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author | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
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committer | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
commit | 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 (patch) | |
tree | 4464880c571602d54f6ae114729bf62a89518057 /noao/onedspec/doc/sbands.hlp | |
download | iraf-osx-40e5a5811c6ffce9b0974e93cdd927cbcf60c157.tar.gz |
Repatch (from linux) of OSX IRAF
Diffstat (limited to 'noao/onedspec/doc/sbands.hlp')
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diff --git a/noao/onedspec/doc/sbands.hlp b/noao/onedspec/doc/sbands.hlp new file mode 100644 index 00000000..0bde52ac --- /dev/null +++ b/noao/onedspec/doc/sbands.hlp @@ -0,0 +1,209 @@ +.help sbands Nov93 onedspec +.ih +NAME +sbands -- bandpass spectrophotometry of spectra +.ih +USAGE +sbands input output bands +.ih +PARAMETERS +.ls input +Input list of spectra to be measured. These may be one dimensional +spectra in individual or "multispec" format or calibrated spatial spectra such +as long slit or Fabry-Perot images. The dispersion axis and summing +parameters are specified by package parameters for the spatial spectra. +.le +.ls output +Output file for the results. This may be a filename or "STDOUT" to +write to the terminal. +.le +.ls bands +Bandpass file consisting of lines with one, two, or three bandpasses per +line. A bandpass is specified by an identification string (quoted if it is +null or contains whitespace), the central wavelength, the width of the +bandpass in wavelength, and a filter filename with the special value "none" +if there is no filter (a flat unit response). This format is described +further in the description section. +.le +.ls apertures = "" +List of apertures to select from the input spectra. For one dimensional +spectra this is the aperture number and for spatial spectra it is +the column or line. If the null string is specified all apertures are +selected. The aperture list syntax is a range list which includes +intervals and steps (see \fBranges\fR). +.le +.ls normalize = yes +Normalize the bandpass fluxes by the bandpass response? If no then +the results will depend on the bandpass widths and filter function +values. If yes then fluxes will be comparable to an average pixel +value. When computing indices and equivalent widths the flux must +either be normalized or the bandpasses and filter response functions +must be the same. +.le +.ls mag = no, magzero = 0. +Output the bandpass fluxes as magnitudes with specified magnitude +zero point? +.le +.ls verbose = yes +Include a verbose header giving a banner, the parameters used, +the bandpasses, and column headings? +.le +.ih +DESCRIPTION +\fBSbands\fR performs bandpass spectrophotometry with one or more bandpasses +on one or more spectra. A list of input spectra is specified. The spectra +may be of any type acceptable in the \fBnoao.onedspec\fR package including +multispec format with nonlinear dispersion, long slit spectra, and even +3D cubes with one dispersion axis. The \fIapertures\fR parameter allows +selecting a subset of the spectra by aperture number. + +The bandpasses are specified in a text file. A bandpass consists of four +fields; an identification name, the wavelength of the bandpass center, a +bandpass width, and a filename for a filter. The identification is a +string which must be quoted if a null name or a name with whitespace is +desired. The identification could be given as the central wavelength if +nothing else is appropriate. The filter field is a filename for a text +file containing the filter values. A filter file consists of a wavelength +ordered list of wavelength and relative response. Extrapolation uses the +end point values and interpolation is linear. The special name "none" is +used if there is no filter. This is equivalent to unit response at all +wavelengths. + +In the bandpass file there may be one, two, or three bandpasses on +a line. Below are some examples of the three cases: + +.nf + alpha 5000 10 myalpha.dat + beta1 4000 100 none beta2 4100 100 none + line 4500 100 none red 4000 200 none blue 5000 200 none +.fi + +The flux in each bandpass is measured by summing each pixel in the interval +multiplied by the interpolated filter response at that pixel. At the edges +of the bandpass the fraction of the pixel in the bandpass is used. If the +bandpass goes outside the range of the data an INDEF value will be reported. +If the \fInormalize\fR option is yes then the total flux is divided by +the sum of the filter response values. If the \fImag\fR option is +yes the flux will be converted to a magnitude (provided it is positive) +using the formula + +.nf + magnitude = magzero - 2.5 * log10 (flux) +.fi + +where \fImagzero\fR is a parameter for the zero point magnitude and log10 +is the base 10 logarithm. Note that there is no attempt to deal with the +pixel flux units. This is the responsibility of the user. + +If there is only one bandpass (on one line of the band file) then only +the band flux or magnitude is reported. If there are two bandpasses +the fluxes or magnitudes for the two bands are reported as well as a +band index, the flux ratio or magnitude difference (depending on the \fImag\fR) +flag, and an equivalent width using the second band as the continuum. +If there are three bandpasses then a continuum bandpass flux is computed +as the interpolation between the bandpass centers to the center of the +first bandpass. The special bandpass identification "cont" will +be reported. + +The equivalent width is obtained from the two bandpasses by the +formula + +.nf + eq. width = (1 - flux1 / flux2) * width1 +.fi + +where flux1 and flux2 are the two bandpass fluxes and width1 is the +width of the first bandpass. Note that for this to be meaningful +the bandpasses should be normalized or have the same width/response. + +The results of measuring each bandpass in each spectrum are written +to the specified output file. This file may be given as "STDOUT" to +write the results to the terminal. The output file contains lines +with the spectrum name and aperture, the band identifications and +fluxes or magnitudes, and the band index and equivalent width (if +appropriate). The \fIverbose\fR option allows creating a more +documented output by including a commented header with the task +name and parameters, the bandpass definitions, and column labels. +The examples below show the form of the output. +.ih +EXAMPLES +The following examples use artificial data and arbitrary bands. + +1. Show example results with one, two, and three bandpass entries in +the bandpass file. + +.nf + cl> type bands + test 6125 50 none red 6025 100 none blue 6225 100 none + test 6125 50 none red 6025 100 none + test 6125 50 none blue 6225 100 none + test 6125 50 none + cl> sbands oned STDOUT bands + + # SBANDS: NOAO/IRAF IRAFX valdes@puppis Mon 15:31:45 01-Nov-93 + # bands = bands, norm = yes, mag = no + # band filter wavelength width + # test none 6125. 50. + # red none 6025. 100. + # blue none 6225. 100. + # test none 6125. 50. + # red none 6025. 100. + # test none 6125. 50. + # blue none 6225. 100. + # test none 6125. 50. + # + # spectrum band flux band flux index eqwidth + oned(1) test 44.33 cont 97.97 0.45 27.37 + oned(1) test 44.33 red 95.89 0.46 26.89 + oned(1) test 44.33 blue 100.04 0.44 27.84 + oned(1) test 44.33 +.fi + +2. This example shows measurements on a long slit spectrum with an +aperture selection and magnitude output. + +.nf + cl> type lsbands.dat + band1 4500 40 none + band2 4600 40 none + band3 4700 40 none + cl> nsum=5 + cl> sbands ls STDOUT lsbands.dat apertures=40-60x5 mag+ magzero=10.1 + + # SBANDS: NOAO/IRAF IRAFX valdes@puppis Mon 15:37:18 01-Nov-93 + # bands = lsbands.dat, norm = yes, mag = yes, magzero = 10.10 + # band filter wavelength width + # band1 none 4500. 40. + # band2 none 4600. 40. + # band3 none 4700. 40. + # + # spectrum band mag + ls[38:42,*](40) band1 3.14 + ls[38:42,*](40) band2 3.19 + ls[38:42,*](40) band3 3.15 + ls[43:47,*](45) band1 3.13 + ls[43:47,*](45) band2 3.15 + ls[43:47,*](45) band3 3.14 + ls[48:52,*](50) band1 2.34 + ls[48:52,*](50) band2 2.43 + ls[48:52,*](50) band3 2.43 + ls[53:57,*](55) band1 3.10 + ls[53:57,*](55) band2 3.15 + ls[53:57,*](55) band3 3.12 + ls[58:62,*](60) band1 3.14 + ls[58:62,*](60) band2 3.19 + ls[58:62,*](60) band3 3.15 +.fi +.ih +REVISIONS +.ls SBANDS V2.10.4 +The flux column is now printed to 6 digits of precision with possible +exponential format to permit flux calibrated spectra to print properly. +.le +.ls SBANDS V2.10.3 +The task is new in this release +.le +.ih +SEE ALSO +splot +.endhelp |