This short (2 min) movie shows large-scale structure in the Local Universe as traced by optically-selected and IRAS (Infrared)-selected galaxies.
In all frames the green sphere represents the Local Group of Galaxies (The Milky Way Galaxy and M31 [Andromeda]).
There are four different scales shown.
First scale (30 Mpc)Notes: The radius of the plotted data is 30 Mpc (2000 km/s assuming a Hubble Constant of 67 km/s/Mpc). The blue surface shows the contour enclosing dense regions of the Universe (superclusters) where the density of galaxies is 2.5 times the average density.
The viewpoint is looking down on the Supergalactic Plane (from negative Supergalactic Z). Supergalactic X is to the right and Supergalactic Y is towards the top.
The plane of the Milky Way runs edge-on along the horizontal axis in this view.
Prominent features are the Virgo and Ursa Major clusters (top and top-right) and Fornax-Eridanus (bottom)
The data source for this and the next two scales is the optical galaxy catalogue of Hudson (93, MNRAS, 265, 43). The smoothing kernel is (1-r/r_smooth)^2 where r_smooth = 500 km/s (7.5 Mpc)
Second scale (60 Mpc):
Notes: The radius is now 60 Mpc (4000 km/s). The smoothing radius is 10.5 Mpc and the contour is at 2x the mean density.
Now we can start to see the Centaurus-Hydra supercluster (part of the Great Attractor) to the middle-upper left.
Third scale (120 Mpc):
Notes: The radius is now 120 Mpc (8000 km/s). The smoothing radius is 15 Mpc and the contour is at 1.5 x the mean density.
We see the Centaurus-Hydra-Pavo (Great Attractor) complex to the left, and on the right-hand side the very large Perseus-Pisces complex. The Coma supercluster is at the top.
Morph to IRAS:
Notes: We do a morph from the distribution of optically-selected galaxies to IRAS infrared-selected galaxies. The IRAS data is from the PSCz redshift survey (Saunders et al. 1999, in prep). The smoothing and contouring threshold are the same for optical and IRAS galaxies, optical is blue and IRAS is red.
Fourth scale (240 Mpc):
Notes: The radius is now 240 Mpc (12000 km/s). The smoothing radius 37.5 Mpc and the contour is 1.15 x the mean density.
Hydra-Cen and Perseus-Pisces are small blobs near the center. The Shapley Concentration is the large blob in the upper left.
Note that there is less of a tendency for superclusters to lie in the Supergalactic plane.
Available for download in two sizes and two gamma. Choose the one which is right for you. Grab the README file as well, which is an ASCII copy of this page.
| Large (533x400) | Small (240x240) | |
| Gamma = 1.8 | PowersOfTwo.mpg (17.9 Mb) | PowersOfTwo_s.mpg (8.8 Mb) |
| Gamma = 3 | PowersOfTwo_hig.mpg (28 Mb) | PowersOfTwo_s_hig.mpg (13 Mb) |