2,421 research outputs found
ASCA Observation of the Low-Luminosity Seyfert 1.5 Galaxy NGC 5033
We present the results of an ASCA observation of the low-luminosity Seyfert
1.5 galaxy NGC 5033. A point-like X-ray source with a luminosity of 2.3x10^{41}
erg s^{-1} in the 2--10 keV band (at 18.7 Mpc; Tully 1988, AAA045.002.054) was
detected at the nucleus. The X-ray light curve shows variability on a timescale
of ~10^4 s with an amplitude of ~20%. The X-ray continuum is represented by a
weakly absorbed (N_H~9x10^{20} {cm^{-2}) power-law with a photon index of
1.72+/-0.04, which is quite similar to Seyfert 1 galaxies with higher
luminosities. A Fe Kalpha emission line is detected at 6.40^{+0.08}_{-0.06} keV
(redshift corrected) and the equivalent width is 290+/-100 eV. The line width
is unresolved. The narrower line width and larger equivalent width compared to
Seyfert 1s imply that fluorescent Fe Kalpha emission from matter further out
from the center than the accretion disk significantly contributes to the
observed Fe Kalpha line. We suggest that fluorescent Fe Kalpha emission from
the putative torus contributes to the observed Fe Kalpha line.Comment: 17 pages, To appear in PASJ, Vol. 51, No.
Equilibrium magnetisation structures in ferromagnetic nanorings
The ground state of the ring-shape magnetic nanoparticle is studied.
Depending on the geometrical and magnetic parameters of the nanoring, there
exist different magnetisation configurations (magnetic phases): two phases with
homogeneous magnetisation (easy-axis and easy-plane phases) and two
inhomogeneous (planar vortex phase and out-of-plane one). The existence of a
new intermediate out-of-plane vortex phase, where the inner magnetisation is
not strongly parallel to the easy axis, is predicted. Possible transitions
between different phases are analysed using the combination of analytical
calculations and micromagnetic simulations.Comment: LaTeX, 19 pages, 11 figure
Bell's inequality with Dirac particles
We study Bell's inequality using the Bell states constructed from four
component Dirac spinors. Spin operator is related to the Pauli-Lubanski pseudo
vector which is relativistic invariant operator. By using Lorentz
transformation, in both Bell states and spin operator, we obtain an observer
independent Bell's inequality, so that it is maximally violated as long as it
is violated maximally in the rest frame.Comment: 7 pages. arXiv admin note: text overlap with arXiv:quant-ph/0308156
by other author
Direct Observation of Non-Monotonic dx2-y2-Wave Superconducting Gap in Electron-Doped High-Tc Superconductor Pr0.89LaCe0.11CuO4
We performed high-resolution angle-resolved photoemission spectroscopy on
electron-doped high-Tc superconductor Pr0.89LaCe0.11CuO4 to study the
anisotropy of the superconducting gap. The observed momentum dependence is
basically consistent with the dx2-y2-wave symmetry, but obviously deviates from
the monotonic dx2-y2 gap function. The maximum gap is observed not at the zone
boundary, but at the hot spot where the antiferromagnetic spin fluctuation
strongly couples to the electrons on the Fermi surface. The present
experimental results unambiguously indicate the spin-mediated pairing mechanism
in electron-doped high-Tc superconductors.Comment: 4 pages, 4 figure
Outflow-Dominated Emission from the Quiescent Massive Black Holes in NGC 4621 and NGC 4697
The nearby elliptical galaxies NGC 4621 and NGC 4697 each host a supermassive
black hole with a mass more than 1e8 Solar masses. Analysis of archival Chandra
data and new NRAO Very Large Array data shows that each galaxy contains a
low-luminosity active galactic nucleus (LLAGN), identified as a faint, hard
X-ray source that is astrometrically coincident with a faint 8.5-GHz source.
The latter has a diameter less than 0.3 arcsec (26 pc for NGC 4621, 17 pc for
NGC 4697). The black holes energizing these LLAGNs have Eddington ratios L(2-10
keV) / L(Edd) ~ 1e-9, placing them in the so-called quiescent regime. The
emission from these quiescent black holes is radio-loud, with log Rx = log
nuLnu(8.5 GHz) / L(2-10 keV) ~ -2, suggesting the presence of a radio outflow.
Also, application of the radio-X-ray-mass relation from Yuan & Cui for
quiescent black holes predicts the observed radio luminosities nuLnu(8.5 GHz)
to within a factor of a few. Significantly, that relation invokes X-ray
emission from the outflow rather than from an accretion flow. The faint, but
detectable, emission from these two massive black holes is therefore consistent
with being outflow-dominated. Observational tests of this finding are
suggested.Comment: 11 pages; 4 figures: emulateapj; to appear in Ap
Arithmetic Orr invariants of absolute Galois groups
Based on the analogies between mapping class groups and absolute Galois groups, we introduce an arithmetic pro- analogue of Orr invariants for a Galois element associated with Galois action on \'etale fundamental groups of punctured projective lines. At the same time, we also introduce pro- Orr space as an arithmetic analogue of Orr space whose third homotopy group is a target group of Orr invariant. We then determine its rank as -module following Igusa-Orr's computation. Moreover, we investigate its relation with Ellenberg's obstruction to -sections associated with lower central series filtration in the context of Grothendieck's section conjecture
Spin decoherence by spacetime curvature
A decoherence mechanism caused by spacetime curvature is discussed. The spin
state of a particle is shown to decohere if only the particle moves in a curved
spacetime. In particular, when a particle is near the event horizon of a black
hole, an extremely rapid spin decoherence occurs for an observer who is static
in a Killing time, however slow the particle's motion is.Comment: 13 pages, 2 figure
Five-dimensional SYM from undeformed ABJM
We expand undeformed ABJM theory around the vacuum solution that was found in
arxiv:0909.3101. This solution can be interpreted as a circle-bundle over a
two-dimensional plane with a singularity at the origin. By imposing periodic
boundary conditions locally far away from the singularity, we obtain a local
fuzzy two-torus over which we have a circle fibration. By performing
fluctuation analysis we obtain five-dimensional SYM with the precise value on
the coupling constant that we would obtain by compactifying multiple M5 branes
on the vacuum three-manifold. In the resulting SYM theory we also find a
coupling to a background two-form.Comment: 23 page
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