Tully Galaxy Images
Overview
We’ve grown accustomed to seeing galaxies as multicolored points. Typically, these colors represent density, where orange galaxies are in a dense, galaxy-rich part of the universe and aqua-colored galaxies are in a less dense, galaxy-poor part of the universe.
The Tully Galaxy Survey is rich for a number of reasons. For one, the galaxy positions are massaged—fingers of god and systematic uncertainties are adjusted to yield a more scientifically accurate rendition of the structure. The Tully Galaxies also have an image attached to each galaxy in the data set.
These images have several qualities:
They are accurately sized
They are inclined when the galaxy’s inclination is known
And, they are representative of the galaxy’s morphological type (spiral, elliptical, etc.)
A view of the Virgo Cluster with the Tully Galaxy points off. Normally these would be a sea of orange points. Here, we see the images of each galaxy. One consequence of sizing the images accurately is that you need to be directly beside them before they will be visible.
Image Size and Visibility
From a wide perspective, these images are impossible to see, hence the need for points. Galaxies are so small relative to our typical view in OpenSpace that one must be right beside them in order for their image to be visible. This is a consequence of having properly-sized images for each galaxy.
While we would never do this in the public show, it is possible to exaggerate the image sizes. Using the menu item , you can make the images larger, to the point that neighboring galaxies are overlapping. This is completely unrealistic and inaccurate, but it can be illustrative at times when used with restraint.
A view of the Virgo Cluster with the galaxy images exaggerated. The galaxy M61 is in the foreground to the left, and many other member galaxies are in view.
Image Sources
Most of these images come from The Galaxy Catalog. This source has a small number of galaxy images and we use those images repeatedly for galaxies of a specific morphological type. In other words, elliptical galaxies may all be represented by the same image throughout the catalog.
A handful of nearby galaxies are represented by their actual images, which come mostly from the National Optical Astronomy Observatory (NOAO).
Each of these images has been altered from its original state. These images were taken from Earth on some of the world’s largest telescopes, so foreground stars from our own Galaxy appear in each image. We are representing galaxies in extragalactic space, so we have removed the stars from each image.
A view of the nearby universe with grossly exaggerated images and labels for galaxy groups (green) and galaxy clusters (orange).
An outrageous exaggeration—the Tully Galaxy Images are so large we can see the structure of the universe from outside the data set. Indeed, the galaxies are so large they are touching one another.
Profiles
Dossier
Census: |
122 images |
|---|---|
Asset File: |
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OpenSpace Version: |
3 |
Reference: |
The Galaxy Catalog; National Optical Astronomy Observatory |
Prepared by: |
Stuart Levy (NCSA) |
Source Version: |
1.05 |
License: |