46 research outputs found

    SMA Imaging of CO(3-2) Line and 860 micron Continuum of Arp 220 : Tracing the Spatial Distribution of Luminosity

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    We used the Submillimeter Array (SMA) to image 860 micron continuum and CO(3-2) line emission in the ultraluminous merging galaxy Arp 220, achieving a resolution of 0.23" (80 pc) for the continuum and 0.33" (120 pc) for the line. The CO emission peaks around the two merger nuclei with a velocity signature of gas rotation around each nucleus, and is also detected in a kpc-size disk encompassing the binary nucleus. The dust continuum, in contrast, is mostly from the two nuclei. The beam-averaged brightness temperature of both line and continuum emission exceeds 50 K at and around the nuclei, revealing the presence of warm molecular gas and dust. The dust emission morphologically agrees with the distribution of radio supernova features in the east nucleus, as expected when a starburst heats the nucleus. In the brighter west nucleus, however, the submillimeter dust emission is more compact than the supernova distribution. The 860 micron core, after deconvolution, has a size of 50-80 pc, consistent with recent 1.3 mm observations, and a peak brightness temperature of (0.9-1.6)x10^2 K. Its bolometric luminosity is at least 2x10^{11} Lsun and could be ~10^{12} Lsun depending on source structure and 860 micron opacity, which we estimate to be of the order of tau_{860} ~ 1 (i.e., N_{H_2} ~ 10^{25} cm^{-2}). The starbursting west nuclear disk must have in its center a dust enshrouded AGN or a very young starburst equivalent to hundreds of super star clusters. Further spatial mapping of bolometric luminosity through submillimeter imaging is a promising way to identify the heavily obscured heating sources in Arp 220 and other luminous infrared galaxies.Comment: ApJ. in press. 26 pages, 10 figure

    Assessment of Culprit Lesion Morphology in Acute Myocardial Infarction Ability of Optical Coherence Tomography Compared With Intravascular Ultrasound and Coronary Angioscopy

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    ObjectivesThe aim of the present study was to evaluate the ability of optical coherence tomography (OCT) for assessment of the culprit lesion morphology in acute myocardial infarction (AMI) in comparison with intravascular ultrasound (IVUS) and coronary angioscopy (CAS).BackgroundOptical coherence tomography is a new intravascular imaging method with a high resolution of approximately 10 μm. This may allow us to assess the vulnerable plaques in detail in vivo.MethodsWe enrolled 30 patients with AMI, and analyzed the culprit lesion by OCT, CAS, and IVUS.ResultsThe average duration from the onset of symptom to OCT imaging was 3.8 ± 1.0 h. The incidence of plaque rupture observed by OCT was 73%, and it was significantly higher than that by CAS (47%, p = 0.035) and IVUS (40%, p = 0.009). Furthermore, OCT (23%) was superior to CAS (3%, p = 0.022) and IVUS (0%, p = 0.005) in the detection of fibrous cap erosion. The intracoronary thrombus was observed in all cases by OCT and CAS, but it was identified in 33% by IVUS (vs. OCT, p < 0.001). Only OCT could estimate the fibrous cap thickness, and it was 49 ± 21 μm. The incidence of thin cap fibroatheroma (TCFA) was 83% in this population by OCT.ConclusionsOptical coherence tomography is a feasible imaging modality in patients with AMI and allows us to identify not only plaque rupture, but also fibrous cap erosion, intracoronary thrombus, and TCFA in vivo more frequently compared with conventional imaging techniques

    Pt Schottky diode gas sensors formed on GaN and AlGaN/GaN heterostructure

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    Exposure of Pt/GaN and Pt/AlGaN/GaN Schottky diodes to H2 gas at moderately high temperatures around 100 °C resulted in marked increase of forward and reverse currents. Increase was much larger in the Pt/AlGaN/GaN diode than in the Pt/GaN diode. Rapid turn-on responses and somewhat slower turn-off responses were observed with reproducible response magnitudes. A rigorous computer simulation of I–V curves indicated that current changes are due to changes in the Schottky barrier height caused either by H-induced formation of interfacial dipole or by hydrogen passivation of interface states

    Geographic Analysis of Trade-Offs Between Amenity and Supply Effects in New Office Buildings (Short Paper)

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    The supply of new office buildings in the neighborhood both positively and negatively affects rents. This study attempts to deepen the quantitative knowledge of this trade-off relationship and estimate the correlation between new supply and rent within a specific geographic area based on a hedonic model. Although the results exhibit biases, they indicate that supply effects become apparent after construction is completed, and that they vary geographically and are related to local market characteristics

    Selective Formation of Homoleptic and Heteroleptic 2,5-Bis( N

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    Practice changes the usage of moment components in executing a multijoint

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    This book explores the significance of riots and public disturbances caused by marginalized youth with a migrant background in France and the Netherlands, and how their demands for recognition, justice and equal opportunities are voiced in uncivil, yet politically meaningful ways

    Experimental Evaluation of Energy Resolutions for Pulsed Neutron Beam in the KURNS-LINAC

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    In this study, experimental evaluations for the energy resolution of pulsed neutron flux in the neutron path were carried out. The capture gamma-rays from a Ta-181 sample were measured by BGO detectors with a TOF method, and the TOF spectra for well-known resonances were obtained. The energy resolution was evaluated by comparing a full width at half maximum of the Ta-181 resonances in the JENDL-4.0. In order to obtain relationships between the energy resolution and the pulsed neutron beam width, the measurements were carried out with the pulsed neutron beam width of 4 μsec, 1 μsec and 0.1 μsec, respectively. As the experimental results, the energy resolution of neutron energy range from 4 eV to 125 eV corresponding to each pulse width were evaluated. For example, the energy resolution at 4.28 eV (Ta-181 first resonance peak) was about 0.5 % for a pulse width of 4 μsec
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