898,357 research outputs found
Spinless Calogero-Sutherland model with twisted boundary condition
In this work, the spinless Calogero-Sutherland model with twisted boundary
condition is studied. The ground state wavefunctions, the ground state
energies, the full energy spectrum are provided in details.Comment: preprint of ETH-L, appearing in recent PR
Line-profile variations in radial-velocity measurements: Two alternative indicators for planetary searches
Aims. We introduce two methods to identify false-positive planetary signals
in the context of radial-velocity exoplanet searches. The first is the
bi-Gaussian cross-correlation function fitting, and the second is the
measurement of asymmetry in radial-velocity spectral line information content,
Vasy.
Methods. We make a systematic analysis of the most used common line profile
diagnosis, Bisector Inverse Slope and Velocity Span, along with the two
proposed ones. We evaluate all these diagnosis methods following a set of
well-defined common criteria and using both simulated and real data. We apply
them to simulated cross-correlation functions created with the program SOAP and
which are affected by the presence of stellar spots, and to real
cross-correlation functions, calculated from HARPS spectra, for stars with a
signal originating both in activity and created by a planet.
Results. We demonstrate that the bi-Gaussian method allows a more precise
characterization of the deformation of line profiles than the standard bisector
inverse slope. The calculation of the deformation indicator is simpler and its
interpretation more straightforward. More importantly, its amplitude can be up
to 30% larger than that of the bisector span, allowing the detection of
smaller-amplitude correlations with radial-velocity variations. However, a
particular parametrization of the bisector inverse slope is shown to be more
efficient on high-signal-to-noise data than both the standard bisector and the
bi-Gaussian. The results of the Vasy method show that this indicator is more
effective than any of the previous ones, being correlated with the
radial-velocity with more significance for signals resulting from a line
deformation. Moreover, it provides a qualitative advantage over the bisector,
showing significant correlations with RV for active stars for which bisector
analysis is inconclusive. (abridged)Comment: 12 pages, 7 figures, accepted for publication in Astronomy and
Astrophysics, comments welcom
COUPLING CHIRAL BOSONS TO GRAVITY
The chiral boson actions of Floreanini and Jackiw (FJ), and of McClain,Wu and
Yu (MWY) have been recently shown to be different representations of the same
chiral boson theory. MWY displays manifest covariance and also a (gauge)
symmetry that is hidden in the FJ side, which, on the other hand, displays the
physical spectrum in a simple manner. We make use of the covariance of the MWY
representation for the chiral boson to couple it to background gravity showing
explicitly the equivalence with the previous results for the FJ representationComment: 8 pages, Latex, no figure
GENHYP - A FORTRAN 5 program for general linear hypothesis testing
GENHYP FORTRAN 5 program for general linear hypothesis testin
Bacteriostatic conformal coating for electronic components
Coating for electronic components used in space applications has bacteriostatic qualities capable of hindering bacterial reproduction, both vegetative and sporulative viable microorganisms. It exhibits high electrical resistivity, a low outgassing rate, and is capable of restraining electronic components when subjected to mechanical vibrations
Bacteriostatic conformal coating and methods of application Patent
Development of bacteriostatic conformal coating and methods of applicatio
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