DR3 Frequently Asked Questions

  1. Some of the spectra have "EB", "EC", or "WB" in their file names. What does this mean? The EB, EC, WB suffixes are tags that were added to the standard DEEP2 maskname (typically a 4-digit #) by the Keck slitmask milling machine when those masks were made. Those masks had been milled previously but either were not observed (due to bad weather, etc.) or were observed under poor conditions, so we opted to reobserve the mask. For a subsequent observing run, the masks were remilled, rather than reusing the old masks, as dust on the mask can create funkiness in the slit function, thereby making the ends of the slits difficult to reduce cleanly. To distinguish duplicate copies of the same slitmask, the Keck milling process added an "A, B, C" to the end of the slitmasks name. This suffix was then put into the header of the raw DEIMOS frame and carried along through the DEEP2/DEIMOS pipeline. Yet another thing that I meant to clean up prior to the release, but time did not allow.

  2. What are the skytweak.xxxx.fits files? For each slitmask, there exists a skytweak file that includes tweaks to the wavelength solutions (slitlet by slitlet), based on calibration to the observed night sky lines. These files can be employed using the deimos_skytweak.pro code, which is included in the DEEP2 spec2d pipeline. The skytweaking is only needed for users concerned about wavelength solutions at the <0.2 angstrom level.

  3. When running the routine fill_gap.pro, I can't find the subroutine, makearr.pro. Where is this routine? This routine should be included in the DEEP2/DEIMOS spec2d code, but was definitely missing from earlier versions. A copy of the needed code can be found here: makearr.pro, along with its subroutine, fan.pro.

created by M. Cooper
last updated 2007aug10