2,985 research outputs found
Enigma of ultraluminous X-ray sources may be resolved by 3D-spectroscopy (MPFS data)
The ultraluminous X-ray sources (ULXs) were isolated in external galaxies for
the last 5 years. Their X-ray luminosities exceed 100-10000 times those of
brightest Milky Way black hole binaries and they are extremely variable. There
are two models for the ULXs, the best black hole candidates. 1. They are
supercritical accretion disks around a stellar mass black hole like that in
SS433, observed close to the disk axes. 2. They are Intermediate Mass Black
Holes (of 100-10000 solar masses). Critical observations which may throw light
upon the ULXs nature come from observations of nebulae around the ULXs. We
present results of 3D-spectroscopy of nebulae around several ULXs located in
galaxies at 3-6 Mpc distances. We found that the nebulae to be powered by their
central black holes. The nebulae are shocked and dynamically perturbed probably
by jets. The nebulae are compared with SS433 nebula (W50).Comment: Proceedings of the ESO and Euro3D Workshop "Science Perspectives for
3D Spectroscopy", Garching (Germany), October 10-14, 2005. M. Kissler-Patig,
M.M. Roth and J.R. Walsh (eds.
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A fuzzy controlled three-phase centrifuge for waste separation
The three-phase centrifuge technology discussed in this paper was developed by Neal Miller, president of Centech, Inc. The three-phase centrifuge is an excellent device for cleaning up oil field and refinery wastes which are typically composed of hydrocarbons, water, and solids. The technology is unique. It turns the waste into salable oil, reusable water, and landfill-able solids. No secondary waste is produced. The problem is that only the inventor can set up and run the equipment well enough to provide an optimal cleanup. Demand for this device has far exceeded a one man operation. There is now a need for several centrifuges to be operated at different locations at the same time. This has produced a demand for an intelligent control system, one that could replace a highly skilled operator, or at least supplement the skills of a less experienced operator. The control problem is ideally suited to fuzzy logic, since the centrifuge is a highly complicated machine operated entirely by the skill and experience of the operator. A fuzzy control system was designed for and used with the centrifuge
Pre- and post-selected ensembles and time-symmetry in quantum mechanics
An expression is proposed for the quantum mechanical state of a pre- and
post-selected ensemble, which is an ensemble determined by the final as well as
the initial state of the quantum systems involved. It is shown that the
probabilities calculated from the proposed state agree with previous
expressions, for cases where they both apply. The same probabilities are found
when they are calculated in the forward- or reverse-time directions. This work
was prompted by several problems raised by Shimony recently in relation to the
state, and time symmetry, of pre- and post-selected ensembles.Comment: RevTex4, 17 pages, no fig
Tracking a northern fulmar from a Scottish nesting site to the Charlie-Gibbs Fracture Zone : Evidence of linkage between coastal breeding seabirds and Mid-Atlantic Ridge feeding sites
Peer reviewedPublisher PD
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A fuzzy control system for a three-phase oil field centrifuge
The three-phase centrifuge discussed here is an excellent device for cleaning up oil field and refinery wastes. These wastes are typically composed of hydrocarbons, water, and solids. This technology converts waste, which is often classified as hazardous, into salable oil, reusable water, and solids that can be placed in landfills. No secondary waste is produced. A major problem is that only one person can set up and run the equipment well enough to provide an optimal cleanup. Demand for this technology has far exceeded a one-man operation. The solution to this problem is an intelligent control system that can replace a highly skilled operator so that several centrifuges can be operated at different locations at the same time
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Phonological, visual, and semantic coding strategies and children's short-term picture memory span
Three experiments addressed controversies in the previous literature on the development of phonological and other forms of short-term memory coding in children, using assessments of picture memory span that ruled out potentially confounding effects of verbal input and output. Picture materials were varied in terms of phonological similarity, visual similarity, semantic similarity, and word length. Older children (6/8-year-olds), but not younger children (4/5-year-olds), demonstrated robust and consistent phonological similarity and word length effects, indicating that they were using phonological coding strategies. This confirmed findings initially reported by Conrad (1971), but subsequently questioned by other authors. However, in contrast to some previous research, little evidence was found for a distinct visual coding stage at 4 years, casting doubt on assumptions that this is a developmental stage that consistently precedes phonological coding. There was some evidence for a dual visual and phonological coding stage prior to exclusive use of phonological coding at around 5-6 years. Evidence for semantic similarity effects was limited, suggesting that semantic coding is not a key method by which young children recall lists of pictures
Evidence for a three-nucleon-force effect in proton-deuteron elastic scattering
Developments in spin-polarized internal targets for storage rings have
permitted measurements of 197 MeV polarized protons scattering from vector
polarized deuterons. This work presents measurements of the polarization
observables A_y, iT_11, and C_y,y in proton-deuteron elastic scattering. When
compared to calculations with and without three-nucleon forces, the
measurements indicate that three-nucleon forces make a significant contribution
to the observables. This work indicates that three-body forces derived from
static nuclear properties appear to be crucial to the description of dynamical
properties.Comment: 8 pages 2 figures Latex, submitted to Phys. Rev. Letter
Lines, Circles, Planes and Spheres
Let be a set of points in , no three collinear and not
all coplanar. If at most are coplanar and is sufficiently large, the
total number of planes determined is at least . For similar conditions and
sufficiently large , (inspired by the work of P. D. T. A. Elliott in
\cite{Ell67}) we also show that the number of spheres determined by points
is at least , and this bound is best
possible under its hypothesis. (By , we are denoting the
maximum number of three-point lines attainable by a configuration of
points, no four collinear, in the plane, i.e., the classic Orchard Problem.)
New lower bounds are also given for both lines and circles.Comment: 37 page
Charge-Symmetry Violation in Pion Scattering from Three-Body Nuclei
We discuss the experimental and theoretical status of charge-symmetry
violation (CSV) in the elastic scattering of pi+ and pi- on 3H and 3He.
Analysis of the experimental data for the ratios r1, r2, and R at Tpi = 142,
180, 220, and 256 MeV provides evidence for the presence of CSV. We describe
pion scattering from the three-nucleon system in terms of single- and
double-scattering amplitudes. External and internal Coulomb interactions as
well as the Delta-mass splitting are taken into account as sources of CSV.
Reasonable agreement between our theoretical calculations and the experimental
data is obtained for Tpi = 180, 220, and 256 MeV. For these energies, it is
found that the Delta-mass splitting and the internal Coulomb interaction are
the most important contributions for CSV in the three-nucleon system. The CSV
effects are rather sensitive to the choice of pion-nuclear scattering
mechanisms, but at the same time, our theoretical predictions are much less
sensitive to the choice of the nuclear wave function. It is found, however,
that data for r2 and R at Tpi = 142 MeV do not agree with the predictions of
our model, which may indicate that there are additional mechanisms for CSV
which are important only at lower energies.Comment: 26 pages of RevTeX, 16 postscript figure
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