918 resultados para Eigenfunctions and fundamental solution


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Context. BD + 60° 73 is the optical counterpart of the X-ray source IGR J00370+6122, a probable accretion-powered X-ray pulsar. The X-ray light curve of this binary system shows clear periodicity at 15.7 d, which has been interpreted as repeated outbursts around the periastron of an eccentric orbit. Aims. We aim to characterise the binary system IGR J00370+6122 by deriving its orbital and physical parameters. Methods. We obtained high-resolution spectra of BD + 60° 73 at different epochs. We used the fastwind code to generate a stellar atmosphere model to fit the observed spectrum and obtain physical magnitudes. The synthetic spectrum was used as a template for cross-correlation with the observed spectra to measure radial velocities. The radial velocity curve provided an orbital solution for the system. We also analysed the RXTE/ASM and Swift/BAT light curves to confirm the stability of the periodicity. Results. BD + 60° 73 is a BN0.7 Ib low-luminosity supergiant located at a distance ~3.1 kpc, in the Cas OB4 association. We derive Teff = 24 000 K and log gc = 3.0, and chemical abundances consistent with a moderately high level of evolution. The spectroscopic and evolutionary masses are consistent at the 1-σ level with a mass M∗ ≈ 15 M⊙. The recurrence time of the X-ray flares is the orbital period of the system. The neutron star is in a high-eccentricity (e = 0.56 ± 0.07) orbit, and the X-ray emission is strongly peaked around orbital phase φ = 0.2, though the observations are consistent with some level of X-ray activity happening at all orbital phases. Conclusions. The X-ray behaviour of IGR J00370+6122 is reminiscent of “intermediate” supergiant X-ray transients, though its peak luminosity is rather low. The orbit is somewhat wider than those of classical persistent supergiant X-ray binaries, which when combined with the low luminosity of the mass donor, explains the low X-ray luminosity. IGR J00370+6122 will very likely evolve towards a persistent supergiant system, highlighting the evolutionary connection between different classes of wind-accreting X-ray sources.

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This study examines the challenges posed to European law by third country access to data held by private companies for the purposes of law enforcement. It pays particular attention to the implications for rule of law and fundamental rights of foreign authorities’ direct access to electronic information falling outside pre-established channels of supranational cooperation. A special focus is given to EU-US relations and the practical issues emerging in transatlantic relations covering mutual legal assistance and evidence gathering for law enforcement purposes in criminal proceedings.

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The European Union is founded on a set of common principles of democracy, the rule of law, and fundamental rights, as enshrined in Article 2 of the Treaty on the European Union. Whereas future Member States are vetted for their compliance with these values before they accede to the Union, no similar method exists to supervise adherence to these foundational principles after accession. EU history proved that this ‘Copenhagen dilemma’ was far from theoretical. EU Member State governments’ adherence to foundational EU values cannot be taken for granted. Violations may happen in individual cases, or in a systemic way, which may go as far as overthrowing the rule of law. Against this background the European Parliament initiated a Legislative Own-Initiative Report on the establishment of an EU mechanism on democracy, the rule of law and fundamental rights and proposed among others a Scoreboard on the basis of common and objective indicators by which foundational values can be measured. This Research Paper assesses the need and possibilities for the establishment of an EU Scoreboard, as well as its related social, economic, legal and political ‘costs and benefits’.

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Includes bibliographical references.

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Mode of access: Internet.

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Mode of access: Internet.

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Includes bibliographical references.