16902285
Energy-Scale Calibration of the Suzaku X-Ray Imaging Spectrometer Using the Checker Flag Charge-Injection Technique in Orbit
The X-ray Imaging Spectrometer (XIS) aboard the Suzaku satellite is an X-ray CCD camera system that has superior performance, such as a low background, high quantum efficiency, and good energy resolution in the 0.2–12 keV band. Because of radiation damage in orbit, however, the charge-transfer inefficiency (CTI) has increased, and hence the energy scale and resolution of the XIS has been degraded since the launch in 2005 July. The CCD has a charge-injection structure, and the CTI of each column and the pulse-height dependence of the CTI are precisely measured by a checker flag charge-injection (CFCI) technique. Our precise CTI correction improved the energy resolution from 230 eV to 190 eV at 5.9 keV in 2006 December. This paper reports on CTI measurements with the CFCI experiments in orbit. Using the CFCI results, we have implemented the time-dependent energy scale and resolution to the Suzaku calibration database.
19609772
Monte Carlo Simulator and Ancillary Response Generator of Suzaku XRT/XIS System for Spatially Extended Source Analysis
We have developed a framework for the Monte-Carlo simulation of the X-Ray Telescopes (XRT) and the X-ray Imaging Spectrometers (XIS) onboard Suzaku, mainly for the scientific analysis of spatially and spectroscopically complex celestial sources. A photon-by-photon instrumental simulator is built on the ANL platform, which has been successfully used in ASCA data analysis. The simulator has a modular structure, in which the XRT simulation is based on a ray-tracing library, while the XIS simulation utilizes a spectral "Redistribution Matrix File" (RMF), generated separately by other tools. Instrumental characteristics and calibration results, e.g., XRT geometry, reflectivity, mutual alignments, thermal shield transmission, build-up of the contamination on the XIS optical blocking filters (OBF), are incorporated as completely as possible. Most of this information is available in the form of the FITS (Flexible Image Transport System) files in the standard calibration database (CALDB). This simulator can also be utilized to generate an "Ancillary Response File" (ARF), which describes the XRT response and the amount of OBF contamination. The ARF is dependent on the spatial distribution of the celestial target and the photon accumulation region on the detector, as well as observing conditions such as the observation date and satellite attitude. We describe principles of the simulator and the ARF generator, and demonstrate their performance in comparison with in-flight data.
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.
15839314
X-Ray Spectroscopy of SN 1006 with Suzaku
We report on observations of SN 1006 with the X-ray Imaging Spectrometers (XIS) on board Suzaku. We firmly detected K-shell emission from Fe, for the first time, and find that the Fe ionization state is quite low. The broad band spectrum extracted from the southeast of the remnant is well fitted with a model consisting of three optically thin thermal non-equilibrium ionization plasmas and a power-law component. Two of the thermal models are highly overabundant in heavy elements and, hence, are likely due to ejecta. These components have different ionization parameters: $n_et \sim 1.4\times 10^{10}$ cm$^{-3}$ s and $n_et \sim 7.7\times 10^8$ cm$^{-3}$ s and it is the later one that produces the Fe-K emission. This suggests that Fe has been heated by the reverse shock more recently than the other elements, consistent with a picture where the ejecta are stratified by composition with Fe in the interior. On the other hand, the third thermal component is assumed to be solar abundance, and we associate it with emission from the interstellar medium (ISM). The electron temperature and ionization parameter are $kT_e \sim $0.5 keV and $n_et \sim 5.8\times 10^9$ cm$^{-3}$ s. The electron temperature is lower than that expected from the shock velocity which suggests a lack of collisionless electron heating at the forward shock. The extremely low ionization parameter and extreme non-equilibrium state are due to the low density of the ambient medium.
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.
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.
118101462
Infrared Features of Lattice Landau Gauge QCD and the Gribov Copy Problem
Infrared features of gluon propagator, ghost propagator, QCD running coupling and the Kugo‐Ojima parameter in lattice Landau gauge QCD are presented. The framework of PMS analysis suggests that there appear infrared, intermediate and ultraviolet regions specified by ΛMS, β0 and β1. The propagators and the running coupling of q > 1GeV are fitted by the MO∼M scheme using the factorization scale as the scale parameter. The running coupling data of q < 14GeV are fitted by the contour improved perturbation method. The Gribov copy problem is studied in SU (2), β = 2.2 samples by comparing the data gauge fixed by the parallel tempering method and the data gauge fixed by the straightforward gauge fixing. The Gribov noise effect turned out to be about 2%.
118853198
Quantum SUSY algebra of Q-lumps in the massive Grassmannian sigma model
We compute the SUSY algebra of the massive Grassmannian sigma model in (2+1) dimensions. We first rederive the action of the model by using Scherk–Schwarz dimensional reduction from theory in (3+1) dimensions. Then, we perform canonical quantization by using the Dirac method. We find that a particular choice of the operator ordering yields the quantum SUSY algebra of Q-lumps with central extension.
59060118
Donaldson = Seiberg-Witten from Mochizuki's formula and instanton counting
We propose an explicit formula connecting Donaldson invariants and Seiberg-Witten invariants of a 4-manifold of simple type via Nekrasov's deformed partition function for the N=2 SUSY gauge theory with a single fundamental matter. This formula is derived from Mochizuki's formula, which makes sense and was proved when the 4-manifold is complex projective. Assuming our formula is true for a 4-manifold of simple type, we prove Witten's conjecture and sum rules for Seiberg-Witten invariants (superconformal simple type condition), conjectured by Mari\~no, Moore and Peradze.
121590949
The full order weak schemes of the Langevin simulations
Abstract New partial differential equations (PDEs) for the full order weak schemes of the Langevin simulations are formulated. They are solved recursively in full order series solutions with respect to √ t (the full order weak Taylor schemes). Arbitrariness involved in the solutions is analyzed and clarified in detail. Specific solutions within some orders are presented as examples of the weak Taylor schemes. These PDEs and their solutions will serve for further developments of efficient higher order Runge-Kutta-like schemes. The similar formulation is possible for the imaginary time Hamiltonian evolution kernels as well.
35912900
Correlation of the ghost and the quark in the lattice Landau gauge QCD
Effects of the quark field on the ghost propagator of the lattice Landau gauge are investigated by using the unquenched SU(3) configurations produced by the MILC collaboration and compared with quenched gauge configurations of SU(2) first copy of the overrelaxation gauge fixing, the parallel tempering (PT) gauge fixing and quenched SU(3) 564 configurations. We measure the color symmetric and the color antisymmetric ghost propagator and the Binder cumulant of the l1 norm and the l2 norm of color antisymmetric ghost propagators and investigate deviation from those of Gaussian distributions. In the first copy samples of quenched SU(2) we observe a large fluctuation in the Binder cumulant at the lowest momentum point. This fluctuation is reduced in the PT gauge fixed samples. The color anti-symmetric ghost propagator of quenched SU(3) configurations depends on the lattice size and is small as compared to the symmetric one in the large lattice of 564. The Binder cumulants of the quenched SU(2) and the Nf = 2 + 1 unquenched SU(3) are almost consistent with 3-d and 8-d Gaussian distribution, respectively. A comparison of the SU(3) unquenched configurations and quenched configurations indicates that the dynamical quarks have the effect of making color antisymmetric ghost propagator closer to the Gaussian distribution and the Kugo-Ojima color confinement parameter c closer to 1.