COS Data Processing Improvements Based on HST SMOV Results

After the Cosmic Origins Spectrograph (COS) was installed onboard the Hubble Space Telescope (HST) in May 2009, it underwent an extensive calibration and characterization check-out during the Servicing Mission Observatory Verification (SMOV) period. The results from this program were used to update reference files and make changes to CALCOS, the COS data processing software .I mprovements to the standard data products are discussed. For the FUV channel, we have begun development of a flat-field correction. As an intermediate step, grid wire shadows are now ignored when combining FP-POS exposures. Pulse-height filtering has been activated to reduce background features. For the NUV channel, vignetting correc- tions are incorporated in the flat field file. For both channels ,i mprovements have been made in the wavelength scales, flux calibration, and data quality flagging. Ad- ditional data are included in the FITS products to allow user st o perform customized processing.