Synoptic study of the SMC SNRs using XMM-Newton

We present a detailed X-ray spectral analysis of 13 supernova remnants (SNR) in the Small Magellanic Cloud (SMC). We apply both single-temperature non-equilibrium ionisation models and models based on the Sedov similarity solution, where applicable. We also present detailed X-ray images of individual SNRs, which reveal a range of different morphological features. Eight remnants, viz DEM S 32, IKT 2, HFPK 419, IKT 6, IKT 16, IKT 18 and IKT 23, are consistent with being in their Sedov evolutionary phase. IKT 6 and IKT 23 both have a clear shell like morphology with oxygen-rich X-ray emitting material in the centre. We draw attention to similarities between these two remnants and the well studied, oxygen-rich remnant IKT 22 (SNR 0102-72.3) and propose that they are more evolved versions of IKT 22. IKT 4, IKT 5, DEM S 128 and IKT 5 are evolved remnants which are in, or in the process of entering, the radiative cooling stage. We argue that the X-ray emission from these four remnants is most likely from the ejecta remains of type Ia SNe. Our modeling allow us to derive estimates for physical parameters, such as densities, ages, masses and initial explosion energies. Our results indicate that the average SMC hydrogen density is a factor of ~6 lower as compared to the Large Magellanic Cloud. This has obvious implications for the evolution and luminosities of the SMC SNRs. We also estimate the average SMC gas phase abundances for the elements O, Ne, Mg, Si and Fe.Comment: submitted to A&

Using the Memories of Multiscale Machines to Characterize Complex Systems

A scheme is presented to extract detailed dynamical signatures from successive measurements of complex systems. Relative entropy based time series tools are used to quantify the gain in predictive power of increasing past knowledge. By lossy compression, data is represented by increasingly coarsened symbolic strings. Each compression resolution is modeled by a machine: a finite memory transition matrix. Applying the relative entropy tools to each machine's memory exposes correlations within many time scales. Examples are given for cardiac arrhythmias and different heart conditions are distinguished.Comment: 4 pages, 2 figure

Measuring the cosmic ray acceleration efficiency of a supernova remnant

Cosmic rays are the most energetic particles arriving at earth. Although most of them are thought to be accelerated by supernova remnants, the details of the acceleration process and its efficiency are not well determined. Here we show that the pressure induced by cosmic rays exceeds the thermal pressure behind the northeast shock of the supernova remnant RCW 86, where the X-ray emission is dominated by synchrotron radiation from ultra-relativistic electrons. We determined the cosmic-ray content from the thermal Doppler broadening measured with optical spectroscopy, combined with a proper-motion study in X- rays. The measured post-shock proton temperature in combination with the shock velocity does not agree with standard shock heating, implying that >50% of the post-shock pressure is produced by cosmic rays.Comment: Published in Science express, 10 pages, 5 figures and 2 table

X-ray spectral imaging and Doppler mapping of Cassiopeia A

A detailed X-ray spectral analysis of Cas A using a deep exposure from the EPIC-MOS cameras on-board XMM-Newton is presented. Spectral fitting was performed on a 15x15 grid of 20"x20" pixels using a two component non-equilibrium ionisation model (NEI) giving maps of ionisation age, temperature, interstellar column density, abundances and Doppler velocities. The abundances of Si, S, Ar and Ca are strongly correlated. The abundance ratios are consistent with the nucleosynthesis yield from the collapse of a 12 Msun progenitor. The abundance ratios Ne/Si, Mg/Si, Fe/Si and Ni/Si are very variable and distinctly different from S/Si, Ar/Si and Ca/Si, in line with the current explosive nucleosynthesis models. The ionisation age and temperature of both NEI components varies considerably over the remnant. Accurate determination of these parameters yield reliable Doppler velocities for both components. The data are consistent with a plasma velocity of 2600 km/s at the shock radius of 153" implying a primary shock velocity of 4000+/-500 km/s. The Si-K and S-K line emission from the cool component is confined to a relatively narrow shell with radius 100-150". This component is almost certainly ejecta material which has been heated by a combination of the reverse shock and heating of ejecta clumps as they plough through the medium which has been pre-heated by the primary shock. The Fe-K line emission is expanding faster and spans a radius range 110-170". The bulk of the Fe emission is confined to two large clumps and it is likely that these too are the result of ablation from ejecta bullets rather swept up circumstellar medium.Comment: 10 pages, 11 figures, submitted to Astronomy and Astrophysic

Test engineering education in Europe: the EuNICE-Test project

The paper deals with a European experience of education in industrial test of ICs and SoCs using remote testing facilities. The project addresses the problem of the shortage in microelectronics engineers aware with the new challenge of testing mixed-signal SoCs far multimedia/telecom market. It aims at providing test training facilities at a European scale in both initial and continuing education contexts. This is done by allowing the academic and industrial partners of the consortium to train engineers using the common test resources center (CRTC) hosted by LIRMM (Laboratoire d'Informatique, de Robotique et de Microelectronique de Montpellier, France). CRTC test tools include up-to-date/high-tech testers that are fully representative of real industrial testers as used on production testfloors. At the end of the project, it is aimed at reaching a cruising speed of about 16 trainees per year per center. Each trainee will have attend at least one one-week training using the remote test facilities of CRTC

The X-ray synchrotron emission of RCW 86 and the implications for its age

We report here X-ray imaging spectroscopy observations of the northeastern shell of the supernova remnant RCW 86 with Chandra and XMM-Newton. Along this part of the shell the dominant X-ray radiation mechanism changes from thermal to synchrotron emission. We argue that both the presence of X-ray synchrotron radiation and the width of the synchrotron emitting region suggest a locally higher shock velocity of V_s = 2700 km/s and a magnetic field of B = 24+/-5 microGauss. Moreover, we also show that a simple power law cosmic ray electron spectrum with an exponential cut-off cannot explain the broad band synchrotron emission. Instead a concave electron spectrum is needed, as predicted by non-linear shock acceleration models. Finally, we show that the derived shock velocity strengthens the case that RCW 86 is the remnant of SN 185.Comment: 5 pages, 4 figures. The last figure is intended as a color plate. Accepted by ApJ Letter