No abstract

We report on the variability of the iron K emission line in the Seyfert 1 galaxy MCG-6-30-15 during a four-day ASCA observation. The line consists of a narrow core at an energy of about 6.4 keV, and a broad red wing extending to below 5 keV, which are interpreted as line emission arising from the inner parts of an accretion disk. The narrow core correlates well with the continuum flux whereas the broad wing weakly anti-correlates. When the source is brightest, the line is dominated by the narrow core, whilst during a deep minimum, the narrow core is very weak and a huge red tail appears. However, at other times when the continuum shows rather rapid changes, the broad wing is more variable than the narrow core, and shows evidence for correlated changes contrary to its long time scale behaviour. The peculiar line profile during the deep minimum spectrum suggests that the line emitting region is very close to a central spinning (Kerr) black hole where enormous gravitational effects operate.

We report on the result of an X-ray observation of the X-ray Nova Velorum 1993 (GRS 1009–45), made with ASCA on 1993 November 10-11. The energy spectrum was extremely soft and accompanied by a hard tail, characteristics of the Galactic black-hole binaries in the soft state. It is well represented by a two-component model consisting of a multicolor disk model or a general relativistic accretion disk model, both describing emission from an optically thick accretion disk, and a power-law component with a photon index of ∼ 2.5. A spectral analysis of the soft component allows an estimation of the mass of the central object. For the optically-estimated distance (> 1 kpc) and inclination (> 37°), the mass is estimated to be $\gt 3.1 M_\odot$. These results strongly support that the compact object is a black hole.

High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.

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.

Objective. To examine whether depsipeptide (FK228), a histone deacetylase (HDA) inhibitor, has inhibitory effects on the proliferation of synovial fibroblasts from rheumatoid arthritis (RA) patients, and to examine the effects of systemic administration of FK228 in an animal model of arthritis.Methods. Autoantibody-mediated arthritis (AMA) was induced in 19 male DBA/1 mice (6-7 weeks old); 10 of them were treated by intravenous administration of FK228 (2.5 mg/kg), and 9 were used as controls. The effects of FK228 were examined by radiographic, histologic, and immunohistochemical analyses and arthritis scores. RA synovial fibroblasts (RASFs) were obtained at the time of joint replacement surgery. In vitro effects of FK228 on cell proliferation were assessed by MTT assay. Cell morphology was examined by light and transmission electron microscopy. The effects on the expression of the cell cycle regulators p16INK4a and p21 WAF1/Cip1 were examined by real-time polymerase chain reaction and Western blot analysis. The acetylation status of the promoter regions of p16INK4a and p21 WAF1/Cip1 were determined by chromatin immunoprecipitation assay.Results. A single intravenous injection of FK228 (2.5 mg/ml) successfully inhibited joint swelling, synovial inflammation, and subsequent bone and cartilage destruction in mice with AMA. FK228 treatment induced histone hyperacetylation in the synovial cells and decreased the levels of tumor necrosis factor ␣ and interleukin-1␤ in the synovial tissues of mice with AMA. Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial hyperplasia, with excessive inflammatory cell infiltration in the joints, leading to erosion of the articular cartilage and marginal bone, with subsequent joint destruction (1). Despite an explosion of information over the last 2 decades, a detailed understanding of the mechanisms of synovial hyperplasia and inflammation is lacking. Recent reports have implicated rapid proliferation of synovial cells, overexpression of inflammatory genes, and impairment of apoptosis, which can allow the persistence of abnormal cells (2-4), in the disease process.Cyclin-dependent kinases (CDKs) are essential Dr.

We have carried out a precise energy spectral analysis of the super-luminal jet source GRS1915+105 observed with ASCA six times from 1994 to 1999. The source was so bright that most SIS data suffered from event pileup. We have developed a new technique to circumvent the pileup effect, which enabled us to study the spectrum in detail and at high resolution (∆E/E ≈ 2 %). In the energy spectra of 1994 and 1995, resonant absorption lines of Ca xx Kα, Fe xxv Kα, Fe xxvi Kα, as well as blends of the absorption lines of Ni xxvii Kα + Fe xxv Kβ and Ni xxviii Kα + Fe xxvi Kβ, were observed. Such absorption lines have not been found in other objects, except for iron absorptions lines from GRO J1655−40, another super-luminal jet source ). We carried out a "curve of growth" analysis for the absorption lines, and estimated column densities of the absorbing ions. We found that a plasma of moderate temperature (0.1-10 keV) and cosmic abundance cannot account for the observed large equivalent widths. The hydrogen column density of such plasma would be so high that the optical depth of Thomson scattering would be too thick (N H 10 24 cm −2 ). We require either a very high kinetic temperature of the ions ( 100 keV) or extreme over-abundances ( 100 Z ⊙ ). In the former case, the ion column densities have reasonable values of 10 17 − 10 18 cm −2 . We modeled the absorber as a photo-ionized disk which envelops the central X-ray source. Using a photo-ionization calculation code, we constrain physical parameters of the plasma disk, such as the ionization parameter, radius, and density. Estimated parameters were found to be consistent with those of a radiation-driven disk wind.

No abstract