44,927 research outputs found
Testing the presence of multiple photometric components in nearby early-type galaxies using SDSS
We investigate two-dimensional image decomposition of nearby, morphologically
selected early-type galaxies (ETGs). We are motivated by recent observational
evidence of significant size growth of quiescent galaxies and theoretical
development advocating a two-phase formation scenario for ETGs. We find that a
significant fraction of nearby ETGs show changes in isophotal shape that
require multi-component models. The characteristic sizes of the inner and outer
component are and kpc. The inner component lies on the
mass-size relation of ETGs at , while the outer component
tends to be more elliptical and hints at a stochastic buildup process. We find
real physical differences between the single- and double-component ETGs, with
the double-component galaxies being younger and more metal-rich. The fraction
of double component ETGs increases with increasing and decreases in
denser environments. We hypothesize that double-component systems were able to
accrete gas and small galaxies until later times, boosting their central
densities, building up their outer parts, and lowering their typical central
ages. In contrast, the oldest galaxies, perhaps due to residing in richer
environments, have no remaining hints of their last accretion episode.Comment: resubmitted to ApJ after referee's repor
Betweenness centrality correlation in social networks
Scale-free (SF) networks exhibiting a power-law degree distribution can be
grouped into the assortative, dissortative and neutral networks according to
the behavior of the degree-degree correlation coefficient. Here we investigate
the betweenness centrality (BC) correlation for each type of SF networks. While
the BC-BC correlation coefficients behave similarly to the degree-degree
correlation coefficients for the dissortative and neutral networks, the BC
correlation is nontrivial for the assortative ones found mainly in social
networks. The mean BC of neighbors of a vertex with BC is almost
independent of , implying that each person is surrounded by almost the
same influential environments of people no matter how influential the person
is.Comment: 4 pages, 4 figures, 1 tabl
Majorana fermions in s-wave noncentrosymmetric superconductor with Rashba and Dresselhaus (110) spin-orbit couplings
The asymmetric spin-orbit (SO) interactions play a crucial role in realizing
topological phases in noncentrosymmetric superconductor (NCS).We investigate
the edge states and the vortex core states in s-wave NCS with Rashba and
Dresselhaus (110) SO couplings by both numerical and analytical methods. In
particular, we demonstrate that there exists a novel semimetal phase
characterized by the flat Andreev bound states in the phase diagram of the
s-wave Dresselhaus NCS which supports the emergence of Majorana fermion (MF).
The flat dispersion implies a peak in the density of states which has a clear
experimental signature in the tunneling conductance measurements and the MFs
proposed here should be experimentally detectable
Spatial conductivity measurements on high T(sub c) superconducting films
High T(sub c) superconducting thin and thick films have potential applications in future NASA flight projects. In anticipation of film use, the Materials Branch is developing a nondestructive, non-contact method of measuring the spatial variation of conductivity across a film sample. This method uses a computer-controlled, X-Y positioning table to scan a conventional eddy current probe across the surface of a film. The induced changes in impedance caused by variations in film conductivity are recorded during the scanning process. Ultimately the two-dimensional data set is displayed using imaging equipment on a personal computer
Higgs bosons of a supersymmetric model at the Large Hadron Collider
It is found that CP symmetry may be explicitly broken in the Higgs sector of
a supersymmetric model with two extra neutral gauge bosons at the
one-loop level. The phenomenology of the model, the Higgs sector in particular,
is studied for a reasonable parameter space of the model, in the presence of
explicit CP violation at the one-loop level. At least one of the neutral Higgs
bosons of the model might be produced via the fusion process at the Large
Hadron Collider.Comment: 23 pages, 5 figures, JHE
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