Mapping the Gas Turbulence in the Coma Cluster: Predictions for Astro-H

Astro-H will be able for the first time to map gas velocities and detect turbulence in galaxy clusters. One of the best targets for turbulence studies is the Coma cluster, due to its proximity, absence of a cool core, and lack of a central active galactic nucleus. To determine what constraints Astro-H will be able to place on the Coma velocity field, we construct simulated maps of the projected gas velocity and compute the second-order structure function, an analog of the velocity power spectrum. We vary the injection scale, dissipation scale, slope, and normalization of the turbulent power spectrum, and apply measurement errors and finite sampling to the velocity field. We find that even with sparse coverage of the cluster, Astro-H will be able to measure the Mach number and the injection scale of the turbulent power spectrum--the quantities determining the energy flux down the turbulent cascade and the diffusion rate for everything that is advected by the gas (metals, cosmic rays, etc.). Astro-H will not be sensitive to the dissipation scale or the slope of the power spectrum in its inertial range, unless they are outside physically motivated intervals. We give the expected confidence intervals for the injection scale and the normalization of the power spectrum for a number of possible pointing configurations, combining the structure function and velocity dispersion data. Importantly, we also determine that measurement errors on the line shift will bias the velocity structure function upward, and show how to correct this bias.Comment: 18 pages, 13 figures. Matches published ApJ version, except that it fixes an error in the left panel of Figure 5 that is being addressed in an ApJ erratu

The relation between gas density and velocity power spectra in galaxy clusters: high-resolution hydrodynamic simulations and the role of conduction

Exploring the ICM power spectrum can help us to probe the physics of galaxy clusters. Using high-resolution 3D plasma simulations, we study the statistics of the velocity field and its relation with the thermodynamic perturbations. The normalization of the ICM spectrum (density, entropy, or pressure) is linearly tied to the level of large-scale motions, which excite both gravity and sound waves due to stratification. For low 3D Mach number M~0.25, gravity waves mainly drive entropy perturbations, traced by preferentially tangential turbulence. For M>0.5, sound waves start to significantly contribute, passing the leading role to compressive pressure fluctuations, associated with isotropic (or slightly radial) turbulence. Density and temperature fluctuations are then characterized by the dominant process: isobaric (low M), adiabatic (high M), or isothermal (strong conduction). Most clusters reside in the intermediate regime, showing a mixture of gravity and sound waves, hence drifting towards isotropic velocities. Remarkably, regardless of the regime, the variance of density perturbations is comparable to the 1D Mach number. This linear relation allows to easily convert between gas motions and ICM perturbations, which can be exploited by Chandra, XMM data and by the forthcoming Astro-H. At intermediate and small scales (10-100 kpc), the turbulent velocities develop a Kolmogorov cascade. The thermodynamic perturbations act as effective tracers of the velocity field, broadly consistent with the Kolmogorov-Obukhov-Corrsin advection theory. Thermal conduction acts to damp the gas fluctuations, washing out the filamentary structures and steepening the spectrum, while leaving unaltered the velocity cascade. The ratio of the velocity and density spectrum thus inverts the downtrend shown by the non-diffusive models, allowing to probe the presence of significant conductivity in the ICM.Comment: Accepted by A&A; 15 pages, 10 figures; added insights and references - thank you for the positive feedbac

Changes of some blood indices and myocardial electrolyte content during hypokinesia

Using special hypokinetic cages, the volume changes of circulating blood, its hematocrit and protein content, volume ratios between extra- and intracellular liquids in the body, as well as electrolyte content in the blood and myocardium during hypokinesia were investigated experimentally in rabbits

Synthesis of alkyd oligomers based on bicyclo[2,2,2] oct-5-ene-2,3-dicarboxylic acid anhydride and its application for obtaining lacquer coatings

The results of studies on the synthesis of modified by oil alkyd resin with the use of bicyclo [2,2,2] oct5-ene-2,3-dicarboxylic acid anhydride as acylation agent in the polycondensation reaction with polyols for obtaining lacquer coatings and the study of their operational properties are presented in this article. It is found that the chemical modification of alkyd resin by replacing phthalic anhydride on bicyclic dicarboxylic acid anhydride allows to increase hardness, strength, adhesion of coatings formed on steel substrates

Modification of polyamide-6 by n, n'-bis-maleamidoacid

Article is devoted to receiving and research of compositions on the basis of industrially made polyamide6 modified by N,N '-bis-maleamidoacid of metaphenylenediamine. Existence in macromolecules of polyamides reactive carboxyl, amide and amino groups, capable to interact with multifunctional monomeric and oligomeric modifiers, gives the chance of receiving the materials possessing properties of sewed polymers. As a result the use of bis-amidoacid as a modifying additive in the system of aliphatic polyamide-6 provides the improvement of strength properties and thermal characteristics of a polymeric material

Curing of epoxydiane resins by modified hardener of amine type

The paper presents the results of a comprehensive study of changes in the properties of filmforming compositions based on epoxydiane oligomer. Curing was carried out by a modified hardener. The degree of structurization changes depending on the amount of the hardener. The effect of timetemperature conditions, ratio of initial oligomers, and nature of the solvent on the process of epoxydiane resin curing by modified polyamide was determined

ОСОБЛИВОСТІ ДОСЛІДЖЕННЯ МОРАЛЬНОЇ ШКОДИ В КРИМІНАЛЬНОМУ ПРОЦЕСІ

The paper considers contradictions which arise after entering amendments in 2014 into article 242 of the Criminal Procedural Code of Ukraine, in which an obligatory appointment of psychological examination for the determination of moral harm amount in criminal trial is allocated. The thought on inexpediency of appointment of the person moral sufferings examination within the limits of criminal proceedings on the basis ofsuch positions is subtatiated: 1) before pronouncement of a court sentence on criminal proceedings a person’s guilt is not proved, in this case forensic psychological examination will be based on not proved premise - possibility of guilt which conflicts to an innocence presumption according to the Criminal Code of Ukraine. The expert conclusion is one of procedural sources ofproofs. Carrying out forensic psychological examination of moral harm within criminal proceedings, the expert, being based on the inadmissible assumption of guilty, creates the proof; 2) if the question of moral sufferings presence is considered within criminal proceedings, the fact of absence of the claimantfault has to be established by the court along with definition of the respondent fault degree; 3) pronouncement of a court sentence with definition of the parties guilty degree is an important point for definitive qualitative and quantitative formalizing moral sufferings. At the stage «before a sentence» the psychological trauma has not been yet led to the fullforming ofmoral sufferings, therefore during carrying out psychological research on the materials of criminal proceedings the amount of compensation should be defined only as "a preliminary"; 4) for the determination of the depth and heaviness of the person’s sufferings a psychologist needs to conduct a research only in 1 yearfrom the moment of injuring events (the person should go through stages of distress after losing close relative, to be treated and feel consequences at health damage).Зазначено суперечності, які виникли після внесення змін до ст. 242 КПК України, де було закріплено обов’язкове призначення психологічної експертизи моральної шкоди в кримінальному процесі. Розглянуто шляхи їх подолання. Обґрунтовано думку про недоцільність призначення експертизи моральних страждань особи в межах кримінального провадження

The relation between gas density and velocity power spectra in galaxy clusters: qualitative treatment and cosmological simulations

We address the problem of evaluating the power spectrum of the velocity field of the ICM using only information on the plasma density fluctuations, which can be measured today by Chandra and XMM-Newton observatories. We argue that for relaxed clusters there is a linear relation between the rms density and velocity fluctuations across a range of scales, from the largest ones, where motions are dominated by buoyancy, down to small, turbulent scales: $(\delta\rho_k/\rho)^2 = \eta_1^2 (V_{1,k}/c_s)^2$, where $\delta\rho_k/\rho$ is the spectral amplitude of the density perturbations at wave number $k$, $V_{1,k}^2=V_k^2/3$ is the mean square component of the velocity field, $c_s$ is the sound speed, and $\eta_1$ is a dimensionless constant of order unity. Using cosmological simulations of relaxed galaxy clusters, we calibrate this relation and find $\eta_1\approx 1 \pm 0.3$. We argue that this value is set at large scales by buoyancy physics, while at small scales the density and velocity power spectra are proportional because the former are a passive scalar advected by the latter. This opens an interesting possibility to use gas density power spectra as a proxy for the velocity power spectra in relaxed clusters, across a wide range of scales.Comment: 6 pages, 3 figures, submitted to ApJ Letter