scholarly journals Visualization of structures and cosmic flows in the local Universe

2012 ◽  
Vol 8 (S289) ◽  
pp. 323-326
Author(s):  
Daniel Pomarède ◽  
Hélène Courtois ◽  
R. Brent Tully
Keyword(s):  
Three Dimensional ◽  
Wiener Filter ◽  
Virgo Cluster ◽  
Distance Measures ◽  
Local Universe ◽  
Peculiar Velocities ◽  
Filter Approach ◽  
Visualization Techniques ◽  
Observational Program ◽  
Great Attractor

AbstractA visualization of 3D structures and cosmic flows is presented using information from the Extragalactic Distance Database V8k redshift catalog and peculiar velocities from the Cosmicflows-1 survey. Structures within a volume bounded at 8000 km s−1 on the cardinal Supergalactic axes are explored in terms of both displaying the positions of the 30,124 galaxies of the catalog and its reconstructed luminosity density field, corrected to account for growing incompleteness with increasing distance. Cosmography of the local Universe is discussed with the intent to identify the most prominent structures, including voids, galaxy clusters, filaments, and walls. The mapping also benefits from precise distance measures provided through the Cosmicflows-1 observational program. Three-dimensional visualizations of the coherent flows of galaxies in the nearby Universe are presented, using recent results based on reconstruction of cosmic flows with the Wiener filter approach. The three major components of the Milky Way's motion, namely expulsion from the Local Void, infall toward the Virgo Cluster, and the bulk flow of the historic Local Supercluster toward the Great Attractor are illustrated using different visualization techniques and analyzed in light of the cosmography derived from the V8k redshift and Cosmicflows-1 distance catalogs.

scholarly journals Large-Scale Flows in the Local Universe

1996 ◽  
Vol 168 ◽  
pp. 175-182 ◽  
Author(s):  
D.S. Mathewson ◽  
V.L. Ford
Keyword(s):  
Large Scale ◽  
Velocity Measurements ◽  
Local Universe ◽  
Peculiar Velocities ◽  
Redshift Surveys ◽  
Density Maps ◽  
The Universe ◽  
Great Wall ◽  
Great Attractor ◽  
Streaming Flow

Peculiar velocity measurements of 2500 southern spiral galaxies show large-scale flows in the direction of the Hydra-Centaurus clusters which fully participate in the flow themselves. The flow is not uniform over this region and seems to be associated with the denser regions which participate in the flow of amplitude about 400km/s. In the less dense regions the flow is small or non-existent. This makes the flow quite asymmetric and inconsistent with that expected from large-scale, parallel streaming flow that includes all galaxies out to 6000km/s as previously thought. The flow cannot be modelled by a Great Attractor at 4300km/s or the Centaurus clusters at 3500km/s. Indeed, from the density maps derived from the redshift surveys of “optical” and IRAS galaxies, it is difficult to see how the mass concentrations can be responsible particularly as they themselves participate in the flow. These results bring into question the generally accepted reason for the peculiar velocities of galaxies that they arise solely as a consequence of infall into the dense regions of the universe. To the N. of the Great Attractor region, the flow increases and shows no sign of diminishing out to the redshift limit of 8000km/s in this direction. We may have detected flow in the nearest section of the Great Wall.

scholarly journals The Great Attractor ? A Cosmic String?

1990 ◽  
Vol 43 (2) ◽  
pp. 167 ◽  
Author(s):  
DS Mathewson
Keyword(s):  
Cosmic String ◽  
Large Scale ◽  
Conclusive Evidence ◽  
Local Universe ◽  
Peculiar Velocities ◽  
Sky Survey ◽  
Angular Extent ◽  
Attractor Model ◽  
Considerable Controversy ◽  
Great Attractor

A brief review is made of the observational work on large-scale streaming motions in the Local Universe. There is considerable controversy as to whether the Great Attractor model of these streaming motions is correct. Preliminary results are presented of a southern sky survey of spiral galaxies to measure their peculiar velocities using the Tully-Fisher relationship. The region of strong peculiar motions has an elongated shape some 80� in angular extent centred roughly on the Great Attractor enclosing the brightest parts of the supergalactic plane. The peculiar velocities reverse in sign at a distance of 4000 km S-i which is conclusive evidence that such a dominant attracting region exists at that distance. However, there is little evidence of galaxies associated with this attracting mass and most galaxies appear to be participating in the streaming motions. The conclusion is that the attractor is largely invisible. It is proposed that a large moving loop of cosmic string is responsible for the peculiar velocities of the galaxies.

scholarly journals Cosmicflows-2

2014 ◽  
Vol 11 (S308) ◽  
pp. 305-309
Author(s):  
R. Brent Tully ◽  
Hélène M. Courtois ◽  
Yehuda Hoffman ◽  
Daniel Pomarède
Keyword(s):  
Three Dimensional ◽  
Wiener Filter ◽  
Radial Component ◽  
Density Field ◽  
Distance Measurements ◽  
Entire Domain ◽  
Cosmic Expansion ◽  
Peculiar Velocity ◽  
Peculiar Velocities

AbstractA compendium of over 8000 galaxy distances has been accumulated. Distance measurements permit the separation of observed velocities into cosmic expansion and peculiar velocity components. Only the radial component of peculiar velocities can be measured and individual errors are large, but a Wiener Filter procedure permits the reconstruction of three-dimensional motions and the density field that is responsible for these motions. A coherent flow pervades the entire domain of ± 15,000 km/s. Techniques are discussed for the separation of local and tidal components of the flow. Laniakea supercluster is identified as a region of contiguous infalling flows.

Density-based discrimination of protein and RNA in the ribosome

1992 ◽  
Vol 50 (1) ◽  
pp. 464-465
Author(s):  
Joachim Frank
Keyword(s):  
Transfer Function ◽  
Spatial Frequency ◽  
Three Dimensional ◽  
Wiener Filter ◽  
Dark Field Image ◽  
Dark Field ◽  
Frequency Range ◽  
Bright Field ◽  
Contrast Transfer Function ◽  
Pass Filter

Cryo-electron microscopy combined with single-particle reconstruction techniques has allowed us to form a three-dimensional image of the Escherichia coli ribosome.In the interior, we observe strong density variations which may be attributed to the difference in scattering density between ribosomal RNA (rRNA) and protein. This identification can only be tentative, and lacks quantitation at this stage, because of the nature of image formation by bright field phase contrast. Apart from limiting the resolution, the contrast transfer function acts as a high-pass filter which produces edge enhancement effects that can explain at least part of the observed variations. As a step toward a more quantitative analysis, it is necessary to correct the transfer function in the low-spatial-frequency range. Unfortunately, it is in that range where Fourier components unrelated to elastic bright-field imaging are found, and a Wiener-filter type restoration would lead to incorrect results. Depending upon the thickness of the ice layer, a varying contribution to the Fourier components in the low-spatial-frequency range originates from an “inelastic dark field” image. The only prospect to obtain quantitatively interpretable images (i.e., which would allow discrimination between rRNA and protein by application of a density threshold set to the average RNA scattering density may therefore lie in the use of energy-filtering microscopes.

Predicting spatial activity patterns in a neural map from a probabilistic atlas of 3-D reconstructed neurons

1995 ◽  
Vol 53 ◽  
pp. 812-813
Author(s):  
G. Jacobs ◽  
F. Theunissen
Keyword(s):  
Activity Patterns ◽  
Three Dimensional ◽  
Sensory System ◽  
Neural System ◽  
Probabilistic Atlas ◽  
Uniform Sample ◽  
Dimensional Reconstruction ◽  
The Time Domain ◽  
And Function ◽  
Visualization Techniques

In order to understand how the algorithms underlying neural computation are implemented within any neural system, it is necessary to understand details of the anatomy, physiology and global organization of the neurons from which the system is constructed. Information is represented in neural systems by patterns of activity that vary in both their spatial extent and in the time domain. One of the great challenges to microscopists is to devise methods for imaging these patterns of activity and to correlate them with the underlying neuroanatomy and physiology. We have addressed this problem by using a combination of three dimensional reconstruction techniques, quantitative analysis and computer visualization techniques to build a probabilistic atlas of a neural map in an insect sensory system. The principal goal of this study was to derive a quantitative representation of the map, based on a uniform sample of afferents that was of sufficient size to allow statistically meaningful analyses of the relationships between structure and function.

scholarly journals Design of a Didactical Activity for the Analysis of Uncertainties in Thermography through the Use of Robust Statistics as Teacher-Oriented Approach

2021 ◽  
Vol 13 (3) ◽  
pp. 402
Author(s):  
Pablo Rodríguez-Gonzálvez ◽  
Manuel Rodríguez-Martín
Keyword(s):  
Open Source ◽  
Robust Statistics ◽  
Three Dimensional ◽  
Learning Material ◽  
Novel Approach ◽  
Learning Programs ◽  
Institutional Learning ◽  
Thermographic Image ◽  
Visualization Techniques ◽  
Free Open Source

The thermography as a methodology to quantitative data acquisition is not usually addressed in the degrees of university programs. The present manuscript proposes a novel approach for the acquisition of advanced competences in engineering courses associated with the use of thermographic images via free/open-source software solutions. This strategy is established from a research based on the statistical and three-dimensional visualization techniques over thermographic imagery to improve the interpretation and comprehension of the different sources of error affecting the measurements and, thereby, the conclusions and analysis arising from them. The novelty is focused on the detection of non-normalities in thermographic images, which is illustrates in the experimental section. Additionally, the specific workflow for the generation of learning material related with this aim is raised for asynchronous and e-learning programs. These virtual materials can be easily deployed in an institutional learning management system, allowing the students to work with the models by means of free/open-source solutions easily. Subsequently, the present approach will give new tools to improve the application of professional techniques, will improve the students’ critical sense to know how to interpret the uncertainties in thermography using a single thermographic image, therefore they will be better prepared to face future challenges with more critical thinking.

Visualizing the Bug Distribution Information Available in Software Bug Repositories

2014 ◽  
pp. 48-66
Author(s):  
N. K. Nagwani ◽  
S. Verma
Keyword(s):  
Open Source ◽  
Three Dimensional ◽  
Distribution Patterns ◽  
Two Dimensional ◽  
Software Bugs ◽  
Process Visualization ◽  
Software Information ◽  
Visualization Techniques ◽  
Software Bug ◽  
Bug Repositories

Software repositories contain a wealth of information that can be analyzed for knowledge extraction. Software bug repositories are one such repository that stores the information about the defects identified during the development of software. Information available in software bug repositories like number of bugs priority-wise, component-wise, status-wise, developers-wise, module-wise, summary-terms-wise, can be visualized with the help of two- or three-dimensional graphs. These visualizations help in understanding the bug distribution patterns, software matrices related to the software bugs, and developer information in the bug-fixing process. Visualization techniques are exploited with the help of open source technologies in this chapter to visualize the bug distribution information available in the software bug repositories. Two-dimensional and three-dimensional graphs are generated using java-based open source APIs, namely Jzy3d (Java Easy 3d) and JFreeChart. Android software bug repository is selected for the experimental demonstrations of graphs. The textual bug attribute information is also visualized using frequencies of frequent terms present in it.

3D Visualization for Hydrocarbon Project Design

2008 ◽  
Author(s):  
Scott Neurauter ◽  
Sabrina Szeto ◽  
Matt Tindall ◽  
Yan Wong ◽  
Chris Wright
Keyword(s):  
Spatial Data ◽  
3D Visualization ◽  
Dimensional Space ◽  
Three Dimensional ◽  
3D Models ◽  
3D Analysis ◽  
Cost Efficient ◽  
Ground Truthing ◽  
Elevation Model ◽  
Visualization Techniques

3D visualization is the process of displaying spatial data to simulate and model a real three dimensional space. Using 3D visualization, Geomatic professionals are enabling pipeline engineers to make better decisions by providing an increased understanding of potential costs earlier in the design process. This paper will focus on the value of visualizing Digital Elevation Model (DEM) data through the use of hillshades and imagery-draped 3D models. From free online DEM data to high resolution Light Detection and Ranging (LiDAR) derived DEM data, the increased availability allows for a broader use of 3D visualization techniques beyond 3D analysis. Of the numerous sources available, two DEM sources will be discussed in this paper, the free low resolution DEM (CDED Level 1) and the more costly but higher resolution LiDAR based DEM. Traditional methods of evaluating potential locations for route and facilities involved a significant cost for ground truthing. Through the use of 3D visualization products, multiple potential locations can be examined for suitability without the expense of field visits for every candidate site. By focusing on the selected candidate locations using a visual desktop study, the time and expense of ground truthing all of the potential sites can be reduced significantly. Exploiting the visual value of DEM permits a productive and cost efficient methodology for initial route and facility placement on hydrocarbon projects.

A Wiener filter approach to shape from shading

2017 ◽  
Author(s):  
Oscar E. Castillo ◽  
Jorge Luis Flores Nuñez ◽  
Jose A. Muñoz ◽  
Ricardo Legarda
Keyword(s):  
Wiener Filter ◽  
Shape From Shading ◽  
Filter Approach

scholarly journals Structure and kinematics of the Bootes filament

2014 ◽  
Vol 11 (S308) ◽  
pp. 187-192
Author(s):  
O. Nasonova ◽  
I. Karachentsev ◽  
V. Karachentseva
Keyword(s):  
Dark Matter ◽  
Stellar Mass ◽  
Average Density ◽  
Virgo Cluster ◽  
Galaxy Groups ◽  
Peculiar Velocities ◽  
Galaxy Distribution ◽  
The Galaxy ◽  
Virial Mass ◽  
Individual Distance

AbstractBootes filament of galaxies is a dispersed chain of groups residing on sky between the Local Void and the Virgo cluster. We consider a sample of 361 galaxies inside the sky area of RA = 13h0...18h.5 and Dec = .5°... + 10° with radial velocities VLG < 2000 km/s to clarify its structure and kinematics. In this region, 161 galaxies have individual distance estimates. We use these data to draw the Hubble relation for galaxy groups, pairs as well as the field galaxies, and to examine the galaxy distribution on peculiar velocities. Our analysis exposes the known Virgo-centric infall at RA < 14h and some signs of outflow from the Local Void at RA > 17h. According to the galaxy grouping criterion, this complex contains the members of 13 groups, 11 pairs and 140 field galaxies. The most prominent group is dominated by NGC 5846. The Bootes filament contains the total stellar mass of 2.7 ×1012M⊙ and the total virial mass of 9.07×1013M⊙, having the average density of dark matter to be Ωm = 0.09, i.e. a factor three lower than the global cosmic value.

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