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10.9 Identifying Spectral Lines

To find the coordinates of a given point on the spectrum, without tedious examination of the vectors, use the following program:


W,F Wavelengths and fluxes of spectrum.
mode There are two possible modes:

0 The coordinates of the horizontal and vertical crosshairs are returned. This is the default mode for TEK devices.

1 The coordinates returned are determined by the vertical crosshair and the nearest flux point on the spectrum to that wavelength. This is the default mode for non-TEK devices.

wsel,fsel Coordinates of points selected (as determined by the mode parameter). These will contain all the points selected.
log If this keyword is set, the user will have the option of sending the plot to a printer. Also, the list of wavelengths selected (wsel) is written to a file (``point.log'') suitable for the program LINEID.
xunit Sets the X axis label (default is ``wave'').
yunit Sets the Y axis label (default is ``Flux'').

You can use resulting values to determine line identifications or wavelength shifts as appropriate. If you set the LOG keyword, and wish to check the wavelengths you selected against the Kelly and Palumbo Line List, you may call LINEID:


TOLERANCE Lines at your wavelengths ±tolerance will be listed in the file ``kandp.log''.
filename The default input filename is ``point.log'' (assumed to be located in the current directory), but you may enter another filename here if you have a different file. Input files must consist of a column of wavelengths (Å, one wavelength per line.

LINEID calls a program called KANDP to locate the lines and write the results to a file. You may call this program directly:


$\lambda$ Wavelength to search for. The implemented version of this program only accepts one wavelength at a time.
tolerance Program will search for $\lambda\pm$ ±tolerance.
element Element to look for (e.g., 'Mg').
ion_l Ionization state. This is an integer starting with 1 (neutral).
ion_u Upper limit of ionizations states to look for. If present, ion_l is interpreted as a lower limit.
air If set, database values are converted to air wavelengths before being compared to $\lambda$. Use this for IUESIPS $\lambda \geq$ >/=2000 Å.

next up previous contents
Next: 10.10 Line Measurements Up: 10 MORE WAYS TO Previous: 10.8 Smoothing and Filtering