The research program of the Liquid Scintillation Detector (LSD) in the Mont Blanc Laboratory

A massive (90 tons) liquid scintillation detector (LSD) has been running since October 1984 in the Mont Blanc Laboratory at a depth of 5,200 hg/sq cm of standard rock. The research program of the experiment covers a variety of topics in particle physics and astrophysics. The performance of the detector, the main fields of research are presented and the preliminary results are discussed

Global Spiral Modes in NGC 1566: Observations and Theory

We present an observational and theoretical study of the spiral structure in galaxy NGC 1566. A digitized image of NGC 1566 in I-band was used for measurements of the radial dependence of amplitude variations in the spiral arms. We use the known velocity dispersion in the disk of NGC 1566, together with its rotation curve, to construct linear and 2D nonlinear simulations which are then compared with observations. A two-armed spiral is the most unstable linear global mode in the disk of NGC 1566. The nonlinear simulations are in agreement with the results of the linear modal analysis, and the theoretical surface amplitude and the velocity residual variations across the spiral arms are in qualitative agreement with the observations. The spiral arms found in the linear and nonlinear simulations are considerably shorter than those observed in the disk of NGC 1566. We argue therefore, that the surface density distribution in the disk of the galaxy NGC 1566 was different in the past, when spiral structure in NGC 1566 was linearly growing.Comment: 41 pages, 20 figures, to be published in the Astrophysical Journa

Local Surface Density of the Galactic Disk from a 3-D Stellar Velocity Sample

We have re-estimated the surface density of the Galactic disk in the solar neighborhood within $\pm$ 0.4 kpc of the Sun using parallaxes and proper motions of a kinematically and spatially unbiased sample of 1476 old bright red giant stars from the Hipparcos catalog with measured radial velocities from Barbier-Brossat & Figon (2000). We determine the vertical distribution of the red giants as well as the vertical velocity dispersion of the sample, (14.4 $\pm$ 0.26 km/sec), and combine these to derive the surface density of gravitating matter in the Galactic disk as a function of the galactic coordinate $z$. The surface density of the disk increases from 10.5 $\pm$ 0.5 $M_{\odot}$ / pc$^2$ within $\pm$ 50 pc to 42 $\pm$ 6 $M_{\odot}$ / pc$^2$ within $\pm$ 350 pc. The estimated volume density of the galactic disk within $\pm$ 50 pc is about 0.1 $M_{\odot}$ / pc$^3$ which is close to the volume density estimates of the observed baryonic matter in the solar neighborhood.Comment: 24 pages, 15 figures, AJ in pres

Numerical Simulation of Collisionless Disk of NGC 1566 Using Graphics Processing Units

A numerical approach is used to study dynamics of a three-dimensional collisionless disk of NGC 1566 galaxy. An equilibrium model was constructed on the basis of observational data. Dynamics was modeled with direct N-body integration involving graphics processing units and CUDA technology. Simulation shows that the disk is unstable to formation of a two-armed spiral pattern. Estimation of pattern angular speed in the model is consistent with observational data.Рассматривается задача о динамике трехмерного бесстолкновительного диска галактики NGC1566, модель которого построена на основе наблюдательных данных. Динамика исследуется методом прямого интегрирования задачи N тел с использованием графических процессоров и технологии CUDA. Результаты моделирования демонстрируют, что диск с параметрами, соответствующими наблюдаемым, неустойчив по отношению к образованию глобального спирального узора. Оценка угловой скорости спирального узора в модели в пределах ошибок согласуется с наблюдениями.Работа выполнена при поддержке Министерства науки и образования (проект 3.858.2017/4.6)

Chemical Evolution of the Galaxy Based on the Oscillatory Star Formation History

We model the star formation history (SFH) and the chemical evolution of the Galactic disk by combining an infall model and a limit-cycle model of the interstellar medium (ISM). Recent observations have shown that the SFH of the Galactic disk violently variates or oscillates. We model the oscillatory SFH based on the limit-cycle behavior of the fractional masses of three components of the ISM. The observed period of the oscillation ($\sim 1$ Gyr) is reproduced within the natural parameter range. This means that we can interpret the oscillatory SFH as the limit-cycle behavior of the ISM. We then test the chemical evolution of stars and gas in the framework of the limit-cycle model, since the oscillatory behavior of the SFH may cause an oscillatory evolution of the metallicity. We find however that the oscillatory behavior of metallicity is not prominent because the metallicity reflects the past integrated SFH. This indicates that the metallicity cannot be used to distinguish an oscillatory SFH from one without oscillations.Comment: 21 pages LaTeX, to appear in Ap

Направления актуализации сметных норм в транспортном строительстве

For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version). ABSTRACT The wide range of conditions for performance of works in transport construction sector traditionally should meet high demands on the methodology for their accounting when calculating the estimated cost. In its current state, the national (federal) budget and regulatory framework is a compromise, especially when it comes to adjusting the costs in different circumstances of natural, climatic, different regional resources, transport accessibility. The article reveals the problem of the sectoral specificity of the use of labor resources at the objects of construction of the railway transport infrastructure. An example of the impact of typical working conditions on quantitative regulatory parameters is given as a calculation and methodical variant of solving economic problems. Keywords: economy, transport construction, norms, estimated cost, analysis, labor intensity, production conditions, coefficients, factors.Текст аннотации на англ. языке и полный текст статьи на англ. языке находится в прилагаемом файле ПДФ (англ. версия следует после русской версии). Широта спектра условий производства работ в транспортном строительстве традиционно предъявляет высокие требования к методологии их учёта при расчёте сметной стоимости. В текущем своём состоянии национальная (федеральная) сметно-нормативная база является компромиссной, особенно когда это касается корректировки затрат в разных обстоятельствах природных, климатических, отличных друг от друга региональных ресурсов, транспортной доступности. Статья раскрывает проблему отраслевой специфики использования трудовых ресурсов на объектах строительства инфраструктуры железнодорожного транспорта. В качестве расчётно-методического варианта решения экономических задач приведён пример воздействия типичных условий производства работ на количественные нормативные параметры

Dynamics of Gaseous Disks in a Non-axisymmetric Dark Halo

The dynamics of a galactic disk in a non-axisymmetric (triaxial) dark halo is studied in detail using high-resolution, numerical, hydrodynamical models. A long-lived, two-armed spiral pattern is generated for a wide range of parameters. The spiral structure is global, and the number of turns can be two or three, depending on the model parameters. The morphology and kinematics of the spiral pattern are studied as functions of the halo and disk parameters. The spiral structure rotates slowly, and its angular velocity varies quasi-periodically. Models with differing relative halo masses, halo semi-axis ratios, distributions of matter in the disk, Mach numbers in the gaseous component, and angular rotational velocities of their halos are considered.Comment: 22 pages, 11 figure

Velocity Shear of the Thick Disk from SPM3 Proper Motions at the South Galactic Pole

The kinematical properties of the Galactic Thick Disk are studied using absolute proper motions from the SPM3 Catalog and 2MASS near-infrared photometry for a sample of ~1200 red giants in the direction of the South Galactic Pole. The photometrically-selected sample is dominated by Thick Disk stars, as indicated by the number-density distribution that varies with distance from the Galactic plane as a single-valued exponential over the range 1<z<4 kpc. The inferred scale height of the Thick Disk is 0.783 +/- 0.048 kpc. The kinematics of the sample are also consistent with disk-like motion. The U-velocity component is roughly constant, reflecting the Sun's peculiar motion, while a considerable shear is seen in the mean rotational velocity, V. The V-velocity profile's dependence on z is linear, with a gradient of dV/dz = -30 +/- 3 km/s/kpc. The velocity dispersions, in both U and V, show a lesser gradient of about 9 +/- 3 km/s/kpc. We demonstrate that the derived velocity and velocity-dispersion profiles are consistent with the assumptions of dynamical equilibrium and reasonable models of the overall Galactic potential.Comment: 38 pages, 9 figures, accepted for publication in A

Field induced single ion magnet based on a quasi octahedral Co ii complex with mixed sulfur oxygen coordination environment

Synthesis and characterization of structure and magnetic properties of the quasi octahedral complex pipH2 [Co TDA 2] 2H2O I , pipH22 piperazine dication, TDA2 amp; 8722; thiodiacetic anion are described. X ray diffraction studies reveal the first coordination sphere of the Co II ion, consisting of two chelating tridentate TDA ligands with a mixed sulfur oxygen strongly elongated octahedral coordination environment. SQUID magnetometry, frequency domain Fourier transform FD FT THz EPR spectroscopy, and high level ab initio SA CASSCF NEVPT2 quantum chemical calculations reveal a strong easy plane type magnetic anisotropy D amp; 8776; 54 cm amp; 8722;1 of complex I. The complex shows field induced slow relaxation of magnetization at an applied DC field of 1000 O

K^+ production in the reaction 58Ni+58Ni^{58}Ni+^{58}Ni at incident energies from 1 to 2 AGeV

Semi-inclusive triple differential multiplicity distributions of positively charged kaons have been measured over a wide range in rapidity and transverse mass for central collisions of $^{58}$Ni with $^{58}$Ni nuclei. The transverse mass ($m_t$) spectra have been studied as a function of rapidity at a beam energy 1.93 AGeV. The $m_t$ distributions of K^+ mesons are well described by a single Boltzmann-type function. The spectral slopes are similar to that of the protons indicating that rescattering plays a significant role in the propagation of the kaon. Multiplicity densities have been obtained as a function of rapidity by extrapolating the Boltzmann-type fits to the measured distributions over the remaining phase space. The total K^+ meson yield has been determined at beam energies of 1.06, 1.45, and 1.93 AGeV, and is presented in comparison to existing data. The low total yield indicates that the K^+ meson can not be explained within a hadro-chemical equilibrium scenario, therefore indicating that the yield does remain sensitive to effects related to its production processes such as the equation of state of nuclear matter and/or modifications to the K^+ dispersion relation.Comment: 24 pages Latex (elsart) 7 PS figures to be submitted to Nucl. Phys