Cross-Talk in the ACS WFC Detectors. II: Using GAIN=2 to Minimize the Effect

Abstract

Cross talk is observed in images taken with ACS WFC between the four CCD quadrants that correspond to the four amplifiers of the detector array (see Giavalisco 2004). The effect manifests itself as (mostly) negative ghost images placed in locations that are mirror-symmetric to those of the generating sources in adjacent quadrants. Here we show that the apparent flux of the ghost images is significantly reduced when the camera is used with gain setting GAIN=2. This corresponds to an average inverse gain of ~2.0 e-/DN, which is adequate to sample the read-out noise of the CCDs, whose average value is 5.25 e-rms. Although the cross talk appears to have negligible photometric effects in most applications and is primarily a cosmetic problem, using the setting GAIN=2 minimizes its effects with no penalty and, in fact, has the added bonus of providing an expanded dynamic range.

8 Figures and Tables

Cite this paper

@inproceedings{Giavalisco2004CrossTalkIT, title={Cross-Talk in the ACS WFC Detectors. II: Using GAIN=2 to Minimize the Effect}, author={Mauro Giavalisco}, year={2004} }