5,563 research outputs found
Survey of CELSS Concepts and Preliminary Research in Japan
Agricultural and other experiments relating to the development of a controlled ecological life support system (CELSS) were proposed. The engineering feasibility of each proposal was investigated by a CELSS experiment concept met study group. The CELSS experiment concept to clarify the goals of CELSS and to determine three phases to achieve the goals. The resulting phases, or missions, and preliminary proposals and studies needed to develop a CELSS are described
Investigating the hard X-ray emission from the hottest Abell cluster A2163 with Suzaku
We present the results from Suzaku observations of the hottest Abell galaxy
cluster A2163 at . To study the physics of gas heating in cluster
mergers, we investigated hard X-ray emission from the merging cluster A2163,
which hosts the brightest synchrotron radio halo. We analyzed hard X-ray
spectra accumulated from two-pointed Suzaku observations. Non-thermal hard
X-ray emission should result from the inverse Compton (IC) scattering of
relativistic electrons by the CMB photons. To measure this emission, the
dominant thermal emission in the hard X-ray band must be modeled in detail. To
this end, we analyzed the combined broad-band X-ray data of A2163 collected by
Suzaku and XMM-Newton, assuming single- and multi-temperature models for
thermal emission and the power-law model for non-thermal emission. From the
Suzaku data, we detected significant hard X-ray emission from A2163 in the
12-60 keV band at the level (or at the level if a
systematic error is considered). The Suzaku HXD spectrum alone is consistent
with the single-T thermal model of gas temperature keV. From the XMM
data, we constructed a multi-T model including a very hot ( keV)
component in the NE region. Incorporating the multi-T and the power-law models
into a two-component model with a radio-band photon index, the 12-60 keV energy
flux of non-thermal emission is constrained within . The 90% upper limit of detected IC
emission is marginal ( in the
12-60 keV). The estimated magnetic field in A2163 is .
While the present results represent a three-fold increase in the accuracy of
the broad band spectral model of A2163, more sensitive hard X-ray observations
are needed to decisively test for the presence of hard X-ray emission due to IC
emission.Comment: 7 pages, 7 figures, A&A accepted. Minor correctio
Fermi Surface Study of Quasi-Two-Dimensional Organic Conductors by Magnetooptical Measurements
Magnetooptical measurements of several quasi-two-dimensional (q2D) organic
conductors, which have simple Fermi surface structure, have been performed by
using a cavity perturbation technique. Despite of the simple Fermi surface
structure, magnetooptical resonance results show a dramatic difference for each
sample. Cyclotron resonances (CR) were observed for q-(BEDT-TTF)2I3 and
(BEDT-TTF)3Br(pBIB), while periodic orbit resonances (POR) were observed for
(BEDT-TTF)2Br(DIA) and (BEDT-TTF)3Cl(DFBIB). The selection of the resonance
seems to correspond with the skin depth for each sample. The effective mass of
POR seems to have a mass enhancement due to the many-body effect, while
effective mass of CR is independent of the strength of the electron-electron
interaction. The scattering time deduced from each resonance's linewidth will
be also presented.Comment: 10 pages, 8 figures, to be published to J. Phys. Soc. Jpn Vol.72 No.1
(accepted
Electric Dipole Moments of Neutron-Odd Nuclei
The electric dipole moments (EDMs) of neutron-odd nuclei with even protons
are systematically evaluated. We first derive the relation between the EDM and
the magnetic moment operators by making use of the core polarization scheme.
This relation enables us to calculate the EDM of neutron-odd nuclei without any
free parameters. From this calculation, one may find the best atomic system
suitable for future EDM experiments.Comment: 4 page
How are Forbush decreases related to interplanetary magnetic field enhancements ?
Aims. Forbush decrease (FD) is a transient decrease followed by a gradual
recovery in the observed galactic cosmic ray intensity. We seek to understand
the relationship between the FDs and near-Earth interplanetary magnetic field
(IMF) enhancements associated with solar coronal mass ejections (CMEs).
Methods. We use muon data at cutoff rigidities ranging from 14 to 24 GV from
the GRAPES-3 tracking muon telescope to identify FD events. We select those FD
events that have a reasonably clean profile, and magnitude > 0.25%. We use IMF
data from ACE/WIND spacecrafts. We look for correlations between the FD profile
and that of the one hour averaged IMF. We ask if the diffusion of high energy
protons into the large scale magnetic field is the cause of the lag observed
between the FD and the IMF. Results. The enhancement of the IMF associated with
FDs occurs mainly in the shock-sheath region, and the turbulence level in the
magnetic field is also enhanced in this region. The observed FD profiles look
remarkably similar to the IMF enhancement profiles. The FDs typically lag the
IMF enhancement by a few hours. The lag corresponds to the time taken by high
energy protons to diffuse into the magnetic field enhancement via cross-field
diffusion. Conclusions. Our findings show that high rigidity FDs associated
with CMEs are caused primarily by the cumulative diffusion of protons across
the magnetic field enhancement in the turbulent sheath region between the shock
and the CME.Comment: accepted in A&
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