9,531 research outputs found
Finding bright <i>z</i> ≥ 6.6 Ly <i>α</i> emitters with lensing: prospects for <i>Euclid</i>
We model the Ly luminosity function to estimate the
number of lensed high Ly emitters that may be detected by the
Euclid Deep Survey. To span the whole range of possible predictions we exploit
two Ly luminosity function models and two strong gravitational lensing
models from the literature. We show that the planned Euclid Deep Survey
observing 40 deg over the 920-1850 nm wavelength range down to a flux limit
of erg scm will enable us to find
between and deg lensed Ly emitters at depending on the adopted Ly luminosity function and strong
gravitational lensing model. The obvious [OII], [OIII] and H
contaminants of the Ly lensed population will be identified with the
help of Euclid's spectral resolving power, while the SKA will enable the
identification of the interloper population of H emitters. By combining
Euclid and the SKA, we will thus be able to identify, for the first time, a
sample of to lensed Ly emitters at .Comment: Accepted for publication in MNRAS on 20 June 2017. (NEW: Amended
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Driven depinning of strongly disordered media and anisotropic mean-field limits
Extended systems driven through strong disorder are modeled generically using
coarse-grained degrees of freedom that interact elastically in the directions
parallel to the driving force and that slip along at least one of the
directions transverse to the motion. A realization of such a model is a
collection of elastic channels with transverse viscous couplings. In the
infinite range limit this model has a tricritical point separating a region
where the depinning is continuous, in the universality class of elastic
depinning, from a region where depinning is hysteretic. Many of the collective
transport models discussed in the literature are special cases of the generic
model.Comment: 4 pages, 2 figure
Models of plastic depinning of driven disordered systems
Two classes of models of driven disordered systems that exhibit
history-dependent dynamics are discussed. The first class incorporates local
inertia in the dynamics via nonmonotonic stress transfer between adjacent
degrees of freedom. The second class allows for proliferation of topological
defects due to the interplay of strong disorder and drive. In mean field theory
both models exhibit a tricritical point as a function of disorder strength. At
weak disorder depinning is continuous and the sliding state is unique. At
strong disorder depinning is discontinuous and hysteretic.Comment: 3 figures, invited talk at StatPhys 2
Plasticity in current-driven vortex lattices
We present a theoretical analysis of recent experiments on current-driven
vortex dynamics in the Corbino disk geometry. This geometry introduces
controlled spatial gradients in the driving force and allows the study of the
onset of plasticity and tearing in clean vortex lattices. We describe plastic
slip in terms of the stress-driven unbinding of dislocation pairs, which in
turn contribute to the relaxation of the shear, yielding a nonlinear response.
The steady state density of free dislocations induced by the applied stress is
calculated as a function of the applied current and temperature. A criterion
for the onset of plasticity at a radial location in the disk yields a
temperature-dependent critical current that is in qualitative agreement with
experiments.Comment: 11 pages, 4 figure
Substrate rigidity deforms and polarizes active gels
We present a continuum model of the coupling between cells and substrate that
accounts for some of the observed substrate-stiffness dependence of cell
properties. The cell is modeled as an elastic active gel, adapting recently
developed continuum theories of active viscoelastic fluids. The coupling to the
substrate enters as a boundary condition that relates the cell's deformation
field to local stress gradients. In the presence of activity, the coupling to
the substrate yields spatially inhomogeneous contractile stresses and
deformations in the cell and can enhance polarization, breaking the cell's
front-rear symmetry.Comment: 6 pages, 4 figures, EPL forma
Mobility through Heterogeneous Networks in a 4G Environment
Serving and Managing users in a heterogeneous environment. 17th WWRF Meeting in Heidelberg, Germany, 15 - 17 November 2006. [Proceeding presented at WG3 - Co-operative and Ad-hoc Networks]The increase will of ubiquitous access of the users to the requested services points towards the integration of heterogeneous networks. In this sense, a user shall be able to access its services through different access technologies, such as WLAN, Wimax, UMTS and DVB technologies, from the same or different network operators, and to seamless move between different networks with active communications. In this paper we propose a mobility architecture able to support this users’ ubiquitous access and seamless movement, while simultaneously bringing a large flexibility to access network operators
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