Spectral plot

One of the most useful facilities for cube analysis is a dynamic spectrum display. Once you have a representative image displayed, click on the mouse over the image a line plot along the spectral axis appears. As you drag the cursor holding down the first mouse button, the spectrum display updates to dynamically to reflect the current spatial location while the data limits are unchanged. If you click again the range will reset to the current spectrum. You can enforce autoscaling as you drag too by enabling Options$\rightarrow$Autoscale in the spectral plot's control bar. This is slower although it allows an intensity independent comparison of the spectra. The Spectrum tab mentioned earlier also allows control of the plotting range along both axes. The Reference: Set button lets you nominate the current spectrum as a reference spectrum. Then as you subsequently drag the mouse you can compare any of the spectra with the reference spectrum. See the figure below.

Figure: GAIA displays a logarithmically scaled, collapsed cube, from which two spectra are shown. The green reference spectrum is from the spatial position marked by the green cross, and the other spectrum corresponds to the blue cross.

The vertical red line shows the plane being displayed in the main viewer. You can drag that line with the mouse to adjust the plane on view, say to inspect where emission at a chosen velocity lies spatially.

Further features of the spectral viewer can be found in the online help.