4.3. Combined Images
We produced combined images in which individual resolved sources could be identified and photometered for two purposes: (1) to allow bright galaxies and stars to be identified and excluded from the EBL measurements, (2) to allow comparison of the galaxy sample and EBL results to other data sets. The measurements of the mean sky flux discussed in Section 5 and Section 10 are obtained from individual WFPC2 exposures. The deepest combined image for each filter is obtained from the four exposures taken during the November and December visits, during which the telescope roll angles were the same. The small differences in the alignment of the WF CCDs prevent data taken during the October visit from being usefully included in combined images for the purposes of accurate photometry. The combined images and resolved source catalogs are available on the NASA/IPAC Extragalactic Database (NED). (2) A sample of the catalogs is shown in Table 2 and the combined F555W image is shown in Figure 7 The F300W, F555W, and F814W catalogs contain 140, 687, and 644 objects, respectively. The photometry of these sources is discussed in the next subsection.
Figure 7. The combined F555W images from November and December visits. The total exposure time is 4 × 1800 sec.
2 Web address: