The ejecta kinematics of supernova remnants (SNRs) is one of crucial clues to understand the explosion mechanism of type Ia supernovae (SNe). In particular, the kinematic asymmetry of iron-peak elements provides the key to understanding physical processes taking place in the core of the exploding white dwarfs (WDs) although it has been poorly understood by observations. In this paper, we show for the first time the asymmetric expansion structure in the line-of-sight direction of Fe ejecta in Kepler's SNR revealed by spectral and imaging analysis using the Chandra archival data. We found that the K$α$ line centroid energy and line width is relatively lower ($<$ 6.4 keV) and narrower ($\sim$80 eV) around the center of the remnant, which implies that the majority of the Fe ejecta in the central region is red-shifted. At the outer regions, we identify bright blue-shifted structures as it might have been ejected as high velocity dense clumps. Taking into account the broad population of the Fe charge states, we estimate the red-shifted velocity of ~2,000 km/s and the blue-shifted velocity of ~3,000 km/s for each velocity structure. We also present a possibility that a portion of the Fe ejecta near the center are interacting with the dense circumstellar medium (CSM) on the near side of the remnant. As the origin of the asymmetric motion of the Fe ejecta, we suggest three scenarios, (1) the asymmetric distribution of the CSM, (2) the "shadow" in Fe cast by the companion star, and (3) the asymmetric explosion.
We report on the results from the analysis of our 114 ks Chandra HETGS observation of the Galactic core-collapse supernova remnant G292.0+1.8. To probe the 3D structure of the clumpy X-ray emitting ejecta material in this remnant, we measured Doppler shifts in emission lines from metal-rich ejecta knots projected at different radial distances from the expansion center. We estimate radial velocities of ejecta knots in the range of -2300 <~ v_r <~ 1400 km s^-1. The distribution of ejecta knots in velocity vs. projected-radius space suggests an expanding ejecta shell with a projected angular thic…
Many supernova remnants (SNRs) are characterized by a knotty ejecta structure. The Vela SNR is an excellent example of remnant in which detached clumps of ejecta are visible as X-ray emitting bullets that have been observed and studied in great detail. We aim at modelling the evolution of ejecta shrapnel in the Vela SNR, investigating the role of their initial parameters (position and density) and addressing the effects of thermal conduction and radiative losses. We performed a set of 2-D hydrodynamic simulations describing the evolution of a density inhomogeneity in the ejecta profile. We exp…
We report our measurements of the bulk radial velocity from a sample of small, metal-rich ejecta knots in Kepler's Supernova Remnant (SNR). We measure the Doppler shift of the He-like Si K$α$ line center energy in the spectra of these knots based on our $Chandra$ High-Energy Transmission Grating Spectrometer (HETGS) observation to estimate their radial velocities. We estimate high radial velocities of up to $\sim$ 8,000 km s$^{-1}$ for some of these ejecta knots. We also measure proper motions for our sample based on the archival $Chandra$ Advanced CCD Imaging Spectrometer (ACIS) data taken in…
We have performed a deep Chandra observation of Galactic Type Ia supernova remnant G299.2-2.9. Here we report the initial results from our imaging and spectral analysis. The observed abundance ratios of the central ejecta are in good agreement with those predicted by delayed-detonation Type Ia supernovae models. We reveal inhomogeneous spatial and spectral structures of metal-rich ejecta in G299.2-2.9. The Fe/Si abundance ratio in the northern part of the central ejecta is higher than that in the southern part. An elongation of ejecta material extends out to the western outermost boundary of t…
We performed general relativistic, long-term, axisymmetric neutrino radiation hydrodynamics simulations for the remnant formed after the binary neutron star merger, which consist of a massive neutron star and a torus surrounding it. As an initial condition, we employ the result derived in a three-dimensional, numerical relativity simulation for the binary neutron star merger. We investigate the properties of neutrino-driven ejecta. Due to the pair-annihilation heating, the dynamics of the neutrino-driven ejecta is significantly modified. The kinetic energy of the ejecta is about two times larg…
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, and the implied mass coordinates, are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks following reverse shock interaction with ejecta inhomogeneities. Based on the fitted emission m…
The thermal structure of the post-shock region of a young supernova remnant (SNR) is heavily affected by two main physical effects, the back-reaction of accelerated cosmic rays (CRs) and the Rayleigh-Taylor (RT) instabilities developing at the contact discontinuity between the ejecta and the shocked interstellar medium (ISM). Here, we investigate the role played by both physical mechanisms in the evolution of SNRs through detailed 3D MHD modeling. Our model describes the expansion of the remnant through a magnetized ISM, including consistently the initial ejecta clumping and the effects on sho…
We present here the results of the X-ray analysis of Galactic supernova remnant G346.6-0.2 observed with {\it Suzaku}. K-shell emission lines of Mg, Si, S, Ca and Fe are detected clearly for the first time. Strong emission lines of Si and S imply that X-ray emission nature of G346.6-0.2 is ejecta-dominated. The ejecta-dominated emission is well fitted with a combined model consisting of thermal plasma in non-equilibrium ionization and a non-thermal component, which can be regarded as synchrotron emission with a photon index of $Γ$ $\sim 0.6$. Absorbing column density of $N_{\rm H}\sim2.1\times…
Clumpy structures are a common feature in X-ray images of young Type Ia supernova remnants (SNRs). Although the precise origin of such clumps remains unclear there are three generic possibilities: clumpiness imposed during the explosion, hydrodynamic instabilities that act during the remnant's evolution, and pre-existing structures in the ambient medium. In this article we focus on discriminating between clumping distributions that arise from the explosion and those from the remnant's evolution using existing 3D hydrodynamical simulations. We utilize the genus statistic for this discrimination…
We report on the discovery of X-ray--emitting O-Ne-Mg-rich ejecta in the middle-aged Galactic O-rich supernova remnant Puppis A with Chandra and XMM-Newton. We use line ratios to identify a low-ionization filament running parallel to the northeastern edge of the remnant that requires supersolar abundances, particularly for O, Ne, and Mg, which we interpret to be from O-Ne-Mg-rich ejecta. Abundance ratios of Ne/O, Mg/O, and Fe/O are measured to be ~2, ~2, and <0.3 times the solar values. Our spatially-resolved spectral analysis from the northeastern rim to the western rim otherwise reveals sub-…
This thesis is devoted to the analysis of X-ray observations of supernova remnants (SNRs), exploiting the diagnostic potential provided by X-ray spectroscopy and complementing it with the synthesis of X-ray observables from multi-dimensional hydrodynamic (HD) and magneto-hydrodynamic (MHD) models. I tackle three open issues: the search for a spectral signature to correctly recover abundance and mass values of the stellar fragments ejected in the SN explosion through their X-ray spectra; the study of anisotropies and the origin of overionized plasma in the mixed-morphology SNR IC 443; the quest…
The supernova remnant (SNR) N49B in the Large Magellanic Cloud is a peculiar example of a core-collapse SNR to show the shocked metal-rich ejecta enriched only in Mg without evidence for a similar overabundance in O and Ne. Based on archival Chandra data we present results from our extensive spatially-resolved spectral analysis of N49B. We find that the Mg-rich ejecta gas extends from the central regions of the SNR out to the southeastern outermost boundary of the SNR. This elongated feature shows an overabundance for Mg similar to that of the main ejecta region at the SNR center, and its elec…
In this paper, we report the detection of ejecta in the middle-aged Galactic supernova remnant G296.1-0.5 with the X-ray Imaging Spectrometer onboard the Suzaku satellite. The spectra of three lobes, north, southeast and southwest and inter-lobe regions, consist of soft (0.3-2.0 keV) emission originated from non-equilibrium ionization plasma. In north, southeast and inter-lobe regions, the thermal emission can be represented by a one-component, in southwest region it can be represented by two- component non-equilibrium ionization (VNEI) model. The spectra of studied regions have lines of N, O,…
I outline the dynamical evolution of the shell remnants of supernovae (SNRs), from initial interaction of supernova ejecta with circumstellar material (CSM) through to the final dissolution of the remnant into the interstellar medium (ISM). Supernova ejecta drive a blast wave through any CSM from the progenitor system; as material is swept up, a reverse shock forms in the ejecta, reheating them. This ejecta-driven phase lasts until ten or more times the ejected mass is swept up, and the remnant approaches the Sedov or self-similar evolutionary phase. The evolution up to this time is approximat…
We show that the expansion of ejecta in Tycho's supernova remnant (SNR) is consistent with a spherically symmetric shell, based on Suzaku measurements of the Doppler broadened X-ray emission lines. All the strong K_alpha line emission show broader widths at the center than at the rim, while the centroid energies are constant across the remnant (except for Ca). This is the pattern expected for Doppler broadening due to expansion of the SNR ejecta in a spherical shell. To determine the expansion velocities of the ejecta, we applied a model for each emission line feature having two Gaussian compo…
G292.0+1.8 (G292) is a young ($\sim$3000 yr), Galactic textbook-type core-collapse supernova remnant (CCSNR). It is characterized by X-ray, optical and infrared emission from ejecta and circumstellar medium (CSM) features, and contains a pulsar (PSR J1124-5916) and pulsar wind nebula that have been observed in X-rays and radio. Previous studies have revealed a complex, dynamically evolving, oxygen-rich remnant, a striking relic from the explosion of a massive star. Here, using our deep (530 ks) $\textit{Chandra}$ ACIS data, we present high spatial-resolution maps (based on a regional grid size…
We present the first direct ejecta velocity measurements of Tycho's supernova remnant (SNR). Chandra's high angular resolution images reveal a patchy structure of radial velocities in the ejecta that can be separated into distinct redshifted, blueshifted, and low velocity ejecta clumps or blobs. The typical velocities of the redshifted and blueshifted blobs are <~ 7,800 km/s and <~ 5,000 km/s, respectively. The highest velocity blobs are located near the center, while the low velocity ones appear near the edge as expected for a generally spherical expansion. Systematic uncertainty on the veloc…
In this work, we present results from a $\sim$201.6 ks observation of G352.7$-$0.1 by using the X-ray Imaging Spectrometer onboard {\it Suzaku} X-ray Observatory. The X-ray emission from the remnant is well described by two-temperature thermal models of non-equilibrium ionization with variable abundances with a column density of $N_{\rm H}$ $\sim$ 3.3$\times$10$^{22}$ cm$^{-2}$. The soft component is characterized by an electron temperature of $kT_{\rm e}$ $\sim$ 0.6 keV, an ionization time-scale of $τ$ $\sim$ 3.4$\times$10$^{11}$ cm$^{-3}$ s, and enhanced Si, S, Ar, and Ca abundances. The har…
Neutron star mergers produce a substantial amount of fast-moving ejecta, expanding outwardly for years after the merger. The interaction of these ejecta with the surrounding medium may produce a weak isotropic radio remnant, detectable in relatively nearby events. We use late-time radio observations of short duration gamma-ray bursts (sGRBs) to constrain this model. Two samples of events were studied: four sGRBs that are possibly in the local (<200 Mpc) universe were selected to constrain the remnant non-thermal emission from the sub-relativistic ejecta, whereas 17 sGRBs at cosmological distan…
Abridged. We aim at exploring to which extent the remnant keeps memory of the asymmetries that develop stochastically in the neutrino-heating layer due to hydrodynamic instabilities (e.g., convective overturn and the standing accretion shock instability) during the first second after core bounce. We coupled a 3D HD model of a neutrino-driven SN explosion with 3D MHD/HD simulations of the remnant formation. The simulations cover 2000 years of expansion and include all physical processes relevant to describe the complexities in the SN evolution and the subsequent interaction of the stellar debri…
Kepler's supernova remnant (SNR) is believed to result from a Type Ia supernova, but be interacting with dense circumstellar material (CSM), which makes its progenitor system a mystery. Using the Chandra ACIS-S 741 ks effective exposure data and an advanced adaptive binning algorithm, we analyse the spectra from tessellated regions in Kepler's SNR. For the first time, we map out the detailed spatial distributions of emission measure (EM), electron temperature, ionization parameter, and metal abundances for both the low- and high-temperature plasma components. The low-temperature plasma diverge…
We report on results of imaging and spectral analysis of the supernova remnant (SNR) RCW 86 observed with Suzaku. The SNR is known to exhibit K-shell emission of low ionized Fe, possibly originating from supernova ejecta. We revealed the global distribution of the Fe-rich plasma in the entire remnant, for the first time; the Fe-K emission was clearly detected from the west, north, and south regions, in addition to the X-ray brighter shells of southwest and northeast, where the presence of the Fe-rich ejecta has already been reported. The spectrum of each region is well represented by a three-c…
Using the unprecedented spectral resolution of the reflection grating spectrometer (RGS) onboard XMM-Newton, we reveal dynamics of X-ray--emitting ejecta in the oxygen-rich supernova remnant Puppis A. The RGS spectrum shows prominent K-shell lines, including O VII He_alpha forbidden and resonance, O VIII Ly_alpha, O VIII Ly_beta, and Ne IX He_alpha resonance, from an ejecta knot positionally coincident with an optical oxygen-rich filament (the so-called Omega filament in the northeast of the remnant). We find that the line centroids are blueshifted by 1480+/-140+/-60 km/s (the first and second…
We present the first three-dimensional measurements of the velocity of various ejecta knots in Tycho's supernova remnant, known to result from a Type Ia explosion. Chandra X-ray observations over a 12-year baseline from 2003 to 2015 allow us to measure the proper motion of nearly 60 "tufts" of Si-rich ejecta, giving us the velocity in the plane of the sky. For the line of sight velocity, we use two different methods: a non-equilibrium ionization model fit to the strong Si and S lines in the 1.2-2.8 keV regime, and a fit consisting of a series of Gaussian lines. These methods give consistent re…
We present a 190 ks observation of the Galactic supernova remnant (SNR) G306.3-0.9 with Suzaku. To study ejecta properties of this possible Type Ia SNR, the absolute energy scale at the Fe-K band was calibrated to a level of uncertainty less than 10 eV by a cross-calibration with the Hitomi microcalorimeter using the Perseus cluster spectra. This enabled us for the first time to accurately determine the ionization state of the Fe K$α$ line of this SNR. The ionization timescale ($τ$) of the Fe ejecta was measured to be $\log_{10} τ$ (cm$^{-3}$ s) $=10.24\pm0.03$, significantly smaller than prev…
We report re-analyses of the Suzaku observations of the Galactic supernova remnant (SNR), G272.2$-$3.2, for which the previous studies were limited below 3 keV. With careful data reduction and background subtraction, we discover the K-shell lines of Ar, Ca, and Fe above 3 keV. The X-ray spectrum of G272.2$-$3.2 consists of two components, a low-temperature collisional ionization equilibrium (CIE) plasma ($kT_{\rm e} \sim 0.2$ keV) and a high-temperature non-equilibrium ionization (NEI) plasma ($kT_{\rm e} = 0.6$-$3$ keV). The CIE plasma has solar abundances over the entire area, hence it would…
We report Chandra observations of the highly asymmetric core-collapse supernova remnant G350.1-0.3. We document expansion over 9 years away from the roughly stationary central compact object, with sky-plane velocities up to $5000 d_{4.5}$ km s$^{-1}$ ($d_{4.5}$ is the distance in units of 4.5 kpc), redshifts ranging from 900 km s$^{-1}$ to 2600 km s$^{-1}$, and three-dimensional space velocities approaching 6000 km s$^{-1}$. Most of the bright emission comes from heavy-element ejecta particularly strong in iron. Iron-enhanced ejecta are seen at 4000 - 6000 km s$^{-1}$, strongly suggesting that…
We investigate the role played by initial clumping of ejecta and by efficient acceleration of cosmic rays (CRs) in determining the density structure of the post-shock region of a Type Ia supernova remnant (SNR) through detailed 3D MHD modeling. Our model describes the expansion of a SNR through a magnetized interstellar medium (ISM), including the initial clumping of ejecta and the effects on shock dynamics due to back-reaction of accelerated CRs. The model predictions are compared to the observations of SN 1006. We found that the back-reaction of accelerated CRs alone cannot reproduce the obs…
We present measurements of the expansion of Kepler's Supernova Remnant (SNR) over three epochs of Chandra X-ray observations from 2000, 2006, and 2014. As the remnant of a historical supernova (observed in 1604 CE), Kepler's SNR presents the rare opportunity to study the dynamical evolution of such an object in real time. Measurements of the asymmetry in forward shock velocity can also provide insight into the nature of the explosion and density of the circumstellar material. Combining data from 2014 with previous epochs in 2000 and 2006, we can observe the proper motion of filaments along the…
We report an X-ray study of the evolved Galactic supernova remnant (SNR) G156.2+5.7 based on six pointing observations with Suzaku. The remnant's large extent (100$\arcmin$ in diameter) allows us to investigate its radial structure in the northwestern and eastern directions from the apparent center. The X-ray spectra were well fit with a two-component non-equilibrium ionization model representing the swept-up interstellar medium (ISM) and the metal-rich ejecta. We found prominent central concentrations of Si, S and Fe from the ejecta component; the lighter elements of O, Ne and Mg were distrib…
Spinning down neutron-star merger remnants with the Tayler-Spruit dynamo: Global simulations reveal the formation of massive disks and neutron-rich ejecta
California Institute of Technology（加州理工学院）；Walter Burke Institute for Theoretical Physics, California Institute of Technology（加州理工学院沃尔特·伯克理论物理研究所）
We present our velocity measurements of 59 clumpy, metal-rich ejecta knots in the supernova remnant (SNR) of SN 1572 (Tycho). We use our 450 ks Chandra High Energy Transmission Grating Spectrometer observation to measure the Doppler shift of the He-like Si K$α$ line-center wavelength emitted from these knots to find their line-of-sight (radial) velocities ($v_r$). We find $v_r$ up to $\sim$ 5500 km s$^{-1}$, with roughly consistent speeds between blueshifted and redshifted ejecta knots. We also measure the proper motions (PMs) for our sample based on archival Chandra Advanced CCD Imaging Spect…
We perform long-term general relativistic neutrino radiation hydrodynamics simulations (in axisymmetry) for a massive neutron star (MNS) surrounded by a torus, which is a canonical remnant formed after the binary neutron star merger. We take into account the effects of viscosity, which is likely to arise in the merger remnant due to magnetohydrodynamical turbulence. As the initial condition, we employ the azimuthally averaged data of the MNS-torus system derived in a three-dimensional, numerical-relativity simulation for the binary neutron star merger. The viscous effect plays key roles for th…
We report measurements of proper motion, radial velocity, and elemental composition for 14 X-ray knots in Kepler's supernova remnant (SNR) using Chandra data. The highest speed knots show both large proper motions (0.11-0.14 "/yr) and high radial velocities (v ~ 8,700--10,020 km/s) with estimated space velocities comparable to the typical Si velocity (~10,000 km/s) seen in SN Ia near maximum light. High speed ejecta knots appear only in specific locations and are morphologically and kinematically distinct from the rest of the ejecta. The proper motions of five knots extrapolate back over the a…
Supernova remnant (SNR) G309.2-0.6 has a peculiar radio morphology with two bright ears to the southwest and northeast, although the main shell outside the ears is roughly circular. Based on an earlier proposal that the supernova ejecta has a jet component with extra energy, the dynamical evolution of the remnant is solved using 3D hydrodynamical (HD) simulation to investigate the formation of the periphery of the remnant. Assuming the ejecta with a kinetic energy of $10^{51}$\,erg and a mass of $3~\mathrm{M}_{\odot}$ evolved in a uniform ambient medium for a time of $\sim 4000$\,yr and the je…
We present results from {\it XMM-Newton/RGS} observations of prominent knots in the southest portion of Tycho's supernova remnant, known to be the remnant of a Type Ia SN in 1572 C.E. By dispersing the photons from these knots out of the remnant with very little emission in front of or behind them, we obtained the nearly uncontaminated spectra of the knots. In the southernmost knot, the RGS successfully resolved numerous emission lines from Si, Ne, O He$α$ and Ly$α$, and Fe L-shell. This is the first clear detection of O lines in Tycho's SNR. Line broadening was measured to be $\sim 3$ eV for …
We analyze three Chandra observations, with a combined exposure time of 99 ks, of the Galactic supernova remnant RCW 103, a young supernova remnant, previously with no clear detection of metal-rich ejecta. Based on our imaging and spectral analyses of these deep Chandra data, we find evidence for metal-rich ejecta emission scattered throughout the remnant. X-ray emission from the shocked ejecta is generally weak, and the shocked circumstellar medium (CSM) is a largely dominant component across the entire remnant. The CSM component shows abundances of ~0.5 solar, while Ne, Mg, Si, S, and Fe abu…
Neutrinos emitted in the coalescence of two neutron stars affect the dynamics of the outflow ejecta and the nucleosynthesis of heavy elements. In this work, we analyze the neutrino emission properties and the conditions leading to the growth of flavor instabilities in merger remnants consisting of a hypermassive neutron star and an accretion disk during the first 10 ms after the merger. The analyses are based on hydrodynamical simulations that include a modeling of neutrino emission and absorption effects via the "Improved Leakage-Equilibration-Absorption Scheme" (ILEAS). We also examine the n…
Spectral analysis of X-ray emission from ejecta in supernova remnants (SNRs) is hampered by the low spectral resolution of CCD cameras, which creates a degeneracy between the best-fit values of abundances and emission measure. The combined contribution of shocked ambient medium and ejecta to the X-ray emission complicates the determination of the ejecta mass and chemical composition, leading to big uncertainties in mass estimates and it can introduce a bias in the comparison between the observed ejecta composition and the yields predicted by explosive nucleosynthesis. We explore the capabiliti…
The aim of this work is to bridge the gap between CC SNe and their remnants by investigating how post-explosion anisotropies in the ejecta influence the structure and chemical properties of the remnant at later times. We performed three-dimensional magneto-hydrodynamical simulations starting soon after the SN event and following the evolution of the system in the circumstellar medium (consisting of the wind of the stellar progenitor), for 5000 years, obtaining the physical scenario of a SNR. Here we focused the analysis on the case of a progenitor red supergiant of 19.8 M_sun. We also investig…
The Vela supernova remnant displays several ejecta, which are fragment-like features protruding beyond the front of its primary blast shock wave. They appear to be "shrapnel", bowshock-shaped relics of the supernova explosion. One of these pieces of shrapnel (A), located in the northeastern edge of the remnant, is peculiar because its X-ray spectrum exhibits a high Si abundance, in contrast to the other observed ejecta fragments, which show enhanced O, Ne, and Mg abundances. We present the analysis of another fragment located opposite to shrapnel A with respect to the center of the shell, in t…
The geometric structure of supernova remnants (SNR) provides a clue to unveiling the pre-explosion evolution of their progenitors. Here we present an X-ray study of N103B (0509-68.7), a Type Ia SNR in the Large Magellanic Cloud, that is known to be interacting with dense circumstellar matter (CSM). Applying our novel method for feature extraction to deep Chandra observations, we have successfully resolved the CSM, Fe-rich ejecta, and intermediate-mass element (IME) ejecta components, and revealed each of their spatial distribution. Remarkably, the IME ejecta component exhibits a double-ring st…
The distribution and kinematics of the circumstellar medium (CSM) around a supernova remnant (SNR) tell us useful information about the explosion of its natal supernova (SN). Kepler's SNR, the remnant of SN1604, is widely regarded to be of Type Ia origin. Its shock is moving through a dense, asymmetric CSM. The presence of this dense gas suggests that its parent progenitor system consisted of a white dwarf and an asymptotic giant branch (AGB) star. In this paper, we analyze a new and long observation with the reflection grating spectrometers (RGS) on board the XMM-Newton satellite, spatially r…
It is now well established that Kepler's supernova remnant is the result of a Type Ia explosion. With an age of 407 years, and an angular diameter of ~ 4', Kepler is estimated to be between 3.0 and 7.0 kpc distant. Unlike other Galactic Type Ia supernova remnants such as Tycho and SN 1006, and SNR 0509-67.5 in the Large Magellanic Cloud, Kepler shows evidence for a strong circumstellar interaction. A bowshock structure in the north is thought to originate from the motion of a mass-losing system through the interstellar medium prior to the supernova. We present results of hydrodynamical and spe…
Supernova explosions are inherently asymmetric and can accelerate new-born neutron stars (NSs) to hundreds of km/s. Two prevailing theories to explain NS kicks are ejecta asymmetries (e.g., conservation of momentum between NS and ejecta) and anisotropic neutrino emission. Observations of supernova remnants (SNRs) can give us insights into the mechanism that generates these NS kicks. In this paper, we investigate the relationship between NS kick velocities and the X-ray morphologies of 18 SNRs observed with the Chandra X-ray Observatory and the Rontgen Satellite (ROSAT). We measure SNR asymmetr…
Supernova remnants (SNRs) are diffuse extended sources characterized by a complex morphology and a non-uniform distribution of ejecta. Such a morphology reflects pristine structures and features of the progenitor supernova (SN) and the early interaction of the SN blast wave with the inhomogeneous circumstellar medium (CSM). Deciphering the observations of SNRs might open the possibility to investigate the physical properties of both the interacting ejecta and the shocked CSM. This requires accurate numerical models which describe the evolution from the SN explosion to the remnant development a…
Here we present three-dimensional high resolution simulations of Type Ia supernova in the presence of a non-degenerate companion. We find that the presence of a nearby companion leaves a long-lived hole in the supernova ejecta. In particular, we aim to study the long term evolution of this hole as the supernova ejecta interacts with the surrounding interstellar medium. Using estimates for the x-ray emission, we find that the hole generated by the companion remains for many centuries after the interaction between the ejecta and the interstellar medium. We also show that the hole is discernible …
Particle acceleration to suprathermal energies in strong astrophysical shock waves is a widespread phenomenon, generally explained by diffusive shock acceleration. Such shocks can also amplify upstream magnetic field considerably beyond simple compression. The complex plasma physics processes involved are often parameterized by assuming that shocks put some fraction $ε_e$ of their energy into fast particles, and another fraction $ε_B$ into magnetic field. Modelers of shocks in supernovae, supernova remnants, and gamma-ray bursters, among other locations, often assume typical values for these f…
Supernova 1604 is the last Galactic supernova for which historical records exist. Johannes Kepler's name is attached to it, as he published a detailed account of the observations made by himself and European colleagues. Supernova 1604 was very likely a Type Ia supernova, which exploded 350 pc to 750 pc above the Galactic plane. Its supernova remnant, known as Kepler's supernova remnant, shows clear evidence for interaction with nitrogen-rich material in the north/northwest part of the remnant, which, given the height above the Galactic plane, must find its origin in mass loss from the supernov…
This paper presents a detailed analysis of supernova remnant (SNR) N103B located in the Large Magellanic Cloud (LMC), based on Suzaku and Chandra observations. The spectrum of the entire SNR was reproduced using 3 ISM components with the kT of 0.32, 0.56, and 0.92keV and one ejecta component of 3.96keV, based on spectral analysis of the Suzaku/XIS data. The ejecta was overabundant in heavy elements, such as Mg, Si, S, Ca, Fe, and Ni. The unprecedentedly high quality of data obtained by XIS, allowed us to correctly distinguish between the emissions from the ISM and the ejecta for the first time…
Recent observations have revealed that the remnants of stellar-coalescence transients are bipolar. This raises the questions of how these bipolar morphologies arise and what they teach us about the mechanisms of mass ejection during stellar mergers and common-envelope phases. In this paper, we analyze hydrodynamic simulations of the lead-in to binary coalescence, a phase of unstable Roche lobe overflow that takes the binary from the Roche limit separation to the engulfment of the more compact accretor within the envelope of the extended donor. As mass transfer runs away at increasing rates, ga…
