Statistical Properties of Molecular Clouds in the Galactic Center

2001 ◽  
Vol 562 (1) ◽  
pp. 348-362 ◽  
Author(s):  
Tomoharu Oka ◽  
Tetsuo Hasegawa ◽  
Fumio Sato ◽  
Masato Tsuboi ◽  
Atsushi Miyazaki ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Galactic Center ◽  
Statistical Properties

scholarly journals 4.10. Statistical properties of dense molecular clouds in the Galactic center region

1998 ◽  
Vol 184 ◽  
pp. 187-188
Author(s):  
Atsushi Miyazaki ◽  
Masato Tsuboi
Keyword(s):  
Survey Data ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Statistical Properties ◽  
Center Region

Data : We used the Galactic center region survey data in CS J=1-0 with the Nobeyama 45-m telescope (Tsuboi, Handa, and Ukita 1997).Cloud Definition : We identified molecular clumps in the positive longitude region of about ∼1deg2 (+0°10′ < l< + 1°42′ and −25′ < b< +25′) within all survey region.

scholarly journals On a Possible Origin of the Gamma-ray Excess around the Galactic Center

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1432
Author(s):  
Dmitry O. Chernyshov ◽  
Andrei E. Egorov ◽  
Vladimir A. Dogiel ◽  
Alexei V. Ivlev
Keyword(s):  
Dark Matter ◽  
Gamma Rays ◽  
Molecular Clouds ◽  
Alternative Explanation ◽  
Gamma Ray ◽  
Galactic Center ◽  
The Self ◽  
Large Area ◽  
Mhd Turbulence ◽  
The Standard Model

Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.

scholarly journals ALMA view of the circumnuclear disk of the Galactic Center: tidally disrupted molecular clouds falling to the Galactic Center

2018 ◽  
Vol 70 (5) ◽  
Author(s):  
Masato Tsuboi ◽  
Yoshimi Kitamura ◽  
Kenta Uehara ◽  
Takahiro Tsutsumi ◽  
Ryosuke Miyawaki ◽  
...  
Keyword(s):  
Molecular Clouds ◽  
Galactic Center ◽  
Circumnuclear Disk

Molecular Clouds in the Central 100-pc of the Galactic Center

1989 ◽  
pp. 135-140 ◽  
Author(s):  
M. Tsuboi ◽  
T. Handa ◽  
M. Inoue ◽  
J. Inatani ◽  
N. Ukita
Keyword(s):  
Molecular Clouds ◽  
Galactic Center

scholarly journals CO and OH in the Galactic Center Region

1980 ◽  
Vol 87 ◽  
pp. 111-112
Author(s):  
Junji Inatani ◽  
Nobuharu Ukita
Keyword(s):  
Emission Line ◽  
Intensity Ratio ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Point Of View ◽  
The Other ◽  
Kinetic Temperature ◽  
Two Dimensional ◽  
Center Region ◽  
Dimensional Distribution

The two-dimensional distribution of molecular clouds in the galactic center region has been investigated in the CO 115 GHz line and in the OH 1665 and 1667 MHz lines. As the former is an emission line, we can find molecular clouds without the unavoidable bias to continuum sources which is inherent in a survey of OH absorption lines. Because the CO line is usually optically thick, the brightness temperature of the line is directly related to the kinetic temperature of the cloud. On the other hand, the real optical depth of the OH line can be obtained from the intensity ratio between 1665 and 1667 MHz lines (assuming LTE). From this point of view we have compared the CO and OH observational results.

scholarly journals 4.15. Dynamics of the Galactic center molecular clouds

1998 ◽  
Vol 184 ◽  
pp. 197-199
Author(s):  
C. W. Lee ◽  
H. M. Lee ◽  
H.B. Ann ◽  
K.H. Kwon
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Combined Effects ◽  
Gravitational Perturbation ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

We have performed Smoothed Particle Hydrodynamics (SPH) simulations in order to understand the dynamical structures of Galactic Center molecular clouds. In our study it was found that the structures of GC molecular clouds could be induced by the combined effects of a gravitational perturbation by rotating bar potential and the hydrodynamic collisions between the clouds.

scholarly journals Measurements of Isotopic Abundances in Interstellar Clouds

1980 ◽  
Vol 87 ◽  
pp. 397-404 ◽  
Author(s):  
Arno A. Penzias
Keyword(s):  
Molecular Clouds ◽  
General Framework ◽  
Galactic Center ◽  
Galactic Plane ◽  
Giant Molecular Clouds ◽  
Interstellar Clouds ◽  
The Galaxy ◽  
Isotopic Abundances ◽  
Si Isotopes

While an examination of the available data reveals some seemingly contradictory results, a general framework having the following outlines can be put forward:1. With the exception of the two galactic center sources SgrA and SgrB, the relative isotopic abundances exhibited by the giant molecular clouds in our Galaxy exhibit few, if any, significant variations from the values obtained by averaging the data from all these sources.2. The 13C/12C and 14N/15N abundance ratios are ∼130% and ∼150%, respectively, of their terrestrial values throughout the galactic plane and somewhat higher, ∼300%, near the galactic center.3. The 16O/18O and 17O/18O abundance ratios are ∼130% and ∼160%, respectively, of their terrestrial values throughout the Galaxy, although the former may be somewhat lower near the galactic center.4. The S and Si isotopes have generally terrestrial abundances.

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