Visualizing SED Data in Iris

As each SED data file is read into Iris, it is automatically displayed in the tool's main window, where you can interact with the plot in various ways. Options for customizing the data display are provided both in the Iris menu bar and within the main display; these are described below.

The Iris menu bar contains the Display option for selecting a previously read spectrogram from the tool's memory buffer for display in the main plot area of Iris, or in a separate, secondary display. The Coplot menu option allows you to select one or multiple spectrograms for plotting or coplotting in the main plot area, respectively.

Display - select a data spectrogram in memory to be plotted in the primary display; or select a spectrogram and send to a separate, secondary display

Coplot - plot one or coplot multiple previously read SEDs in the Iris main display

When the Coplot option is selected, a "Spectrograms in memory" window opens in which more than one data set entry may be selected, using the mouse cursor plus the Shift or Control key.

Clicking the "Plot/Coplot" button will plot all selected data sets simultaneously in the Iris main display, if their physical units are deemed compatible by Iris's internal units conversion mechanism. The resulting plot will be displayed and stored in the memory buffer as "Coplot".

Note that the coplotting process does not involve combining, coadding, or splicing the spectral data in memory in any way; the raw data from the multiple input spectrograms is completely preserved in the resulting combination. This means that two separate SED data segments loaded into Iris for a particular source - e.g., observed with two differeny observatories and spanning separate (or overlapping) spectral ranges - may be offset from one another, as Iris does not scale, trim, and join the separate segments to form a seamless SED for the source.

The Pan option at the bottom of the Iris main display allows you to view the full spectral range covered by all SED data which has been read into the session, beyond the edges of the data segment which is currently displayed.

Right-clicking the cursor over a data segment or point in the plot will bring up a window with various tabs containing associated metadata information, as well as the independent and dependent data arrays (or point). Selecting the "Coplot" menu option and then right-clicking on a filename in the window that appears, allows you to simultaneously view the metadata for all points loaded from the chosen file.

The metadata information associated with a data segment or point includes many details, such as segment type, e.g., "SPECTRUM" or "Photometry Point"; data identification, e.g., the instrument used to obtain the data, in which observing mode, and the bandpass covered by the data; curation information such as the publisher of the data, e.g., Hopkins Ultraviolet Telescope, and the rights to the data, whether "PUBLIC" or not; among many other details.

The x and y data values shown for a data segment are referred to as the "Spectral Axis" and "Flux Axis", respectively, and reflect the values as they were imported into Iris from NED or uploaded from a file on your hard disk - i.e., not what is currently plotted in the Iris display (in the event that you changed the units of the data plot within the display). For example, if the data were uploaded in Jansky flux units versus frequency in Hertz, but then you change the display units to ergs/s/cm2/Angstrom versus Angstrom, the data point values returned will be in Jansky flux units and Hertz.