Removing the Pattern Noise from all HST/STIS Side-2 CCD Data
Abstract
When HST/STIS resumed operations in July 2001 using its redundant "Side-2" electronics, the read-noise of the CCD detector appeared to have increased by ∼1 e- due to a superimposed and highly variable "herring-bone" pattern-noise. For programs aiming to detect signals near the STIS design limits, the impact of this noise is far more serious than implied by a mere 1 e- increase in amplitude of the read-noise, as it is of a systematic nature and can result in ~8 e- relative deviations (peak-to-valley). On this poster, I discuss the nature of the pattern noise, and summarize a method to robustly detect and remove this noise from raw STIS CCD frames (Jansen et al. 2003, 2010; Brown 2001). I report on a Cycle 16/17 Archival Calibration Legacy program to remove the pattern-noise from *all* raw, unbinned Side-2 STIS/CCD frames taken between 2001 July and 2004 August -- representing a gain in effective sensitivity of a factor ~3 at low S/N. Pattern-free raw datasets, pattern-only images, and bias reference images are available from http://stis2.sese.asu.edu/ . A very similar pattern noise is present also in data taken after the successful repair of STIS during SM4. Presently public data (2009 June through 2011 October) were recently processed and are available from the same URL. This work was mostly funded by grants HST-GO-9066 and HST-AR-11258 from STScI, which is operated by AURA under NASA contract NAS5-26555.
- Publication:
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American Astronomical Society Meeting Abstracts #221
- Pub Date:
- January 2013
- Bibcode:
- 2013AAS...22134411J