X-ray emission from thin plasmas. Collisional ionization for atoms and ions of H to Zn

Every observation of astrophysical objects involving a spectrum requires atomic data for the interpretation of line fluxes, line ratios and ionization state of the emitting plasma. One of the processes which determines it is collisional ionization. In this study an update of the direct ionization (DI) and excitation-autoionization (EA) processes is discussed for the H to Zn-like isoelectronic sequences. In the last years new laboratory measurements and theoretical calculations of ionization cross sections have become available. We provide an extension and update of previous published reviews in the literature. We include the most recent experimental measurements and fit the cross sections of all individual shells of all ions from H to Zn. These data are described using an extension of Younger's and Mewe's formula, suitable for integration over a Maxwellian velocity distribution to derive the subshell ionization rate coefficients. These ionization rate coefficients are incorporated in the high-resolution plasma code and spectral fitting tool SPEX V3.0.Comment: Accepted for publication in A&A, 22 pages, 18 figure

Iron abundance distribution in the hot gas of merging galaxy clusters

We present XMM-Newton/EPIC observations of six merging galaxy clusters and study the distributions of their temperature, iron (Fe) abundance and pseudo-entropy along the merging axis. For the first time, we focus simultaneously, and in a comprehensive way, on the chemical and thermodynamic properties of the freshly collided intracluster medium (ICM). The Fe distribution of these clusters along the merging axis is found to be in good agreement with the azimuthally-averaged Fe abundance profile in typical non-cool-core clusters out to $r_{500}$. In addition to showing a moderate central abundance peak, though less pronounced than in relaxed systems, the Fe abundance flattens at large radii towards $\sim$0.2-0.3 $Z_\odot$. Although this shallow metal distribution is in line with the idea that disturbed, non-cool-core clusters originate from the merging of relaxed, cool-core clusters, we find that in some cases, remnants of metal-rich and low entropy cool cores can persist after major mergers. While we obtain a mild anti-correlation between the Fe abundance and the pseudo-entropy in the (lower entropy, $K$ = 200-500 keV cm$^2$) inner regions, no clear correlation is found at (higher entropy, $K$ = 500-2300 keV cm$^2$) outer radii. The apparent spatial abundance uniformity that we find at large radii is difficult to explain through an efficient mixing of freshly injected metals, particularly in systems for which the time since the merger is short. Instead, our results provide important additional evidence in favour of the early enrichment scenario - in which the bulk of the metals are released outside galaxies at $z$ > 2-3 - and extend it from cool-core and (moderate) non-cool-core clusters to a few of the most disturbed merging clusters as well. These results constitute a first step towards a deeper understanding of the chemical history of merging clusters.Comment: Accepted for publication in A&A, 21 pages with 17 figures and 19 table

X-ray study of the double radio relic Abell 3376 with Suzaku

We present an X-ray spectral analysis of the nearby double radio relic merging cluster Abell 3376 ( z = 0.046), observed with the Suzaku XIS instrument. These deep (similar to 360 ks) observations cover the entire double relic region in the outskirts of the cluster. These diffuse radio structures are amongst the largest and arc-shaped relics observed in combination with large-scale X-ray shocks in a merging cluster. We confirm the presence of a stronger shock (M-W = 2.8 +/- 0.4) in the western direction at r similar to 26 0, derived from a temperature and surface brightness discontinuity across the radio relic. In the east, we detect a weaker shock ( M-E = 1.5 +/- 0.1) at r similar to 8', possibly associated with the "notch" of the eastern relic, and a cold front at r similar to 3'. Based on the shock speed calculated from the Mach numbers, we estimate that the dynamical age of the shock front is similar to 0.6 Gyr after core passage, indicating that Abell 3376 is still an evolving merging cluster and that the merger is taking place close to the plane of the sky. These results are consistent with simulations and optical and weak lensing studies from the literature

Science with hot astrophysical plasmas

We present some recent highlights and prospects for the study of hot astrophysical plasmas. Hot plasmas can be studied primarily through their X-ray emission and absorption. Most astrophysical objects, from solar system objects to the largest scale structures of the Universe, contain hot gas. In general we can distinguish collisionally ionised gas and photoionised gas. We introduce several examples of both classes and show where the frontiers of this research in astrophysics can be found. We put this also in the context of the current and future generation of X-ray spectroscopy satellites. The data coming from these missions challenge the models that we have for the calculation of the X-ray spectra

Coupling of erbium-implanted silicon to a superconducting resonator

Erbium-implanted silicon is promising for both photonic and quantum-technology platforms, since it possesses both telecommunications and integrated-circuit processing compatibility. However, several different Er centers are generated during the implantation and annealing process, the presence of which could hinder the development of these applications. When Si is coimplanted with 10 17 cm − 3 Er and 10 20 cm − 3 O ions, and the appropriate annealing process is used, one of these centers, which is present at higher Er concentrations, can be eliminated. Characterization of samples with Er concentrations of < 10 17 cm − 3 is limited by the sensitivity of standard electron paramagnetic resonance (EPR) instruments. The collective coupling strength between a superconducting (SC) Nb N lumped-element resonator and a 10 17 cm − 3 Er -implanted Si sample at 20 mK is measured to be about 1 MHz, which provides a basis for the characterization of low-concentration Er -implanted Si and for future networks of hybrid quantum systems that exchange quantum information over the telecommunication network. Of six known Er -related EPR centers, only one trigonal center couples to the SC resonator

Mass-invariance of the iron enrichment in the hot haloes of massive ellipticals, groups, and clusters of galaxies

X-ray measurements find systematically lower Fe abundances in the X-ray emitting haloes pervading groups ($kT\lesssim1.7$ keV) than in clusters of galaxies. These results have been difficult to reconcile with theoretical predictions. However, models using incomplete atomic data or the assumption of isothermal plasmas may have biased the best fit Fe abundance in groups and giant elliptical galaxies low. In this work, we take advantage of a major update of the atomic code in the spectral fitting package SPEX to re-evaluate the Fe abundance in 43 clusters, groups, and elliptical galaxies (the CHEERS sample) in a self-consistent analysis and within a common radius of 0.1$r_{500}$. For the first time, we report a remarkably similar average Fe enrichment in all these systems. Unlike previous results, this strongly suggests that metals are synthesised and transported in these haloes with the same average efficiency across two orders of magnitude in total mass. We show that the previous metallicity measurements in low temperature systems were biased low due to incomplete atomic data in the spectral fitting codes. The reasons for such a code-related Fe bias, also implying previously unconsidered biases in the emission measure and temperature structure, are discussed

Tunable magnetoresistance in an asymmetrically coupled single molecule junction

Phenomena that are highly sensitive to magnetic fields can be exploited in sensors and non-volatile memories1. The scaling of such phenomena down to the single-molecule level2,3 may enable novel spintronic devices4. Here, we report magnetoresistance in a single-molecule junction arising from negative differential resistance that shifts in a magnetic field at a rate two orders of magnitude larger than Zeeman shifts. This sensitivity to the magnetic field produces two voltage-tunable forms of magnetoresistance, which can be selected via the applied bias. The negative differential resistance is caused by transient charging5,6,7 of an iron phthalocyanine (FePc) molecule on a single layer of copper nitride (Cu2N) on a Cu(001) surface, and occurs at voltages corresponding to the alignment of sharp resonances in the filled and empty molecular states with the Cu(001) Fermi energy. An asymmetric voltage-divider effect enhances the apparent voltage shift of the negative differential resistance with magnetic field, which inherently is on the scale of the Zeeman energy8. These results illustrate the impact that asymmetric coupling to metallic electrodes can have on transport through molecules, and highlight how this coupling can be used to develop molecular spintronic applications

X-ray spectroscopy of merging galaxy clusters

This thesis focuses on the X-ray spectral analysis of merging galaxy clusters and the plasma code development for future high-resolution X-ray spectroscopy observations. This work deepens in two different aspects of these merging clusters still under debate: one, the study of the thermal (X-ray shocks) component and its correlation with the non-thermal (radio shocks/relics) component, and two, their metal enrichment history. The first one is crucial to understand how the shocks propagate and heat the ICM as well as to determine the physical association between these two components. The second one aims to contribute to a better knowledge of the metals origin, evolution and distribution in merging clusters, which can reveal important information on the dynamical history of the mergers. SRONHigh Energy Astrophysic

X-ray study of the double radio relic Abell 3376 with Suzaku

We present an X-ray spectral analysis of the nearby double radio relic merging cluster Abell 3376 ( z = 0.046), observed with the Suzaku XIS instrument. These deep (similar to 360 ks) observations cover the entire double relic region in the outskirts of the cluster. These diffuse radio structures are amongst the largest and arc-shaped relics observed in combination with large-scale X-ray shocks in a merging cluster. We confirm the presence of a stronger shock (M-W = 2.8 +/- 0.4) in the western direction at r similar to 26 0, derived from a temperature and surface brightness discontinuity across the radio relic. In the east, we detect a weaker shock ( M-E = 1.5 +/- 0.1) at r similar to 8', possibly associated with the "notch" of the eastern relic, and a cold front at r similar to 3'. Based on the shock speed calculated from the Mach numbers, we estimate that the dynamical age of the shock front is similar to 0.6 Gyr after core passage, indicating that Abell 3376 is still an evolving merging cluster and that the merger is taking place close to the plane of the sky. These results are consistent with simulations and optical and weak lensing studies from the literature

Synergy of Inorganic Fillers in Composite Thermoplastic Polymer/Ionic Liquid/LiTFSI Electrolytes

The development of novel solid electrolytes, which can be processed using solvent-free methods, is one of the keys for successful industrialization of solid state batteries and their further implementation in electrical vehicles. Here, we study thermoplastic solid state electrolytes based on polyethylene oxide (PEO), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYRTFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and two inorganic fillers with different morphology and nature (modified sepiolite (TPGS-S) and garnet-type LiLaZrNbO (LLZNO) prepared by solvent free extrusion method. Several thermoplastic polymer electrolytes (TPEs) are prepared and comprehensively studied. Composite thermoplastic electrolyte TPE-S10G10 containing 10 wt% of TPGS-S and 10 wt% of LLZNO fillers shows the best electrochemical performance in Li-LiFePO solid state batteries operating under 0.2C/0.5D cycling conditions at 60 &Deg;C. Solid state cell with TPE-S10G10 electrolyte retains 80% of initial discharge capacity after 540 cycles. Thus, a synergetic effect of using two different fillers, which can be exploited during the development of TPEs, is clearly demonstrated.This study was supported by the Comunidad de Madrid (Project Ref. LIQUORGAS-CM, S2013/MAE-2800). Francisco González is grateful to CONACYT-SENER for the scholarship granted (CVU559770/Registro297710)