3,572 research outputs found
The way forward
For the last few decades the study of disks around stars young and old and of
different types have progressed significantly. During the same time a
completely new discipline, the study of exoplanets, planets orbiting stars
other than our Sun, have emerged. Both these fields, which are interconnected,
have benefited from the development of new instrumentation, and especially by
telescopes and detectors deployed in space. In this chapter we are describing
the state of the art of such instruments and make an inventory of what is being
currently developed. We also state some of the requirements of the next steps
and what type of instruments will lead the way forward.Comment: 25 pages, 4 figure
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High resolution CO observations of S88-B
CO J = 2-1 and 13CO J = 2-1 and 1-0 observations have been made of the H II region S88-B, using the 15-m James Clerk Maxwell telescope in Hawaii and the 20-m telescope at Onsala. The core of the cloud is resolved into a horseshoelike structure which surrounds a diffuse reflection nebula. The central core has a mass of ≥ 1000 M⊙, with 400 M⊙ in the horseshoe structure. The gas in the horse in the horseshoe appears highly fragmented, and has a kinetic temperature of ≈ 60 K, suggesting it is closely coupled to the dust temperature. A recently formed high mass star appears to be in the process of evacuating a cavity, possibly through a large molecular outflow that is found to show an accelerated component in its blue-shifted lobe. A velocity gradient across the horseshoe structure suggest ordered motion, and could represent rotation in the parental cloud
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High signal/noise <sup>13</sup>CO observations of the bipolar outflow in L1551
New high-signal/noise 13CO observations of the bipolar outflow in the molecular cloud L1551 are reported. Contrary to earlier observations of CO J = 1-0 and 2-1, no strong spatial dependence is found for the velocity profile of these spectra. The implications of these observations are such that the model of an empty shell for this source is less likely, and a model consisting of a shell which contains significant amounts of outflowing molecular gas inside the swept-up cavity walls is suggested
Se människan i var och en av oss! En studie om likabehandling av studenter med annan etnisk bakgrund i högskolan
Syfte
Syftet med undersökningen är att upptäcka vilken innebörd som ges åt begreppet likabehandling samt att få fram de uppfattningar som kan finnas i högskolan om likabehandling av studenter med annan etnisk tillhörighet. Dessutom är avsikten att försöka beskriva hur dessa uppfattningar kan påverka i mötet mellan lärare och studenter med annan etnisk bakgrund inom lärarutbildningen.
Teori
Den fenomenografiska forskningsansatsen med kvalitativa ostrukturerade intervjuer ligger som grund för empirin, med tolkning som instrument. Ett eklektiskt angreppssätt har använts för att försöka förstå komplexiteten i forskningsområdet. Det etnologiska perspektivet försöker förstå och förklara människors tänkesätt och handlingar medan det etnografiska perspektivet som är sprunget ur etnologin, beskriver handlingar och utsagor och hur dessa förändras hela tiden och i olika situationer. Socialpsykologins tredje perspektiv, stämplingsteorin, används som en förklaringsmodell för hur avvikande beteende, utseende och egenskaper används för att dela in människor i olika fack.
Metod
Trattekniken innebär att intervjun inleds med en öppen övergripande fråga, som i denna studie handlade om fenomenet likabehandling. Intervjuerna fick mer karaktären av samtal, men där studiens fem frågeområden stod i fokus för innehållet. Två pilotintervjuer genomfördes först, och därefter följde ytterligare åtta intervjuer med lärarutbildare och åtta med utländska lärare.
Samtliga intervjuer spelades in. Det insamlade materialet har bearbetats i en begreppsanalys och beskrivits i en delvis fenomenografisk modell där begreppen indelats i kategorier. De olika begreppen har bearbetats i flera steg för att försöka nå en metareflektion av innehållet i intervjuerna.
Resultat
Ett helikopterperspektiv på studiens resultatbeskrivning visar att det som framträder som kontentan av lärarutbildarnas utsagor är begreppen Osäkerhet, Språket och Mötet. De utländska lärarnas utsagor ger andra sammanfattande begrepp, Lika värde, Förutfattade meningar, Annorlundahet och Bortvalda. Det som uppfattas som svårt och problematiskt i mötet mellan lärare och studenter med annan etnisk tillhörighet inom lärarutbildningen verkar inte vara samma sak. Lärarutbildarnas absolut största svårighet att hantera och där flera känner sig provocerade rör svenska språket. Det som är svårast att uppleva för de utländska lärarna är gruppindelningen i olika sammanhang, där de ofta riskerar att bli bortvalda. Bland lärarutbildarna råder ingen enighet om vad likabehandling av studenter i högskolan innebär. Vad det innebär för de utländska lärarna är dock entydigt
Characteristics of proposed 3 and 4 telescope configurations for Darwin and TPF-I
The Darwin and TPF-I missions are Infrared free flying interferometer
missions based on nulling interferometry. Their main objective is to detect and
characterize other Earth-like planets, analyze the composition of their
atmospheres and their capability to sustain life, as we know it. Darwin and
TPF-I are currently in study phase. A number of mission architectures of 3 and
4 free flying telescopes are evaluated on the basis of the interferometer's
response, ability to distinguish multiple planet signatures and starlight
rejection capabilities. The characteristics of the new configurations are
compared also to the former, more complex Bowtie baseline architectures as well
as evaluated on base of their science capability.Comment: 4 pages, 2 figure
High Angular Resolution, Sensitive CS J=2-1 and J=3-2 Imaging of the Protostar L1551 NE: Evidence for Outflow-Triggered Star Formation ?
High angular resolution and sensitive aperture synthesis observations of CS
() and CS () emissions toward L1551 NE, the second brightest
protostar in the Taurus Molecular Cloud, made with the Nobeyama Millimeter
Array are presented. L1551 NE is categorized as a class 0 object deeply
embedded in the red-shifted outflow lobe of L1551 IRS 5. Previous studies of
the L1551 NE region in CS emission revealed the presence of shell-like
components open toward L1551 IRS 5, which seem to trace low-velocity shocks in
the swept-up shell driven by the outflow from L1551 IRS 5. In this study,
significant CS emission around L1551 NE was detected at the eastern tip of the
swept-up shell from = 5.3 km s to 10.1 km s, and
the total mass of the dense gas is estimated to be 0.18 0.02 .
Additionally, the following new structures were successfully revealed: a
compact disklike component with a size of 1000 AU just at L1551 NE,
an arc-shaped structure around L1551 NE, open toward L1551 NE, with a size of
AU, i.e., a bow shock, and a distinct velocity gradient of the
dense gas, i.e., deceleration along the outflow axis of L1551 IRS 5. These
features suggest that the CS emission traces the post-shocked region where the
dense gas associated with L1551 NE and the swept-up shell of the outflow from
L1551 IRS 5 interact. Since the age of L1551 NE is comparable to the timescale
of the interaction, it is plausible that the formation of L1551 NE was induced
by the outflow impact. The compact structure of L1551 NE with a tiny envelope
was also revealed, suggesting that the outer envelope of L1551 NE has been
blown off by the outflow from L1551 IRS 5.Comment: 29 pages, 12 figures, Accepted for Publication in the Astrophysical
Journa
Trawling for Terrorists: A Big Data Analysis of Conceptual Meanings and Contexts in Swedish Newspapers, 1780–1926
Towards a Molecular Inventory of Protostellar Discs
The chemical environment in circumstellar discs is a unique diagnostic of the
thermal, physical and chemical environment. In this paper we examine the
structure of star formation regions giving rise to low mass stars, and the
chemical environment inside them, and the circumstellar discs around the
developing stars.Comment: 9 page PDF, 550 kbyte
The X-ray Luminosities of HH Objects
The recent detection of X-ray emission from HH 2 and HH 154 with the Chandra
and XMM-Newton satellites (respectively) have opened up an interesting, new
observational possibility in the field of Herbig-Haro objects. In order to be
able to plan further X-ray observations of other HH objects, it is now of
interest to be able to estimate their X-ray luminosities in order to choose
which objects to observe. This paper describes a simple, analytic model for
predicting the X-ray luminosity of a bow shock from the parameters of the flow
(i.e., the size of the bow shock, its velocity, and the pre-shock density). The
accuracy of the analytic model is analyzed through a comparison with the
predictions obtained from axisymmetric, gasdynamic simulations of the leading
working surface of an HH jet. We find that our analytic model reproduces the
observed X-ray luminosities of HH 2 and HH 154, and we propose that HH~80/81 is
a good candidate for future observations with Chandra.Comment: 10 pages (8 text, 2 figures
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