15416702
The Suzaku Observation of RCW 86 Northeastern Shell
This paper reports the Suzaku results on the northeast shell of RCW 86. With the spatial and spectral analysis, we separated the X-rays into three distinct components; low (kTe ∼0.3 keV) and high (kTe ∼1.8 keV) temperature plasmas and a non-thermal component, and discovered their spatial distributions are different from each other. The low temperature plasma is dominated at the east rim, whereas the non-thermal emission is the brightest at the northeast rim which is spatially connected from the east rim. The high temperature plasma, found to contain the ∼6.42 keV line (Kα of low-ionized iron), is enhanced at the inward region with respect to the east rim and has no spatial correlation with the non-thermal X-ray (the northeast). The FeKα line, therefore, is not related to the non-thermal emission but originates from Fe-rich ejecta heated to the high temperatures by the reverse shock. Since the metal abundances of the low temperature plasma are sub-solar, the most possible origin of this component is interstellar medium heated by a blast wave. The non-thermal X-ray, which has a power-law index of ∼ 2.8, is likely to be synchrotron emission. A possible scenario to explain these morphologies and spectra is: A fast moving blast wave in a thin cavity of OB association collided with a dense interstellar medium or cloud at the east region very recently. As the result, the reverse shock in this interior decelerated, and arrived at the Fe-rich region of the ejecta and heated it. In the
53371172
Temporal and Spatial Analyses of Spectral Indices of Nonthermal Emissions Derived from Hard X-Rays and Microwaves
We studied electron spectral indices of nonthermal emissions seen in hard X-rays (HXRs) and microwaves. We analyzed 12 flares observed by the Hard X-Ray Telescope aboard Yohkoh, Nobeyama Radio Polarimeters, and the Nobeyama Radioheliograph (NoRH), and compared the spectral indices derived from total fluxes of HXRs and microwaves. Except for four events, which have very soft HXR spectra suffering from the thermal component, these flares show a gap Δδ between the electron spectral indices derived from HXRs δ X and those from microwaves δμ (Δδ = δ X – δμ) of about 1.6. Furthermore, from the start to the peak times of the HXR bursts, the time profiles of the HXR spectral index δ X evolve synchronously with those of the microwave spectral index δμ, keeping the constant gap. We also examined the spatially resolved distribution of the microwave spectral index by using NoRH data. The microwave spectral index δμ tends to be larger, which means a softer spectrum, at HXR footpoint sources with stronger magnetic field than that at the loop tops. These results suggest that the electron spectra are bent at around several hundreds of keV, and become harder at the higher energy range that contributes the microwave gyrosynchrotron emission.
13583595
New CTI Correction Method for Spaced-Row Charge Injection of the Suzaku X-Ray Imaging Spectrometer
The charge transfer inefficiency (CTI) of the X-ray CCDs on board the Suzaku satellite (X-ray Imaging Spectrometers; XIS) has increased since the launch due to radiation damage, and the energy resolution has been degraded. To improve the CTI, we have applied a spaced-row charge injection (SCI) technique to the XIS in orbit; by injecting charges into CCD rows periodically, the CTI is actively decreased. The CTI in the SCI mode depends on the distance between a signal charge and a preceding injected row, and the pulse height shows periodic positional variations. Using in-flight data of onboard calibration sources and of the strong iron line from the Perseus cluster of galaxies, we studied the variation in detail. We developed a new method to correct the variation. By applying the new method, the energy resolution (FWHM) at 5.9 keV at March 2008 is ~155 eV for the front-illuminated CCDs and ~175 eV for the back-illuminated CCD.
6264457
Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission
We have observed the diffuse X-ray emission from the Galactic center (GC) using the X-ray Imaging Spectrometer (XIS) on Suzaku. The high-energy resolution and the low-background orbit provide excellent spectra of the GC diffuse X-rays (GCDX). The XIS found many emission lines in the GCDX near the energy of K-shell transitions of iron and nickel. The most pronounced features are Fe I Kat 6.4 keV and K-shell absorption edge at 7.1 keV, which are from neutral and/or low ionization states of iron, and the K-shell lines at 6.7 keV and 6.9 keV from He-like (Fe XXV K�) and hydrogenic (Fe XXVI Ly�) ions of iron. In addition, Klines from neutral or low ionization nickel (Ni I K�) and He-like nickel (Ni XXVII K�), and Fe I K�, Fe XXV K�, Fe XXVI Ly�, Fe XXV K and Fe XXVI Ly are detected for the first time. The line center energies and widths of Fe XXV Kand Fe XXVI Lyfavor a collisional excitation (CE) plasma for the origin of the GCDX. The electron temperature determined from the line flux ratio of Fe XXV-K�/ Fe XXV-Kis similar to the ionization temperature determined from that of Fe XXV-K�/FeXXVI-Ly�. Thus it would appear that the GCDX plasma is close to ionization equilibrium. The 6.7 keV flux and temperature distribution to the galactic longitude is smooth and monotonic, in contrast to the integrated point source flux distribution. These facts support the hypothesis that the GCDX is truly diffuse emission rather than the integration of the outputs of a large number of unresolved point sources. In addition, our results demonstrate that the chemical composition of Fe in the interstellar gas near the GC is constrained to be about 3.5 times solar.
118367993
POSSIBLE CHARGE-EXCHANGE X-RAY EMISSION IN THE CYGNUS LOOP DETECTED WITH SUZAKU
X-ray spectroscopic measurements of the Cygnus Loop supernova remnant indicate that metal abundances throughout most of the remnant's rim are depleted to ~0.2 times the solar value. However, recent X-ray studies have revealed in some narrow regions along the outermost rim anomalously enhanced abundances (up to ~1 solar). The reason for these anomalous abundances is not understood. Here, we examine X-ray spectra in annular sectors covering nearly the entire rim of the Cygnus Loop using Suzaku (21 pointings) and XMM-Newton (1 pointing). We find that spectra in the enhanced abundance regions commonly show a strong emission feature at ~0.7?keV. This feature is likely a complex of He-like O K(? + ? + ), although other possibilities cannot be fully excluded. The intensity of this emission relative to He-like O K? appears to be too high to be explained as thermal emission. This fact, as well as the spatial concentration of the anomalous abundances in the outermost rim, leads us to propose an origin from charge-exchange processes between neutrals and H-like O. We show that the presence of charge-exchange emission could lead to the inference of apparently enhanced metal abundances using pure thermal emission models. Accounting for charge-exchange emission, the actual abundances could be uniformly low throughout the rim. The overall abundance depletion remains an open question.
55146394
The X-ray Study of Small-Scale Shock Structures in the Non-thermal SNRs
The shock front of SNRs is the most probable acceleration site of high energy particles (up to, or more than TeV) as already confirmed by the hard X-ray observations of the synchrotron emission from accelerated electrons. The remarkable spatial resolution of the X-ray observatory Chandra enables us to investigate the small-scale structure of the spatial distribution of accelerated electrons close to the shock front, which may lead us to deep understanding of acceleration mechanism. We have found hard X-ray filaments having a sharp rise in upstream and rather slow decay in downstream from the shocked region of six SNRs (Cas A, Tycho, Kepler, SN 1006, RCW 86, and 30 Dor C) using the Chandra archive data. For all the SNRs, we found that the scale width of the filaments is significantly smaller than that of the thermal plasma derived from the Sedov solution, The scale width becomes larger as increasing radius of the SNR, which may be followed by the understanding of the history of acceleration and energy loss of electrons in the shock front.
119514655
What the Gribov copy tells about confinement and the theory of dynamical chiral symmetry breaking
We performed lattice Landau gauge QCD simulation on {beta}=6.0,16{sup 4},24{sup 4},32{sup 4} and {beta}=6.4,32{sup 4},48{sup 4} and 56{sup 4} by adopting the gauge fixing that minimizes the norm of the gauge field, and measured the running coupling by using the gluon propagator and the ghost propagator. In view of ambiguity in the vertex renormalization factor Z{sub 1} in the lattice, we adjust the normalization of the running coupling by the perturbative QCD results near the highest momentum point. It has a maximum {alpha}{sub s}(q){approx_equal}2.1(3) at around q=0.5 GeV and decreases as q approaches 0, and the Kugo-Ojima parameter reached -0.83(2). The infrared exponent of the ghost propagator at 0.4 GeV region is {alpha}{sub G}=0.20 but there is an exceptional Gribov copy with {alpha}{sub G}=0.27. The features of the exceptional Gribov copy are investigated by measuring four one-dimensional Fourier transform (1-d FT) of the gluon propagator transverse to each lattice axis. We observe, in general, correlation between absolute value of the Kugo-Ojima parameter and the degree of reflection positivity violation in the 1-d FT of the gluon propagator. The 1-d FT of the exceptional Gribov copy has an axis whose samplewise gluon propagator manifestly violates reflection positivity, and the average ofmore » the Cartan subalgebra components of the Kugo-Ojima parameter along this axis is consistent to -1. The running coupling of the ensemble average shows a suppression at 0 momentum, but when the ghost propagator of the exceptional Gribov copy is adopted, the suppression disappears and the data implies presence of the infrared fixed point {alpha}{sub s}(0){approx}2.5(5) and {kappa}=0.5 suggested by the Dyson-Schwinger approach in the multiplicative renormalizable scheme. Comparison with the SU(2) QCD and N{sub f}=2 unquenched SU(3) QCD are also made.« less
118831238
Instanton moduli spaces and $\mathscr W$-algebras
We describe the (equivariant) intersection cohomology of certain moduli spaces ("framed Uhlenbeck spaces") together with some structures on them (such as e.g.\ the Poincar\'e pairing) in terms of representation theory of some vertex operator algebras ("$\mathscr W$-algebras").
14300277
Morita equivalence of noncommutative supertori
In this paper we study the extension of Morita equivalence of noncommutative tori to the supersymmetric case. The structure of the symmetry group yielding Morita equivalence appears to be intact but its parameter field becomes supersymmetrized having both body and soul parts. Our result is mainly in the two dimensional case in which noncommutative supertori have been constructed recently: The group SO(2,2,VZ0), where VZ0 denotes Grassmann even number whose body part belongs to Z, yields Morita equivalent noncommutative supertori in two dimensions.
122154679
A Study of tunneling in Hamiltonian systems via Monte Carlo simulation and Rayleigh-Ritz variation
Abstract Energy spectra of Hamiltonian systems which contain potential barriers are studied in the Monte Carlo simulation and the Rayleigh-Ritz variation. The onset of tunneling and splitting of the eigenergies are observed as the coupling constant increases. Consistency of the results of the Monte Carlo simulation is checked by two independent data fittings.
56216283
K-theoretic Donaldson invariants via instanton counting
In this paper we study the holomorphic Euler characteristics of determinant line bundles on moduli spaces of rank 2 semistable sheaves on an algebraic surface X, which can be viewed as $K$-theoretic versions of the Donaldson invariants. In particular, if X is a smooth projective toric surface, we determine these invariants and their wallcrossing in terms of the K-theoretic version of the Nekrasov partition function (called 5-dimensional supersymmetric Yang-Mills theory compactified on a circle in the physics literature). Using the results of math.AG/0606180 we give an explicit generating function for the wallcrossing of these invariants in terms of elliptic functions and modular forms.