Synthesis and Structure of the Metallaborane Cp*3(μ-H)W3B8H8from the Thermolysis of Cp*H3WB4H8(Cp* = η5-C5Me5). A Close-Packed 11-Atom Boron-Rich Cluster

1998 ◽  
Vol 120 (32) ◽  
pp. 8283-8284 ◽  
Author(s):  
Andrew S. Weller ◽  
Maoyu Shang ◽  
Thomas P. Fehlner
Keyword(s):  
Rich Cluster

scholarly journals Jet-gas interactions at crucial jet power for feedback

2014 ◽  
Vol 10 (S313) ◽  
pp. 260-265
Author(s):  
D. M. Worrall ◽  
M. Birkinshaw
Keyword(s):  
Gas Flows ◽  
Rich Cluster ◽  
Power Sources ◽  
X Ray ◽  
Wide Range ◽  
Higher Power ◽  
Radiative Power ◽  
Gas Interactions ◽  
Work Done ◽  
Radio Luminosity Function

AbstractMost X-ray studies of radio-mode feedback have concentrated on locally-abundant low-power radio sources in relatively rich cluster environments. But the scaling found between mechanical and radiative power, when combined with the radio luminosity function, means that half of the heating in the local Universe is expected from higher-power sources, which lie within a factor of about three of the FRI/II transition, and these sources encounter a wide range of atmosphere properties. We summarize what is observed at FRI/II transition powers from a complete sample observed with modest Chandra exposure times. We then discuss two systems with deep Chandra data. In one we find that the work done in driving shocks exceeds that in evacuating cavities. This source also displays a remarkable jet-cloud interaction, and revealing hotspot X-ray emission. In the second we find evidence of radio-emitting plasma running along boundaries between gas of different temperature, apparently lubricating the gas flows and inhibiting heat transfer, and itself being heavily structured by the process.

scholarly journals Spectroscopy of arcs in the rich cluster Abell 963

1991 ◽  
Vol 249 (1) ◽  
pp. 184-190 ◽  
Author(s):  
Richard Ellis ◽  
Jeremy Allington-Smith ◽  
Ian Smail
Keyword(s):  
Rich Cluster ◽  
The Rich

Structure of the Oxygen-Rich Cluster Cation Al2O7+and its Reactivity toward Methane and Water

2011 ◽  
Vol 133 (42) ◽  
pp. 16930-16937 ◽  
Author(s):  
Zhe-Chen Wang ◽  
Thomas Weiske ◽  
Robert Kretschmer ◽  
Maria Schlangen ◽  
Martin Kaupp ◽  
...  
Keyword(s):  
Rich Cluster ◽  
Cluster Cation

scholarly journals The Origin of Absorption Spectra in Quasi-Stellar Objects

1980 ◽  
Vol 92 ◽  
pp. 107-117 ◽  
Author(s):  
Ray J. Weymann
Keyword(s):  
Absorption Line ◽  
Absorption Spectra ◽  
Classification Scheme ◽  
Spectral Characteristics ◽  
Type A ◽  
Galactic Halos ◽  
Evolutionary Sequence ◽  
Rich Cluster ◽  
Stellar Objects ◽  
Quasi Stellar Objects

A classification scheme for QSO absorption line spectra is described which ascribes the origin of the lines to at least four mechanisms: (A) Explosive ejection of material at speeds up to 0.1 c. (B) Absorption by highly ionized material moving in a rich cluster in which the QSO is embedded. (C-1) Cosmologically distant intervening material with ‘normal’ abundances, probably associated with large galactic halos. (C-2) Cosmologically distant intervening material consisting of primordial uncondensed gas. Examples of each type of spectra are given and their ionization and other spectral characteristics discussed. The similarity between the development of novae spectra and a possible evolutionary sequence of the explosive ejecta of type A is striking and suggestive. Several difficulties and unsolved problems involving this scheme are noted. Finally, we speculate on the interpretation of two interesting objects (PKS 0237-23 and the ‘twin quasars’ 0957+56A,B) in the context of this scheme.

scholarly journals Spatially Resolved Spectroscopy of Starburst and Post-Starburst Galaxies in the Rich z ∼0.55 Cluster CL 0016+16

2010 ◽  
Vol 27 (3) ◽  
pp. 360-373 ◽  
Author(s):  
Michael B. Pracy ◽  
Warrick J. Couch ◽  
Harald Kuntschner
Keyword(s):  
Age Distribution ◽  
Starburst Galaxies ◽  
Small Sample ◽  
Spectral Signature ◽  
Rich Cluster ◽  
Spatially Resolved ◽  
Radial Profiles ◽  
Field Samples ◽  
The Rich ◽  
Spatially Resolved Spectroscopy

AbstractWe have used the Low Resolution Imaging Spectrograph on the W. M. Keck I telescope to obtain spatially resolved spectroscopy of a small sample of six ‘post-starburst’ and three ‘dusty-starburst’ galaxies in the rich cluster CL 0016+16 at z=0.55. We use this to measure radial profiles of the Hδ and [OII]λ3727 lines which are diagnostic probes of the mechanisms that give rise to the abrupt changes in star formation rates in these galaxies. In the post-starburst sample we are unable to detect any radial gradients in the Hδ line equivalent width — although one galaxy exhibits a gradient from one side of the galaxy to the other. The absence of Hδ gradients in these galaxies is consistent with their production via interaction with the intracluster medium; however, our limited spatial sampling prevents us from drawing robust conclusions. All members of the sample have early-type morphologies, typical of post-starburst galaxies in general, but lack the high incidence of tidal tails and disturbances seen in local field samples. This argues against a merger origin and adds weight to a scenario where truncation by the intra-cluster medium is at work. The post-starburst spectral signature is consistent over the radial extent probed with no evidence of [OII]λ3727 emission and strong Hδ absorption at all radii, i.e. the post-starburst classification is not an aperture effect. In contrast the ‘dusty-starburst’ sample shows a tendency for a central concentration of [OII]λ3727 emission. This is most straightforwardly interpreted as the consequence of a central starburst. However, other possibilities exist such as a non-uniform dust distribution (which is expected in such galaxies) and/or a non-uniform starburst age distribution. The members of the sample exhibit late-type and irregular morphologies.

scholarly journals The Mass‐to‐Light Ratio of Early‐Type Galaxies: Constraints from Gravitational Lensing in the Rich Cluster AC 114

1998 ◽  
Vol 499 (2) ◽  
pp. 600-607 ◽  
Author(s):  
Priyamvada Natarajan ◽  
Jean‐Paul Kneib ◽  
Ian Smail ◽  
Richard S. Ellis
Keyword(s):  
Gravitational Lensing ◽  
Early Type ◽  
Rich Cluster ◽  
The Rich

RCS 043938-2904.9: A New Rich Cluster of Galaxies at [FORMULA][F]z=0.951[/F][/FORMULA]

2004 ◽  
Vol 617 (1) ◽  
pp. L17-L20 ◽  
Author(s):  
L. Felipe Barrientos ◽  
Michael D. Gladders ◽  
H. K. C. Yee ◽  
Leopoldo Infante ◽  
Erica Ellingson ◽  
...  
Keyword(s):  
Rich Cluster ◽  
Cluster Of Galaxies

scholarly journals Rich cluster microlensing

1995 ◽  
Vol 275 (1) ◽  
pp. L41-L45 ◽  
Author(s):  
Mark A. Walker ◽  
Peter M. Ireland
Keyword(s):  
Rich Cluster

Bubbles and element clusters in rock melts: A chicken and egg problem

2021 ◽  
Author(s):  
Renelle Dubosq ◽  
Pia Pleše ◽  
Brian Langelier ◽  
Baptiste Gault ◽  
David Schneider
Keyword(s):  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Growth Dynamics ◽  
Gas Bubbles ◽  
Atom Probe ◽  
Bubble Nucleation ◽  
Interface Element ◽  
Rich Cluster ◽  
Heterogeneous Distribution ◽  
Rapid Decompression

<p>The nucleation and growth dynamics of gas bubbles and crystals play a vital function in determining the eruptive behaviour of a magma. Their rate and relative timing, among other factors, are controlled by the magma’s ascent rate. Investigating the kinetics of decompression-induced degassing and crystallization processes can thus give us insight into the rheology of magmas. For example, the rapid decompression of magmas inhibits microlite crystallization and bubble nucleation during ascent leading to crystallization and degassing at shallow levels. This results in a drastic increase in viscosity and an over pressured system, which can lead to violent eruptions. Although many experiments and numerical simulations of magma decompression have been carried out, nascent and initial bubble nucleation remain poorly understood. It is widely accepted that there are two ways bubbles can nucleate within a melt: heterogeneous (on a pre-existing surface) and homogeneous nucleation (within the melt), where homogeneous nucleation requires a higher volatile supersaturation. It has since been tentatively suggested that homogeneous nucleation is simply a variety of heterogeneous nucleation where nucleation occurs on the surface of submicroscopic crystals. However, evidence of these crystals is equivocal. Thus, we have combined novel 2D and 3D structural and chemical microscopy techniques including scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS) mapping, and atom probe tomography (APT) to investigate the presence of sub-nanometer scale chemical heterogeneities in the vicinity of gas bubbles within an experimental andesitic melt. The combined STEM and EELS data reveal a heterogeneous distribution of bubbles within the melt ranging between 20-100 nm in diameter, some of which have Fe and/or Ca element clusters at the bubble-melt interface. Element clusters enriched in Fe, Ca, and Na are also observed heterogeneously distributed within the melt. The reconstructed APT data reveals bubbles as low ionic density regions overlain by a Na-, Ca-, and K-rich cluster and heterogeneously distributed Fe clusters within the bulk of the melt. Based on these observations, our data demonstrate the existence of nano-scale chemical heterogeneities within the melt and at the bubble-melt interface of bubbles that were previously interpreted to be nucleated homogeneously within the melt, therefore contributing to the proposed hypothesis that homogeneous nucleation could in fact be a variety of heterogeneous nucleation. These results highlight the need to redefine homogeneous nucleation and revisit whether bubbles or crystals occur first within volcanic melts. </p>

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