Search results for "REMNANT"
showing 10 items of 120 documents
Shock-cloud interaction in the Vela SNR observed with XMM-Newton
2005
We analyzed an XMM-Newton EPIC observation of a bright knot, named FilD, in the northern rim of the Vela SNR, where the shock has encountered a cloud. The good combination of sensitivity, spectral, and spatial resolution allowed us to describe the internal structure of the observed ISM clouds and to obtain estimates of their temperature, density, O, Ne, and Fe abundances, and of their extension along the line of sight. We also examined the interaction of the shock with the FilD knot and estimated that the time elapsed from the shock impact is about one cloud crushing time. Our analysis allowed us to conclude that the observed X-ray emission is best explained by the propagation of transmitte…
On the metal abundances inside mixed-morphology supernova remnants: the case of IC 443 and G166.0+4.3
2009
Recent developments on the study of mixed morphology supernova remnants (MMSNRs) have revealed the presence of metal rich X-ray emitting plasma inside a fraction of these remnant, a feature not properly addressed by traditional models for these objects. Radial profiles of thermodynamical and chemical parameters are needed for a fruitful comparison of data and model of MMSNRs, but these are available only in a few cases. We analyze XMM-Newton data of two MMSNRs, namely IC443 and G166.0+4.3, previously known to have solar metal abundances, and we perform spatially resolved spectral analysis of the X-ray emission. We detected enhanced abundances of Ne, Mg and Si in the hard X-ray bright peak i…
PSR 1758 – 24 and G5.4 – 1.2, a remarkable pulsar–supernova remnant association
1991
Τiming observations made over an 18-month period using the Parkes radiotelescope show that the pulsar PSR 1758-24 is young and is located at the extreme western edge of the compact nebula G5.27-0.90 which is associated with supernova remnant G5.4-1.2. These results confirm the association of this pulsar with the supernova remnant. They also imply that the pulsar was born with such a high velocity that is has overtaken the supernova remnant shell and now lies outside the shell
The importance of magnetic-field-oriented thermal conduction in the interaction of SNR shocks with interstellar clouds
2008
We explore the importance of magnetic-field-oriented thermal conduction in the interaction of supernova remnant (SNR) shocks with radiative gas clouds and in determining the mass and energy exchange between the clouds and the hot surrounding medium. We perform 2.5D MHD simulations of a shock impacting on an isolated gas cloud, including anisotropic thermal conduction and radiative cooling; we consider the representative case of a Mach 50 shock impacting on a cloud ten-fold denser than the ambient medium. We consider different configurations of the ambient magnetic field and compare MHD models with or without the thermal conduction. The efficiency of the thermal conduction in the presence of…
Hydrodynamic simulations of the interaction of supernova shock waves with a clumpy environment: the case of the RX J0852.0-4622 (Vela Jr.) supernova …
2013
Observations in all electromagnetic bands show that many supernova remnants (SNRs) have a very aspherical shape. This can be the result of asymmetries in the supernova explosion or a clumpy circumstellar medium. We study the generation of inhomogeneities and the mixing of elements arising from these two sources in multidimensional hydrodynamic simulations of the propagation of a supernova blast wave into a cloudy environment. We model a specific SNR, Vela Jr (RX J0852.0-4622). By comparing our results with recent observations, we can constrain the properties of the explosion. We find that a very energetic explosion of several 10^{51} erg occurring roughly about 800 years ago is consistent w…
Hydrodynamic modelling of ejecta shrapnel in the Vela supernova remnant
2013
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 explored different initial setups. We found that the final position of the shrapnel is very sensitive …
Crushing of Interstellar Gas Clouds in Supernova Remnants: the Role of Thermal Conduction and Radiative Losses
2004
We model hydrodynamic interactions of an old supernova remnant shock wave with a small interstellar gas cloud, taking into account the effects of thermal conduction and radiative losses. In particular, we consider a representative case of a Mach 30 shock impacting on an isolated cloud with density contrast χ = 10 with respect to the ambient medium. Thermal conduction appears to be effective in suppressing the Kelvin-Helmholtz and Rayleigh-Taylor instabilities which would develop at the cloud boundaries. We demonstrate that the radiative losses play a crucial role in the dynamics of the shock-cloud interaction, dominating evolution of the shocked cloud medium.
Effects of non-uniform interstellar magnetic field on synchrotron X-ray and inverse-Compton γ-ray morphology of supernova remnants
2011
Context. Observations of SuperNova Remnants (SNRs) in X-ray and γ-ray bands promise to contribute important information to our understanding of the kinematics of charged particles and magnetic fields in the vicinity of strong non-relativistic shocks and, therefore, the nature of Galactic cosmic rays. The accurate analysis of SNR images collected in different energy bands requires theoretical modeling of synchrotron and inverse Compton emission from SNRs. Aims. We develop a numerical code (remlight) to synthesize, from MHD simulations, the synchrotron radio, X-ray, and inverse Compton γ-ray emission originating in SNRs expanding in a non-uniform interstellar medium (ISM) and/or non-uniform i…
Additional Evidence for a Pulsar Wind Nebula in the Heart of SN 1987A from Multiepoch X-Ray Data and MHD Modeling
2022
Since the day of its explosion, supernova (SN) 1987A has been closely monitored to study its evolution and to detect its central compact relic. In fact, the formation of a neutron star is strongly supported by the detection of neutrinos from the SN. However, besides the detection in the Atacama Large Millimeter/submillimeter Array (ALMA) data of a feature that is compatible with the emission arising from a proto-pulsar wind nebula (PWN), the only hint for the existence of such elusive compact object is provided by the detection of hard emission in NuSTAR data up to ~ 20 keV. We report on the simultaneous analysis of multi-epoch observations of SN 1987A performed with Chandra, XMM-Newton and…