Presentation is loading. Please wait.

Presentation is loading. Please wait.

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 1/23 Interactive Visualization of Intercluster Galaxy Structures in the Horologium-Reticulum Supercluster.

Similar presentations


Presentation on theme: "The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 1/23 Interactive Visualization of Intercluster Galaxy Structures in the Horologium-Reticulum Supercluster."— Presentation transcript:

1 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 1/23 Interactive Visualization of Intercluster Galaxy Structures in the Horologium-Reticulum Supercluster Matthew C. Fleenor Roanoke College Jameson Miller UNC Chapel Hill Cory W. Quammen UNC Chapel Hill

2 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 2/23 Data description Galaxy positions in RA- DEC-cz coordinate system >Right-ascension (RA) ~ longitude >Declination (DEC) ~ latitude >cz – radial dimension (recessional velocity) ~2500 galaxy locations ~30 clusters

3 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 3/23 Domain questions What is the distribution of intercluster galaxies? Are there large void regions? How many? Does the supercluster have filaments? How do clusters fit into the structure defined by intercluster galaxies?

4 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 4/23 Standard 2D plots

5 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 5/23 Overvieew

6 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 6/23 Prior 3D experience Collaborators viewed data in immersive environment Got lost – no context

7 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 7/23 Previous interactive tools Cosmic Explorer [Song1993] SGI Explorer [Christensen1995] PartiView [Levy2001] AstroMD [Gheller2002]

8 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 8/23 Whats missing Ability to group galaxies into structures they define >Voids >Filaments Reference axes in all three RA-DEC-cz dimensions

9 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 9/23 Data types Sparse 3D position data Nominal (categorical) data >Intercluster galaxies vs. clusters >User-defined groups indicating structure (filament, void boundary) Intercluster Galaxy Cluster Group 1 Group 2 …

10 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 10/23 Nominal encoding 3D glyphs >Enough screen real estate >Distinct shapes encode object type >Depth queues from perspective and occlusion Nominal color encoding >Group membership >Encoded by 10 of 12 colors recommended by Ware2004

11 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 11/23 RA-DEC-cz reference axes Orientation to dataset Colored with just- noticeably-different color than background Can turn sides, top, and bottom on or off

12 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 12/23 Curved drop lines Explicit connection between galaxies and reference axes Curved to fit RA- DEC-cz coordinate system Allows comparison to standard plots

13 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 13/23 Structure perception Structure-from- motion >Strongest shape cue Torsional rocking >Structure-from-motion without interaction Stereo >Complements other techniques >User can control eye- separation parameter

14 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 14/23 Confirmation of analysis Quantitative analysis shows two separate overdensities Overdensities pop out in visualization ~95% correspondence between grouping by hand and quantitative grouping

15 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 15/23 Positive result Quick identification of void regions Selection of galaxies along rim defines bounds of void Offline sphere-fitting refines estimation Six voids identified Known clusters reside around voids

16 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 16/23 Negative result Previous 2D plots identified potential filament structure When rotated in 3D, filament is shown to be two separate structures

17 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 17/23 Computation vs. visualization Voids – could compute Filaments – maybe could compute Visualization helps astronomers know where to focus quantitative analysis

18 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 18/23 Effective techniques User-controlled interaction >Critical for maintaining viewer orientation >Interactive scaling allows snapping between overview of data and local features, giving context when zooming in >Home key moves back to a familiar orientation Torsional rocking >Rocking aids void definition when far galaxies peek out from closer galaxy >View angle optimization Stereo >Stereo is helpful for finding galaxies bordering voids >Picking with mouse was hampered by stereo >Collaborators came across campus to use it!

19 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 19/23 Software Called GyVe (Galaxy Viewer) Built on VTK, Python, and Tkinter Available at Runs on Windows and Linux

20 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 20/23 Future work Isosurfaces – initial attempt unused Image processing for identifying voids from density projections Add interactive statistical tools Haptic probes to feel around for structures

21 The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 21/23 Acknowledgements NSF Grant AST (Fleenor) James A. Rose Russell M. Taylor II


Download ppt "The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL 1/23 Interactive Visualization of Intercluster Galaxy Structures in the Horologium-Reticulum Supercluster."

Similar presentations


Ads by Google