WFC3: UVIS and IR Flat Fields
Abstract
Differences in the pixel-to-pixel response of UVIS and IR detectors arise from variations in the pixel thickness and non-uniform doping and can affect the photometric accuracy of astronomical data. Additional low-order structures may be introduced by the system illumination pattern and variations in the filter response. Flat fielding removes these variations by normalizing astronomical images to an image of a uniform light source through the entire optical path. As a result, the flux of a source should then be independent of its position on the detector.
Flat fields used in WFC3 image reduction combine flat-fields acquired during the last thermal-vacuum campaign (TV3) with low-order corrections obtained from in-flight observations of rich stellar clusters. Measurements from ground based flats and SMOV4 observations show that the current flat field data are accurate to better than 3%. In this paper we discuss the flat-fields that will be used in the calibration of WFC3 data and their effect onWFC3 UVIS and IR photometry.- Publication:
-
American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21546303D