11,003 research outputs found
Magnetic fields in single late-type giants in the Solar vicinity: How common is magnetic activity on the giant branches?
We present our first results on a new sample containing all single G,K and M
giants down to V = 4 mag in the Solar vicinity, suitable for
spectropolarimetric (Stokes V) observations with Narval at TBL, France. For
detection and measurement of the magnetic field (MF), the Least Squares
Deconvolution (LSD) method was applied (Donati et al. 1997) that in the present
case enables detection of large-scale MFs even weaker than the solar one (the
typical precision of our longitudinal MF measurements is 0.1-0.2 G). The
evolutionary status of the stars is determined on the basis of the evolutionary
models with rotation (Lagarde et al. 2012; Charbonnel et al., in prep.) and
fundamental parameters given by Massarotti et al. (1998). The stars appear to
be in the mass range 1-4 M_sun, situated at different evolutionary stages after
the Main Sequence (MS), up to the Asymptotic Giant Branch (AGB). The sample
contains 45 stars. Up to now, 29 stars are observed (that is about 64 % of the
sample), each observed at least twice. For 2 stars in the Hertzsprung gap, one
is definitely Zeeman detected. Only 5 G and K giants, situated mainly at the
base of the Red Giant Branch (RGB) and in the He-burning phase are detected.
Surprisingly, a lot of stars ascending towards the RGB tip and in early AGB
phase are detected (8 of 13 observed stars). For all Zeeman detected stars v
sin i is redetermined and appears in the interval 2-3 km/s, but few giants with
MF possess larger v sin i.Comment: 4 pages, 3 figures, Proceedings IAU Symposium No. 302, 201
Multiscale 3D Shape Analysis using Spherical Wavelets
©2005 Springer. The original publication is available at www.springerlink.com:
http://dx.doi.org/10.1007/11566489_57DOI: 10.1007/11566489_57Shape priors attempt to represent biological variations within a population. When variations are global, Principal Component Analysis (PCA) can be used to learn major modes of variation, even from a limited training set. However, when significant local variations exist, PCA typically cannot represent such variations from a small training set. To address this issue, we present a novel algorithm that learns shape variations from data at multiple scales and locations using spherical wavelets and spectral graph partitioning. Our results show that when the training set is small, our algorithm significantly improves the approximation of shapes in a testing set over PCA, which tends to oversmooth data
The Parkes HI Zone of Avoidance Survey
A blind HI survey of the extragalactic sky behind the southern Milky Way has
been conducted with the multibeam receiver on the 64-m Parkes radio telescope.
The survey covers the Galactic longitude range 212 < l < 36 and Galactic
latitudes |b| < 5, and yields 883 galaxies to a recessional velocity of 12,000
km/s. The survey covers the sky within the HIPASS area to greater sensitivity,
finding lower HI-mass galaxies at all distances, and probing more completely
the large-scale structures at and beyond the distance of the Great Attractor.
Fifty-one percent of the HI detections have an optical/NIR counterpart in the
literature. A further 27% have new counterparts found in existing, or newly
obtained, optical/NIR images. The counterpart rate drops in regions of high
foreground stellar crowding and extinction, and for low-HI mass objects. Only
8% of all counterparts have a previous optical redshift measurement. A notable
new galaxy is HIZOA J1353-58, a possible companion to the Circinus galaxy.
Merging this catalog with the similarly-conducted northern extension (Donley et
al. 2005), large-scale structures are delineated, including those within the
Puppis and Great Attractor regions, and the Local Void. Several
newly-identified structures are revealed here for the first time. Three new
galaxy concentrations (NW1, NW2 and NW3) are key in confirming the diagonal
crossing of the Great Attractor Wall between the Norma cluster and the CIZA
J1324.7-5736 cluster. Further contributors to the general mass overdensity in
that area are two new clusters (CW1 and CW2) in the nearer Centaurus Wall, one
of which forms part of the striking 180 deg (100/h Mpc) long filament that
dominates the southern sky at velocities of ~3000 km/s, and the suggestion of a
further Wall at the Great Attractor distance at slightly higher longitudes.Comment: Published in Astronomical Journal 9 February 2016 (accepted 26
September 2015); 42 pages, 7 tables, 18 figures, main figures data tables
only available in the on-line version of journa
Matching small functions using centroid jitter and two beam position monitors
Matching to small beta functions is required to preserve emittance in plasma
accelerators. The plasma wake provides strong focusing fields, which typically
require beta functions on the mm-scale, comparable to those found in the final
focusing of a linear collider. Such beams can be time consuming to
experimentally produce and diagnose. We present a simple, fast, and noninvasive
method to measure Twiss parameters in a linac using two beam position monitors
only, relying on the similarity of the beam phase space and the jitter phase
space. By benchmarking against conventional quadrupole scans, the viability of
this technique was experimentally demonstrated at the FLASHForward
plasma-accelerator facility.Comment: 8 pages, 7 figure
Instability of the Fermi-liquid fixed point in an extended Kondo model
We study an extended SU(N) single-impurity Kondo model in which the impurity
spin is described by a combination of Abrikosov fermions and Schwinger bosons.
Our aim is to describe both the quasiparticle-like excitations and the locally
critical modes observed in various physical situations, including non-Fermi
liquid (NFL) behavior in heavy fermions in the vicinity of a quantum critical
point and anomalous transport properties in quantum wires. In contrast with
models with either pure bosonic or pure fermionic impurities, the strong
coupling fixed point is unstable against the conduction electron kinetic term
under certain conditions. The stability region of the strong coupling fixed
point coincides with the region where the partially screened, effective
impurity repels the electrons on adjacent sites. In the instability region, the
impurity tends to attract electrons to the neighboring sites, giving
rise to a double-stage Kondo effect with additional screening of the impurity.Comment: 10 pages, 2 figures, Proceedings of the NATO Workshop on "Concepts in
Electron Correlations", Hvar,October 200
3-D unrestricted TDHF fusion calculations using the full Skyrme interaction
We present a study of fusion cross sections using a new generation
Time-Dependent Hartree-Fock (TDHF) code which contains no approximations
regarding collision geometry and uses the full Skyrme interaction, including
all of the time-odd terms. In addition, the code uses the Basis-Spline
collocation method for improved numerical accuracy. A comparative study of
fusion cross sections for is made with the older TDHF
results and experiments. We present results using the modern Skyrme forces and
discuss the influence of the new terms present in the interaction.Comment: 7 pages, 10 figure
Effervescent atomization: A new atomizing technique for the energy-efficient spray drying of food liquids with high viscosity
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