Large‐Area Mapping at 850 Microns. II. Analysis of the Clump Distribution in the ρ Ophiuchi Molecular Cloud

2000 ◽  
Vol 545 (1) ◽  
pp. 327-339 ◽  
Author(s):  
Doug Johnstone ◽  
Christine D. Wilson ◽  
Gerald Moriarty‐Schieven ◽  
Gilles Joncas ◽  
Graeme Smith ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Large Area ◽  
Clump Distribution

Large Area Mapping at 850 Microns. III. Analysis of the Clump Distribution in the Orion B Molecular Cloud

2001 ◽  
Vol 559 (1) ◽  
pp. 307-317 ◽  
Author(s):  
Doug Johnstone ◽  
Mike Fich ◽  
George F. Mitchell ◽  
Gerald Moriarty‐Schieven
Keyword(s):  
Molecular Cloud ◽  
Large Area ◽  
Clump Distribution

Large Area Mapping at 850 μm. IV. Analysis of the Clump Distribution in the Orion B South Molecular Cloud

2006 ◽  
Vol 639 (1) ◽  
pp. 259-274 ◽  
Author(s):  
Doug Johnstone ◽  
Henry Matthews ◽  
George F. Mitchell
Keyword(s):  
Molecular Cloud ◽  
Large Area ◽  
Clump Distribution

scholarly journals Fermi-LAT Detection of Extended Gamma-Ray Emission in the Vicinity of SNR G045.7-00.4: Evidence of Escaping Cosmic Rays Interacting with the Surrounding Molecular Clouds

2021 ◽  
Vol 923 (1) ◽  
pp. 106
Author(s):  
Hai-Ming Zhang ◽  
Ruo-Yu Liu ◽  
Yang Su ◽  
Hui Zhu ◽  
Shao-Qiang Xi ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Molecular Cloud ◽  
Molecular Clouds ◽  
Supernova Remnant ◽  
Milky Way ◽  
Gamma Ray ◽  
Molecular Gas ◽  
Western Boundary ◽  
Large Area ◽  
Gamma Ray Emission

Abstract We present an analysis of Fermi Large Area Telescope data of the gamma-ray emission in the vicinity of a radio supernova remnant (SNR), G045.7-00.4. To study the origin of the gamma-ray emission, we also make use of the CO survey data of Milky Way Imaging Scroll Painting to study the massive molecular gas complex that surrounds the SNR. The whole size of the gigaelectronvolt emission is significantly larger than that of the radio morphology. Above 3 GeV, the gigaelectronvolt emission is resolved into two sources: one is spatially consistent with the position of the SNR with a size comparable to that of the radio emission, and the other is located outside of the western boundary of the SNR and spatially coincident with the densest region of the surrounding molecular cloud. We suggest that the gigaelectronvolt emission of the western source may arise from cosmic rays (CRs) that have escaped the SNR and illuminated the surrounding molecular cloud. We find that the gamma-ray spectra of the western source can be consistently explained by this scenario with a total energy of ∼1050 erg in escaping CRs assuming the escape is isotropic.

scholarly journals CARMA LARGE AREA STAR FORMATION SURVEY: OBSERVATIONAL ANALYSIS OF FILAMENTS IN THE SERPENS SOUTH MOLECULAR CLOUD

2014 ◽  
Vol 790 (2) ◽  
pp. L19 ◽  
Author(s):  
M. Fernández-López ◽  
H. G. Arce ◽  
L. Looney ◽  
L. G. Mundy ◽  
S. Storm ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Large Area ◽  
Observational Analysis

scholarly journals UV penetrated clumpy molecular cloud cores

1991 ◽  
Vol 147 ◽  
pp. 235-244
Author(s):  
Jürgen Stutzki ◽  
Reinhard Genzel ◽  
Urs Graf ◽  
Andrew I. Harris ◽  
Amiel Sternberg ◽  
...  
Keyword(s):  
Fine Structure ◽  
Mass Spectrum ◽  
Molecular Cloud ◽  
Filling Factor ◽  
Large Fraction ◽  
Volume Filling ◽  
Direct Observations ◽  
Cloud Cores ◽  
Clump Distribution ◽  
Cloud Material

Recent observations of sub-mm and far-IR atomic fine structure and molecular rotational lines give evidence that due to the clumpiness of the molecular cloud cores the UV radiation from newly formed stars affects a very large fraction of the cloud material. Direct observations of the clumpy structure in M17 SW allow to derive several parameters of the clump distribution, in particular the clump mass spectrum and the volume filling factor. Implications of these results in regard to star formation are shortly discussed.

scholarly journals UV penetrated clumpy molecular cloud cores

1991 ◽  
Vol 147 ◽  
pp. 235-244
Author(s):  
Jürgen Stutzki ◽  
Reinhard Genzel ◽  
Urs Graf ◽  
Andrew I. Harris ◽  
Amiel Sternberg ◽  
...  
Keyword(s):  
Fine Structure ◽  
Mass Spectrum ◽  
Molecular Cloud ◽  
Filling Factor ◽  
Large Fraction ◽  
Volume Filling ◽  
Direct Observations ◽  
Cloud Cores ◽  
Clump Distribution ◽  
Cloud Material

Recent observations of sub-mm and far-IR atomic fine structure and molecular rotational lines give evidence that due to the clumpiness of the molecular cloud cores the UV radiation from newly formed stars affects a very large fraction of the cloud material. Direct observations of the clumpy structure in M17 SW allow to derive several parameters of the clump distribution, in particular the clump mass spectrum and the volume filling factor. Implications of these results in regard to star formation are shortly discussed.

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

TEM Study of a Tilt Boundary in Hot-Pressed Silicon

1981 ◽  
Vol 39 ◽  
pp. 160-161
Author(s):  
C. B. Carter ◽  
J. Rose ◽  
D. G. Ast
Keyword(s):  
Electron Diffraction ◽  
Imaging Technique ◽  
Interface Structure ◽  
Large Area ◽  
Weak Beam ◽  
Lattice Fringe ◽  
Electron Diffraction Technique ◽  
Tilt Boundaries ◽  
Beam Technique ◽  
Twist Boundaries

The hot-pressing technique which has been successfully used to manufacture twist boundaries in silicon has now been used to form tilt boundaries in this material. In the present study, weak-beam imaging, lattice-fringe imaging and electron diffraction techniques have been combined to identify different features of the interface structure. The weak-beam technique gives an overall picture of the geometry of the boundary and in particular allows steps in the plane of the boundary which are normal to the dislocation lines to be identified. It also allows pockets of amorphous SiO2 remaining in the interface to be recognized. The lattice-fringe imaging technique allows the boundary plane parallel to the dislocation to be identified. Finally the electron diffraction technique allows the periodic structure of the boundary to be evaluated over a large area - this is particularly valuable when the dislocations are closely spaced - and can also provide information on the structural width of the interface.

P20 phosphor on polyimide as a large area high-resolution transmission screen for slow scan CCD systems

1995 ◽  
Vol 53 ◽  
pp. 20-21
Author(s):  
C. C. Ahn ◽  
S. Karnes ◽  
M. Lvovsky ◽  
C. M. Garland ◽  
H. A. Atwater ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
High Energy ◽  
Practical Implementation ◽  
Line Pair ◽  
Modulation Transfer ◽  
Large Area ◽  
Ccd Imaging ◽  
Transmission Electron ◽  
The One ◽  
Beam Broadening

The bane of CCD imaging systems for transmission electron microscopy at intermediate and high voltages has been their relatively poor modulation transfer function (MTF), or line pair resolution. The problem originates primarily with the phosphor screen. On the one hand, screens should be thick so that as many incident electrons as possible are converted to photons, yielding a high detective quantum efficiency(DQE). The MTF diminishes as a function of scintillator thickness however, and to some extent as a function of fluorescence within the scintillator substrates. Fan has noted that the use of a thin layer of phosphor beneath a self supporting 2μ, thick Al substrate might provide the most appropriate compromise for high DQE and MTF in transmission electron microcscopes which operate at higher voltages. Monte Carlo simulations of high energy electron trajectories reveal that only little beam broadening occurs within this thickness of Al film. Consequently, the MTF is limited predominantly by broadening within the thin phosphor underlayer. There are difficulties however, in the practical implementation of this design, associated mostly with the mechanical stability of the Al support film.

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