, D. J.; Tajima, H.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Vianello, G.; Wells, B.; Wood, K. S.; Wood, M.; Yassine, M.; den Hartog, P. R.; Zimmer, S.

    2016-05-01

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

  14. Supernova remnants, pulsar wind nebulae and their interaction

    van der Swaluw, E.

    2001-01-01

    A supernova explosion marks the end of the evolution of a massive star. What remains of the exploded star is a high density neutron star or a black hole. The material which has been ejected by the supernova explosion will manifest itself as a supernova remnant: a hot bubble of gas expanding in the interstellar medium. This thesis deals with the phenomena after the supernova explosion. The emphasis will be on those supernova remnants which are interacting with a pulsar wind nebula. The latter ...

  15. A Survey of Hydroxyl Toward Supernova Remnants: Evidence for Extended 1720 MHz Maser Emission

    Hewitt, J W; Wardle, M

    2008-01-01

    We present the results of GBT observations of all four ground-state hydroxyl (OH) transitions toward 16 supernova remnants which show OH(1720 MHz) maser emission. This species of maser is well established as an excellent tracer of an ongoing interaction between the remnant and dense molecular material. For ten remnants we detect a significantly higher flux density with a single dish than has been reported with interferometric observations. We infer that spatially extended, low level maser emission is a common phenomenon that traces the large-scale interaction in maser-emitting supernova remnants. Additionally we use a collisional pumping model to fit the physical conditions under which OH is excited behind the supernova shock front.

  16. Supernova remnants, pulsar wind nebulae and their interaction

    Swaluw, E. van der

    2001-01-01

    A supernova explosion marks the end of the evolution of a massive star. What remains of the exploded star is a high density neutron star or a black hole. The material which has been ejected by the supernova explosion will manifest itself as a supernova remnant: a hot bubble of gas expanding in the

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

    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...

  18. Detecting X-ray Synchrotron Emission in Supernova Remnants Implications for Abundances and Cosmic Rays

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

    2000-01-01

    The 10^51 ergs released in a supernova have far reaching consequences in the galaxy, determining elemental abundances, accelerating cosmic rays, and affecting the makeup of the interstellar medium. Recently the spectra of several supernova remnants have been found to be dominated by nonthermal emission. Separating the thermal and nonthermal components is important not only for the understanding of cosmic-ray acceleration and shock microphysics properties but for accurate assessment of the temperatures and line strengths. New models designed to model spatially resolved synchrotron X-rays from type Ia supernovae can contribute to the understanding of both the thermal physics (dynamics, abundances) and nonthermal physics (shock acceleration, magnetic-field amplification) of supernova remnants. I will describe model fits to SN 1006, emphasizing the physical constraints that can be placed on SNRs, abundances, and the cosmic-ray acceleration process.

  19. New supernova remnants in M33

    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 Hα + [NII], Hβ, [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]:Hα + [NII] ratios which may be SNRs. Spectra of seven of these nebulae were obtained subsequently and show that the majority are indeed SNRs

  20. Limits on Enhanced Radio Wave Scattering by Supernova Remnants

    Spitler, L G; Spitler, Laura G.; Spangler, Steven R.

    2005-01-01

    We report multifrequency observations with the NRAO Very Long Baseline Array (VLBA) of the compact radio sources J0128+6306 and J0547+2721, which are viewed through the supernova remnants G127.1+0.5 and S147, respectively. Observations were made at frequencies of 1.427, 1.667, 2.271, and 4.987 GHz. The lines of sight to these sources pass through the shock wave and upstream and downstream turbulent layers of their respective supernova remnants, and thus might detect cosmic-ray generated turbulence produced during the Fermi acceleration process. For both sources, we detect interstellar scattering, characterized by a component of the angular size which scales as the square of the observing wavelength. The magnitude of the scattering is characterized by an effective scattering angular size theta_S0 at a frequency of 1 GHz of 13.2 +/- 2.6 milliarcseconds (mas) for J0128+6306 and 6.7 +/- 2.2 mas for J0547+2721. These angular sizes are consistent with the ``incidental'' scattering for any line of sight out of the g...

  1. Discovery of optical candidate supernova remnants in Sagittarius

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

    2012-01-01

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

  2. The imprint of presupernova evolution on supernova remnants

    Badenes Montoliu, Carles; Bravo Guil, Eduardo

    2001-01-01

    The evolution of Type Ia supernova binary system progenitors is highly uncertain. Several evolutionary models predict that the accretion of mass onto the white dwarf is accompanied by mass ejection from the binary in the form of a powerful wind, but very few observations have been made during the initial phase of formation of supernova remnants, when the interaction of supernova ejecta with presupernova wind could be tested. Here we present hydrodynamical simulations of supernova ejecta inter...

  3. Generation of Cosmic rays in Historical Supernova Remnants

    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.

  4. CORRELATION OF SUPERNOVA REMNANT MASERS AND GAMMA-RAY SOURCES

    Supernova remnants (SNRs) interacting with molecular clouds are potentially exciting systems in which to detect evidence of cosmic ray acceleration. Prominent γ-ray emission is produced via the decay of neutral pions when cosmic rays encounter nearby dense clouds. In many of the SNRs coincident with γ-ray sources, the presence of OH (1720 MHz) masers is used to identify interaction with dense gas and to provide a kinematic distance to the system. In this Letter we use statistical tests to demonstrate that there is a correlation between these masers and a class of GeV- to TeV-energy γ-ray sources coincident with interacting remnants. For pion decay the γ-ray luminosity provides a direct estimate of the local cosmic ray density. We find the cosmic ray density is enhanced by one to two orders of magnitude over the local solar value, comparable to X-ray-induced ionization in these remnants. The inferred ionization rates are sufficient to explain non-equilibrium chemistry in the post-shock gas, where high columns of hydroxyl are observed.

  5. Observation of the Supernova Remnant IC 443 with VERITAS

    Humensky, T B

    2007-01-01

    Shell-type supernova remnants (SNRs) accelerate particles at the shock front between the expanding remnant and the swept-up interstellar medium. If these particles include protons and nuclei, very-high-energy gamma-ray emission may result from the decay of pions produced in interactions between cosmic rays and the local insterstellar medium. For SNRs that are interacting with a nearby molecular cloud, such as IC 443, the enhanced matter density provides a target medium that can amplify the gamma-ray emission. IC 443 also contains the pulsar wind nebula (PWN) CXOU J061705.3+222127. PWNe are the most plentiful galactic sources of very-high-energy gamma rays, which are produced in the shock formed at the collision of the pulsar wind with the ambient medium. VERITAS is an array of four 12-m telescopes dedicated to gamma-ray astronomy in the energy band above 100 GeV. Located on Mt. Hopkins in southern Arizona, VERITAS operated during the 2006-2007 season in 2-, 3-, and 4-telescope observation modes. In this talk,...

  6. Progress toward the Laboratory Simulation of Young Supernova Remnants

    Progress in experiments to simulate the hydrodynamics of supernova remnants (SNRs) in the laboratory is reported. The experiment design involves shock heating of a dense material, which expands to become the ejecta that drive a blast wave through low-density foam. In the design, a variety of issues, such as radiative preheat of the unshocked matter, had to be addressed. A careful analysis of the scaling between hydrodynamic systems shows that the experiment is a good, scaled model of a local region in a young SNR. Measurements of the basic hydrodynamic behavior for two blast-wave velocities are nearly complete. Measurements of hydrodynamic instabilities at the contact surface between the ejecta and the low-density matter will commence in the near future. (c) 2000 The American Astronomical Society

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

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

    2007-01-01

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

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

    Williams, Brian J.; Borkowski, Kazimierz; 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 micron IR spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 micron, 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 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) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are approx 80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km/s) into moderate density material (n(sub o) approx 50-100 / cubic cm) 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.

  9. Six Years of Chandra Observations of Supernova Remnants

    Weisskopf, Martin C.; Hughes, John P.

    2005-01-01

    We present a review of the first six years of Chandra X-ray Observatory observations of supernova remnants. From the official "first-light" observation of Cassiopeia A that revealed for the first time the compact remnant of the explosion, to the recent million-second spectrally-resolved observation that revealed new details of the stellar composition and dynamics of the original explosion, Chandra observations have provided new insights into the supernova phenomenon. We present an admittedly ...

  10. The Hot and Energetic Universe: The astrophysics of supernova remnants and the interstellar medium

    Decourchelle, A; Badenes, C; Ballet, J; Bamba, A; Bocchino, F; Kaastra, J; Kosenko, D; Lallement, R; Lee, J; Lemoine-Goumard, M; Miceli, M; Paerels, F; Petre, R; Pinto, C; Plucinsky, P; Renaud, M; Sasaki, M; Smith, R; Tatischeff, V; Tiengo, A; Valencic, L; Vink, J; Wang, D; Wilms, J

    2013-01-01

    The study of both supernova remnants and the hot and cold phases of the interstellar medium are essential for understanding the final stages of stellar evolution and their feedback on the evolution of galaxies through injection of energy and heavy elements. These studies are also crucial for understanding the physics of supernovae, their cosmological implication, and the origin of galactic cosmic rays. The unique capabilities of Athena+ will allow us to explore a new parameter space. Spatially-resolved high-resolution spectroscopy using Athena+ X-IFU of young remnants will allow to characterize individual parcels of ejected material in the line of sight in terms of kinematics, ionization and composition, providing access to the three dimensional geometry of the explosion. Athena+ will also allow studying shock physics and particle acceleration in supernova remnants, as well as their interaction with their environment. Athena+ X-IFU will also characterize the ionization mechanisms competing in forming the comp...

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

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

  12. The laboratory simulation of unmagnetized supernova remnants Absence of a blast wave

    Borovsky, J. E.; Pongratz, M. B.; Roussel-Dupre, R. A.; Tan, T.-H.

    1984-01-01

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

  13. VERITAS Observations of the Geminga Supernova Remnant

    ,

    2015-01-01

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

  14. Supernova Remnant Progenitor Masses in M31

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

    2012-01-01

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

  15. Long slit echelle spectroscopy of supernova remnants IN M33

    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 IIα 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

  16. Five Years in the Mid-Infrared Development of the SN 1987A Supernova Remnant

    Dwek, Eliahu

    2009-01-01

    Spitzer has been used to monitor the mid-IR evolution of SN 1987A over a 5 year period as it develops into a supernova remnant through interaction with its surrounding environment. This interaction is dominated by the collision of the ejecta with the pre-existing equatorial ring. The mid-IR continuum indicates an increasing mass of shock-heated silicate dust, but without any significant change in temperature of the dust grains. Comparison of the IR and X-ray evolution of the remnant can be used to infer plasma conditions and the processing of the dust in the shock-heated X-ray emitting gas.

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

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

    2013-01-01

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

  18. Discovery of optical candidate supernova remnants in Sagittarius

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

    2012-08-01

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

  19. Acceleration of cosmic rays in supernova-remnants

    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

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

    Blondin, J M; Reynolds, S P

    2001-01-01

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

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

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

    2014-10-20

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

  2. Supernova Remnants in the Local Group I: A model for the radio luminosity function and visibility times of supernova remnants

    Sarbadhicary, Sumit K; Chomiuk, Laura; Caprioli, Damiano; Huizenga, Daniel

    2016-01-01

    Supernova remnants (SNRs) in Local Group galaxies offer unique insights into the origin of different types of supernovae. In order to take full advantage of these insights, one must understand the intrinsic and environmental diversity of SNRs in the context of their host galaxies. We introduce a semi-analytic model that reproduces the statistical properties of a radio continuum-selected SNR population, taking into account the detection limits of radio surveys, the range of SN kinetic energies, the measured ISM and stellar mass distribution in the host galaxy from multi-wavelength images and the current understanding of electron acceleration and field amplification in SNR shocks from first-principle kinetic simulations. Applying our model to the SNR population in M33, we reproduce the SNR radio luminosity function with a median SN rate of $\\sim 3.1 \\times 10^{-3}$ per year and an electron acceleration efficiency, $\\epsilon_{\\rm{e}} \\sim 4.2 \\times 10^{-3}$. We predict that the radio visibility times of $\\sim 7...

  3. The Impact of a Supernova Remnant on Fast Radio Bursts

    Piro, Anthony L

    2016-01-01

    Fast radio bursts (FRBs) are millisecond bursts of radio radiation that appear to come from cosmological distances. Although their progenitors remain mysterious, the timescales and energetics of the events have lead to many theories associating FRBs with young neutron stars. Motivated by this, I explore the interaction of FRBs with young supernova remnants (SNRs), and I discuss the potential observational consequences and constraints of such a scenario. As the SN ejecta plows into the interstellar medium (ISM), a reverse shock is generated that passes back through the material and ionizes it. This leads to a dispersion measure (DM) associated with the SNR as well as a time derivative for DM. Times when DM is high are generally overshadowed by free-free absorption, which, depending on the mass of the ejecta and the density of the ISM, may be probed at frequencies of $400\\,{\\rm MHz}$ to $1.4\\,{\\rm GHz}$ on timescales of $\\sim100-500\\,{\\rm yrs}$ after the SN. Magnetic fields generated at the reverse shock may be...

  4. TeV Gamma-Rays from Old Supernova Remnants

    Yamazaki, R; Bamba, A; Yoshida, T; Tsuribe, T; Takahara, F; Yamazaki, Ryo; Kohri, Kazunori; Bamba, Aya; Yoshida, Tatsuo; Tsuribe, Toru; Takahara, Fumio

    2006-01-01

    We study the emission from an old supernova remnant (SNR) with an age of around 10^5 yrs and that from a giant molecular cloud (GMC) encountered by the SNR. When the SNR age is around 10^5 yrs, hadron acceleration is efficient enough to emit TeV gamma-rays both at the shock of the SNR and that in the GMC. The maximum energy of primarily accelerated electrons is so small that TeV gamma-rays and X-rays are dominated by hadronic processes, pi^0-decay and synchrotron radiation from secondary electrons, respectively. However, if the SNR is older than several 10^5 yrs, there are few high-energy particles emitting TeV gamma-rays because of the energy loss effect and/or the wave damping effect occurring at low-velocity isothermal shocks. It is found that the ratio of TeV gamma-ray (1-10 TeV) to X-ray (2-10 keV) energy flux can be more than ~10^2. Such a source showing large flux ratio may be a possible origin of recently discovered unidentified TeV sources.

  5. Slow Diffusion of Cosmic-Rays around a Supernova Remnant

    Fujita, Yutaka; Takahara, Fumio

    2010-01-01

    We study the escape of cosmic-ray protons accelerated at a supernova remnant (SNR). We are interested in their propagation in interstellar medium (ISM) after they leave the shock neighborhood where they are accelerated, but when they are still near the SNR with their energy density higher than that in the average ISM. Using Monte-Carlo simulations, we found that the cosmic-rays with energies of <~TeV excite Alfven waves around the SNR on a scale of the SNR itself if the ISM is highly ionized. Thus, even if the cosmic-rays can leave the shock, scattering by the waves prevents them from moving further away from the SNR. The cosmic-rays form a slowly expanding cosmic-ray bubble, and they spend a long time around the SNR. This means that the cosmic-rays cannot actually escape from the SNR until a fairly late stage of the SNR evolution. This is consistent with some results of Fermi and H.E.S.S. observations.

  6. The Imprint of Presupernova Winds on Supernova Remnant Evolution: Towards More Realistic Models for Type Ia Supernova Remnants and their Spectra

    Badenes, C.; E. Bravo

    2002-01-01

    Supernova remnants are usually analysed in the light of hydrodynamical models of the interaction of supernova ejecta with either a constant density ambient medium or a circumstellar medium produced by a constant presupernova wind. However, the ejection of energetic wind during the presupernova phase changes the ambient medium structure and, consequently, the early supernova remnant evolution. We have analysed the evolution of young remnants of type Ia supernovae, focusing on the imprint of th...

  7. The Impact of a Supernova Remnant on Fast Radio Bursts

    Piro, Anthony L.

    2016-06-01

    Fast radio bursts (FRBs) are millisecond bursts of radio radiation whose progenitors, so far, remain mysterious. Nevertheless, the timescales and energetics of these events have lead to many theories associating FRBs with young neutron stars (NSs). Motivated by this, I explore the interaction of FRBs with young supernova remnants (SNRs), and I discuss the potential observational consequences and constraints of such a scenario. As the supernova (SN) ejecta plows into the interstellar medium (ISM), a reverse shock is generated that passes back through the material and ionizes it. This leads to a dispersion measure (DM) associated with the SNR as well as a time derivative for DM. The times when DM is high are generally overshadowed by free–free absorption, which, depending on the mass of the ejecta and the density of the ISM, may be probed at frequencies of 400 {{MHz}}–1.4 {{GHz}} on timescales of ∼100–500 years after the SN. Magnetic fields generated at the reverse shock may be high enough to explain Faraday rotation that has been measured for one FRB. If FRBs are powered by the spin energy of a young NS (rather than by magnetic energy), the NS must have a magnetic field ≲ {10}11{--}{10}12 {{G}} to ensure that it does not spin down too quickly while the SNR is still optically thick at radio frequencies. In the future, once there are distance measurements to FRBs and their energetics are better understood, the spin of the NS can also be constrained.

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

    Hewitt, John W.

    2011-01-01

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

  9. Non-linear diffusion of cosmic rays escaping from supernova remnants I: the effect of neutrals

    Nava, Lara; Marcowith, Alexandre; Morlino, Giovanni; Ptuskin, Vladimir S

    2016-01-01

    Supernova remnants are believed to be the main sources of galactic Cosmic Rays (CR). Within this framework, particles are accelerated at supernova remnant shocks and then released in the interstellar medium. The mechanism through which CRs are released and the way in which they propagate still remain open issues. The main difficulty is the high non-linearity of the problem: CRs themselves excite the magnetic turbulence that confines them close to their sources. We solve numerically the coupled differential equations describing the evolution in space and time of the escaping particles and of the waves generated through the CR streaming instability. The warm ionized and warm neutral phases of the interstellar medium are considered. These phases occupy the largest fraction of the disk volume, where most supernovae explode, and are characterised by the significant presence of neutral particles. The friction between those neutrals and ions results in a very effective wave damping mechanism. It is found that stream...

  10. SUPERNOVA REMNANT PROGENITOR MASSES IN M31

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

  11. SUPERNOVA REMNANT PROGENITOR MASSES IN M31

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

    2012-12-10

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

  12. Multifrequency Studies of Bright Radio Supernova Remnants. III. X-Ray and Radio Observations of 3C 397

    Dyer, K. K.; Reynolds, S. P.

    1999-01-01

    Radio-bright, presumably young supernova remnants offer the opportunity of studying strong-shock physics and the nature of the interaction of ejected material with the surrounding medium. We use VLA and ROSAT images of the radio-bright supernova remnant 3C 397 (G41.1--0.3) to examine the shock structure in both thermal X-ray emission and nonthermal radio emission. The unusual rectangular morphology can be seen in VLA maps at 20 and 6 cm wavelength at a resolution of 6", and in ROSAT HRI image...

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

    Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.;

    2016-01-01

    The all-sky Planck survey in 9 frequency bands was used to search for emission from all 274 known Galactic supernova remnants. Of these, 16 were detected in at least two Planck frequencies. The radio-through-microwave spectral energy distributions were compiled to determine the mechanism for...... microwave emission. In only one case, IC 443, is there high-frequency emission clearly from dust associated with the supernova remnant. In all cases, the low-frequency emission is from synchrotron radiation. As predicted for a population of relativistic particles with energy distribution that extends...

  14. X-Ray Studies of Supernova Remnants: A Different View of Supernova Explosions

    Badenes, Carles

    2010-01-01

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent data sets accumulated on young, ejecta dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints o...

  15. The oxygen-rich supernova remnant in the Small Magellanic Cloud

    The authors report ultraviolet and optical spectra of 1E 0102--7219, the oxygen-rich supernova remnant in the Small Magellanic Cloud. The UV data contain strong lines of oxygen, carbon, neon, and magnesium. OI recombination lines in the optical and UV permit the relative line intensities to be determined from 1200 angstrom to 1 micron. Models assuming shock excitation and x-ray photoionization have been calculated and compared with the observations

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

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

    2015-01-01

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

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

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

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

    Humensky, Brian

    2015-01-01

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

  19. On the Nonthermal Emission from the Supernova Remnant W51C

    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 emission from W51C. Th...

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

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

  1. The Neutron Star Born in the Antlia Supernova Remnant

    Tetzlaff, Nina; Torres, Guillermo; 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 dist...

  2. TYPING SUPERNOVA REMNANTS USING X-RAY LINE EMISSION MORPHOLOGIES

    We present a new observational method to type the explosions of young supernova remnants (SNRs). By measuring the morphology of the Chandra X-ray line emission in 17 Galactic and Large Magellanic Cloud SNRs with a multipole expansion analysis (using power ratios), we find that the core-collapse SNRs are statistically more asymmetric than the Type Ia SNRs. We show that the two classes of supernovae can be separated naturally using this technique because X-ray line morphologies reflect the distinct explosion mechanisms and structure of the circumstellar material. These findings are consistent with recent spectropolarimetry results showing that core-collapse supernovae explosions are intrinsically more asymmetric.

  3. Supernova 1987A: A young supernova remnant in an aspherical progenitor wind

    Gaensler, B. M.; Manchester, R. N.; Staveley-Smith, L.; Wheaton, V; Tzioumis, A. K.; Reynolds, J. E.; Kesteven, M. J.

    1999-01-01

    The interaction between the ejecta from Supernova 1987A and surrounding material is producing steadily brightening radio and X-ray emission. The new-born supernova remnant has been significantly decelerated by this interaction, while its morphology reflects the axisymmetric nature of the progenitor wind.

  4. Supernova 1987A A young supernova remnant in an aspherical progenitor wind

    Gaensler, B M; Staveley-Smith, L; Wheaton, V C; Tzioumis, A K; Reynolds, J E; Kesteven, M J

    1999-01-01

    The interaction between the ejecta from Supernova 1987A and surrounding material is producing steadily brightening radio and X-ray emission. The new-born supernova remnant has been significantly decelerated by this interaction, while its morphology reflects the axisymmetric nature of the progenitor wind.

  5. Are the models for type Ia supernova progenitors consistent with the properties of supernova remnants?,

    Badenes, C.; Hughes, J. P.; E. Bravo; Langer, N.

    2007-01-01

    We explore the relationship between the models for progenitor systems of Type Ia supernovae and the properties of the supernova remnants that evolve after the explosion. Most models for Type Ia progenitors in the single-degenerate scenario predict substantial outflows during the presupernova evolution. Expanding on previous work, we estimate the imprint of these outflows on the structure of the circumstellar medium at the time of the supernova explosion, and the effect that this modified circ...

  6. HI absorption spectra for Supernova Remnants in the VGPS survey

    Leahy, Denis

    2016-01-01

    The set of supernova remnants (SNR) from Green's SNR catalog which are found in the VLA Galactic Plane Survey (VGPS) are the objects considered in this study. For these SNR, we extract and analyse HI absorption spectra in a uniform way and construct a catalogue of absorption spectra and distance determinations.

  7. Expectation on Observation of Supernova Remnants with the LHAASO Project

    Liu, Ye; Chen, Songzhan; Chen, Yang; Cui, Shuwang; He, Huihai; Huang, Xingtao; Ma, Xinhua; Yuan, Qiang; Zhang, Xiao

    2016-01-01

    Supernova remnants (SNRs) are believed to be the most important acceleration sites for cosmic rays (CRs) below $\\sim10^{15}$ eV in the Galaxy. High energy photons, either directly from the shocks of the SNRs or indirectly from the interaction between SNRs and the nearby clouds, are crucial probes for the CR acceleration. Big progresses on observations of SNRs have been achieved by space- and ground-based $\\gamma$-ray facilities. However, whether $\\gamma$-rays come from accelerated hadrons or not, as well as their connection with the CRs observed at Earth, remains in debate. Large High Altitude Air Shower Observatory (LHAASO), the next generation experiment, is designed to survey the northern part of the very high energy $\\gamma$-ray sky from $\\sim 0.3$ TeV to PeV with the sensitivity of $\\lesssim1\\%$ of the Crab nebula flux. In this paper, we indicate that LHAASO will be dedicated to enlarging the $\\gamma$-ray SNR samples and improving the spectral and morphological measurements. These measurements, especiall...

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

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

    2013-04-01

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

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

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

    2016-01-01

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

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

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

    2015-01-01

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

  11. Properties of optically selected supernova remnant candidates in M33

    Lee, Jong Hwan; Lee, Myung Gyoon, E-mail: leejh@astro.snu.ac.kr, E-mail: mglee@astro.snu.ac.kr [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    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]/Hα and round morphology in the continuum-subtracted Hα 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, α = 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]/Hα) of the remnants has two concentrations at [S II]/Hα ∼ 0.55 and ∼0.8, as in M31. Interestingly, L {sub X} (and L {sub 20cm}) 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.

  12. Properties of Optically Selected Supernova Remnant Candidates in M33

    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]/Hα and round morphology in the continuum-subtracted Hα 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, α = 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]/Hα) of the remnants has two concentrations at [S II]/Hα ~ 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.

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

    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 ...

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

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

    1997-01-01

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

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

    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...

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

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

    2014-01-01

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

  17. The supernova remnant W51C: a plausible source of galactic cosmic rays?

    Gozzini, S. R.; Carmona, E.; Jankowski, F.; Krause, J.; Reichardt, I.; MAGIC Collaboration

    2013-02-01

    Supernova remnants are a probable site of acceleration of particles via diffusive shock processes. High energies carried by electrons or protons are radiated into photons detectable from radio to γ rays. MAGIC has recently observed W51C, one of the most luminous galactic supernova remnants, and completed its spectrum between 50 GeV and 5 TeV. We modelled different processes for high energy photon emission of this source, and compared the predictions with the measured spectral energy distribution. It is plausible that hadrons are accelerated in the expansion front of this source, in interaction with the surrounding molecular cloud, and photons are produced in the decay of neutral mesons created in hadronic collisions.

  18. First optical detection from the supernova remnant G 15.1-1.6

    Boumis, P; Christopoulou, P E; Mavromatakis, F; Xilouris, E M; Goudis, C D

    2008-01-01

    Deep optical CCD images of the supernova remnant G 15.1-1.6 were obtained and filamentary and diffuse emission has been discovered. The images, taken in the emission lines of Halpha+[N II], [S II] and [O III], reveal filamentary and diffuse structures all around the remnant. The radio emission at 4850 MHz in the same area is found to be well correlated with the brightest optical filaments. The IRAS 60 micron emission may also be correlated with the optical emission but to a lesser extent. The flux calibrated images suggest that the optical emission originates from shock-heated gas ([S II]/Halpha > 0.4), while there is a possible HII region ([S II]/Halpha ~0.3) contaminating the supernova remnant's emission to the east. Furthermore, deep long-slit spectra were taken at two bright filaments and also show that the emission originates from shock heated gas. An [O III] filamentary structure has also been detected further to the west but it lies outside the remnant's boundaries and possibly is not associated to it....

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

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

    2015-01-01

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

  20. The 1st Fermi Lat Supernova Remnant Catalog

    Acero, Fabio; Ackermann, Markus; Ajello, Marco; Baldini, Luca; Ballet, Jean; Barbiellini, Guido; Bastieri, Denis; Bellazzini, Ronaldo; Bissaldi, E.; Blandford, Roger; Bloom, E. D.; Bonino, Raffaella; Bottacini, Eugenio; Bregeon, J.; Bruel, Philippe

    2015-01-01

    To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope. Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which the positions of known remnants are scrambled in Gala...

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

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

    2013-01-01

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

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

    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.

  3. Understanding hadronic gamma-ray emission from supernova remnants

    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

  4. Galactic Propagation of Cosmic Rays from Individual Supernova Remnants

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

    2015-01-01

    It is widely believed that supernova remnants are the best candidate sources for the observed cosmic ray flux up to the knee, i.e. up to ~PeV energies. Indeed, the gamma-ray spectra of some supernova remnants can be well explained by assuming the decay of neutral pions which are created in hadronic interactions. Therefore, fitting the corresponding gamma spectra allows us to derive the spectra of cosmic rays at the source which are locally injected into our Galaxy. Using these spectra as a starting point, we propagate the cosmic rays through the Galaxy using the publicly available GALPROP code. Here, we will present first results on the contribution of those SNRs to the total cosmic ray flux and discuss implications.

  5. New supernova remnants from deer radio continuum surveys

    Based on radio continuum surveys of the Galactic plane at wavelengths of 21 cm and 11 cm we have so far identified about 32 new supernova remnants in the area 357 degrees .4 ≤ l ≤ 76 degrees, |b| ≤ 5 degrees. This increases the number of known objects in this field by about 68%. Most of them are in the galactic latitude range |b| > 0 degrees.5. Some implications are discussed

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

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

  7. Fermi Large Area Telescope Detection of Supernova Remnant RCW 86

    Yuan, Qiang; Liu, Siming; Zhang, Bing

    2014-01-01

    Using $5.4$ year Fermi-LAT data, we report the detection of GeV $\\gamma$-ray emission from the shell-type supernova remnant RCW 86 (G315.4-2.3) with a significance of $\\sim5.1\\sigma$. The data slightly favors an extended emission of this supernova remnant. The spectral index of RCW 86 is found to be very hard, $\\Gamma\\sim1.4$, in the $0.4$ to $300$ GeV range. A one zone leptonic model can well fit the multi-wavelength data from radio to very high energy $\\gamma$-rays. The very hard GeV $\\gamma$-ray spectrum and the inferred low gas density seem to disfavor the hadronic origin of the $\\gamma$-rays. The $\\gamma$-ray behavior of RCW 86 is very similar to several other TeV shell-type supernova remnants, e.g., RX J1713.7-3946, RX J0852.0-4622, SN 1006 and HESS J1731-347.

  8. A Newly Recognized Very Young Supernova Remnant in M83

    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....

  9. Correlation of Supernova Remnant Masers and Gamma-Ray Sources

    Hewitt, John W; Wardle, Mark

    2009-01-01

    Supernova remnants interacting with molecular clouds are potentially exciting systems in which to detect evidence of cosmic ray acceleration. Prominent gamma-ray emission is produced via the decay of neutral pions when cosmic rays encounter the nearby dense clouds. In many of the supernova remnants coincident with gamma-ray sources, the presence of OH(1720 MHz) masers is used to identify interaction with dense gas and to provide a kinematic distance to the system. In this paper we use statistical tests to demonstrate that there is a correlation between these masers and a class of GeV- to TeV-energy gamma-ray sources coincident with interacting remnants. For pion decay, the gamma-ray luminosity provides a direct estimate of the local cosmic ray density. We find the cosmic ray density is enhanced by one to two orders of magnitude over the local solar value, comparable to X-ray-induced ionization in these remnants. The inferred ionization rates are sufficient to explain non-equilibrium chemistry in the post-shoc...

  10. 3D simulations of young core-collapse supernova remnants undergoing efficient particle acceleration

    Ferrand, Gilles

    2016-01-01

    Within our Galaxy, supernova remnants are believed to be the major sources of cosmic rays up to the "knee". However important questions remain regarding the share of the hadronic and leptonic components, and the fraction of the supernova energy channelled into these components. We address such question by the means of numerical simulations that combine a hydrodynamic treatment of the shock wave with a kinetic treatment of particle acceleration. Performing 3D simulations allows us to produce synthetic projected maps and spectra of the thermal and non-thermal emission, that can be compared with multi-wavelength observations (in radio, X-rays, and gamma-rays). Supernovae come in different types, and although their energy budget is of the same order, their remnants have different properties, and so may contribute in different ways to the pool of Galactic cosmic-rays. Our first simulations were focused on thermonuclear supernovae, like Tycho's SNR, that usually occur in a mostly undisturbed medium. Here we present...

  11. Supernova Shock Breakout from a Red Supergiant

    Schawinski, Kevin; Justham, Stephen; Wolf, Christian; Podsiadlowski, Philipp; Sullivan, Mark; Steenbrugge, Katrien C.; Bell, Tony; Roeser, Hermann-Josef; Walker, Emma; Astier, Pierre; Balam, Dave; Balland, Christophe; Carlberg, Ray; Conley, Alex; Fouchez, Dominque

    2008-01-01

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

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

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

    2013-01-01

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

  13. Hadronic Scenarios for Gamma-Ray Emission from Three Supernova Remnants Interacting with Molecular Clouds

    Yu, Huan; Fang, Jun; Zhang, Li

    2014-04-01

    GeV γ-rays detected with the large area telescope on board the Fermi Gamma-ray space telescope in the direction of HB21, MSH 17-39 and G337.0-0.1 have been recently reported. The three supernova remnants (SNRs) show interactions with molecular clouds, and they are effective gamma-ray emitters as the relativistic protons accelerated by the SNR shocks inelastically colliding with the dense gas in the clouds. The origin of the observed γ-rays for the three remnants is investigated in the scenario of the diffusive shock acceleration. In the model, a part of the SNR shock transmits into the nearby molecular clouds, and the shock velocity is greatly reduced. As a result, a shock with a relatively low Alfvén Mach number is generated, and the spectra of the accelerated protons and the γ-ray photons produced via proton-proton interaction can be obtained. The results show that the observed γ-ray spectra for the three SNRs interacting with the molecular clouds can be reproduced. It can be concluded that the hadronic origin of the γ-rays for the three SNRs is approved, and the ability of SNR shocks to accelerate protons is also supported.

  14. A CO (J = 1-0) survey of five supernova remnants at l = 70 degrees-110 degrees

    A program of CO observations of five selected supernova remnants is in progress on the 4-m radio telescope at Nagoya. The authors report observations of two supernova remnants, G78.2 + 2.1 (the γ Cygni SNR) and HB21. In these two remnants we have obtained evidence for the interaction between the supernova remnants and molecular gas

  15. R-Process Ejecta in the VELA Supernova Remnant

    Wallerstein, George

    1990-12-01

    Groundbased, X-ray and radio studies reveal many properties of supernovae but none except for the neutrinos from SN1987A have been able to tell us anything about the mechanism of the explosion. By looking for r-process and heavy iron-peak isotopes we can estimate the amount of neutronized material ejected and hence get a grip on what actually happened during the explosion. We will search for interstellar absorption lines of KrI, HgII, Os II, W II, and Pt II in stars within and behind the Vela supernova remnant. Substantial quantities of these elements are expected to be ejected in supernova explosions. However, recent competing theories of the supernova explosion mechanism predict differing amounts of r-process ejecta and in this way our observation will provide important constraints on these models. This will be a direct observational input on the supernova mechanism, a theoretical problem on which much time, effort, and manpower have been expended.

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

    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.

  17. Discovery of A Large Cavity around the Tycho's Supernova Remnant

    Chen, Xuepeng; Yang, Ji

    2016-01-01

    We present large-field (3x2 deg^2) and high-sensitivity CO(1-0) molecular line observations toward the Tycho's supernova remnant, using the 13.7-meter radio telescope of the Purple Mountain Observatory. Based on the CO observations, we discover a large cavity around the remnant, with radii of about 0.3x0.6 deg (or ~13x27 pc at a distance of 2.5 kpc), which is further supported by the complementary infrared images from the space telescopes. The observed CO line broadenings and asymmetries in the surrounding clouds, the infrared pillar-like structures found around the remnant, in concert with enhanced 12CO(2-1)/(1-0) intensity ratio detected in previous studies, indicate strong interaction of the large cavity with a wind in the region. After excluding the scenario of a large bubble produced by bright massive stars, we consider that the large cavity could be most likely explained by the accretion wind from the progenitor system of the Tycho's supernova. The CO gas kinematics indicates that the large cavity is ex...

  18. Interaction between the Supernova Remnant HB 3 and the Nearby Star-Forming Region W3

    Zhou, Xin; Fang, Min; Su, Yang; Sun, Yan; Chen, Yang

    2016-01-01

    We performed millimeter observations in CO lines toward the supernova remnant (SNR) HB 3. Substantial molecular gas around -45 km s^-1 is detected in the conjunction region between the SNR HB 3 and the nearby W3 complex. This molecular gas is distributed along the radio continuum shell of the remnant. Furthermore, the shocked molecular gas indicated by line wing broadening features is also distributed along the radio shell and inside it. By both morphological correspondence and dynamical evidence, we confirm that the SNR HB 3 is interacting with the -45 km s^-1 molecular cloud (MC), in essence, with the nearby H II region/MC complex W3. The red-shifted line wing broadening features indicate that the remnant is located at the nearside of the MC. With this association, we could place the remnant at the same distance as the W3/W4 complex, which is 1.95 +- 0.04 kpc. The spatial distribution of aggregated young stellar object candidates (YSOc) shows a correlation to the shocked molecular strip associated with the ...

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

    Crawford, E. J.; Filipović, 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); Urošević, 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 Γ = 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 α = –0.59 ± 0.09, we find that an equipartition magnetic field for the remnant is ∼90 μG, 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%.

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

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

    2014-01-01

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

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

    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...

  2. Radio structure of the remnant of Tycho's supernova (SN 1572)

    The radio emission from the remnant of Tycho's supernova of 1572 arises in a nearly circular, clumpy shell. A very distinct, thin bright rim just outside the main shell can be seen around most of the periphery of the remnant. The outer edge of radio emission, usually defined by this bright rim, coincides perfectly with the outer X-ray boundary. Most of the emission is polarized by a modest amount, with the outer rim particularly prominent. Observations at several wavelengths are used to map out the rotation measure at high angular resolution, and determine the intrinsic magnetic field direction. The magnetic field shows a somewhat cellular pattern but with a net radial orientation and a generally fairly low degree of polarization. 44 refs

  3. 84 gigahertz observations of five Crab-like supernova remnants

    Flux density measurements at 3.6 mm have been made to extend the frequency coverage for three Crablike remnants and two Crablike components within remnants whose large-scale morphologies show shell-type structure. All five objects show flat, polarized, nonthermal radio spectra and associated X-ray emission characteristic of this class. The flux density is found to be lower than expected on the basis of an extrapolation of the spectrum from lower frequencies. If this is due to steepening caused by evolutionary effects, severe constraints can be put on the characteristics of the objects showing spectral steepening: all must be less than 2000 yr old, and the supernovae in which they were born must all have had very unusual properties. 30 refs

  4. Dynamics of supernova remnants in the Galactic Centre

    Bortolas, Elisa; Spera, Mario

    2016-01-01

    The Galactic centre (GC) is a unique place to study the extreme dynamical processes occurring near a super-massive black hole (SMBH). Here we simulate a large set of binaries orbiting the SMBH while the primary member undergoes a supernova (SN) explosion, in order to study the impact of SN kicks on the orbits of stars and dark remnants in the GC. We find that SN explosions are efficient in scattering neutron stars and other light stars on new (mostly eccentric) orbits, while black holes (BHs) tend to retain memory of the orbit of their progenitor star. SN kicks are thus unable to eject BHs from the GC: a cusp of dark remnants may be lurking in the central parsec of our Galaxy.

  5. Constraints on the distribution of supernova remnants with Galactocentric radius

    Green, D A

    2015-01-01

    Supernova remnants (SNRs) in the Galaxy are an important source of energy injection into the interstellar medium, and also of cosmic rays. Currently there are 294 known SNRs in the Galaxy, and their distribution with Galactocentric radius is of interest for various studies. Here I discuss some of the statistics of Galactic SNRs, including the observational selection effects that apply, and difficulties in obtaining distances for individual remnants from the `Sigma-D' relation. Comparison of the observed Galactic longitude distribution of a sample of bright Galactic SNRs -- which are not strongly affected by selection effects -- with those expected from models is used to constrain the Galactic distribution of SNRs. The best-fitting power-law/exponential model is more concentrated towards the Galactic centre than the widely used distribution obtained by Case & Bhattacharya (1998).

  6. High-energy antiprotons from old supernova remnants

    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.

  7. Radio and X-ray emission from supernova remnants

    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 study 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 we have simulated statistical relations radio - X-ray luminosities (not surface brightnesses) 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

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

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

  9. New Models for X-Ray Synchrotron Radiation from the Remnant of Supernova 1006 AD

    Dyer, K K; Borkowski, K J

    2000-01-01

    Galactic cosmic rays up to energies of around 10^15 eV are assumed to originate in supernova remnants (SNRs). The shock wave of a young SNR like SN 1006 AD can accelerate electrons to energies greater than 1 TeV, where they can produce synchrotron radiation in the X-ray band. A new model (SRESC) designed to model synchrotron X-rays from Type Ia supernovae can constrain values for the magnetic-field strength and electron scattering properties, with implications for the acceleration of the unseen ions which dominate the cosmic-ray energetics. New observations by ASCA, ROSAT, and RXTE have provided enormously improved data, which now extend to higher X-ray energies. These data allow much firmer constraints. We will describe model fits to these new data on SN 1006 AD, emphasizing the physical constraints that can be placed on SNRs and on the cosmic-ray acceleration process.

  10. 3D simulations of the non-thermal broad-band emission from young supernova remnants including efficient particle acceleration

    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...

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

    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. Spitzer observations of the N157B supernova remnant and its surroundings

    Micelotta, E R; Israel, F P; 10.1051/0004-6361/200809849

    2009-01-01

    (Aims): We study the LMC interstellar medium in the field of the nebula N157B, which contains a supernova remnant, an OB association, ionized gas, and high-density dusty filaments in close proximity. We investigate the relative importance of shock excitation by the SNR and photo-ionization by the OB stars, as well as possible interactions between the supernova remnant and its environment. (Methods): We apply multiwavelength mapping and photometry, along with spatially resolved infrared spectroscopy, to identifying the nature of the ISM using new infrared data from the Spitzer space observatory and X-ray, optical, and radio data from the literature. (Results): The N157B SNR has no infrared counterpart. Infrared emission from the region is dominated by the compact blister-type HII region associated with 2MASS J05375027-6911071 and excited by an O8-O9 star. This object is part of an extended infrared emission region that is associated with a molecular cloud. We find only weak emission from the shock-indicator [F...

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

    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...

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

    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.

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

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

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

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

    2014-05-20

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

  17. The 1st Fermi Lat Supernova Remnant Catalog

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

    2015-01-01

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

  18. Dynamical evolution of supernova remnants breaking through molecular clouds

    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...

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

    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.

  20. Evolution of Supernova Remnants near the Galactic Center

    Yalinewich, Almog; Sari, Re'em

    2016-01-01

    Supernovae near the galactic center evolve differently from regular galactic supernovae. This is mainly due to the environment into which the supernova remnants propagate. Instead of a static, uniform density medium, SNRs near the galactic center propagate into a wind swept environment with a velocity away from the galactic center, and a graded density profile. This causes these SNRs to be non - spherical, and to evolve faster than their galactic counterparts. We develop an analytic theory for the evolution of explosions within a stellar wind, and verify it using a hydrodynamic code. We show that such explosions can evolve in one of three possible morphologies. Using these results we discuss the association between the two SNRs (SGR East and SGR A's bipolar radio/X-ray Lobes) and the two neutron stars (the cannonball and SGR J1745-2900) near the galactic center. We show that, given the morphologies of the SNR and positions of the neutron stars, the only possible association is between SGR A's bipolar radio/X-...

  1. High-velocity, high-excitation neutral carbon in a cloud in the Vela supernova remnant

    Jenkins, Edward B.; Wallerstein, George

    1995-01-01

    HD 72089 is situated behind the Vela supernova remnant, and the interstellar absorption lines in the spectrum of this star are remarkable for two reasons. First, there are six distinct velocity components that span the (heliocentric) velocity range -60 to +121 km/s in the lines of Na I and Ca II. Second, two of the components at high velocity, one at +85 km/s and another at +121.5 km/s, have densities that are large enough to produce observable lines from neutral carbon. The gas moving at +121.5 km/s has such a large pressure that the excited fine-structure levels of the ground electronic state of C I are collisionally populated nearly in proportion to their level degeneracies. This high-velocity gas exhibits unusually low column densities of Mg I and Na I, compared to that of C I. We propose that the +121.5 km/s component represents gas that has cooled and recombined in a zone that follows a shock driven into a cloud by the very recent passage of a supernova blast wave. A representative preshock density of n(sub H) approximately = 13/cc and velocity v(sub s) = 100 km/s is indicated by the strength of diffuse (O III) emission lines seen in directions very near HD 72089. The strong collisional population of excited C I and apparent absence of excited levels of O I give a most favorable fit to the conditions 1000 less than n(sub H) less than 2900/cc over a temperature range 300 less than T less than 1000 K. The fact that the compression is not substantially more than this indicates that the preshock gas may have had an embedded, transverse magnetic field with a strength B greater than or approximately = 1 micro-G. The large dynamical pressure of the supernova blast wave that would be needed to create the cloud shock that we describe implies that the energy of the supernova was 8 x 10(exp 51) ergs, if the Vela remnant is 500 pc away. We can bring this value much closer to typical supernova energies E less than or approximately = 10(exp 51) ergs if the distance to the

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

    Biscaro, Chiara

    2015-01-01

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

  3. Supernova Shock Breakout from a Red Supergiant

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

    2008-01-01

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

  4. Discovery of optical emission from the supernova remnant G 32.8-0.1 (Kes 78)

    Boumis, P; Alikakos, J; Christopoulou, P E; Mavromatakis, F; Katsiyannis, A C; Goudis, C D

    2009-01-01

    Deep optical CCD images of the supernova remnant G 32.8-0.1 were obtained where filamentary and diffuse emission was discovered. The images were acquired in the emission lines of Halpha+[N II] and [S II]. Filamentary and diffuse structures are detected in most areas of the remnant, while no significant [O III] emission is present. The flux-calibrated images suggest that the optical emission originates from shock-heated gas since the [S II]/Halpha ratio is greater than 1.2. The Spitzer images at 8 micron and 24 micron show a few filamentary structures to be correlated with the optical filaments, while the radio emission at 1.4 GHz in the same area is found to be very well correlated with the brightest optical filaments. Furthermore, the results from deep long-slit spectra also support the origin of the emission to be from shock-heated gas ([S II]/Halpha > 1.5). The absence of [O III] emission indicates slow shocks velocities into the interstellar "clouds" (< 100 km/s), while the [S II] 6716/6731 ratio indic...

  5. 3D simulations of supernova remnants evolution including non-linear particle acceleration

    Ferrand, Gilles; Ballet, Jean; Teyssier, Romain; Fraschetti, Federico

    2009-01-01

    If a sizeable fraction of the energy of supernova remnant shocks is channeled into energetic particles (commonly identified with Galactic cosmic rays), then the morphological evolution of the remnants must be distinctly modified. Evidence of such modifications has been recently obtained with the Chandra and XMM-Newton X-ray satellites. To investigate these effects, we coupled a semi-analytical kinetic model of shock acceleration with a 3D hydrodynamic code (by means of an effective adiabatic index). This enables us to study the time-dependent compression of the region between the forward and reverse shocks due to the back reaction of accelerated particles, concomitantly with the development of the Rayleigh-Taylor hydrodynamic instability at the contact discontinuity. Density profiles depend critically on the injection level eta of particles: for eta up to about 10^-4 modifications are weak and progressive, for eta of the order of 10^-3 modifications are strong and immediate. Nevertheless, the extension of the...

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

    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...

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

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

    2011-01-01

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

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

    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 γ-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 γ-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 γ-ray studies that are providing important constraints on our understanding of cosmic rays in our Galaxy.

  9. The contribution of supernova remnants to the galactic cosmic ray spectrum

    Caprioli, D; Blasi, P

    2009-01-01

    The supernova paradigm for the origin of galactic cosmic rays has been deeply affected by the development of the non-linear theory of particle acceleration at shock waves. Here we discuss the implications of applying such theory to the calculation of the spectrum of cosmic rays at Earth as accelerated in supernova remnants and propagating in the Galaxy. The spectrum is calculated taking into account the dynamical reaction of the accelerated particles on the shock, the generation of magnetic turbulence which enhances the scattering near the shock, and the dynamical reaction of the amplified field on the plasma. Most important, the spectrum of cosmic rays at Earth is calculated taking into account the flux of particles escaping from upstream during the Sedov-Taylor phase and the adiabatically decompressed particles confined in the expanding shell and escaping at later times. We show how the spectrum obtained in this way is well described by a power law in momentum with spectral index close to -4, despite the co...

  10. Origin of Galactic Cosmic Rays from Supernova Remnants

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

    2014-11-15

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

  11. The Likely Fermi Detection of the Supernova Remnant SN 1006

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

    2016-05-01

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

  12. Origin of Galactic Cosmic Rays from Supernova Remnants

    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. Type Ia Supernova Remnants: Shaping by Iron Bullets

    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.

  14. Observations of Supernova Remnants with the Sardinia Radio Telescope

    Egron, E; Loru, S; Iacolina, M N; Marongiu, M; Righini, S; Mulas, S; Murtas, G; Bachetti, M; Concu, R; Melis, A; Trois, A; Ricci, R; Pilia, M

    2016-01-01

    In the frame of the Astronomical Validation activities for the 64m Sardinia Radio Telescope, we performed 5-22 GHz imaging observations of the complex-morphology supernova remnants (SNRs) W44 and IC443. We adopted innovative observing and mapping techniques providing unprecedented accuracy for single-dish imaging of SNRs at these frequencies, revealing morphological details typically available only at lower frequencies through interferometry observations. High-frequency studies of SNRs in the radio range are useful to better characterize the spatially-resolved spectra and the physical parameters of different regions of the SNRs interacting with the ISM. Furthermore, synchrotron-emitting electrons in the high-frequency radio band are also responsible for the observed high-energy phenomenology as -e.g.- Inverse Compton and bremsstrahlung emission components observed in gamma-rays, to be disentangled from hadron emission contribution (providing constraints on the origin of cosmic rays).

  15. Molecules and dust in Cassiopeia A. II. Dust sputtering and diagnosis of supernova dust survival in remnants

    Biscaro, Chiara; Cherchneff, Isabelle

    2016-04-01

    We study the dust evolution in the supernova remnant Cassiopeia A. We follow the processing of dust grains that formed in the Type II-b supernova ejecta by modelling the sputtering of grains. The dust is located in dense ejecta clumps that are crossed by the reverse shock. We also investigate further sputtering in the inter-clump medium gas once the clumps have been disrupted by the reverse shock. The dust evolution in the dense ejecta clumps of Type II-P supernovae and their remnants is also explored. We study oxygen-rich clumps that describe the oxygen core of the ejecta, and carbon-rich clumps that correspond to the outermost carbon-rich ejecta zone. We consider the various dust components that form in the supernova, several reverse shock velocities and inter-clump gas temperatures, and derive grain-size distributions and masses for the dust as a function of time. Both non-thermal sputtering within clumps and thermal sputtering in the inter-clump medium gas are studied. We find that non-thermal sputtering in the clumps is important for all supernova types and accounts for reducing the grain population by ~ 40% to 80% in mass, depending on the clump gas over-density, the grain type and size, and the shock velocity in the clump. A Type II-b SN forms small grains that are sputtered within the clumps and in the inter-clump medium. For Cas A, silicate grains do not survive thermal sputtering in the inter-clump medium, while alumina, silicon carbide, and carbon dust may survive in the remnant. Our derived masses of currently processed silicate, alumina and carbon grains agree well with the values derived from the observations of warm dust, and seem to indicate that the dust is currently being processed within clumps by non-thermal sputtering. Out of the ~ 0.03M⊙ of dust formed in the ejecta, between 30% and 60% of this mass is present today in Cas A, and only 6% to 11% of the initial mass will survive the remnant phase. Grains formed in Type II-P supernovae are

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

    Morlino, G

    2015-01-01

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

  17. NH$_3$(3,3) and CH$_3$OH near Supernova Remnants: GBT and VLA Observations

    McEwen, Bridget; Sjouwerman, Loránt

    2016-01-01

    We report on Green Bank Telescope 23.87 GHz NH$_3$(3,3), emission observations in five supernova remnants interacting with molecular clouds (G1.4$-$0.1, IC443, W44, W51C, and G5.7$-$0.0). The observations show a clumpy gas density distribution, and in most cases the narrow line widths of $\\sim3-4$\\,km\\,s$^{-1}$ are suggestive of maser emission. Very Large Array observations reveal 36~GHz and/or 44~GHz CH$_3$OH, maser emission in a majority (72\\%) of the NH$_3$, peak positions towards three of these SNRs. This good positional correlation is in agreement with the high densities required for the excitation of each line. Through these observations we have shown that CH$_3$OH, and NH$_3$, maser emission can be used as indicators of high density clumps of gas shocked by supernova remnants, and provide density estimates thereof. Modeling of the optical depth of the NH$_3$(3,3) emission is compared to that of CH$_3$OH, constraining the densities of the clumps to a typical density of the order of $10^5$~cm$^{-3}$ for ...

  18. FUSE Observations of an X-Ray Bright Region in the Vela Supernova Remnant

    Sankrit, R; Blair, W P; Sembach, K R; Jenkins, E B; Sankrit, Ravi

    2000-01-01

    We present the results of a FUSE observation of an X-ray selected knot in the Vela supernova remnant. Spectra were obtained through the 30"x30" low resolution aperture and the 4"x20" medium resolution aperture. O VI 1032,1038 and C III 977 are detected strongly in both spectra, and S VI 933,944 is detected weakly only in the larger aperture spectrum. We also report the first detection of C II 1037 emission in a supernova remnant. The spectra show the presence of two kinematic components along the line of sight - one with both low and high excitation emission centered at a velocity of -50 km/s and another with only low excitation emission centered at a velocity of +100 km/s. We associate the -50 km/s component with the observed X-ray knot, and find a dynamical pressure of 3.7x10^{-10} dyne cm^{-2} driving the shock. We compare our results with data obtained using the Hopkins Ultraviolet Telescope at nearby locations and find that differences in the spectra imply the existence of two emitting components in the ...

  19. The supernova remnant W44: a ase of cosmic-Ray reacceleration

    Cardillo, Martina; Blasi, Pasquale

    2016-01-01

    Supernova remnants (SNRs) are thought to be the primary sources of Galactic Cosmic Rays (CRs). In the last few years, the wealth of gamma-ray data collected by GeV and TeV instruments has provided important information about particle energisation in these astrophysical sources, allowing us to make progress in assessing their role as CR accelerators. In particular, the spectrum of the gamma-ray emission detected by AGILE and Fermi-LAT from the two middle aged Supernova Remnants (SNRs) W44 and IC443, has been proposed as a proof of CR acceleration in SNRs. Here we discuss the possibility that the radio and gamma-ray spectra from W44 may be explained in terms of re-acceleration and compression of Galactic CRs. The recent measurement of the interstellar CR flux by Voyager I has been instrumental for our work, in that the result of the reprocessing of CRs by the shock in W44 depends on the CR spectrum at energies that are precluded to terrestrial measurement due to solar modulation. We introduce both CR protons an...

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

    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 ...

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

    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

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

  3. DISCOVERY OF NEW INTERACTING SUPERNOVA REMNANTS IN THE INNER GALAXY

    OH(1720 MHz) masers are excellent signposts of interaction between supernova remnants (SNRs) and molecular clouds. Using the Green Bank Telescope and Very Large Array we have surveyed 75 SNRs and six candidates for masers. Four SNRs are detected with OH masers: G5.4-1.2, G5.7-0.0, G8.7-0.1, and G9.7-0.0. Two SNRs, G5.7-0.0 and G8.7-0.1, have TeV γ-ray counterparts which may indicate a local cosmic ray enhancement. It has been noted that maser-emitting (ME) SNRs are preferentially distributed in the molecular ring and nuclear disk. We use the present and existing surveys to demonstrate that masers are strongly confined to within |l| ≤ 50 deg. at a rate of 15% of the total SNR population. All new detections are within 10 deg. Galactic longitude emphasizing this trend. Additionally, a substantial number of SNR masers have peak fluxes at or below the detection threshold of existing surveys. This calls into question whether maser surveys of Galactic SNRs can be considered complete and how many ME remnants remain to be detected in the Galaxy.

  4. FERMI LARGE AREA TELESCOPE OBSERVATION OF SUPERNOVA REMNANT S147

    We present an analysis of gamma-ray data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope in the region around supernova remnant (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 >5σ confidence level. The gamma-ray flux is (3.8 ± 0.6) × 10–8 photons cm–2 s–1, corresponding to a luminosity of 1.3 × 1034 (d/1.3 kpc)2 erg s–1 in this energy range. The gamma-ray emission exhibits a possible spatial correlation with the prominent Hα filaments of SNR 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 π mesons produced through the proton-proton collisions in the filaments. The reacceleration of the pre-existing cosmic rays and subsequent adiabatic compression in the filaments is sufficient to provide the energy density required of high-energy protons.

  5. FERMI LARGE AREA TELESCOPE OBSERVATION OF SUPERNOVA REMNANT S147

    Katsuta, J.; Uchiyama, Y.; Tanaka, T.; Tajima, H.; Bechtol, K.; Funk, S.; Lande, J. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d' Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Hanabata, Y. [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Lemoine-Goumard, M. [Universite Bordeaux 1, CNRS/IN2p3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, 33175 Gradignan (France); Takahashi, T., E-mail: katsuta@slac.stanford.edu, E-mail: uchiyama@slac.stanford.edu [Institute of Space and Astronautical Science, Japanese Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)

    2012-06-20

    We present an analysis of gamma-ray data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope in the region around supernova remnant (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) Multiplication-Sign 10{sup -8} photons cm{sup -2} s{sup -1}, corresponding to a luminosity of 1.3 Multiplication-Sign 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 the prominent H{alpha} filaments of SNR 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. The reacceleration of the pre-existing cosmic rays and subsequent adiabatic compression in the filaments is sufficient to provide the energy density required of high-energy protons.

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

    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; 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Koehlenbeck, S; Kokeyama, K; Kondrashov, V; Korobko, M; Korth, W Z; Kowalska, I; Kozak, D B; Kringel, V; Krishnan, B; Królak, A; Krueger, C; Kuehn, G; Kumar, A; Kumar, P; Kuo, L; Kutynia, A; Landry, M; Lantz, B; Larson, S; Lasky, P D; Lazzarini, A; Lazzaro, C; Le, J; Leaci, P; Leavey, S; Lebigot, E; Lebigot, E O; Lee, C H; Lee, H K; Lee, H M; Leonardi, M; Leong, J R; Leroy, N; Letendre, N; Levin, Y; Levine, B; Lewis, J; Li, T G F; Libbrecht, K; Libson, A; Lin, A C; Littenberg, T B; Lockerbie, N A; Lockett, V; Logue, J; Lombardi, A L; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J; Lubinski, M J; Lück, H; Lundgren, A P; Lynch, R; Ma, Y; Macarthur, J; MacDonald, T; Machenschalk, B; MacInnis, M; Macleod, D M; Magaña-Sandoval, F; Magee, R; Mageswaran, M; Maglione, C; Mailand, K; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Mandel, I; Mandic, V; Mangano, V; Mansell, G L; Mantovani, M; Marchesoni, F; Marion, F; Márka, S; Márka, Z; Markosyan, A; Maros, E; Martelli, F; Martellini, L; 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Nitz, A H; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Ochsner, E; O'Dell, J; Oelker, E; Ogin, G H; Oh, J J; Oh, S H; Ohme, F; Oppermann, P; Oram, R; O'Reilly, B; Ortega, W; O'Shaughnessy, R; Osthelder, C; Ott, C D; Ottaway, D J; Ottens, R S; Overmier, H; Owen, B J; Padilla, C; Pai, A; Pai, S; Palashov, O; Palomba, C; Pal-Singh, A; Pan, H; Pankow, C; Pannarale, F; Pant, B C; Paoletti, F; Papa, M A; Paris, H; Pasqualetti, A; Passaquieti, R; Passuello, D; Patrick, Z; Pedraza, M; Pekowsky, L; Pele, A; Penn, S; Perreca, A; Phelps, M; Pichot, M; Piergiovanni, F; Pierro, V; Pillant, G; Pinard, L; Pinto, I M; Pitkin, M; Poeld, J; Poggiani, R; Post, A; Poteomkin, A; Powell, J; Prasad, J; Predoi, V; Premachandra, S; Prestegard, T; Price, L R; Prijatelj, M; Principe, M; Privitera, S; Prix, R; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; Pürrer, M; Qin, J; Quetschke, V; Quintero, E; Quiroga, G; Quitzow-James, R; Raab, F J; Rabeling, D S; Rácz, I; Radkins, H; Raffai, P; Raja, S; 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Vetrano, F; Viceré, A; Vincent-Finley, R; Vinet, J -Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Vousden, W D; Vyatchanin, S P; Wade, A R; Wade, L; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, H; Wang, M; Wang, X; Ward, R L; Warner, J; Was, M; Weaver, B; Wei, L -W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Wessels, P; Westphal, T; Wette, K; Whelan, J T; White, D J; Whiting, B F; Wilkinson, C; Williams, L; Williams, R; Williamson, A R; Willis, J L; Willke, B; Wimmer, M; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Worden, J; Xie, S; Yablon, J; Yakushin, I; Yam, W; Yamamoto, H; Yancey, C C; Yang, Q; Yvert, M; Zadrożny, A; Zanolin, M; Zendri, J -P; Zhang, Fan; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhu, X J; Zucker, M E; Zuraw, S; Zweizig, J

    2014-01-01

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

  7. Search for surviving companions in type Ia supernova remnants

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

    2014-09-01

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

  8. Search for surviving companions in type Ia supernova remnants

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

  9. Gamma-ray emission from young supernova remnants: Hadronic or leptonic?

    Gabici, Stefano; Aharonian, Felix

    2016-07-01

    The debate on the nature of the gamma-ray emission from young supernova remnants is still open. Ascribing such emission to hadronic rather than leptonic processes would provide an evidence for the acceleration of protons and nuclei, and this fact would fit with the very popular (but not proven) paradigm that supernova remnants are the sources of Galactic cosmic rays. Here, we discuss this issue with a particular focus on the best studied gamma-ray-bright supernova remnant: RX J1713.7-3946.

  10. Gamma-ray emission from young supernova remnants: hadronic or leptonic?

    Gabici, S.; Aharonian, F. A.

    2015-01-01

    The debate on the nature of the gamma-ray emission from young supernova remnants is still open. Ascribing such emission to hadronic rather than leptonic processes would provide an evidence for the acceleration of protons and nuclei, and this fact would fit with the very popular (but not proven) paradigm that supernova remnants are the sources of Galactic cosmic rays. Here, we discuss this issue with a particular focus on the best studied gamma-ray-bright supernova remnant: RX~J1713.7-3946.