Friday, May 4, 2012

Clarification of the sky coverage of the public GMBCG catalog for DR7

In the GMBCG public catalog, it does not contain the stripe 44, stripe 79 and partial stripe 38, 39 and partial stripe 9, see the Figure 1. If you compare this with  sdss dr7 footprint Figure 2,, you will see that the public GMBCG catalog coverage is actually almost the same as the legacy spectroscopic footprint. We choose this area eventually because it is supposed to have the best photometry (according to my colleague Brian Yanny). The mask used is the version 7.2 of the vagc lss mask from the NYC group.

We got the number of 8240 deg^2 in our paper from somewhere on the dr7 website. I noticed that now the webpage show the number is 8423 deg^2 that includes the stripe 44 and the complete stripe 38, 39, 9. So, after removing those extra stripes, a better estimate of the area covered by the public GMBCG catalog should be the legacy spectroscopic coverage, i.e., 8032 deg^2. But be aware that due to the complication of the mask, you should probably expect +/- 5% variation of the actual area.

Thanks Dr. Tommaso Giannantonio for raising this question.

Figure 1

Figure 2