239 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
Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
Multiplicity is one of the most fundamental observable properties of massive
O-type stars and offers a promising way to discriminate between massive star
formation theories. Nevertheless, companions at separations between 1 and 100
mas remain mostly unknown due to intrinsic observational limitations. [...] The
Southern MAssive Stars at High angular resolution survey (SMASH+) was designed
to fill this gap by providing the first systematic interferometric survey of
Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162
O-type stars with NACO/SAM, respectively probing the separation ranges 1-45 and
30-250mas and brightness contrasts of Delta H < 4 and Delta H < 5. Taking
advantage of NACO's field-of-view, we further uniformly searched for visual
companions in an 8''-radius down to Delta H = 8. This paper describes the
observations and data analysis, reports the discovery of almost 200 new
companions in the separation range from 1mas to 8'' and presents the catalog of
detections, including the first resolved measurements of over a dozen known
long-period spectroscopic binaries.
Excluding known runaway stars for which no companions are detected, 96
objects in our main sample (DEC < 0 deg; H<7.5) were observed both with PIONIER
and NACO/SAM. The fraction of these stars with at least one resolved companion
within 200mas is 0.53. Accounting for known but unresolved spectroscopic or
eclipsing companions, the multiplicity fraction at separation < 8'' increases
to f_m = 0.91 +/- 0.03. The fraction of luminosity class V stars that have a
bound companion reaches 100% at 30mas while their average number of physically
connected companions within 8'' is f_c = 2.2 +/- 0.3. This demonstrates that
massive stars form nearly exclusively in multiple systems. Additionally, the
nine non-thermal (NT) radio emitters observed by SMASH+ are all resolved [...]Comment: 57 pages, 20 figures, 7 tables; accepted for publication in ApJ
Population of ground and lowest excited states of Sulfur via the dissociative recombination of SH+ in the diffuse interstellar medium
Our previous study on dissociative recombination of ground state SH into
states of SH is extended by taking into account the contribution of
states recently explored by quantum chemistry methods. Multichannel
quantum defect theory is employed for the computation of cross sections and
rate coefficients for dissociative recombination, but also for vibrational
excitation. Furthermore, we produce the atomic yields resulting from
recombination, quantifying the generation of sulfur atoms in their ground
(\mbox{P}) and lowest excited (\mbox{D}) states respectively.Comment: 9 pages, 8 figures, 3 table
Population of ground and lowest excited states of Sulfur via the dissociative recombination of SH+ in the diffuse interstellar medium
Psychotherapy in Europe
Psychotherapy was an invention of European modernity, but as the 20th century unfolded, and we trace how it crossed national and continental borders, its goals and the particular techniques by which it operated become harder to pin down. This introduction briefly draws together the historical literature on psychotherapy in Europe, asking comparative questions about the role of location and culture, and networks of transmission and transformation. It introduces the six articles in this special issue on Greece, Hungary, Yugoslavia, Russia, Britain and Sweden as well as its parallel special issue of History of Psychology on ‘Psychotherapy in the Americas’. It traces what these articles tell us about how therapeutic developments were entangled with the dramatic, and often traumatic, political events across the continent: in the wake of the Second World War, the emergence of Communist and authoritarian regimes, the establishment of welfare states and the advance of neoliberalism
New Technologies’ Promise to the Self and the Becoming of the Sacred: Insights from Georges Bataille’s Concept of Transgression
This article draws on Georges Bataille’s concept of transgression, a key element in Bataille’s theory of the sacred, to highlight structural implications of the way the self-empowerment ethos of new technologies suffuses the digital tracking culture. Pointing to the original conceptual stance of transgression, worked out against prohibition, I first argue that, beyond a critique of new technologies’ promise of self-empowerment as coming at the expense of an acknowledgement of the ultimate taboo—death—is the problem of the sanitizing of the tension between the crossing of the line of the symbolic taboo and prohibition; this undermines a “libidinal investment” towards the sacred, which is central in Bataille’s theory. Second, focussing on “eroticism”, since this embodies the emancipative potential of the Bataillean sacred, I argue that while a fear of eroticism marks out the digital technological realm, this is covered up by the blurring of boundaries between pleasure, fun and sex(iness) that currently governs our experience with technological devices
Global shifts, theoretical shifts: changing geographies of religion
10.1177/0309132510362602Progress in Human Geography346755-77
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
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