Internal Completeness Analysis for Catalog Extended Sources
Found in Two-Scan Coverage Areas (SPOS=2)

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This analysis examines the internal completeness of 2MASS Final Catalog extended sources. A separate analysis exists for the Final Catalog point sources.

The Level 1 requirements for point source completeness in absence of confusion is 90% at 15.0,14.3,13.5 magnitudes for J,H,K, respectively.

Source Selection

Sources selected for this analysis came from non-confused regions of the sky and fell in the two-scan only overlap regions. Extended source default magnitudes were used. Each band was computed independently and if a source had no default magnitude for desired band, the source was not used in the band analysis.

NOTE:The data were NOT filtered on size parameter. This additional filtering could affect the completeness plots at the bright end.

• Select non-confused sources:
  • DENSITY < 3.2
  • DUP_SRC <= 1.^*
  • PROXimity > 10 filtered out additional possible confusion
• Select sources with SPOS = 2 , where SPOS is the number of possible detections for a source (m). This assures the source fell within a two-scan coverage area.

^* ((DUP_SRC <= 1 and USE_SRC = 1) or (DUP_SRC = 0 and USE_SRC = 0)).

Processing

Two histogram files were made for each band [J,H,K] from 8 to 20 magnitude using a bin size of .5 magnitude.
One contained sources with SDET = 2, where SDET is the number of actual detections for a source (n), and the other contained sources where SDET=1. Completeness was computed for each bin and each band using equation {1}. Results were plotted. Lines on the plots show the Level 1 magnitudes and completeness requirements. Points on the completeness plots are at the mid-bin position.

The completeness algorithm

C = (sdet2 + (sdet1 / 2)) / (sdet2 + sdet1)         {1}
where
sdet2 = number of sources having an apparition in each overlapping scan.
sdet1 = number of sources having an apparition in one of two scans.

Results

Extended source completeness PROX filtered and all densities (no DENSITY filter):

Figures:

Figure 1	Figure 2	Figure 3

Tables:

Table J	Table H	Table K

Extended source completeness PROX filtered and DENSITY < 3.2 (low density):

Figures:

Figure 1	Figure 2	Figure 3

Tables:

Table J	Table H	Table K

Extended Source completeness no PROX and no DENSITY:

Figures:

Figure 1	Figure 2	Figure 3

Tables:

Table J	Table H	Table K

Tables of the completeness results:

[Last Updated: 2002 Oct 30; by Sherry Wheelock]

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