linespec: Make a spectrum from a list of emission and/or absorption lines

Package: rvsao

Usage

linespec linefile specfile

Parameters

linefile ""
Filename with list of emission or absorption lines in the format
Center wavelength of line in Angstroms
Half-width of line: in Angstroms if positive,
in km/sec if negative
Height of line in counts (this is arbitrary)
Name of line
linedir ""
Directory for line list (null string means current directory)
linewidth 2.0
Half-width at half-max of Gaussian emission lines in Angstroms This instrumental function is convolved with the spectrum from linefile.
maxwidth no
Use maximum of line or instrument width (yes) or convolve instrument with spectrum (no).
zspec 0
Delta lambda / lambda to which to shift individual spectral lines. This is useful for making spectra for very distant objects and supercedes velspec if it is not zero.
velspec 0
If this is not zero, shift the wavelengths of all specified lines to this velocity.
continuum 0
Continuum level for output spectrum. This is useful if software to be used on the created spectrum has problems with a continuum of zero or absorption lines with negative nadirs.
specobj = ""
Title for output spectrum
specfile = ""
File name for output spectrum
specdir = ""
Directory for output spectrum (null string means current directory)
st_lambda = INDEF
Starting wavelength in angstroms for output file
end_lambda = INDEF
Ending wavelength in angstroms for output file
pix_lambda 0.25,
Wavelength per pixel in Angstroms
spec_plot = yes
If yes, a plot of the output spectrum is displayed. Cursor commands are activated for zooming in on a portion of the spectrum and hard copies may be made to stdplot using the @ command. If maxwidth is no, the spectrum is displayed both before and after it is convolved with the instrumental Gaussian.
spec_int no
If yes, interact with the graph of the output spectrum
device = "stdgraph"
Interactive device on which to display a graphic summary of XCSAO's results.
plotter = "stdplot"
Second, non-interactive device on which to plot the graphic summary of results.
verbose yes
Print summary to log file (yes or not).
logfiles = "STDOUT,linespec.log"
All results from LINTEMP are recorded in these files.
debug = no
If yes, values of the parameters fit to the selected peak are recorded in the log files. This is most useful for debugging.
cursor = ""
Graphics cursor input. When null the standard cursor is used otherwise the specified file is used.

Description

LINESPEC reads a list of positions of emission and/or absorptions lines and creates a spectrum with Gaussian lines of the the indicated half-widths at the indicated positions, writing a one-dimensional IRAF file with the appropriate keywords in the header. If velspec is nonzero, the emission lines are shifted to that redshift velocity.

Cursor

The following keystrokes are active for spectrum template plots in addition to the normal IRAF cursor facilities (a list of those is available with the command ":.help"):
@
Make a hard copy on the device designated by plotter.
c
Prints cursor position in x and y. This is the default. All other undefined keys perform this same function.
d
Replaces a region between the marked vertical cursors with interpolated values from the edges of the marked region. This is can be used to eliminate lines from a template without changing the line list, though the line will still appear in the image header.
n
Smooth spectrum n times before plotting. This affects the actual spectrum, so it is usually not a good idea to exit from a plot with this set to any value other than 0.
q
Quit and exit.
r
Forces a replot of the current spectrum at the original scale.
u
Redisplay the entire plot after zooming.
z
Zoom in on the region marked by two successive <z>'s

Example

To make a emission line template from a list of commonly observed emission lines: cl> linespec emtemp.dat emtemp

See also

On-line help is available over the World Wide Web at http://tdc-www.harvard.edu/iraf/rvsao/linespec