3,176 research outputs found

    An Unbiased Survey for Molecular Clouds in the Southern Galactic Warp

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    We have made an unbiased survey for molecular clouds in the Galactic Warp. This survey, covering an area of 56 square degrees at l = 252 deg to 266 deg and b = -5 deg to -1 deg, has revealed 70 molecular clouds, while only 6 clouds were previously known in the region. The number of molecular clouds is, then, an order of magnitude greater than previously known in this sector at R > 14.5 kpc. The mass of the clouds is in a range from 7.8x10(2) Mo to 8.4x10(4) Mo, significantly less than the most massive giant molecular clouds in the inner disk, ~10(6) Mo, while the cloud mass spectrum characterized by a power law is basically similar to other parts of the Galaxy. The X factor, N(H2)/Wco(12CO), derived from the molecular clouds in the Warp is estimated to be 3.5(+/-1.8) times larger than that in the inner disk. The total molecular mass in the Warp is estimated as 7.3x10(5) Mo, and total mass in the far-outer Galaxy (R > 14.5 kpc) can be estimated as 2x10(7) Mo. The spatial correlation between the CO and HI distribution appears fairly good, and the mass of the molecular gas is about 1% of that of the atomic gas in the far-outer Galaxy. This ratio is similar to that in the interarm but is ten times smaller than those of the spiral arms. Only 6 of the 70 Warp clouds show signs of star formation at the IRAS sensitivity and star formation efficiency for high-mass stars in the Warp is found to be smaller than those in other molecular clouds in the Galaxy.Comment: 29 pages, including 12 (pages of) figures, accepted for PASJ, and will be published in PASJ Vol.57, No.6. Tables and color-figures are available on-line: http://www.a.phys.nagoya-u.ac.jp/~masa/study/nakagawa_etal2005_warp.pd

    Semiclassical Study on Tunneling Processes via Complex-Domain Chaos

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    We investigate the semiclassical mechanism of tunneling process in non-integrable systems. The significant role of complex-phase-space chaos in the description of the tunneling process is elucidated by studying a simple scattering map model. Behaviors of tunneling orbits are encoded into symbolic sequences based on the structure of complex homoclinic tanglement. By means of the symbolic coding, the phase space itineraries of tunneling orbits are related with the amounts of imaginary parts of actions gained by the orbits, so that the systematic search of significant tunneling orbits becomes possible.Comment: 26 pages, 28 figures, submitted to Physical Review

    Catalogue of 12CO(J=1-0) and 13CO(J=1-0) Molecular Clouds in the Carina Flare Supershell

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    We present a catalogue of 12CO(J=1-0) and 13CO(J=1-0) molecular clouds in the spatio-velocity range of the Carina Flare supershell, GSH 287+04-17. The data cover a region of ~66 square degrees and were taken with the NANTEN 4m telescope, at spatial and velocity resolutions of 2.6' and 0.1 km/s. Decomposition of the emission results in the identification of 156 12CO clouds and 60 13CO clouds, for which we provide observational and physical parameters. Previous work suggests the majority of the detected mass forms part of a comoving molecular cloud complex that is physically associated with the expanding shell. The cloud internal velocity dispersions, degree of virialization and size-linewidth relations are found to be consistent with those of other Galactic samples. However, the vertical distribution is heavily skewed towards high-altitudes. The robust association of high-z molecular clouds with a known supershell provides some observational backing for the theory that expanding shells contribute to the support of a high-altitude molecular layer.Comment: To be published in PASJ Vol. 60, No. 6. (Issued on December 25th 2008). 35 pages (including 13 pages of tables), 7 figures. Please note that formatting problems with the journal macro result in loss of rightmost data columns in some long tables. These will be fixed in the final published issue. In the meantime, please contact the authors for missing dat

    Band Crossing studied by GCM with 3D-CHFB

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    We solved the constrained Hill-Wheeler Equation, and found several signatures of multi-band crossing in 182 Os.Comment: LaTeX 3 pages, 3 eps figures; Contribution to International Conference, Nuclear Structure at the extreme,Lewes, UK, (1998) Jun.17-1

    Cranked Hartree-Fock-Bogoliubov Calculation for Rotating Bose-Einstein Condensates

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    A rotating bosonic many-body system in a harmonic trap is studied with the 3D-Cranked Hartree-Fock-Bogoliubov method at zero temperature, which has been applied to nuclear many-body systems at high spin. This method is a variational method extended from the Hartree-Fock theory, which can treat the pairing correlations in a self-consistent manner. An advantage of this method is that a finite-range interaction between constituent particles can be used in the calculation, unlike the original Gross-Pitaevskii approach. To demonstrate the validity of our method, we present a calculation for a toy model, that is, a rotating system of ten bosonic particles interacting through the repulsive quadrupole-quadrupole interaction in a harmonic trap. It is found that the yrast states, the lowest-energy states for the given total angular momentum, does not correspond to the Bose-Einstein condensate, except a few special cases. One of such cases is a vortex state, which appears when the total angular momentum LL is twice the particle number NN (i.e., L=2NL=2N).Comment: accepted to Phys. Rev.
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