lss_invran

These files contain random points distributed with equal surface density across the entire sky.

A number of such files exist in the directory

$LSS_REDUX/sample/invran

with names like

lss_invran-#.sample.fits

Each file uses a different random seed.

The columns of this file are:

  1. RA: right ascension, J2000, degrees
  2. DEC: declination, J2000, degrees
  3. ILSS: polygon in lss_geometry to which this point belongs (zero-indexed, -1 if outside the geometry)
  4. EBV: E(B-V) in the direction of this random point (from SFD dust map))
  5. INBSMASK: 1 if in the bright star mask, 0 if not

An ASCII version of the file under the name

lss_invran-#.sample.dat

exists in the same directory. It has the four columns

[ra] [dec] [ilss] [ebv] [inbsmask]

The idea of these files is that you can remove anything for which ILSS is not -1 and be left with an inverse random catalog. More precisely, you should use the completeness in each polygon from the lss_geometry file. Ie. if FGOTMAIN for that polygon is 0.3, you should remove the random point with 30 percent probability. This procedure will yield a truly inverse mask of the survey including the completeness.

A copy of these invran catalogs also exists in the pre-redshift subsamples, in directories like:

$LSS_REDUX/sample/letter/invran

with names like

invran-#.sampleletter.fits

This file has the columns:

  1. RA: right ascension, J2000, degrees
  2. DEC: declination, J2000, degrees
  3. SECTOR: sector (as described in the tiling documentation) to which this point belongs
  4. MREGION: the magnitude limit region (area of the sky with constant magnitude limit) to which this point belongs
  5. FGOT: completeness of the sector
  6. MMAX: faint magnitude limit of the mregion
  7. INBSMASK: 1 if in the bright star mask, 0 if not

These files do NOT have the completeness FGOT applied yet, so before you use them you need to use the magnitude limit to assign a random redshift in the range you are interested in (accounting, of course, for the fact that the surface density is greater in regions with fainter magnitude limits), and then apply the completeness fraction FGOT as described above.

An ASCII version of the file under the name

invran-#.sampleletter.dat

exists in the same directory. It has the columns

[ra] [dec] [sector] [mregion] [fgot] [mmax] [inbsmask]

NYU Value-Added Galaxy Catalog

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