Spectrum HDF_67 (Object ID 5106). The data is shown in cyan, the error array in purple. (The spikes represent the position of bad columns.)
These were taken in the LDSS++ microslit/object-sky mode. For full details of this novel approach to faint object spectroscopy see the November and January 1998 AAO Newsletter. Please reference as Glazebrook et al., 2006 (AJ) for any use and further details.
We used a Volume Phase Holographic Grating (the first use of such for low-resolution redshift work!) from Kaiser Optical Systems with a central wavelength of 7800 Angstroms and a dispersion is 2.6 Angstroms/pixel. The peak grating transmission was measured at 82%. The spectra central wavelengths range from 6000-8000A. The spectral resolution with the 1 arcsec microslits is 9A (measured FWHM). Each spectra is 2048 pixels. They are given in raw form (so must be smoothed with the PSF to give optimal signal/noise). Also they are unfluxed.
The spectra include variance arrays for computation of errors. These were computed from the data counts, CCD gain and readnoise and were used for the cosmic-ray clipping. The deep depletion MITLL3 CCD has a very high red QE (87% peak) but contains numerous bad cloumns - the location of these are flagged by setting the variance values > 1e30. A text file list of X positions in the spectra is also available.
The spectra are available in FITS format - the DATA and VARIANCE arrays are given in seperate files. See also the README file with the spectra.The data were reduced using a combination of IRAF and the Perl Data Language.