1,005 research outputs found
Multifractal dimensions for critical random matrix ensembles
Based on heuristic arguments we conjecture that an intimate relation exists
between the eigenfunction multifractal dimensions of the eigenstates of
critical random matrix ensembles ,
. We verify this relation by extensive numerical calculations. We
also demonstrate that the level compressibility describing level
correlations can be related to in a unified way as
, thus generalizing existing relations with
relevance to the disorder driven Anderson--transition.Comment: 6 pages, 9 figure
The Radio Galaxy Population in the SIMBA SImulations
We examine the 1.4GHz radio luminosities of galaxies arising from star
formation and active galactic nuclei (AGN) within the state-of-the-art
cosmological hydrodynamic simulation Simba. Simba grows black holes via
gravitational torque limited accretion from cold gas and Bondi accretion from
hot gas, and employs AGN feedback including jets at low Eddington ratios. We
define a population of radio loud AGN (RLAGN) based on the presence of ongoing
jet feedback. Within RLAGN we define high and low excitation radio galaxies
(HERGs and LERGs) based on their dominant mode of black hole accretion: torque
limited accretion representing feeding from a cold disk, or Bondi representing
advection-dominated accretion from a hot medium. Simba predicts good agreement
with the observed radio luminosity function (RLF) and its evolution, overall as
well as separately for HERGs and LERGs. Quiescent galaxies with AGN-dominated
radio flux dominate the RLF at > W Hz, while star
formation dominates at lower radio powers. Overall, RLAGN have higher black
hole accretion rates and lower star formation rates than non-RLAGN at a given
stellar mass or velocity dispersion, but have similar black hole masses. Simba
predicts a LERG number density of 8.53 Mpc, higher than
for HERGs, broadly as observed. While LERGs dominate among most massive
galaxies with the largest black holes and HERGs dominate at high specific star
formation rates, they otherwise largely populate similar-sized dark matter
halos and have similar host galaxy properties. Simba thus predicts that deeper
radio surveys will reveal an increasing overlap between the host galaxy
demographics of HERGs and LERGs.Comment: 17 pages, 9 figures, Accepted for publication in MNRA
Equivalent layered models for functionally graded plates
Functionally graded plates whose material properties vary continuously through the thickness are modelled as exactly equivalent plates composed of up to four isotropic layers. Separate models are derived for analysis using classical plate theory, first-order and higher-order shear deformation theory. For cases where Poisson’s ratio varies through the thickness, the integrations required to obtain the membrane, coupling and out-of-plane stiffness matrices are performed accurately using a series solution. The model is verified by comparison with well converged solutions from approximate models in which the plate is divided into many isotropic layers. Critical buckling loads and undamped natural frequencies are found for a range of illustrative examples
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