- Select Button:
- Use this button to enter the galaxy selection mode.
- Cluster Selection Dropdown:
- Use this menu to select which galaxy cluster you wish to analyze.
- Cluster View Pane:
- An image of the selected cluster will appear in this pane. If
the image is too large to be viewed in the pane, you can use the
scroll bars to view the hidden portions of the image.
When you move your mouse over a galaxy in the image, information
regarding that galaxy will appear in the small window to the right.
When you click on a galaxy, a circle will be drawn around it, indicating
that it has been added to the data set for analysis. Clicking the galaxy
again will toggle its selection off. Holding down
CONTROL while clicking will deselect all of the galaxies.
- Analyze Button:
- Clicking this button will bring you to the analysis screen, where
you can analyze the cluster based upon the galaxies you have chosen.
- Lower and Upper bounds of dispersion calculation:
- In these fields you can alter the upper and lower bounds of the
standard deviation calculation for the velocity histogram. This
will allow you to get more accurate results by eliminating
poor data points from the calculation.
- Hubble Constant:
- Enter a value for the Hubble Constant. It will be used in
calculating the distance to the galaxy cluster, which in turn will
be used to calculate other properties of the cluster.
- Velocity Histogram:
- Displays the number of galaxies that fall into each range of velocity.
It also displays the mean velocity and velocity dispersion (standard deviation)
of the current data set.
- Fractional Luminosity Graph:
- Displays the fractional luminosity of the cluster, based upon
the selected galaxies, as a function of the radius from the center
of the cluster. The half-light radius (in arcseconds) of the cluster
is indicated by the dotted line.
- Calculate Button:
- After changing the bounds of the dispersion calculation or entering
a new Hubble Constant, press this button to recalculate the various
properties of the cluster with the updated values.
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