Appendix 3. Long Exposure (6x) Scan Databases, Catalogs and Images

5. Data Processing

d. Extended Source Processing

Identification and characterization of extended sources in the 6x image data is based closely on the extended source processor used for the main survey data that is described in IV.5. A number of modifications have been made to optimize processing for the enhanced surface brightness and sensitivity of the deeper imaging. The most important changes are as follows:

Important Note About Large Galaxies: The 6x extended source processor is not modified or tuned to properly measure large galaxies. As a result, the 6x extended source WDB and 6x-XSC do not contain accurate measurements of extended sources that span more than one scan. Because large galaxies are well-characterized by the Large Galaxy Atlas (LGA) processing from the main survey, such processing was not carried out for the 6x data.

i. Sample 6x Extended Sources

Figures 6-9 show images of a selection of extended sources extracted during 6x data processing. In each image, the left panel shows a three-color, background-removed "postage stamp" image. The right panel shows the same image with stars removed. The Ks-band (fiducial) elliptical isophotal radius is shown in the figures in blue. The isophotal elliptical Ks magnitude (k_m_k20fe), sem-imajor axis length and axial ratio of the galaxies are given in in the figure captions. Only one image is displayed for the faint galaxy in Figure 9 because no foreground stars were subtracted.

Figure 6 - Ks=10.89 r=17.8" b/a=0.9 Figure 7 - Ks=11.06 r=21.2" b/a=0.9

Figure 8 - Ks=11.67 r=23.9" b/a=0.4 Figure 9 - Ks=15.46 r=5.0" b/a=1.0

[Last Updated: 2007 January 8; by T. Jarrett and R. Cutri]

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