258 research outputs found
Sparse aperture masking at the VLT II. Detection limits for the eight debris disks stars Pic, AU Mic, 49 Cet, Tel, Fomalhaut, g Lup, HD181327 and HR8799
Context. The formation of planetary systems is a common, yet complex
mechanism. Numerous stars have been identified to possess a debris disk, a
proto-planetary disk or a planetary system. The understanding of such formation
process requires the study of debris disks. These targets are substantial and
particularly suitable for optical and infrared observations. Sparse Aperture
masking (SAM) is a high angular resolution technique strongly contributing to
probe the region from 30 to 200 mas around the stars. This area is usually
unreachable with classical imaging, and the technique also remains highly
competitive compared to vortex coronagraphy. Aims. We aim to study debris disks
with aperture masking to probe the close environment of the stars. Our goal is
either to find low mass companions, or to set detection limits. Methods. We
observed eight stars presenting debris disks ( Pictoris, AU
Microscopii, 49 Ceti, Telescopii, Fomalhaut, g Lupi, HD181327 and
HR8799) with SAM technique on the NaCo instrument at the VLT. Results. No close
companions were detected using closure phase information under 0.5 of
separation from the parent stars. We obtained magnitude detection limits that
we converted to Jupiter masses detection limits using theoretical isochrones
from evolutionary models. Conclusions. We derived upper mass limits on the
presence of companions in the area of few times the diffraction limit of the
telescope around each target star.Comment: 7 pages, All magnitude detection limits maps are only available in
electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr
(130.79.128.5
Calcul d'une formule barymétrique adaptée au zébu Gobra
Les auteurs donnent à partir de l'observation de 7 596 couples de poids-périmètres thoraciques relevés chez des zébus Gobra du Sénégal, un tableau de conversion du périmètre thoracique en poids, utilisable directement dans les conditions de travail sur le terrain (enquêtes, suivis d'évolution pondérale...
The Subaru Coronagraphic Extreme Adaptive Optics system: enabling high-contrast imaging on solar-system scales
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a
multipurpose high-contrast imaging platform designed for the discovery and
detailed characterization of exoplanetary systems and serves as a testbed for
high-contrast imaging technologies for ELTs. It is a multi-band instrument
which makes use of light from 600 to 2500nm allowing for coronagraphic direct
exoplanet imaging of the inner 3 lambda/D from the stellar host. Wavefront
sensing and control are key to the operation of SCExAO. A partial correction of
low-order modes is provided by Subaru's facility adaptive optics system with
the final correction, including high-order modes, implemented downstream by a
combination of a visible pyramid wavefront sensor and a 2000-element deformable
mirror. The well corrected NIR (y-K bands) wavefronts can then be injected into
any of the available coronagraphs, including but not limited to the phase
induced amplitude apodization and the vector vortex coronagraphs, both of which
offer an inner working angle as low as 1 lambda/D. Non-common path, low-order
aberrations are sensed with a coronagraphic low-order wavefront sensor in the
infrared (IR). Low noise, high frame rate, NIR detectors allow for active
speckle nulling and coherent differential imaging, while the HAWAII 2RG
detector in the HiCIAO imager and/or the CHARIS integral field spectrograph
(from mid 2016) can take deeper exposures and/or perform angular, spectral and
polarimetric differential imaging. Science in the visible is provided by two
interferometric modules: VAMPIRES and FIRST, which enable sub-diffraction
limited imaging in the visible region with polarimetric and spectroscopic
capabilities respectively. We describe the instrument in detail and present
preliminary results both on-sky and in the laboratory.Comment: Accepted for publication, 20 pages, 10 figure
Charles Taylor, Mikhail Epstein and ‘minimal religion’
The final publication is available at Springer via http://dx.doi.org/10.1007/s11153-015-9508-3In A Secular Age Charles Taylor endorses Mikhail Epstein’s notion of ‘minimal religion’ as his preferred orientation to the good for Western secular society. This article examines the basis of Epstein’s ‘minimal religion’ which rests on the psychoanalytic theories of Sigmund Freud and Carl Jung. It is shown that Freud’s theories are incompatible with Taylor’s own thought, and in the case of Jung, Epstein fails to develop the latter’s contribution to our understanding of religion. Moreover, although Taylor endorses Epstein’s work he makes no reference to Jung. To this end, the importance of Jung’s theories in relation to religion are elucidated and offered as a way to forge a dialogue between a nuanced humanist position and the theistic vision offered by Taylor
Ernst Jünger and the problem of Nihilism in the age of total war
As a singular witness and actor of the tumultuous twentieth century, Ernst Jünger remains a controversial and enigmatic figure known above all for his vivid autobiographical accounts of experience in the trenches of the First World War. This article will argue that throughout his entire oeuvre, from personal diaries to novels and essays, he never ceased to grapple with what he viewed as the central question of the age, namely that of the problem of nihilism and the means to overcome it. Inherited from Nietzsche’s diagnosis of Western civilization in the late nineteenth century to which he added an acute observation of the particular role of technology within it, Jünger would employ this lens to make sense of the seemingly absurd industrial slaughter of modern war and herald the advent of a new voluntarist and bellicist order that was to imminently sweep away timorous and decadent bourgeois societies obsessed with security and self-preservation. Jünger would ultimately see his expectations dashed, including by the forms of rule that National Socialism would take, and eventually retreated into a reclusive quietism. Yet he never abandoned his central problematique of nihilism, developing it further in exchanges with Martin Heidegger after the Second World War. And for all the ways in which he may have erred, his life-long struggle with meaning in the age of technique and its implications for war and security continue to make Jünger a valuable interlocutor of the present
Psychotherapy in historical perspective
This article will briefly explore some of the ways in which the past has been used as a means to talk about psychotherapy as a practice and as a profession, its impact on individuals and society, and the ethical debates at stake. It will show how, despite the multiple and competing claims about psychotherapy’s history and its meanings, historians themselves have, to a large degree, not attended to the intellectual and cultural development of many therapeutic approaches. This absence has the potential consequence of implying that therapies have emerged as value-free techniques, outside of a social, economic and political context. The relative neglect of psychotherapy, by contrast with the attention historians have paid to other professions, particularly psychiatry, has also underplayed its societal impact. This article will foreground some of the instances where psychotherapy has become an object of emerging historical interest, including the new research that forms the substance of this special issue of History of the Human Sciences
Global shifts, theoretical shifts: changing geographies of religion
10.1177/0309132510362602Progress in Human Geography346755-77
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