450 research outputs found

    A luminous blue kilonova and an off-axis jet from a compact binary merger at z=0.1341

    Get PDF
    The recent discovery of a faint gamma-ray burst (GRB) coincident with the gravitational wave (GW) event GW 170817 revealed the existence of a population of low-luminosity short duration gamma-ray transients produced by neutron star mergers in the nearby Universe. These events could be routinely detected by existing gamma-ray monitors, yet previous observations failed to identify them without the aid of GW triggers. Here we show that GRB150101B was an analogue of GRB170817A located at a cosmological distance. GRB 150101B was a faint short duration GRB characterized by a bright optical counterpart and a long-lived X-ray afterglow. These properties are unusual for standard short GRBs and are instead consistent with an explosion viewed off-axis: the optical light is produced by a luminous kilonova component, while the observed X-rays trace the GRB afterglow viewed at an angle of ~13 degrees. Our findings suggest that these properties could be common among future electromagnetic counterparts of GW sources.Comment: 28 pages, 8 figures, 2 tables. Accepted for publicatio

    Design and Fabrication of Electrostatically Actuated Silicon Microshutters Arrays

    Get PDF
    We have developed a new fabrication process to actuate microshutter arrays (MSA) electrostatically at NASA Goddard Space Flight Center. The microshutters are fabricated on silicon with thin silicon nitride membranes. A pixel size of each microshutter is 100 x 200 micrometers 2. The microshutters rotate 90 degrees on torsion bars. The selected microshutters are actuated, held, and addressed electrostatically by applying voltages on the electrodes the front and back sides of the microshutters. The atomic layer deposition (ALD) of aluminum oxide was used to insulate electrodes on the back side of walls; the insulation can withstand over 100 V. The ALD aluminum oxide is dry etched, and then the microshutters are released in vapor HF

    Development and Operation of the Microshutter Array System

    Get PDF
    The microshutter array (MSA) is a key component in the James Webb Space Telescope Near Infrared Spectrometer (NIRSpec) instrument. The James Webb Space Telescope is the next generation of a space-borne astronomy platform that is scheduled to be launched in 2013. However, in order to effectively operate the array and meet the severe operational requirements associated with a space flight mission has placed enormous constraints on the microshutter array subsystem. This paper will present an overview and description of the entire microshutter subsystem including the microshutter array, the hybridized array assembly, the integrated CMOS electronics, mechanical mounting module and the test methodology and performance of the fully assembled microshutter subsystem. The NIRSpec is a European Space Agency (ESA) instrument requiring four fully assembled microshutter arrays, or quads, which are independently addressed to allow for the imaging of selected celestial objects onto the two 4 mega pixel IR detectors. Each microshutter array must have no more than approx.8 shutters which are failed in the open mode (depending on how many are failed closed) out of the 62,415 (365x171) total number of shutters per array. The driving science requirement is to be able to select up to 100 objects at a time to be spectrally imaged at the focal plane. The spectrum is dispersed in the direction of the 171 shutters so if there is an unwanted open shutter in that row the light from an object passing through that failed open shutter will corrupt the spectrum from the intended object

    Synthesis and Complexing Properties of p-Toluensulfonylamido and Phosphorylamido Derivatives of Second-Generation Hyperbranched Polyester

    Get PDF
    © 2018, Pleiades Publishing, Ltd. Hyperbranched polyesters containing terminal p-toluenesulfonylamido and diethoxyphosphorylamido groups have been synthesized, and their complexes with copper(II) and cobalt(II) ions have been prepared. The thermal stability of the ligands and their metal complexes has been studied by differential scanning calorimetry

    Critical import insurance as a tool to support entrepreneurs under sanctions

    Get PDF
    The article substantiates the relevance of state support for critical imports in modern conditions of political and economic restrictions. The current economic and political conditions of Russia’s development introduce significant business risks when concluding import contracts for importing critical goods and implementing additional supportive measures for importers of those goods that are duly recognized as critically important for the country’s economic development. As a result of the conducted research the conclusion about the lack of theoretical approaches to the understanding of critical imports and normative fixation of the sought concept has been made. Based on the analysis of regulatory legal acts of the Eurasian Economic Union and federal legislation of Russia, the system of support for critical imports at the supranational level and the level of the Russian Federation has been described. The commodity structure of the critical imported products lists has been analyzed. On the basis of them the conclusion about the large-scale dependence of the Russian Federation on foreign-made goods has been made. The necessity of state support of insurance of advance payments for imports of critical goods has been assessed and the algorithm of state support of advance payments insurance for critical goods imports described. The conclusion about the need for a comprehensive approach to support critical imports has been formulated and the one of the possible tools for its implementation proposed

    Synthesis and spectral characteristics of 2,2-bis(hydroxymethyl)propionic acid derivatives as model compounds for the estimation of properties of modified hyperbranched polyesters polyols

    Get PDF
    © 2015 Pleiades Publishing, Ltd. New amino and carboxy derivatives of methyl 2,2-bis(hydroxymethyl)propionate have been synthesized as models of terminal fragments of hyperbranched polyester polyamines and polyesters polycarboxylic acids, and their spectral characteristics have been studied
    corecore