4,536 research outputs found
Suzaku Detection of Thermal X-Ray Emission Associated with the Western Radio Lobe of Fornax A
We present the results of X-ray mapping observations of the western radio
lobe of the Fornax A galaxy, using the X-ray Imaging Spectrometer (XIS) onboard
the Suzaku satellite with a total exposure time of 327 ks. The purpose of this
study is to investigate the nature and spatial extent of the diffuse thermal
emission around the lobe by exploiting the low and stable background of the
XIS. The diffuse thermal emission had been consistently reported in all
previous studies of this region, but its physical nature and relation to the
radio lobe had not been examined in detail. Using the data set covering the
entire western lobe and the central galaxy NGC 1316, as well as comparison sets
in the vicinity, we find convincingly the presence of thermal plasma emission
with a temperature of ~1 keV in excess of conceivable background and
contaminating emission (cosmic X-ray background, Galactic halo, intra-cluster
gas of Fornax, interstellar gas of NGC 1316, and the ensemble of point-like
sources). Its surface brightness is consistent with having a spherical
distribution peaking at the center of the western lobe with a projected radius
of ~12 arcmin. If the volume filling factor of the thermal gas is assumed to be
unity, its estimated total mass amounts to ~10^{10} M_sun, which would be
~10^{2} times that of the central black hole and comparable to that of the
current gas mass of the host galaxy. Its energy density is comparable to or
larger than those in the magnetic field and non-thermal electrons responsible
for the observed radio and X-ray emission.Comment: 10 pages, 5 figures, accepted for publication in PAS
Internal Josephson Effects in Spinor Dipolar Bose--Einstein Condensates
We theoretically study the internal Josephson effect, which is driven by spin
exchange interactions and magnetic dipole-dipole interactions, in a three-level
system for spin-1 Bose--Einstein condensates, obtaining novel spin dynamics. We
introduce single spatial mode approximations into the Gross--Pitaevskii
equations and derive the Josephson type equations, which are analogous to
tunneling currents through three junctions between three superconductors. From
an analogy with two interacting nonrigid pendulums, we identify unique varied
oscillational modes, called the 0--, 0--, --,
2n\pi & running--, , and phase modes. These Josephson modes in the three states are expected
to be found in real atomic Bose gas systems.Comment: 9 pages, 13 figure
Maximal entanglement of two spinor Bose-Einstein condensates
Starting with two weakly-coupled anti-ferromagnetic spinor condensates, we
show that by changing the sign of the coefficient of the spin interaction,
, via an optically-induced Feshbach resonance one can create an
entangled state consisting of two anti-correlated ferromagnetic condensates.
This state is maximally entangled and a generalization of the Bell state from
two anti-correlated spin-1/2 particles to two anti-correlated spin atomic
samples, where is the total number of atoms.Comment: 5 pages, 3 figures, accepted for publication in PR
Supersymmetry in gauge theories with extra dimensions
We show that a quantum-mechanical N=2 supersymmetry is hidden in 4d mass
spectrum of any gauge invariant theories with extra dimensions. The N=2
supercharges are explicitly constructed in terms of differential forms. The
analysis can be extended to extra dimensions with boundaries, and for a single
extra dimension we clarify a possible set of boundary conditions consistent
with 5d gauge invariance, although some of the boundary conditions break 4d
gauge symmetries.Comment: 18 page
Gas, Iron and Gravitational Mass in Galaxy Clusters: The General Lack of Cluster Evolution at z < 1.0
We have analyzed the ASCA data of 29 nearby clusters of galaxies
systematically, and obtained temperatures, iron abundances, and X-ray
luminosities of their intracluster medium (ICM). We also estimate ICM mass
using the beta model, and then evaluate iron mass contained in the ICM and
derive the total gravitating mass. This gives the largest and most homogeneous
information about the ICM derived only by the ASCA data. We compare these
values with those of distant clusters whose temperatures, abundances, and
luminosities were also measured with ASCA, and find no clear evidence of
evolution for the clusters at z<1.0. Only the most distant cluster at z=1.0,
AXJ2019.3+1127, has anomalously high iron abundance, but its iron mass in the
ICM may be among normal values for the other clusters, because the ICM mass may
be smaller than the other clusters. This may suggest a hint of evolution of
clusters at z ~ 1.0.Comment: 23 pages including 5 figures. Using PASJ2.sty, and PASJ95.sty.
Accepted by PAS
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