Quick Reduce

mods_quickreduce

The mods_quickreduce software is an IDL-based quick reduction tool which outputs sky-subtracted, wavelength-calibrated spectra. It can only be used on full frame spectroscopic data. It available from all partner accounts on the mountain obsN workstations, the 64-bit OS machines, obs1, obs2.  Currently, the quick reduction pipeline can only be used on MODS1 data.

To run the quick reduce software:

1. Open IDL, using the command modsidl, in a directory on obs1 or obs2 in which you have write permission and which contains the MODS file you wish to process.
   1. modsidl is a script that sets the correct paths before starting IDL.
   2. A recommended place to work is ~/Scratch/<UTdate>.
2. Run: mods_quickreduce, ’<filename>’, [options]
   1. There are two main options one can use.
      1. /calwave  — this uses a stock wavelength calibration. This option is necessary and valid only for longslit spectra.
         
      2. apertures = [1,2,…N] — this tells the program which apertures/slits to work on. apertures = [1] will reduce only the central slit segment in the segmented long-slits. The 5 segments of the long slit are numbered, from bottom to top: 4, 2, 1, 3, 5.
      3. mods_quickreduce, ‘mods1C.YYYYMMDD.NNNN.fits’, /calwave, apertures=[1]
      4. To reduce a MOS spectrum, the mms file must be in the working directory.
      5. In this quick-reduction pipeline, the sky regions cannot be selected manually. Therefore, sky subtraction may not work well for extended objects.
      6. The output of mods_quickreduce is a file with the suffix “x2d” (mods1C.YYYYMMDD.NNNN_x2d.fits) file which can be viewed using dispMODSx2d.
         1. The output *_x2d.fits file, for long-slit mode at least, has 6 extensions and can be displayed as a multi-extension FITS file in ds9, however the advantage of dispMODSx2d is that the 2D spectrum is displayed with both pixel and wavelength scales. For long-slit mode, the extensions are:
            0 = OTF
            1 = sky subtracted
            2 = variance
            3 = sky
            4 = wavelength image
            5 = slit mask
            6 = Slit BinTable