2,897 research outputs found
Unmasking the Active Galactic Nucleus in PKS J2310-437
PKS J2310-437 is an AGN with bright X-ray emission relative to its weak radio
emission and optical continuum. It is believed that its jet lies far enough
from the line of sight that it is not highly relativistically beamed. It thus
provides an extreme test of AGN models. We present new observations aimed at
refining the measurement of the source's properties. In optical photometry with
the NTT we measure a central excess with relatively steep spectrum lying above
the bright elliptical galaxy emission, and we associate the excess wholly or in
part with the AGN. A new full-track radio observation with the ATCA finds that
the core 8.64GHz emission has varied by about 20 per cent over 38 months, and
improves the mapping of the weak jet. With Chandra we measure a
well-constrained power-law spectral index for the X-ray core, uncontaminated by
extended emission from the cluster environment, with a negligible level of
intrinsic absorption. Weak X-ray emission from the resolved radio jet is also
measured. Our analysis suggests that the optical continuum in this radio galaxy
has varied by at least a factor of four over a timescale of about two years,
something that should be testable with further observations. We conclude that
the most likely explanation for the bright central X-ray emission is
synchrotron radiation from high-energy electrons.Comment: 7 pages, 12 figure
SU(3) Latent Heat and Surface Tension from Tree Level and Tadpole Improved Actions
We analyze the latent heat and surface tension at the SU(3) deconfinement
phase transition with tree level and tadpole improved Symanzik actions on
lattices with temporal extent and 4 and spatial extent , 6 and 8. In comparison to the standard Wilson action we do find a
drastic reduction of cut-off effects already with tree level improved actions.
On lattices with temporal extent results for the surface tension and
latent heat obtained with a tree level improved action agree well with those
obtained with a tadpole improved action. A comparison with
calculations, however, shows that results obtained with tadpole action remain
unaffected by cut-off effects even on this coarse lattice, while the tree level
action becomes sensitive to the cut-off. For the surface tension and latent
heat we find and , respectively.Comment: 11 pages, LaTeX2e File, 3 Postscript figure
Large area silicon sheet by EFG
Progress in a program to produce high speed, thin, wide silicon sheets for fabricating 10% efficient solar cells is reported. An EFG ribbon growth system was used to perform growth rate and ribbon thickness experiments. A new, wide ribbon growth system was developed. A theoretical study of stresses in ribbons was also conducted. The EFG ribbons were observed to exhibit a characteristic defect structure which is orientation dependent in the early stages of growth
Finite reduction and Morse index estimates for mechanical systems
A simple version of exact finite dimensional reduction for the variational
setting of mechanical systems is presented. It is worked out by means of a
thorough global version of the implicit function theorem for monotone
operators. Moreover, the Hessian of the reduced function preserves all the
relevant information of the original one, by Schur's complement, which
spontaneously appears in this context. Finally, the results are
straightforwardly extended to the case of a Dirichlet problem on a bounded
domain.Comment: 13 pages; v2: minor changes, to appear in Nonlinear Differential
Equations and Application
High intensity X/ γ photon beams for nuclear physics and photonics
In this manuscript we review the challenges of Compton back-scattering sources in advancing photon beam performances in the1−20MeVenergy range, underlining the design criteria bringing tomaximum spectral luminosity and briefly describing the main achieve-ments in conceiving and developing new devices (multi-bunch RF cav-ities and Laser recirculators) for the case of ELI-NP Gamma BeamSystem (ELI-NP-GBS)
Delivery status of the ELI-NP gamma beam system
International audienceThe ELI-NP GBS is a high intensity and monochromatic gamma source under construction in Magurele (Romania). The design and construction of the Gamma Beam System complex as well as the integration of the technical plants and the commissioning of the overall facility, was awarded to the Eurogammas Consortium in March 2014. The delivery of the facility has been planned in for 4 stages and the first one was fulfilled in October 31st 2015. The engineering aspects related to the delivery stage 1 are presented
A Bio-Polymer Transistor: Electrical Amplification by Microtubules
Microtubules (MTs) are important cytoskeletal structures, engaged in a number
of specific cellular activities, including vesicular traffic, cell
cyto-architecture and motility, cell division, and information processing
within neuronal processes. MTs have also been implicated in higher neuronal
functions, including memory, and the emergence of "consciousness". How MTs
handle and process electrical information, however, is heretofore unknown. Here
we show new electrodynamic properties of MTs. Isolated, taxol-stabilized
microtubules behave as bio-molecular transistors capable of amplifying
electrical information. Electrical amplification by MTs can lead to the
enhancement of dynamic information, and processivity in neurons can be
conceptualized as an "ionic-based" transistor, which may impact among other
known functions, neuronal computational capabilities.Comment: This is the final submitted version. The published version should be
downloaded from Biophysical Journa
Annealing-Dependent Magnetic Depth Profile in Ga[1-x]Mn[x]As
We have studied the depth-dependent magnetic and structural properties of
as-grown and optimally annealed Ga[1-x]Mn[x]As films using polarized neutron
reflectometry. In addition to increasing total magnetization, the annealing
process was observed to produce a significantly more homogeneous distribution
of the magnetization. This difference in the films is attributed to the
redistribution of Mn at interstitial sites during the annealing process. Also,
we have seen evidence of significant magnetization depletion at the surface of
both as-grown and annealed films.Comment: 5 pages, 3 figure
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