scholarly journals High-Velocity Molecular Gas in the Galactic Center Radio Lobe

1996 ◽  
Vol 459 (2) ◽  
Author(s):  
Yoshiaki Sofue
Keyword(s):  
High Velocity ◽  
Galactic Center ◽  
Molecular Gas ◽  
Radio Lobe

scholarly journals Two New Views of the Galactic Center

1996 ◽  
Vol 169 ◽  
pp. 283-284 ◽  
Author(s):  
D.T. Jaffe ◽  
R. Plume ◽  
S. Pak
Keyword(s):  
Interstellar Medium ◽  
High Velocity ◽  
Molecular Clouds ◽  
Large Scale ◽  
Galactic Center ◽  
Molecular Gas ◽  
The Galaxy ◽  
Physical Effects ◽  
Velocity Dispersions ◽  
Internal Velocity

The inner few hundred parsecs of the Galactic Center contains ∼10% of the molecular ISM in the Galaxy. The conditions in this gas are significantly different from those in molecular clouds elsewhere in the Galaxy. Typical temperatures, densities, and internal velocity dispersions are higher (Güesten 1989). There is also evidence for a large amount of molecular gas which is not bound to distinct clouds (Stark et al. 1989). High velocity bulk gas motions and velocity discontinuities open up the possibility of a role for powerful large-scale shocks in ISM excitation. The very different nature of the dense ISM in the inner Galaxy make it useful as a laboratory for physical effects in the interstellar medium and a proving ground for ideas about the interaction of gas and stars in the nuclei of other galaxies.

scholarly journals Shocked Molecular Hydrogen from Star Forming Regions

1987 ◽  
Vol 115 ◽  
pp. 181-181 ◽  
Author(s):  
Adair P. Lane ◽  
John Bally
Keyword(s):  
Shock Waves ◽  
High Velocity ◽  
Molecular Hydrogen ◽  
Near Infrared ◽  
Young Stars ◽  
Emission Lines ◽  
Molecular Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Post Shock

Near infrared (2 micron) emission lines from molecular hydrogen provide a powerful probe of the morphology and energetics of outflows associated with stellar birth. The H2 emission regions trace the location of shock waves formed when the high velocity outflow from young stars encounters dense quiescent gas. Since H2 is the dominant coolant of the hot post-shock molecular gas, the H2 lines provide a measure of the fraction of the total mechanical luminosity radiated away from the cloud.

The Warm Molecular Gas in the Galactic Center

2002 ◽  
pp. 331-332
Author(s):  
N. J. Rodríguez-Fernández ◽  
J. Martín-Pintado ◽  
P. De Vicente ◽  
A. Fuente
Keyword(s):  
Galactic Center ◽  
Molecular Gas

How maser observations unravel the gas motions in the Galactic Center

2017 ◽  
Vol 13 (S336) ◽  
pp. 176-179
Author(s):  
K. Immer ◽  
M. Reid ◽  
A. Brunthaler ◽  
K. Menten ◽  
Q. Zhang ◽  
...  
Keyword(s):  
Spectral Line ◽  
Proper Motion ◽  
Galactic Center ◽  
Galactic Plane ◽  
Orbital Dynamics ◽  
Line Of Sight ◽  
Molecular Gas ◽  
Kinematic Structure ◽  
3D Motion ◽  
Motion Measurements

AbstractThe Central Molecular Zone (CMZ), the inner 450 pc of our Galaxy, is an exceptional region where the volume and column densities, gas temperatures, velocity dispersions, etc. are much higher than in the Galactic plane. It has been suggested that the formation of stars and clusters in this area is related to the orbital dynamics of the gas. The complex kinematic structure of the molecular gas was revealed by spectral line observations. However, these results are limited to the line-of-sight-velocities. To fully understand the motions of the gas within the CMZ, we have to know its location in 6D space (3D location + 3D motion). Recent orbital models have tried to explain the inflow of gas towards and its kinematics within this region. With parallax and proper motion measurements of masers in the CMZ we can discriminate among these models and constrain how our Galactic Center is fed with gas.

scholarly journals The Molecular Outflow and CO Bullets in HH111

1997 ◽  
Vol 182 ◽  
pp. 141-152 ◽  
Author(s):  
J. Cernicharo ◽  
R. Neri ◽  
Bo Reipurth
Keyword(s):  
High Velocity ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Kinetic Temperature ◽  
Low Velocity ◽  
Molecular Outflow ◽  
Hh Objects ◽  
Physical Phenomena ◽  
First Time

We present high angular resolution observations of the molecular outflow associated with the optical jet and HH objects of the HH111 system. Interferometric observations in the CO J =2–1 and J =1–0 lines of the high velocity bullets associated with HH111 are presented for the first time. The molecular gas in these high velocity clumps has a moderate kinetic temperature and a mass of a few 10–4 M⊙ per bullet. We favor the view that HH jets and CO bullets, which represent different manifestations of the same physical phenomena, are driving the low-velocity molecular outflow.

scholarly journals Bipolar Outflows and Stellar Jets

1987 ◽  
Vol 115 ◽  
pp. 213-237 ◽  
Author(s):  
Ronald L. Snell
Keyword(s):  
Physical Properties ◽  
High Velocity ◽  
Molecular Clouds ◽  
Early Stage ◽  
Young Stellar Objects ◽  
Molecular Gas ◽  
Bipolar Outflows ◽  
Stellar Objects ◽  
Stellar Jets ◽  
Almost All

A wealth of data is now available on the energetic mass outflows that are associated with young stellar objects. This phenomenon is thought to occur at a very early stage in the evolution of stars of almost all masses. The discovery of this energetic event was first made through observations of the rapidly expanding molecular gas that surrounds many of these young stellar objects. A review of the physical properties, including the energetics and morphology, of the expanding molecular gas is presented in this paper. In addition, the role these energetic winds play in affecting the dynamics of the parental molecular clouds is also discussed. Finally, the results of detailed studies of the structure and kinematics of the high velocity molecular gas are reviewed and the evidence for existance of wind-swept cavities and molecular shells within the clouds are presented.

scholarly journals Wide-Line Molecular Clouds and the Gamma-Ray Deficit Toward the Galactic Center

1989 ◽  
Vol 136 ◽  
pp. 157-158 ◽  
Author(s):  
J. G. Stacy ◽  
M. E. Bitran ◽  
T. M. Dame ◽  
P. Thaddeus
Keyword(s):  
Gravitational Field ◽  
Molecular Clouds ◽  
Stellar Population ◽  
Gamma Ray ◽  
Galactic Center ◽  
Molecular Gas ◽  
Show Evidence ◽  
Wide Line ◽  
Γ Ray ◽  
Co Emission

The discrepancy between observed and predicted γ-ray emission toward the Galactic Center is attributed to a unique population of wide-line molecular clouds. The most prominent objects of this class show evidence of rotation and a significant stellar population. The observed 12CO emission traces the gravitational field produced primarily by stars, not molecular gas.

scholarly journals The Nature of the Galactic Center Arc

1996 ◽  
Vol 169 ◽  
pp. 263-269 ◽  
Author(s):  
E. Serabyn
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Galactic Center ◽  
Magnetic Energy ◽  
Linear Structure ◽  
High Energy ◽  
Molecular Gas ◽  
Synchrotron Emission ◽  
Interferometric Imaging ◽  
Relativistic Particles

Ever since the Galactic Center Arc was resolved into its component filaments a decade ago, it has been clear that its linear structure arises from the influence of a strong magnetic field. However, the origin and nature of the contributory phenomena have remained elusive. Since what is seen is synchrotron emission from relativistic particles, of prime interest is a knowledge of the acceleration mechanism involved. Interferometric imaging of the molecular gas in the vicinity of the Arc has now provided a tantalizing clue to the Arc's origin: molecular clumps coinciding with the endpoints of a number of the Arc's filaments point to these clumps as the source of the relativistic particles. This suggests that as dense molecular clumps course through the ambient magnetic field at the Galactic Center, magnetic energy is liberated in their leading layers via field reconnection, precipitating rapid acceleration of free charges to high energy.

scholarly journals Long-Term Variations of the Compact Radio Source Sgr A∗ at the Galactic Center

1989 ◽  
Vol 136 ◽  
pp. 535-541 ◽  
Author(s):  
Jun-Hui Zhao ◽  
R. D. Ekers ◽  
W. M. Goss ◽  
K. Y. Lo ◽  
Ramesh Narayan
Keyword(s):  
Radio Source ◽  
Flux Density ◽  
High Velocity ◽  
Galactic Center ◽  
Light Curves ◽  
Radio Flux ◽  
Compact Radio Source ◽  
Sgr A ◽  
Long Term Variations

We investigate the long-term flux density variations of the compact radio source Sgr A∗ at the galactic center by combining recent VLA observations with previous Green Bank interferometer data. We present radio flux density light-curves for Sgr A∗ at 20, 11, 6 and 3.7 cm from 1974 to 1987. Long-term variability with a timescale of at least 5 years is seen at 20 cm and there is evidence for more rapid variations at the shorter wavelengths. The variability timescales at 20, 11 and 6 cm fit the λ2 scaling predicted by the theory of refractive scintillation suggesting that the variability could be due to this cause. However, the timescales are relatively short, implying an unusually high velocity in the scattering screen. The modulation index of the variability is large and relatively independent of wavelength.

scholarly journals Detailed distributions of the CO J = (2 − 1)/J = (1 − 0) intensity ratios toward a large area of the central molecular zone

2013 ◽  
Vol 9 (S303) ◽  
pp. 106-108
Author(s):  
Kazufumi Torii ◽  
Rei Enokiya ◽  
Yasuo Fukui ◽  
Hiroaki Yamamoto ◽  
Akiko Kawamura ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Galactic Center ◽  
Galactic Plane ◽  
Area Coverage ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Large Area ◽  
First Results ◽  
Intensity Ratios ◽  
Sgr A

AbstractWe present the first results of the new CO J = (2 − 1) observations toward the central molecular zone (CMZ) using the NANTEN2 telescope at an angular resolution of 100″. Large area coverage of 4° × 2° in l and b and a high angular resolution of 100″ enable us to investigate detailed structures of the molecular gas in the CMZ including peculiar molecular filaments perpendicularly to the Galactic plane to b > |0.5°|. The major components of the CMZ, e.g., Sgr A, Sgr B and Sgr C cloud complexes, show high CO J = (2 − 1)/J = (1 − 0) ratios around 0.9, indicating highly excited conditions of the molecular gas, while the local foreground components show less than 0.4. The molecular filaments show the typical ratios of 0.6–0.7 indicate that they are indeed located in the Galactic center.

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