The Cosmic Origins Spectrograph: NUV Imaging Performance
Abstract
The Cosmic Origins Spectrograph (COS) includes an NUV imaging mode, which is selected by means of the optical elements MIRRORA or MIRRORB. While the greatest use of this imaging capability is expected to be for target acquisition, science exposures may be obtained as well. COS NUV imaging (with MIRRORA) has specific advantages over other NUV imaging options available on HST, which renders it especially powerful for the purpose of spatially resolving faint, compact, and/or time-variable targets. It features the best spatial sampling available for any imaging mode on HST within its field of view of about 2 arcsec in radius, a much lower dark current rate than the NUV-MAMA detector aboard STIS, and no read noise or charge transfer inefficiency which hamper CCD observations of faint targets in the NUV. This paper reports on the on-orbit calibration of the COS NUV imaging modes, concentrating on accurate measurements of the point spread function, imaging quality, plate scale, photometric zeropoints, and throughput as functions of (a) measurement aperture size and (b) target location within the COS aperture.
- Publication:
-
American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21546402G