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We present high resolution studies of the nuclear region in NGC 3079 with phase-referenced VLBI monitoring between its water maser and continuum emission. From results of the observations, NGC 3079 showed relative motion between core-jet-like continuum components. One of the components (A) relative to the reference maser feature moved with an apparent subluminal velocity along the SE-NW direction, almost parallel to alignment of the components. On the other hand, the position of the other component (B) did not show such a significant change. If the maser gas is associated with a rotating disk, the maser gas should be gravitationally bound to the central mass. This suggests that B and A are the nucleus and jet, respectively.
A new approach is proposed to analyze Bremsstrahlung X-rays that are emitted from laser-produced plasmas (LPP) and are measured by a stack type spectrometer. This new method is based on a spectral tomographic reconstruction concept with the variational principle for optimization, without referring to the electron energy distribution of a plasma. This approach is applied to the analysis of some experimental data obtained at a few major laser facilities to demonstrate the applicability of the method. Slope temperatures of X-rays from LPP are determined with a two-temperature model, showing different spectral characteristics of X-rays depending on laser properties used in the experiments.
We present recent observation results of Sgr A* at millimeter obtained with VLBI arrays in Korea and Japan.
7 mm monitoring of Sgr A* is part of our AGN large project. The results at 7 epochs during 2013-2014, including high resolution maps, flux density and two-dimensional size measurements are presented. The source shows no significant variation in flux and structure related to the G2 encounter in 2014. According to recent MHD simulations by kawashima et al., flux and magnetic field energy can be expected to increase several years after the encounter; We will keep our monitoring in order to test this prediction.
Astrometric observations of Sgr A* were performed in 2015 at 7 and 3.5 millimeter simultaneously. Source-frequency phase referencing was applied and a combined ”core-shift” of Sgr A* and a nearby calibrator was measured. Future observations and analysis are necessary to determine the core-shift in each source.
To address its temperature and density we made observations of the galactic plane in CO (2-1) line with VST1 and VST2. Using a kinetic model we estimate the volume emissivities and the line intensity ratio as a function of galactocentric radius. Using data in the first and 4th quadrants separately we got shallow gradient in the both quadrants; at the smaller radius is the higher in ratio. The gradient is contributed by less bright pixels in the l-v diagram, suggesting molecular gas in interarm is different along the galactocentric radius but in arm is not.
We conducted an observation of weak HI and OH absorption features in the parsec-scale nuclear region of NGC 3079 using a global VLBI network; the VLBA, the VLA and the Green Bank 43-m telescope of NRAO. One mas corresponds to 0.076 pc in NGC 3079.
The nearby radio galaxy M87 offers a unique opportunity for exploring the connection between γ-ray production and jet formation at an unprecedented linear resolution. However, the origin and location of the γ-rays in this source is still elusive. Based on previous radio/TeV correlation events, the unresolved jet base (radio core) and the peculiar knot HST-1 at >120 pc from the nucleus are proposed as candidate site(s) of γ-ray production. Here we report our intensive, high-resolution radio monitoring observations of the M87 jet with the VLBI Exploration of Radio Astrometry (VERA) and the European VLBI Network (EVN) from February 2011 to October 2012. During this period, an elevated level of the M87 flux is reported at TeV with VERITAS. We detected a remarkable flux increase in the radio core with VERA at 22/43 GHz coincident with the VHE activity. Meanwhile, HST-1 remained quiescent in terms of its flux density and structure at radio. These results strongly suggest that the TeV γ-ray activity in 2012 originates in the jet base within 0.03 pc (projected) from the central supermassive black hole.
Fast-electron beam stopping mechanisms in media ranging from solid to warm dense matter have been investigated experimentally and numerically. Laser-driven fast electrons have been transported through solid Al targets and shock-compressed Al and plastic foam targets. Their propagation has been diagnosed via rear-side optical self-emission and Kα X-rays from tracer layers. Comparison between measurements and simulations shows that the transition from collision-dominated to resistive field-dominated energy loss occurs for a fast-electron current density ~5 × 1011 A cm−2. The respective increases in the stopping power with target density and resistivity have been detected in each regime. Self-guided propagation over 200μm has been observed in radially compressed targets due to ~1kT magnetic fields generated by resistivity gradients at the converging shock front.
An ultra-small tactile sensor with functions of signal processing and digital communication has been prototyped based on MEMS-CMOS integration technology. The designed analog-digital mixed signal ASIC allows many tactile sensors to connect each other on a common bus line, which drastically reduces the number of wire. The ASIC capacitively detects the deformation of a force sensor and sends digital data to the common bus line when the force exceeds a threshold. The digital data contain a physical ID of each sensor, 32-bit sensing data and 16-bit cyclic redundancy check (CRC) code. In this study, a novel wafer-level integration and packaging technology were developed, and a chip-size-packaged tactile sensor with a small footprint (2.5mm×2.5mm) and a low profile (0.27mm) was prototyped and tested. The sensor autonomously sends digital data like a tactile receptor of human.
An inductor in standard CMOS process having an inductance of 52 nH and a quality factor of 1.5 at frequency equal to 80 Mhz was fabricated. The polymer passivation layer of the standard CMOS inductor was etched out. The silicon substrate under the inductor, having a thickness of 280 μm was also etched out by deep reactive ion etching (DRIE). Ferrite material ZnFe2O4 and amorphous material Fe4.7Co70.3Si15B10 was then sputtered on top of the inductor sequentially. The same sputtering procedure was also performed into the bottom of the inductor. The result is an inductor that is sandwiched by multiple ferromagnetic layers. The inductance of the new ferromagnetic inductor has increased by 15% from 52 nH to 60 nH. The quality factor has also increased by 20% from 1.5 to 1.8.
We present the internal proper motion of 6.7-GHz methanol masers in S269, an Ultra Compact HII region. The maser distribution in S269 consists of several maser groups, and the spatial structure of the main groups A and B are consistent with the past VLBI image. The remarkable result of comparing the two VLBI maps is that 6.7-GHz methanol maser distribution and velocity range within each group have been kept for eight years. Angular separation between the two groups A and B increases by 3.6 mas, which corresponds to a velocity of 11.5 km s−1.
We present VLBI maps of the 6.7 GHz methanol maser emission in 32 sources obtained using the Japanese VLBI Network (JVN) and the East-Asian VLBI Network (EAVN). All of the observed sources provide new VLBI maps, and the spatial morphologies have been classified into five categories similar to the results obtained from European VLBI Network observations (Bartkiewicz et al. 2009). The 32 methanol sources are being monitored to measure the relative proper motions of the methanol maser spots.
We present the results of the Nobeyama Radio Observatory (NRO) M 33 All Disk (30′ × 30′,
or 7.3 kpc × 7.3 kpc) Survey of Giant Molecular Clouds (NRO MAGiC) based on
12CO(J = 1–0) observations using the NRO 45-m telescope and
12CO(J = 3–2) observations using the ASTE 10-m telescope.
The spatial resolution of the resultant 12CO(J = 1–0) map is
193, corresponding to 81 pc, which is sufficient to identify each Giant Molecular Cloud
(GMC) in the disk. We found clumpy structures with a typical spatial scale of
~100 pc, corresponding to GMCs, and no diffuse, smoothly distributed component
of molecular gas at this sensitivity.
We obtained a map of the molecular fraction,
fmol = ΣH2/(ΣHi + ΣH2),
at a 100-pc resolution. This is the first fmol map covering an
entire galaxy with a GMC-scale resolution. The correlation between
fmol and gas surface density shows two distinct sequences.
The presence of two correlation sequences can be explained by differences in metallicity,
i.e., higher (~2-fold) metallicity in the central region
(r < 1.5 kpc) than in the outer parts. Alternatively,
differences in scale height can also account for the two sequences, i.e.,
increased scale height toward the outer disk.
Recent epidemiological data suggest a link between the consumption of bovine offal products and Shiga toxin-producing Escherichia coli (STEC) infection in Japan. This study thus examined the prevalence of STEC in various types of these foods. PCR screened 229 bovine offal products for the presence of Shiga toxin (stx) gene. Thirty-eight (16·6%) samples were stx positive, of which eight were positive for rfbEO157 and three were positive for wzyO26. Four O157 and one O26 STEC isolates were finally obtained from small-intestine and omasum products. Notably, homogenates of bovine intestinal products significantly reduced the extent of growth of O157 in the enrichment process compared to homogenates of beef carcass. As co-incubation of O157 with background microbiota complex from bovine intestinal products in buffered peptone water, in the absence of meat samples, tended to reduce the extent of growth of O157, we reasoned that certain microbiota present in offal products played a role. In support of this, inoculation of generic E. coli from bovine intestinal products into the homogenates significantly reduced the extent of growth of O157 in the homogenates of bovine intestinal and loin-beef products, and this effect was markedly increased when these homogenates were heat-treated prior to inoculation. Together, this report provides first evidence of the prevalence of STEC in a variety of bovine offal products in Japan. The prevalence data herein may be useful for risk assessment of those products as a potential source of human STEC infection beyond the epidemiological background. The growth characteristic of STEC O157 in offal products also indicates the importance of being aware when to test these food products.