774 research outputs found

    Virgo High-Resolution CO Survey :V. Circumnuclear Elliptical Ring in NGC 4569

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    We present high-resolution (1\farcs8 -- 4\farcs5) CO data of the Virgo spiral galaxy NGC 4569, obtained using the Nobeyama Millimeter Array. We found that the molecular gas is highly concentrated in the circumnuclear region with two off-center peaks. A CO image with the highest angular resolution of 2\farcs0 \times 1\farcs8 shows that six blobs likely form a circumnuclear elliptical ring (CER) with a semi-major axis radius of 720 pc. The CER shows a strongly twisted velocity field, and the position--velocity (PV) diagram shows significant forbidden velocity components. These kinetic features are understood as being non-circular motion due to a bar-potential. We found that the CER coincides with the Hα\alpha bright central core and that the mass ratio of the molecular gas to the dynamical mass is about 18%. These results support a gaseous inflow scenario induced by a weak bar potential and self-gravity of the gas.Comment: 14 pages, 11 figures, and 6 table

    The Virgo High-Resolution CO Survey. III. NGC 4254

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    We present high-angular-resolution (1".5 - 5") interferometer observations of the \co emission in the central region of the SA(s)c galaxy NGC 4254. The observations were obtained using the Nobeyama Millimeter-wave Array (NMA) during the course of a long-term CO line survey of Virgo spirals. We present the spectra, channel maps, integrated intensity distributions, velocity fields, position--velocity diagrams, and compare the data with various optical images. The rotation velocity is already finite at the nucleus, or at least it rises steeply to 80 km/s within the central 1", indicating the existence of a massive core of 10^8 Msun within 1" (80 pc) radius. The CO intensity maps show that the inner disk has well-developed multiple spiral arms, winding out from a bar-shaped elongated molecular complex. In addition to the bisymmetric spiral arms, an asymmetric tightly wound arm with high molecular gas density is found to wind out from the molecular bar. The molecular spiral arms, particularly the tightly wound arm, well traces optical dark lanes, and are associated with Hα\alpha arms having many H {\sc ii} regions. The inner asymmetric spiral structures can be explained by ram-pressure distortion of inter-arm low density regions of the inner disk by the intra-cluster gas wind, and is indeed reproduced by a hydrodynamical simulation.Comment: PASJ 2003 in press, Latex 9 pages, 10 figures. (Bigger size gif/ps figures available at http://www.ioa.s.u-tokyo.ac.jp/radio/virgo/

    QCD preheating: New frontier of baryogenesis

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    We find that QCD can create the cosmological matter abundance via out-of-equilibrium processes during the QCD phase transition, that is what we call the QCD preheating, where the dynamic transition of the QCD vacuum characterized by the quark condensate takes place instantaneously. This mechanism works when the Universe undergoes subsequent supercooled QCD transition. We also find that the QCD preheating can work to create the baryon asymmetry of the Universe if there is the new physics communicated with QCD. These are new pictures of the thermal history around the QCD-phase transition epoch, and thus the dynamic aspect of the QCD vacuum opens a new frontier to explore low-scale matter generation such as baryogenesis. Pursuing the QCD reheating era would also help deeply understanding the subatomic-scale physics in the thermal history of the Universe.Comment: 12 pages, 3 figures; setups for QCD preheating refined; a version accepted in Phys.Rev.

    Newly Designed Specula for Laryngomicroscopy

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    We produced specula for laryngomicroscopy to observe blind spots in the operating field. Use of these specula has facilitated detailed observation of the lower surface of the false vocal folds, laryngeal ventricle, and subglottis, which were previously in blind spots. The specula are useful in the following ways: 1) clarifying blind spots for improved diagnosis and providing more accurate surgical margins; 2) observing the lower lips of the vocal folds in phonosurgery; and 3) Vaporizing with laser reflection. The specula are cheap and easy to use and are well worth considering for application to laryngomicroscopy
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