2,902 research outputs found
SIDE, a fiber fed spectrograph for the 10.4 m Gran Telescopio Canarias (GTC)
SIDE (Super Ifu Deployable Experiment) will be a second-generation,
common-user instrument for the Grantecan (GTC) on La Palma (Canary Islands,
Spain). It is being proposed as a spectrograph of low and intermediate
resolution, highly efficient in multi-object spectroscopy and 3D spectroscopy.
SIDE features the unique possibility of performing simultaneous visible and NIR
observations for selected ranges. The SIDE project is leaded by the Instituto
de Astrofisica de Andalucia (IAA-CSIC) in Granada (Spain) and the SIDE
Consortium is formed by a total of 10 institutions from Spain, Mexico and USA.
The SIDE Feasibility Study has been completed and currently the project is
under revision by the GTC Project Office.Comment: 9 pages, 6 figures, to appear in "Ground-based and Airborne
Instrumentation for Astronomy II" SPIE conference Proc. 7014, Marseille,
23-28 June 200
The spherical collapse model with shell crossing
In this work, we study the formation and evolution of dark matter halos by
means of the spherical infall model with shell-crossing. We present a framework
to tackle this effect properly based on the numerical follow-up, with time, of
that individual shell of matter that contains always the same fraction of mass
with respect to the total mass. In this first step, we do not include angular
momentum, velocity dispersion or triaxiality. Within this framework - named as
the Spherical Shell Tracker (SST) - we investigate the dependence of the
evolution of the halo with virial mass, with the adopted mass fraction of the
shell, and for different cosmologies. We find that our results are very
sensitive to a variation of the halo virial mass or the mass fraction of the
shell that we consider. However, we obtain a negligible dependence on
cosmology. Furthermore, we show that the effect of shell-crossing plays a
crucial role in the way that the halo reaches the stabilization in radius and
the virial equilibrium. We find that the values currently adopted in the
literature for the actual density contrast at the moment of virialization,
delta_vir, may not be accurate enough. In this context, we stress the problems
related to the definition of a virial mass and a virial radius for the halo.
The question of whether the results found here may be obtained by tracking the
shells with an analytic approximation remains to be explored.Comment: 15 pages, 4 figures, 9 tables, replaced to match the published MNRAS
versio
Using synchronization to improve earthquake forecasting in a cellular automaton model
A new forecasting strategy for stochastic systems is introduced. It is
inspired by the concept of anticipated synchronization between pairs of chaotic
oscillators, recently developed in the area of Dynamical Systems, and by the
earthquake forecasting algorithms in which different pattern recognition
functions are used for identifying seismic premonitory phenomena. In the new
strategy, copies (clones) of the original system (the master) are defined, and
they are driven using rules that tend to synchronize them with the master
dynamics. The observation of definite patterns in the state of the clones is
the signal for connecting an alarm in the original system that efficiently
marks the impending occurrence of a catastrophic event. The power of this
method is quantitatively illustrated by forecasting the occurrence of
characteristic earthquakes in the so-called Minimalist Model.Comment: 4 pages, 3 figure
Astrophysical inputs on the SUSY dark matter annihilation detectability
If dark matter (DM), which is considered to constitute most of the mass of
galaxies, is made of supersymmetric (SUSY) particles, the centers of galaxies
should emit gamma-rays produced by their self-annihilation. We present accurate
estimates of continuum gamma-ray fluxes due to neutralino annihilation in the
central regions of the Milky Way. We use detailed models of our Galaxy, which
satisfy available observational data, and include some important physical
processes, which were previously neglected. Our models predict that spatially
extended annihilation signal should be detected at high confidence levels by
incoming experiments assuming that neutralinos make up most of the DM in the
Universe and that they annihilate according to current SUSY models.Comment: 4 pages, submitted to Physical Review Letter
Animal images database: validation of 120 images for human-animal studies
There has been increasing interest in the study of human-animal relations. This contrasts with the lack of normative resources and materials for research purposes. We present subjective norms for a set of 120 open-source colour images of animals spanning a total of 12 biological categories (e.g., mammals, insects, reptiles, arachnids). Participants (N = 509, 55.2% female, MAge = 28.05, SD = 9.84) were asked to evaluate a randomly selected sub-set of 12 animals on valence, arousal, familiarity, cuteness, dangerousness, edibility, similarity to humans, capacity to think, capacity to feel, acceptability to kill for human consumption and feelings of care and protection. Animal evaluations were affected by individual characteristics of the perceiver, particularly gender, diet and companion animal ownership. Moral attitudes towards animals were predominantly predicted by ratings of cuteness, edibility, capacity to feel and familiarity. The Animal Images Database (Animal.ID) is the largest open-source database of rated images of animals; the stimuli set and item-level data are freely available online.info:eu-repo/semantics/publishedVersio
Nonlocality of Majorana modes in hybrid nanowires
Spatial separation of Majorana zero modes distinguishes trivial from topological midgap states and is key to topological protection in quantum computing applications. Although signatures of Majorana zero modes in tunneling spectroscopy have been reported in numerous studies, a quantitative measure of the degree of separation, or nonlocality, of the emergent zero modes has not been reported. Here, we present results of an experimental study of nonlocality of emergent zero modes in superconductor-semiconductor hybrid nanowire devices. The approach takes advantage of recent theory showing that nonlocality can be measured from splitting due to hybridization of the zero mode in resonance with a quantum dot state at one end of the nanowire. From these splittings as well as anticrossing of the dot states, measured for even and odd occupied quantum dot states, we extract both the degree of nonlocality of the emergent zero mode, as well as the spin canting angles of the nonlocal zero mode. Depending on the device measured, we obtain either a moderate degree of nonlocality, suggesting a partially separated Andreev subgap state, or a highly nonlocal state consistent with a well-developed Majorana modeThis research was supported by Microsoft, the Danish National Research Foundation, the European Commission, and the Spanish Ministry of Economy and Competitiveness through Grants No. FIS2015-65706-P, No. FIS2015-64654-P, and No. FIS2016-80434-P (AEI/FEDER, EU), the Ramón y Cajal programme Grant No. RYC-2011-09345, and the María de Maeztu Programme for Units of Excellence in R&D (Grant No. MDM-2014-0377). C.M.M. acknowledges support from the Villum Foundation. M.-T.D. acknowledges support from State Key Laboratory of High Performance Computing, Chin
C/O white dwarfs of very low mass: 0.33-0.5 Mo
The standard lower limit for the mass of white dwarfs (WDs) with a C/O core
is roughly 0.5 Mo. In the present work we investigated the possibility to form
C/O WDs with mass as low as 0.33 Mo. Both the pre-WD and the cooling evolution
of such nonstandard models will be described.Comment: Submitted to the "Proceedings of the 16th European White Dwarf
Workshop" (to be published JPCS). 7 pages including 13 figure
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